Immortal Time Bias: A Frequently Unrecognized Threat to Validity in the Evaluation of Postoperative Radiotherapy

Comparison of metastasis and prognosis between early-onset and late-onset hepatocellular carcinoma: A population-based study

Background

While hepatocellular carcinoma (HCC) represents a highly heterogeneous disease with variable oncogenesis mechanisms and biological features, little is understood about differences in distant metastasis (DM) and prognosis between early-onset and late-onset HCC. This study defined early-onset disease as cancer diagnosed at age younger than 50 years and aimed to present a comprehensive analysis to characterize these disparities based on age.

Methods

Information of HCC patients was retrospectively collected from the SEER database and our hospital. Patient demographics, tumor characteristics, and survival were compared between the two groups. A 1:1 propensity score matching (PSM) was adopted to adjust confounding factors. Logistic and cox analysis were utilized to explore risk factors of DM and prognosis, respectively. Besides, the survival differences were assessed by the Kaplan-Meier curve and log-rank test.

Results

In total, 19187 HCC patients obtained from the SEER database and 129 HCC patients obtained from our own center were enrolled. Among 19187 patients with HCC, 3376 were identified in the matched cohort, including 1688 early-onset patients and 1688 late-onset patients. Compared with late-onset HCC, early-onset HCC was more likely to occur in female (25.2% vs. 22.9%, P = 0.030), have large tumors (>10.0 cm, 24.1% vs. 14.6%, P = 0.000), harbor poorly differentiated/undifferentiated cancers (17.0% vs. 14.0%, P = 0.003), present advanced clinical stage (T3+T4, 33.7% vs. 28.5%; N1, 9.2% vs. 6.7%; P = 0.000), and develop DM (13.0% vs. 9.5%, P = 0.000). After adjustment for confounders by PSM, we discovered that early-onset HCC remained an independent risk factor for DM. However, combined with Kaplan-Meier curve and cox analysis, early-onset HCC was an independent favorable predictor of survival. We validated these data on an independent cohort from our hospital.

Conclusion

In this population-based study, despite developing DM more frequently, early-onset HCC exhibited a superior prognosis than late-onset HCC. Nevertheless, further research is warranted to understand the underlying aetiologic basis for the disparities.

Time interval between surgery and adjuvant chemotherapy in patients with gastric cancer after gastrectomy: a population-based cohort study using a nationwide claim database

Background

Adjuvant chemotherapy can reduce recurrence rates by eradicating microscopic metastases which may persist after curative resection. However, the optimal time interval (TI) between the surgery and chemotherapy remains controversial.

Objectives

This study investigated the optimal TI between surgery and chemotherapy.

Design

A population-based cohort study using a nationwide claims database.

Methods

The data were obtained from the Korean National Health Insurance Service (NHIS) of Korea. We included patients who underwent gastrectomy between 2013 and 2018. To determine the optimal cutoff point of TI, a restricted cubic spline Cox regression model was established, and categorized the population into three groups based on TI: the early (⩽20 days), the late (⩾35 days), and the reference group (21-34 days), and with the reference group having the lowest mortality and recurrence. Propensity score matching was performed for each group. The primary outcomes were disease-free survival (DFS) and overall survival (OS).

Results

After excluding ineligible participants, 6602 patients were included. The median DFS and OS did not differ significantly between the early and reference groups (p = 0.7258 and p = 0.6056, respectively). In comparison between the late and reference groups, it was significantly lower in the late group (p = 0.0079). Five-year DFS rates were 77.6% and 81.3% in the late and reference groups, respectively. The late group showed worse OS than the reference group (p = 0.0336). Five-year OS rates were 82.1% and 85.0% in the late and reference groups, respectively. In the multivariable analysis, DFS in the late group retained inferiority [adjusted hazard ratio (aHR): 1.138, 95% confidence interval (CI): 1.003-1.292, p = 0.045]. OS showed a worse trend without significance compared to the reference group (aHR: 1.138, 95% CI: 0.984-1.317, p = 0.0805).

Conclusion

Adjuvant chemotherapy after gastrectomy in patients with gastric cancer should be initiated within 5 weeks of surgery. A delay of more than 5 weeks may have a detrimental effect on the subsequent disease course.

Minimizing Intracranial Disease Before Stereotactic Radiation in Single or Solitary Brain Metastases

BACKGROUND AND OBJECTIVES

Stereotactic radiotherapy (SRT) in multiple fractions (typically ≤5) can effectively treat a wide range of brain metastases, including those less suitable for single-fraction stereotactic radiosurgery (SRS). Prior prospective studies on surgical resection with stereotactic radiation have focused exclusively on SRS, and retrospective studies have shown equivocal results regarding whether surgery is associated with improved outcomes compared with SRT alone. We compared resection with postoperative cavity SRT or SRS to SRT alone in patients with 1 brain metastasis, while including patients receiving SRS alone as an additional reference group.

METHODS

We studied 716 patients in a retrospective, single-institution cohort diagnosed with single or solitary brain metastases from 2007 to 2020. Patients receiving whole-brain radiotherapy were excluded. Cox proportional hazards models were constructed for overall survival and additional intracranial outcomes.

RESULTS

After adjustment for potential confounders, surgery with cavity SRT/SRS was associated with decreased all-cause mortality (hazard ratio [HR]: 0.39, 95% CI [0.27-0.57], P = 1.52 × 10 -6 ) compared with SRT alone, along with lower risk of neurological death attributable to intracranial tumor progression (HR: 0.46, 95% CI [0.22-0.94], P = 3.32 × 10 -2 ) and radiation necrosis (HR: 0.15, 95% CI [0.06-0.36], P = 3.28 × 10 -5 ). Surgery with cavity SRS was also associated with decreased all-cause mortality (HR: 0.52, 95% CI [0.35-0.78], P = 1.46 × 10 -3 ), neurological death (HR: 0.30, 95% CI [0.10-0.88], P = 2.88 × 10 -2 ), and radiation necrosis (HR: 0.14, 95% CI [0.03-0.74], P = 2.07 × 10 -2 ) compared with SRS alone. Surgery was associated with lower risk of all-cause mortality and neurological death in cardinality-matched subsets of the cohort. Among surgical patients, gross total resection was associated with extended overall survival (HR: 0.62, 95% CI [0.40-0.98], P = 4.02 × 10 -2 ) along with lower risk of neurological death (HR: 0.31, 95% CI [0.17-0.57], P = 1.84 × 10 -4 ) and local failure (HR: 0.34, 95% CI [0.16-0.75], P = 7.08 × 10 -3 ).

CONCLUSION

In patients with 1 brain metastasis, minimizing intracranial disease specifically before stereotactic radiation is associated with improved oncologic outcomes.

Competing risks analysis of external versus internal radiation in patients with hepatocellular carcinoma after controlling for immortal time bias

PURPOSE

In cohort studies on liver cancer, there are often immortal time bias and interference of competing risk events. This study proposes to explore the role of internal and external radiotherapy for hepatocellular carcinoma using SEER data, using a competing risk model and controlling immortal time bias.

METHODS

Data of SEER from 2004 till 2015 was included. To analyze whether there was a difference in survival between HCC (hepatocellular carcinoma) patients receiving external radiation and internal radiation, we used a competing risk analysis after excluding immortal time bias, and created a nomogram to assess the risk of cancer-specific death (CSD) in hepatocellular carcinoma patients receiving radiotherapy.

RESULTS

Potential confounding factors adjusted, there was no significant difference in CSD between external and internal radiation therapy [HR and its 95% CI = 1.098 (0.874-1.380)]. The constructed nomogram performed better than the traditional AJCC model. The AUC and calibration curve results showed that this well-calibrated nomogram could be used to make clinical decisions regarding the prognosis and personalized treatment of hepatocellular carcinoma treated. There was no difference in the cumulative risk of death between patients with liver cancer treated with external radiation therapy and internal radiation therapy.

CONCLUSION

There is no difference in the cumulative risk of death between patients with liver cancer treated with external radiation therapy and internal radiation therapy. The nomogram predicts the results more accurately. These results can be used to guide the choice of treatment options for patients with HCC and to predict their survival prognosis.

Immortal-time bias in older vs younger age groups: a simulation study with application to a population-based cohort of patients with colon cancer

BACKGROUND

In observational studies, the risk of immortal-time bias (ITB) increases with the likelihood of early death, itself increasing with age. We investigated how age impacts the magnitude of ITB when estimating the effect of surgery on 1-year overall survival (OS) in patients with Stage IV colon cancer aged 50-74 and 75-84 in England.

METHODS

Using simulations, we compared estimates from a time-fixed exposure model to three statistical methods addressing ITB: time-varying exposure, delayed entry and landmark methods. We then estimated the effect of surgery on OS using a population-based cohort of patients from the CORECT-R resource and conducted the analysis using the emulated target trial framework.

RESULTS

In simulations, the magnitude of ITB was larger among older patients when their probability of early death increased or treatment was delayed. The bias was corrected using the methods addressing ITB. When applied to CORECT-R data, these methods yielded a smaller effect of surgery than the time-fixed exposure approach but effects were similar in both age groups.

CONCLUSION

ITB must be addressed in all longitudinal studies, particularly, when investigating the effect of exposure on an outcome in different groups of people (e.g., age groups) with different distributions of exposure and outcomes.

Consolidative Radiotherapy for Metastatic Urothelial Bladder Cancer Patients with No Progression and with No More than Five Residual Metastatic Lesions Following First-Line Systemic Therapy: A Retrospective Analysis

Local consolidative radiotherapy in the treatment of metastatic malignancies has shown promising results in several types of tumors. The objective of this study was to assess consolidative radiotherapy to the bladder and to residual metastases in metastatic urothelial bladder cancer with no progression following first-line systemic therapy.

MATERIALS/METHODS

Patients who received first-line therapy for the treatment of metastatic urothelial bladder cancer (mUBC) and who were progression-free following treatment with no more than five residual metastases were retrospectively identified through the database of four Comprehensive Cancer Centers, between January 2005 and December 2018. Among them, patients who received subsequent definitive radiotherapy (of EQD2Gy > 45Gy) to the bladder and residual metastases were included in the consolidative group (irradiated (IR) group), and the other patients were included in the observation group (NIR group). Progression-free survival (PFS) and overall survival (OS) were determined from the start of the first-line chemotherapy using the Kaplan-Meier method. To prevent immortal time bias, a Cox model with time-dependent covariates and 6-month landmark analyses were performed to examine OS and PFS.

RESULTS

A total of 91 patients with at least stable disease following first-line therapy and with no more than five residual metastases were analyzed: 51 in the IR group and 40 in the NIR group. Metachronous metastatic disease was more frequent in the NIR group (19% vs. 5%, p = 0.02); the median number of metastases in the IR group vs. in the NIR group was 2 (1-9) vs. 3 (1-5) (p = 0.04) at metastatic presentation, and 1 (0-5) vs. 2 (0-5) (p = 0.18) after completion of chemotherapy (residual lesions), respectively. Two grade 3 toxicities (3.9%) and no grade 4 toxicity were reported in the IR group related to radiotherapy. With a median follow up of 85.9 months (95% IC (36.7; 101.6)), median OS and PFS were 21.7 months (95% IC (17.1; 29.7)) and 11.1 months (95% IC (9.9; 14.1)) for the whole cohort, respectively. In multivariable analysis, consolidative radiotherapy conferred a benefit in both PFS (HR = 0.49, p = 0.007) and OS (HR = 0.47, p = 0.015) in the whole population; in the landmark analysis at 6 months, radiotherapy was associated with improved OS (HR = 0.48, p = 0.026), with a trend for PFS (HR = 0.57, p = 0.082).

CONCLUSION

Consolidative radiotherapy for mUBC patients who have not progressed after first-line therapy and with limited residual disease seems to confer both OS and PFS benefits. The role of consolidative radiotherapy in the context of avelumab maintenance should be addressed prospectively.

Local Prostate Radiation Therapy and Symptomatic Local Events in De Novo Metastatic Prostate Cancer

PURPOSE

Local prostate radiation therapy (LPRT) for low-burden metastatic prostate cancer (mPCa) improves overall survival and is the standard of care. The role of LPRT in reducing symptomatic local events (SLE) remains unclear. We aimed to identify SLE risk factors and to evaluate the association between LPRT and SLE in mPCa.

METHODS AND MATERIALS

We conducted a retrospective, population-based cohort study of patients initially diagnosed with mPCa between 2005 and 2016 in a cancer registry. Patient, tumor, and treatment characteristics were obtained from chart review and the cancer registry. The coprimary endpoints were genitourinary (GU) and gastrointestinal (GI) SLE, identified by physician billing claims between 2004 and 2017 for diagnostic or therapeutic procedures potentially related to GU and GI SLE. The effect of LPRT on SLE was evaluated using both recurrent event (Andersen-Gill model) and time-to-first-event sequential landmark analyses. Risk factors for SLE were assessed by multivariable Cox regression. LPRT was defined as ≥40 Gy within 1 year of diagnosis. Metastatic burden was defined per the STAMPEDE trial.

RESULTS

Of 1363 patients, 46 (3.4%) received LPRT. Median follow-up was 27.3 and 28.9 months in the control and LPRT groups, respectively. LPRT was associated with less recurrent GU SLE (hazard ratio [HR], 0.34; 95% confidence interval [CI], 0.17-0.67; P = .002), upper tract obstruction (HR, 0.20; 95% CI, 0.05-0.84; P = .03), and cystoscopy (HR, 0.38; 95% CI, 0.15-0.96; P = .04). Metastatic burden was not associated with SLE.

CONCLUSIONS

LPRT in mPCa was associated with less recurrent GU SLE, specifically for upper tract obstruction and cystoscopy.

Impact of multi-agent systemic therapy on all-cause and disease-specific survival for people living with HIV who are diagnosed with non-Hodgkin lymphoma: population-based analyses from the state of Georgia

For people living with HIV (PLWH) who are subsequently diagnosed with non-Hodgkin lymphoma (NHL), we investigate the impact of standard-of-care (SoC) cancer treatment on all-cause, NHL-specific, and HIV-specific survival outcomes. The focus is on a registry-derived, population-based sample of HIV + adults diagnosed with NHL within 2004-2012 in the state of Georgia. SoC treatment is defined as receipt of multi-agent systemic therapy (MAST). In multivariable survival analyses, SoC cancer treatment is significantly associated with better all-cause and NHL-specific survival, but not better HIV-specific survival across 2004-2017. Having a CD4 count <200 near the time of cancer diagnosis and Ann Arbor stage III/IV disease are associated with worse all-cause and HIV-specific survival; the effects on NHL survival trend negative but are not significant. Future work should expand the geographic base and cancers examined, deepen the level of clinical detail brought to bear, and incorporate the perspectives and recommendations of patients and providers.

Patterns of Failure and Optimal Treatment Paradigm for Large, Inoperable, Node-Negative Non-small Cell Lung Cancer

OBJECTIVES

The ideal non-operative treatment for patients with large, node-negative non-small cell lung cancer (NSCLC) is poorly defined. To inform optimal treatment paradigms for this cohort, we examined patterns of failure and the impact of radiation therapy (RT) and chemotherapy receipt.

MATERIALS AND METHODS

Node-negative NSCLC patients with 5+ cm primary tumors receiving definitive RT at our institution were identified. Sites of initial progression were analyzed. Local progression, regional/distant progression, progression-free survival, and overall survival were analyzed via cumulative incidence function and Kaplan-Meier. Associations between local vs. regional/distant progression with treatment and clinicopathologic variables were assessed via univariable and multivariable competing risks regression.

RESULTS AND CONCLUSION

We identified 88 patients for analysis. Among patients with recurrent disease (N = 36), initial patterns of failure analysis showed that isolated distant (27.8%) and isolated regional progression (22.2%) were most common. Distant or regional failure as a component of initial failure was seen in 88.9% of patients who progressed, while isolated local failure was uncommon (11.1%). Univariable and multivariable competing risks regression showed that receipt of SBRT was associated with reduced risk of local progression (HR 0.23, P = .012), and receipt of chemotherapy was associated with reduced risk of regional/distant progression (HR 0.12, P = .040). In conclusion, patients with large, node-negative NSCLC treated with definitive RT are at high risk of regional and distant progression. SBRT correlates with a reduced risk of local failure while chemotherapy is associated with reduced regional/distant progression in this patient population. Ideal treatment may include SBRT when feasible with appropriate systemic therapy.

Hyperkalemia-Related Discontinuation of Renin-Angiotensin-Aldosterone System Inhibitors and Clinical Outcomes in CKD: A Population-Based Cohort Study

RATIONALE & OBJECTIVE

Renin-angiotensin-aldosterone system (RAAS) inhibitors are evidence-based therapies that slow the progression of chronic kidney disease (CKD) but can cause hyperkalemia. We aimed to evaluate the association of discontinuing RAAS inhibitors after an episode of hyperkalemia and clinical outcomes in patients with CKD.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Adults in Manitoba (7,200) and Ontario (n = 71,290), Canada, with an episode of de novo RAAS inhibitor-related hyperkalemia (serum potassium ≥ 5.5 mmol/L) and CKD.

EXPOSURE

RAAS inhibitor prescription.

OUTCOME

The primary outcome was all-cause mortality. Secondary outcomes were cardiovascular (CV) mortality, fatal and nonfatal CV events, dialysis initiation, and a negative control outcome (cataract surgery).

ANALYTICAL APPROACH

Cox proportional hazards models examined the association of RAAS inhibitor continuation (vs discontinuation) and outcomes using intention to treat approach. Sensitivity analyses included time-dependent, dose-dependent, and propensity-matched analyses.

RESULTS

The mean potassium and mean estimated glomerular filtration rate were 5.8 mEq/L and 41 mL/min/1.73 m², respectively, in Manitoba; and 5.7 mEq/L and 41 mL/min/1.73 m², respectively, in Ontario. RAAS inhibitor discontinuation was associated with a higher risk of all-cause mortality (Manitoba: HR, 1.32 [95% CI, 1.22-1.41]; Ontario: HR, 1.47 [95% CI, 1.41-1.52]) and CV mortality (Manitoba: HR, 1.28 [95% CI, 1.13-1.44]; and Ontario: HR, 1.32 [95% CI, 1.25-1.39]). RAAS inhibitor discontinuation was associated with an increased risk of dialysis initiation in both cohorts (Manitoba: HR, 1.65 [95% CI, 1.41-1.85]; Ontario: HR, 1.11 [95% CI, 1.08-1.16]).

LIMITATIONS

Retrospective study and residual confounding.

CONCLUSIONS

RAAS inhibitor discontinuation is associated with higher mortality and CV events compared with continuation among patients with hyperkalemia and CKD. Strategies to maintain RAAS inhibitor treatment after an episode of hyperkalemia may improve clinical outcomes in the CKD population.

Treatment paradigms and survival outcomes in esophageal adenocarcinoma with liver metastasis: a retrospective cohort study using the SEER database

Background

Esophageal adenocarcinoma with liver metastasis (EACLM) at the time of diagnosis has a poor prognosis and few therapeutic options. The best treatment options and prognostic factors for EACLM patients are unclear. The present study sought to explore the optimal treatment modalities for and the prognosis of these patients.

Methods

Patients diagnosed with EACLM at the time of diagnosis were identified from the Surveillance, Epidemiology and End Results (SEER) database between 2010 and 2015. The last follow-up date was December 31, 2018. Treatment patterns were divided into four groups: local therapy (surgery/radiation), systemic therapy [chemotherapy (CT)], combination therapy (surgery/radiation + CT), and no treatment. The Kaplan-Meier (K-M) method and log-rank test were used for overall survival (OS) and disease-specific survival (DSS). Univariable and multivariable Cox regression were performed to identify the prognostic factors. Propensity score-matching (PSM) analyses were performed for sensitive analyses.

Results

A total of 925 patients diagnosed with EACLM were included in the study. The median OS was 12, 10, 3, and 2 months for combination therapy, systemic therapy, local therapy, and no treatment, respectively (P<0.001). After PSM, the patients who received systemic treatment had a better OS (median 9 vs. 2 months; P<0.001) and DSS (median 9 vs. 3 months; P<0.001) than those who received no treatment. Compared to systemic therapy, combination therapy did not increase patients' OS (median 13 vs. 12 months, P=0.069) but did improve their DSS (median 19 vs. 13 months, P=0.048).

Conclusions

EACLM patients might benefit the most from systemic therapy and combination therapy. For patients who are well-tolerated, combination therapy should be considered as a preferable option.

Retrospective comparative effectiveness research: will changing the analytical methods change the results?

In medicine, retrospective cohort studies are used to compare treatments to one another. We hypothesize that the outcomes of retrospective comparative effectiveness research studies can be heavily influenced by biostatistical analytic choices, thereby leading to inconsistent conclusions. We selected a clinical scenario currently under investigation: survival in metastatic prostate, breast, or lung cancer after systemic vs systemic + definitive local therapy. We ran >300 000 regression models (each representing a publishable study). Each model had various forms of analytic choices (to account for bias): propensity score matching, left truncation adjustment, landmark analysis, and covariate combinations. There were 72 549 lung, 14 904 prostate, and 13 857 breast cancer patients included. In the most basic analysis, which omitted propensity score matching, left truncation adjustment, and landmark analysis, all of the HRs were < 1 (generally, 0.60-0.95, favoring addition of local therapy), with all P-values < 0.001. Left truncation adjustment landmark analysis produced results with non-significant P-values. The combination of propensity score matching, left truncation adjustment, landmark analysis, and covariate combinations generally produced P-values that were > 0.05 and/or HRs that were > 1 (favoring systemic therapy alone). The use of more statistical methods to reduce the selection bias caused reported HR ranges to approach 1.0. By varying analytic choices in comparative effectiveness research, we generated contrary outcomes. Our results suggest that some retrospective observational studies may find a treatment improves outcomes for patients, while another similar study may find it does not, simply based on analytical choices. This article is protected by copyright. All rights reserved.

Patterns of Adjuvant Chemotherapy Use and Association With Survival in Adults 80 Years and Older With Pancreatic Adenocarcinoma

IMPORTANCE

Patients 80 years and older with pancreatic ductal adenocarcinoma (PDAC) have not consistently received treatments that have established benefits in younger older adults (aged 60-79 years), yet patients 80 years and older are increasingly being offered surgery. Whether adjuvant chemotherapy (AC) provides additional benefit among patients 80 years and older with PDAC following surgery is not well understood.

OBJECTIVE

To describe patterns of AC use in patients 80 years and older following surgical resection of PDAC and to compare overall survival between patients who received AC and those who did not.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study among patients 80 years or older diagnosed with PDAC (stage I-III) between 2004 to 2016 who underwent a pancreaticoduodenectomy at hospitals across the US reporting to the National Cancer Database.

EXPOSURES

AC vs no AC 90 days following diagnosis of PDAC.

MAIN OUTCOMES AND MEASURES

The proportion of patients who received AC was assessed over the study period. Overall survival was compared between patients who received AC and those who did not using Kaplan-Meier estimates and multivariable Cox proportional hazards regression. A landmark analysis was performed to address immortal time bias. A propensity score analysis was performed to address indication bias. Subgroup analyses were conducted in node-negative, margin-negative, clinically complex, node-positive, and margin-positive cohorts.

RESULTS

Between 2004 and 2016, 2569 patients 80 years and older (median [IQR] age, 82 [81-84] years; 1427 were women [55.5%]) underwent surgery for PDAC. Of these patients, 1217 (47.4%) received AC. Findings showed an 18.6% (95% CI, 8.0%-29.0%; P = .001) absolute increase in the use of AC among older adults who underwent a pancreaticoduodenectomy comparing rates in 2004 vs 2016. Receipt of AC was associated with a longer median survival (17.2 months; 95% CI, 16.1-19.0) compared with those who did not receive AC (12.7 months; 95% CI, 11.8-13.6). This association was consistent in propensity and subgroup analyses. In multivariable analysis, receipt of AC (hazard ratio [HR], 0.72; 95% CI, 0.65-0.79; P < .001), female sex (HR, 0.88; 95% CI, 0.80-0.96; P < .001), and surgery in the more recent time period (≥2011) (HR, 0.90; 95% CI, 0.82-0.99; P = .02) were associated with a decreased hazard of death. An increased hazard of death was associated with higher pathologic stage (stage II: HR, 1.68; 95% CI, 1.43-1.97; P < .001; stage III: HR, 2.39; 95% CI, 1.88-3.04; P < .001), positive surgical margins (HR, 1.49; 95% CI, 1.34-1.65; P < .001), length of stay greater than median (10 days) (HR, 1.17; 95% CI, 1.07-1.28; P < .001), and receipt of oncologic care at a nonacademic facilities (Community Cancer Program: HR, 1.20; 95% CI, 1.07-1.35; P < .001; Integrated Network Cancer Program: HR, 1.25; 95% CI, 1.07-1.46; P < .001).

CONCLUSIONS AND RELEVANCE

In this cohort study, the use of AC among patients who underwent resection for PDAC increased over the study period, yet it still was administered to fewer than 50% of patients. Receipt of AC was associated with a longer median survival.

Epidemiology of brain metastases and leptomeningeal disease

Brain metastases affect a significant percentage of patients with advanced extracranial malignancies. Yet, the incidence of brain metastases remains poorly described, largely due to limitations of population-based registries, a lack of mandated reporting of brain metastases to federal agencies, and historical difficulties with delineation of metastatic involvement of individual organs using claims data. However, in 2016, the Surveillance Epidemiology and End Results (SEER) program released data relating to the presence vs absence of brain metastases at diagnosis of oncologic disease. In 2020, studies demonstrating the viability of utilizing claims data for identifying the presence of brain metastases, date of diagnosis of intracranial involvement, and initial treatment approach for brain metastases were published, facilitating epidemiologic investigations of brain metastases on a population-based level. Accordingly, in this review, we discuss the incidence, clinical presentation, prognosis, and management patterns of patients with brain metastases. Leptomeningeal disease is also discussed. Considerations regarding individual tumor types that commonly metastasize to the brain are provided.

Population-based estimates of survival among elderly patients with brain metastases

BACKGROUND

Prognostic estimates for patients with brain metastases (BM) stem from younger, healthier patients enrolled in clinical trials or databases from academic centers. We characterized population-level prognosis in elderly patients with BM.

METHODS

Using Surveillance, Epidemiology, and End Results (SEER)-Medicare data, we identified 9882 patients ≥65 years old with BM secondary to lung, breast, skin, kidney, esophageal, colorectal, and ovarian primaries between 2014 and 2016. Survival was assessed by primary site and evaluated with Cox regression.

RESULTS

In total, 2765 versus 7117 patients were diagnosed with BM at primary cancer diagnosis (synchronous BM, median survival = 2.9 mo) versus thereafter (metachronous BM, median survival = 3.4 mo), respectively. Median survival for all primary sites was ≤4 months, except ovarian cancer (7.5 mo). Patients with non-small-cell lung cancer (NSCLC) receiving epidermal growth factor receptor (EGFR)- or anaplastic lymphoma kinase (ALK)-based therapy for synchronous BM displayed notably better median survival at 12.5 and 20.1 months, respectively, versus 2.8 months exhibited by other patients with NSCLC; survival estimates in melanoma patients based on receipt of BRAF/MEK therapy versus not were 6.7 and 2.8 months, respectively. On multivariable regression, older age, greater comorbidity, and type of managing hospital were associated with poorer survival; female sex, higher median household income, and use of brain-directed stereotactic radiation, neurosurgical resection, or systemic therapy (versus brain-directed non-stereotactic radiation) were associated with improved survival (all P < 0.05).

CONCLUSIONS

Elderly patients with BM have a poorer prognosis than suggested by prior algorithms. If prognosis is driven by systemic and not intracranial disease, brain-directed therapy with potential for significant toxicity should be utilized cautiously.

Practical demonstration of time bias with administration of adjuvant therapy in lung cancer

PURPOSE/BACKGROUND

Immortal time bias (ITB) can hinder appropriate interpretations of studies administering adjuvant therapies. Given the increase in National Cancer Data Base (NCDB) analyses evaluating postoperative radiation therapy (PORT) as an adjuvant therapy, we sought to practically demonstrate the effects of ITB by performing a series of simulated NCDB analyses.

METHODS

A simulated NCDB analysis was performed to examine how the reported benefit of PORT in stage III non-small cell lung cancer (NSCLC) may change with adjustment for ITB utilizing sequential land mark analysis (SLMA) and time dependent Cox (TDC) modeling.

RESULTS

On the simulation analysis of 6440 NSCLC patients, we found that the omission of PORT without ITB adjustment was associated with an increased risk of death (HR 1.17, p < 0.0001). After performing a sequential LMA, the detrmient of omitting PORT continued to decrease until it was no longer significant at 8 months, HR 1.05 (p = 0.09). With the TDC model, although still significant, the relative benefit of PORT decreased, to a HR of 1.07 (p = 0.02).

CONCLUSIONS

Immortal time bias can alter the results of survival analyses if not carefully accounted for. Adjusting for this bias is essential for accurate data interpretation and to better quantify the impact and effect size of adjuvant therapies such as PORT.

Immune Status in Merkel Cell Carcinoma: Relationships With Clinical Factors and Independent Prognostic Value

BACKGROUND

Immunosuppression (IS) currently is not considered in staging for Merkel cell carcinoma (MCC). An analysis of the National Cancer Database (NCDB) was performed to investigate immune status as an independent predictor of overall survival (OS) for patients with MCC and to describe the relationship between immune status and other prognostic factors.

METHODS

The NCDB was queried for patients with a diagnosis of MCC from 2010 to 2016 who had known immune status. Multivariable Cox proportional hazards models were used to define factors associated with OS. Secondary models were constructed to assess the association between IS etiology and OS. Multivariable logistic regression models were used to characterize relationships between immune status and other factors.

RESULTS

The 3-year OS was lower for the patients with IS (44.6%) than for the immunocompetent (IC) patients (68.7%; p < 0.0001). Immunosuppression was associated with increased adjusted mortality hazard (hazard ratio [HR], 2.36, 95% confidence interval [CI], 2.03-2.75). The etiology of IS was associated with OS (p = 0.0015), and patients with solid-organ transplantation had the lowest 3-year OS (32.7%). Immunosuppression was associated with increased odds of greater nodal burden (odds ratio [OR], 1.70; 95% CI, 1.37-2.11) and lymphovascular invasion (OR, 1.58; 95% CI, 1.23-2.03).

CONCLUSIONS

Immune status was independently prognostic for the OS of patients with localized MCC. The etiology of IS may be associated with differential survival outcomes. Multiple adverse prognostic factors were associated with increased likelihood of IS. Immune status, and potentially the etiology of IS, may be useful prognostic factors to consider for future MCC staging systems.

Describing Treatment Patterns for Elderly Patients with Intrahepatic Cholangiocarcinoma and Predicting Prognosis by a Validated Model: A Population-Based Study

Background: Elderly patients with Intrahepatic Cholangiocarcinoma (ICC) are frequently under-represented in clinical trials, which leads to the unclear management of ICC in elderly patients. This study aimed to describe treatment patterns and establish a reliable nomogram in elderly ICC patients.

Methods: Based on the Surveillance, Epidemiology, and End Results (SEER) database, we conducted a retrospective analysis of 1651 elderly patients (≥65 years) diagnosed with ICC between 2004 and 2016.

Results: For the whole study population, 29.3% received only chemotherapy, 26.7% no tumor-directed therapy, 19.1% surgery alone, 17.5% radiotherapy, and 7.4% surgery plus chemotherapy. Compared with the age group of 65-74 years, patients aged ≥75 years were less likely to accept treatment. Among patients 66-74 years of age, surgery alone resulted in a median overall survival (OS) of 30 months, surgery combined with chemotherapy 26 months, radiotherapy 17 months, chemotherapy alone 10 months and no therapy 3 months; while among patients ≥75 years of age, the median OS was 21, 25, 14, 9 and 4, respectively. Moreover, independent prognostic indicators including age, gender, grade, tumor size, T stage, N stage, M stage, and treatment were incorporated to construct a nomogram. The C-indexes of the OS nomogram were 0.725 and 0.724 for the training and validation cohorts, respectively. Importantly, the predictive model harbored a better discriminative power than the American Joint Committee on Cancer TNM staging system.

Conclusion: Active treatment should not be abandoned among all the elderly patients with ICC. The validated nomogram provided an effective and practical tool to accurately evaluate prognosis and to guide personalized treatment for elderly ICC patients.

Injection Drug Use Endocarditis: An Inner-City Hospital Experience

Background

There has been a rise in the incidence of injection drug use and associated infective endocarditis.

Methods

The clinical outcomes of 39 patients admitted with injection drug use-associated infective endocarditis were collected with a mean follow-up of 14 months. The outcomes were compared for patients treated medically with those undergoing surgical intervention. Re sults: The mean age was 39 ± 11 years; 54% were female. Thirty-two patients (82%) had native and 7 (18%) prosthetic infective endocarditis. The tricuspid valve was affected in 17 patients (43%), the mitral in 10 (26%), the aortic in 4 (10%), and multiple valves in 8 (20%). Sixteen (41%) patients underwent surgery, and 23 (59%) were treated with medical therapy. The indications for surgery included heart failure, systemic emboli, recurrent infection, and vegetation size ≥10 mm. Patients undergoing surgery had a higher rate of paravalvular abscess (25% vs 0%, P = 0.02), valve perforation (37% vs 11%, P = 0.04), and mitral valve involvement (44% vs 13%, P = 0.06), whereas medically treated patients had higher tricuspid valve involvement (61% vs 19%, P = 0.02). During follow-up, 26% of medical and 31% of surgical cohort patients died (P = 0.7). Mortality was highest (54%) among those who continued medical management despite an indication for surgery. Univariate predictors of mortality were age (odds ratio [OR] 1.09, 95% confidence interval [CI]: 1.01-1.17; P = 0.02), heart failure (OR 6.9; 95% CI: 1.24-37.49; P = 0.02), septicemia (OR 4.40; 95% CI:0.99-19.54; P = 0.05), and shock (OR 10.8; 95% CI: 1.68-69.92; P = 0.01).

Conclusions

Despite contemporary therapy, patients with injection drug use-associated infective endocarditis remain at high risk of complications and poor clinical outcomes. These findings highlight the need for developing new care pathways and a team approach for effective management.

Definitive Local Therapy Is Associated with Improved Survival in Metastatic Soft Tissue Sarcomas

Background: Definitive local therapy is often utilized in patients with metastatic soft tissue sarcomas (STS) to reduce morbidity associated with local tumor progression. We hypothesize that it is associated with improved overall survival (OS). Methods: Patients with newly diagnosed metastatic STS treated with chemotherapy were identified from the National Cancer Database and dichotomized into cohorts: 1. definitive local therapy (defined as either definitive dose radiotherapy, definitive surgery, or surgery with perioperative radiotherapy) or 2. conservative therapy (defined as systemic therapy with or without palliative therapy). The association between definitive local therapy and OS, and factors associated with the receipt of definitive local therapy were assessed. Results: Total of 4180 patients were identified. Compared with the conservative therapy, receipt of any definitive local therapy was associated with improved OS (median 17.9 vs. 10.1 months). The survival benefit remained on multivariate analyses and propensity-score matched analyses, with a stepwise improvement with surgery and combined modality local therapy, specifically radiotherapy (HR: 0.77; p < 0.001), surgery (HR: 0.67; p < 0.001), and combined surgery and radiotherapy (HR: 0.42; p < 0.001). Conclusions: Analysis of a large national cancer registry of patients with metastatic STS suggests that chemotherapy plus definitive local therapy is associated with a significant survival benefit compared to the standard chemotherapy alone.

Access to Tyrosine Kinase Inhibitors and Survival in Patients with Advanced EGFR+ and ALK+ Positive Non-small-cell Lung Cancer Treated in the Real-World

INTRODUCTION

We assessed the proportion of patients with advanced epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) positive non-small-cell lung cancer (NSCLC) who receive tyrosine kinase inhibitors (TKIs) in the real-world, predictors of TKI use, and impact of TKI therapy on overall survival (OS).

MATERIALS AND METHODS

We identified patients diagnosed with stage IV EGFR⁺ and ALK⁺ positive NSCLC from January 1, 2010 to December 31, 2018, in the Cancer Surveillance System registry and linked their records to Medicare and commercial insurance claims. We reported the proportions of patients with 1 or more TKI claims versus no TKI claims and used logistic regression to identify predictors of TKI use. We evaluated the effect of TKI use on OS by applying extended Cox proportional hazard models with TKI use as a time-dependent exposure and landmark analysis in a subcohort (N = 105). We adjusted Cox models for confounding patient characteristics.

RESULTS

Of 117 eligible patients (median age = 69; 62% women; 88% EGFR⁺), 21 (17.9%) had no TKI claims. Diagnosis in 2015 to 2018 was independently associated with lower likelihood of TKI therapy compared with 2010 to 2014 (adjusted odds ratio, 0.29; P = .020). TKI use was associated with longer OS in a multivariate extended Cox model and in the landmark analysis (adjusted hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.33; 0.99; P = .048; adjusted HR, 0.55; 95% CI, 0.30; 1.00; P = .050).

CONCLUSION

Approximately 18% of patients with advanced EGFR⁺ and ALK⁺ positive NSCLC do not receive TKIs and have inferior survival. Further studies need to investigate barriers of access to TKIs in biomarker-selected patients.

Prolonged inpatient stay after upfront total laryngectomy is associated with overall survival

OBJECTIVES

To investigate factors and complications associated with prolonged inpatient length of stay (LOS) in patients who receive total laryngectomy (TL), and to analyze its effect on short-term and long-term overall survival (OS).

METHODS

The National Cancer Database (NCDB) was queried from 2004 to 2016 for patients with laryngeal cancer, who received TL within 60 days of diagnosis, and who had an inpatient LOS ≥1 night. Multivariable binary logistic regression and survival analyses on propensity score matched cohorts with Kaplan-Meier analysis and extended Cox regression were utilized.

RESULTS

Eight thousand two hundred and ninety-eight patients from the NCDB were included. Median inpatient LOS was 8 days after TL (IQR: 7, 12). Prolonged LOS was defined as above the 75th percentile or 13 days or greater. On multivariable analysis, increasing patient age (OR 1.14 per 10 years, P = .003), female sex (OR 1.35, P < .001), and Charlson-Deyo comorbidity score of ≥2 compared to a score of 0 (OR 1.43, P < .001) were associated with prolonged LOS. Patients treated at high surgical case volume centers had a decreased likelihood for prolonged LOS (OR 0.67, P < .001). Ninety-day mortality increased over time in patients who stayed ≥13 days. Prolonged LOS was independently associated with worse OS on multivariable analysis (HR 1.40, 95% CI: 1.22, 1.61) in a matched cohort.

CONCLUSIONS

Prolonged LOS after TL serves as a strong indicator for postoperative long-term mortality and may help identify patients who warrant closer surveillance.

LEVEL OF EVIDENCE

3.

Radiotherapy Plus Chemotherapy Leads to Prolonged Survival in Patients With Anaplastic Thyroid Cancer Compared With Radiotherapy Alone Regardless of Surgical Resection and Distant Metastasis: A Retrospective Population Study

BACKGROUND

Whether anaplastic thyroid cancer (ATC) patients benefit more from radiotherapy plus chemotherapy (RCT) than from radiotherapy alone (RT) was controversial. We aimed to investigate the effectiveness of RCT versus RT on ATC overall and within subgroups by surgical resection and distant metastasis in a large real-world cohort.

METHODS

Patients with ATC diagnosed between 2004 and 2015 were identified from the Surveillance, Epidemiology, and End Results Program database. Inverse probability weighting (IPW) was performed to balance variables between the two groups. Multivariate Cox proportional hazard model and Fine-Gray compete-risk model were carried out to investigate prognostic factors relating to overall survival (OS) and cancer-specific survival (CSS). Subgroup analysis was carried out, and a forest plot was graphed.

RESULTS

Of the 491 ATC patients, 321 (65.4%) were in the RCT group and 170 (34.6%) were in the RT group. The median OS was 4 months [interquartile range (IQR) 2-7] and 2 months (IQR 1-4) for patients in the RCT and RT groups, respectively. As indicated by the inverse probability weighting multivariate regression, RCT was associated with significantly improved OS (adjusted HR = 0.69, 95% CI = 0.56-0.85, p < 0.001) and CSS (adjusted subdistribution HR = 0.77, 95% CI = 0.61-0.96, p = 0.018). The prominent effect of RCT versus RT alone remains significant within each subgroup stratified by surgical resection and distant metastasis. Older age, single marital status, surgical resection, distant metastasis, and tumor extension were significant prognostic factors of survival.

CONCLUSIONS

RCT contributes to prolonged OS and CSS compared with RT alone in ATC patients, regardless of surgical resection and distant metastasis. RCT should be preferentially applied to ATC patients.

Tumor infiltrating lymphocyte grade in Merkel cell carcinoma: relationships with clinical factors and independent prognostic value

INTRODUCTION

Surrogate markers of the host immune response are not currently included in AJCC staging for Merkel cell carcinoma (MCC), and have not been consistently associated with clinical outcomes. We performed an analysis of a large national database to investigate tumor infiltrating lymphocyte (TIL) grade as an independent predictor of overall survival (OS) for patients with MCC and to characterize the relationship between TIL grade and other clinical prognostic factors.

MATERIAL AND METHODS

The NCDB was queried for patients with resected, non-metastatic MCC with known TIL grade (absent, non-brisk and brisk). Multivariable Cox regression modeling was performed to define TIL grade as a predictor of OS adjusting for other relevant clinical factors. Multinomial, multivariable logistic regression was performed to characterize the relationship between TIL grade and other clinical prognostic factors. Multiple imputation was performed to account for missing data bias.

RESULTS

Both brisk (HR 0.55, CI 0.36-0.83) and non-brisk (HR 0.77, CI 0.60-0.98) were associated with decreased adjusted hazard of death relative to absent TIL grade. Adverse clinical factors such as 1-3 positive lymph nodes, lymphovascular invasion (LVI) and immunosuppression were associated with increased likelihood of non-brisk TIL relative to absent TIL grade (p values <.05). Extracapsular extension (ECS) was associated with decreased likelihood of brisk TIL relative to absent TIL grade (p<.05).

DISCUSSION

Histopathologic TIL grade was independently predictive for OS in this large national cohort. Significant differences in the likelihood of non-brisk or brisk TIL relative to absent grade were present with regards to LVI, ECS and immune status. TIL grade may be a useful prognostic factor to consider in addition to more granular characterization of TIL morphology and immunophenotype.

Revisiting the Radiation Therapy Oncology Group 1221 Hypothesis: Treatment for Stage III/IV HPV-Negative Oropharyngeal Cancer

OBJECTIVE

In 2014, the Radiation Therapy Oncology Group 1221 trial was initiated to analyze whether surgery with risk-based radiation therapy or chemoradiation therapy was superior to chemoradiation therapy alone in patients with clinically staged T1-2N1-2bM0 HPV-negative oropharyngeal squamous cell carcinoma. However, the study was prematurely terminated. Given the lack of a randomized controlled trial, we retrospectively approached the same question using large national cancer databases.

STUDY DESIGN

Retrospective cohort study.

SETTING

The National Cancer Database and Surveillance, Epidemiology, and End Results (SEER) program from 2010 to 2016.

METHODS

We identified 3004 patients in the National Cancer Database and 670 patients in the SEER database. Statistical techniques included Kaplan-Meier survival analysis, binary and multinomial logistic regressions, Cox proportional hazard regressions, and inverse propensity score weighting.

RESULTS

On weighted multivariable Cox regression, patients recommended to receive frontline surgery had improved overall survival as compared with those recommended to receive chemoradiation therapy alone (hazard ratio [HR], 0.77; 95% CI, 0.68-0.86). On post hoc multivariable analysis based on therapy actually received, frontline surgery with adjuvant chemoradiation therapy was associated with improved overall survival (HR, 0.59; 95% CI, 0.50-0.71) as compared with chemoradiation therapy without surgery. Analysis of the SEER cohort revealed improved overall survival (HR, 0.69; 95% CI, 0.54-0.87) and head and neck cancer-specific survival (HR, 0.59; 95% CI, 0.41-0.84) in patients recommended to receive frontline surgery over chemoradiation therapy alone.

CONCLUSION

Our findings support the use of surgery with risk-based addition of adjuvant therapy in patients with cT1-2N1-2bM0 HPV-negative oropharyngeal cancer.

Advancing Pan-cancer Gene Expression Survial Analysis by Inclusion of Non-coding RNA

Non-coding RNAs occupy a significant fraction of the human genome. Their biological significance is backed up by a plethora of emerging evidence. One of the most robust approaches to demonstrate non-coding RNA's biological relevance is through their prognostic value. Using the rich gene expression data from The Cancer Genome Altas (TCGA), we designed Advanced Expression Survival Analysis (AESA), a web tool which provides several novel survival analysis approaches not offered by previous tools. In addition to the common single-gene approach, AESA computes the gene expression composite score of a set of genes for survival analysis and utilizes permutation test or cross-validation to assess the significance of log-rank statistic and the degree of over-fitting. AESA offers survival feature selection with post-selection inference and utilizes expanded TCGA clinical data including overall, disease-specific, disease-free, and progression-free survival information. Users can analyse either protein-coding or non-coding regions of the transcriptome. We demonstrated the effectiveness of AESA using several empirical examples. Our analyses showed that non-coding RNAs perform as well as messenger RNAs in predicting survival of cancer patients. These results reinforce the potential prognostic value of non-coding RNAs. AESA is developed as a module in the freely accessible analysis suite MutEx. Abbreviation: ACC: Adrenocortical Carcinoma (n = 92); BLCA: Bladder Urothelial Carcinoma (n = 412); BRCA: Breast Invasive Carcinoma (n = 1098); CESC: Cervical Squamous Cell Carcinoma and Endocervical Adenocarcinoma (n = 307); CHOL: Cholangiocarcinoma (n = 51); COAD: Colon Adenocarcinoma (n = 461); DLBC: Lymphoid Neoplasm Diffuse Large B-cell Lymphoma (n = 58); ESCA: Oesophageal Carcinoma (n = 185); GBM: Glioblastoma Multiforme (n = 617); HNSC: Head and Neck Squamous Cell Carcinoma (n = 528); KICH: Kidney Chromophobe (n = 113); KIRC: Kidney Renal Clear Cell Carcinoma (n = 537); KIRP: Kidney Renal Papillary Cell Carcinoma (n = 291); LAML: Acute Myeloid Leukaemia (n = 200); LGG: Brain Lower Grade Glioma (n = 516); LIHC: Liver Hepatocellular Carcinoma (n = 377); LUAD: Lung Adenocarcinoma (n = 585); LUSC: Lung Squamous Cell Carcinoma (n = 504); MESO: Mesothelioma (n = 87); OV: Ovarian Serous Cystadenocarcinoma (n = 608) PAAD: Pancreatic Adenocarcinoma (n = 185); PCPG: Pheochromocytoma and Paraganglioma (n = 179); PRAD: Prostate Adenocarcinoma (n = 500); READ: Rectum Adenocarcinoma (n = 172); SARC: Sarcoma (n = 261); SKCM: Skin Cutaneous Melanoma (n = 470); STAD: Stomach Adenocarcinoma (n = 443); TGCT: Testicular Germ Cell Tumours (n = 150); THCA: Thyroid Carcinoma (n = 507) THYM: Thymoma (n = 124); UCEC: Uterine Corpus Endometrial Carcinoma (n = 560); UCS: Uterine Carcinosarcoma (n = 57); UVM: Uveal Melanoma (n = 80).

Optimizing the Treatment Pattern for De Novo Metastatic Nasopharyngeal Carcinoma Patients: A Large-Scale Retrospective Cohort Study

Objectives

To investigate the optimal treatment pattern in patients with de novo metastatic nasopharyngeal carcinoma (NPC).

Methods

We assessed 502 consecutive and unselected de novo metastatic NPC patients in Sun Yat-sen University Cancer Center (SYSUCC) from November 2006 to October 2016 in our study. All patients were treated with palliative chemotherapy (PCT) and 308 patients received locoregional radiotherapy (LRRT) subsequently. Our primary study endpoint was overall survival (OS).

Results

The patients treated with LRRT were associated with improved survival on univariate analysis (3-year OS rate 63.7% vs. 31.8%, P < 0.001) and multivariate analysis (HR 0.52, 95%CI 0.40-0.68, P < 0.001). The overall survival benefit of more than 4 PCT cycles was significant in female (HR 0.45, 95% CI 0.24-0.86, P = 0.016) and patients with multiple metastatic sites (HR 0.42, 95% CI 0.26-0.66, P < 0.001). The application of concurrent chemotherapy (CCT) was not associated with better survival among patients receiving LRRT (HR 1.31, 95% CI 0.92-1.86, P = 0.141).

Conclusion

LRRT prolonged survival in de novo metastatic NPC. For patients treated with multiple metastatic sites, more than 4 cycles of PCT is necessary. CCT does not improve survival in de novo metastatic NPC patients.

Primary Treatment Selection for Clinically Node-Negative Merkel Cell Carcinoma of the Head and Neck

OBJECTIVE

Merkel cell carcinoma practice guidelines recommend sentinel lymph node biopsy after wide local excision for the initial management of clinically node-negative disease without distant metastases (cN0M0). Despite guideline publication, treatment selection remains variable. We hypothesized that receipt of guideline-recommended care would be more common in patients evaluated at academic centers and institutions with high melanoma case volumes and that such therapy would be associated with improved overall survival.

STUDY DESIGN

Retrospective cohort analysis.

SETTING

The National Cancer Database from 2004 to 2015.

METHODS

A total of 3500 patients were included. We utilized Kaplan-Meier analysis and logistic and Cox proportional hazard regressions. Survival analysis was performed on inverse probability-weighted cohorts.

RESULTS

There has been a trend toward evaluation at academic programs at a rate of 1.58% of patients per year (95% CI, 1.06%-2.11%) since 2004. However, the percentage of patients receiving guideline-compliant primary tumor excision and lymph node evaluation has plateaued at approximately 50% since 2012. Guideline-compliant surgical management was more commonly provided to patients evaluated at academic programs than nonacademic programs but only when those institutions had a high melanoma case volume (odds ratio, 2.01; 95% CI, 1.62-2.48). Receipt of guideline-compliant primary tumor excision and lymph node evaluation was associated with improved overall survival (hazard ratio, 0.70; 95% CI, 0.64-0.76).

CONCLUSION

Facility factors affect rates of receipt of guideline-compliant initial surgical management for patients with node-negative Merkel cell carcinoma. Given the survival benefit of such treatment, patients may benefit from care at hospitals with high melanoma case volumes.

The effect of omission of adjuvant radiotherapy after neoadjuvant chemotherapy and breast conserving surgery with a pathologic complete response

OBJECTIVE(S)

Neoadjuvant chemotherapy (NAC) is a standard of care for locally advanced breast cancers. Adjuvant radiotherapy (RT) after NAC is an area of active research. We hypothesize overall survival (OS) is not altered by omitting RT in women with a pathologic complete response (pCR) to NAC after breast conserving survery (BCS).

METHODS

Patients from the National Cancer Database who underwent NAC, BCS, and had a pCR were included. Inflammatory disease, <6 months follow up, and unknown variables were excluded. Descriptive statistics characterized the retained cohort. Logistic regression analyzed the influence of variables on the rate of RT omission. Cox proportional hazard modeling analyzed the influence of prognostic variables on OS.

RESULTS

Of 5383 women included, 364 (7%) omitted RT. 5-year OS was 94.1% with RT, 93% without. RT omission was most likely in women >70yo (adjusted OR2.4, 95%CI 1.58-3.65, p < .0001;reference 40-49 yo), Hispanic (AOR 1.73, 95%CI 1.19-2.52, p = .0044; reference non-Hispanic), ≥20 miles from treatment facility (20-49 miles; AOR 1.45, 95%CI 1.09-1.93, p = .0109: >50 miles; AOR 2.02, 95%CI 1.42-2.87, p < .0001;reference 0-19 miles), grade 1 (AOR 4.29, 95%CI 2.16-8.51, p < .0001; reference grade 3), and clinical T4 disease (AOR 3.17, 95%CI 1.74-5.79, p = .0002; reference T0/1). Women ≥60yo (60-69: AHR 2.33, 95%CI 1.41-3.83, p = .0009:70+:AHR 2.4, 95%CI 1.24-4.62, p = .0092; reference 40-49) and with N1 and N3 disease (N1: AHR 1.67, 95% CI 2.28-3.24, p = .0034; N3: AHR3.37,95%CI2.01-5.65,p < .0001) showed increased death. Triple-positive (AHR 0.18, 95%CI 0.07-0.43, p = .0002) and HER2+ patients (AHR 0.44, 95%CI 0.30-0.64, p < .0001) had improved OS compared to triple-negative disease. No survival difference was seen with omission of RT (log-rank test: p = .1783; Cox model AHR 1.33, 95%CI 0.76-2.31, p = .3181).

CONCLUSION

Women ≥70, of Hispanic origin, living ≥20 miles from treatment facility, and grade 1 disease were more likely to omit RT. HER2+ patients had favorable OS, while older age and N3 disease were negative prognostic factors. Omitting RT after a pCR to NAC and BCS was not found to affect OS.

Management trends for anaplastic meningioma with adjuvant radiotherapy and predictors of long-term survival

OBJECTIVEThe purpose of this study was to describe effects of adjuvant radiotherapy (RT) for anaplastic meningiomas (AMs) on long-term survival, and to analyze patient and RT characteristics associated with long-term survival.METHODSThe authors queried a retrospective cohort of patients with AM from the National Cancer Database (NCDB) diagnosed between 2004 and 2015 to describe treatment trends. For outcome analysis, patients with at least 10 years of follow-up were included, and they were stratified based on adjuvant RT status and propensity matched to controls for covariates. Survival curves were compared. A data-driven approach was used to find a biologically effective dose (BED) of RT with the largest difference between survival curves. Factors associated with long-term survival were quantified.RESULTSThe authors identified 2170 cases of AM in the NCDB between 2004 and 2015. They observed increased use of adjuvant RT in patients treated with higher doses. A total of 178 cases met the inclusion criteria for outcome analysis. Forty-five percent (n = 80) received adjuvant RT. Patients received a BED of 80.23 ± 16.6 Gy (mean ± IQR). The median survival time was not significantly different (32.8 months for adjuvant RT vs 38.5 months for no RT; p = 0.57, log-rank test). Dichotomizing the patients at a BED of 81 Gy showed maximal difference in survival distribution with a decrease in median survival in favor of no adjuvant RT (31.2 months for adjuvant RT vs 49.7 months for no RT; p = 0.03, log-rank test), but this difference was not significant after false discovery rate correction. Age was a significant predictor for long-term survival.CONCLUSIONSAMs are aggressive tumors that carry a poor prognosis. Conventional adjuvant RT improves local control. However, the effect of adjuvant radiation on overall survival is unclear. Further investigation into this area is warranted.

Does Subglottic Squamous Cell Carcinoma Warrant a Different Strategy Than Other Laryngeal Subsites?

OBJECTIVES/HYPOTHESIS

Subglottic squamous cell carcinoma (SSCC) is a rare cancer with limited evidence-based treatment guidelines. This study aimed to describe the treatment patterns for SSCC and to determine which treatments provide the best overall survival.

STUDY DESIGN

Retrospective database review.

METHODS

The National Cancer Database (NCDB) was queried for patients treated for SSCC from 2004 through 2014. Overall survival (OS) rates were determined by the Kaplan-Meier method. Clinicopathologic characteristics were assessed by univariable and multivariable Cox proportional hazards models, which corrected for age, sex, race, insurance status, income quartile, residence, Charlson-Deyo comorbidity score, facility type providing treatment, tumor grade, and clinical N and T category.

RESULTS

In this cohort of 549 patients with SSCC, the 5-year OS was 48.2%. SSCC presented at an advanced stage (American Joint Committee on Cancer stage III or IV) in 60.1% of cases; 78.3% of cases had no nodal metastases. Among only stage IV cases, multivariable analysis showed that radiotherapy (RT) (hazard ratio [HR] = 5.944; 95% confidence interval [CI]: 2.76-12.8; P < .001) and chemoradiotherapy (CRT) (HR = 2.321; 95% CI: 1.36-3.97; P = .002) were both associated with decreased 5-year OS compared to a group consisting of all surgeries. When this analysis was repeated for only stage III cases, RT (HR = 1.134; 95% CI: 0.38-3.37; P = .821) and CRT (HR = 1.784; 95% CI: 0.78-4.08; P = .170) were equivalent to surgery.

CONCLUSIONS

Using the NCDB to study the largest cohort of SSCC with known staging and treatment, primary surgery may provide a better 5-year OS in advanced-stage SSCC.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E1117-E1124, 2021.

The effect of adjuvant radiotherapy on overall survival in adults with intracranial ependymoma

BACKGROUND

Adult intracranial ependymoma is rare, and the role for adjuvant radiotherapy (RT) is not well defined.

METHODS

We used the National Cancer Database (NCDB) to select adults (age ≥ 22 years) with grade 2 to 3 intracranial ependymoma status postresection between 2004 and 2015 and treated with adjuvant RT vs observation. Four cohorts were generated: (1) all patients, (2) grade 2 only, (3) grade 2 status post-subtotal resection only, (4) and grade 3 only. The association between adjuvant RT use and overall survival (OS) was assessed using multivariate Cox and propensity score matched analyses.

RESULTS

A total of 1787 patients were included in cohort 1, of which 856 patients (48%) received adjuvant RT and 931 (52%) were observed. Approximately two-thirds of tumors were supratentorial and 80% were grade 2. Cohorts 2, 3, and 4 included 1471, 345, and 316 patients, respectively. There was no significant association between adjuvant RT use and OS in multivariate or propensity score matched analysis in any of the cohorts. Older age, male sex, urban location, higher comorbidity score, earlier year of diagnosis, and grade 3 were associated with increased risk of death.

CONCLUSIONS

This large NCDB study did not demonstrate a significant association between adjuvant RT use and OS for adults with intracranial ependymoma, including for patients with grade 2 ependymoma status post-subtotal resection. The conflicting results regarding the efficacy of adjuvant RT in this patient population highlight the need for high-quality studies to guide therapy recommendations in adult ependymoma.

Evaluation of the Use of Cancer Registry Data for Comparative Effectiveness Research

Importance

Researchers often analyze cancer registry data to assess for differences in survival among cancer treatments. However, the retrospective, nonrandomized design of these analyses raises questions about study validity.

Objective

To examine the extent to which comparative effectiveness analyses using observational cancer registry data produce results concordant with those of randomized clinical trials.

Design, Setting, and Participants

In this comparative effectiveness study, a total of 141 randomized clinical trials referenced in the National Comprehensive Cancer Network Clinical Practice Guidelines for 8 common solid tumor types were identified. Data on participants within the National Cancer Database (NCDB) diagnosed between 2004 and 2014, matching the eligibility criteria of the randomized clinical trial, were obtained. The present study was conducted from August 1, 2017, to September 10, 2019. The trials included 85 118 patients, and the corresponding NCDB analyses included 1 344 536 patients. Three Cox proportional hazards regression models were used to determine hazard ratios (HRs) for overall survival, including univariable, multivariable, and propensity score-adjusted models. Multivariable and propensity score analyses controlled for potential confounders, including demographic, comorbidity, clinical, treatment, and tumor-related variables.

Main Outcomes and Measures

The main outcome was concordance between the results of randomized clinical trials and observational cancer registry data. Hazard ratios with an NCDB analysis were considered concordant if the NDCB HR fell within the 95% CI of the randomized clinical trial HR. An NCDB analysis was considered concordant if both the NCDB and clinical trial P values for survival were nonsignificant (P ≥ .05) or if they were both significant (P < .05) with survival favoring the same treatment arm in the NCDB and in the randomized clinical trial.

Results

Analyses using the NCDB-produced HRs for survival were concordant with those of 141 randomized clinical trials in 79 univariable analyses (56%), 98 multivariable analyses (70%), and 90 propensity score models (64%). The NCDB analyses produced P values concordant with randomized clinical trials in 58 univariable analyses (41%), 65 multivariable analyses (46%), and 63 propensity score models (45%). No clinical trial characteristics were associated with concordance between NCDB analyses and randomized clinical trials, including disease site, type of clinical intervention, or severity of cancer.

Conclusions and Relevance

The findings of this study suggest that comparative effectiveness research using cancer registry data often produces survival outcomes discordant with those of randomized clinical trial data. These findings may help provide context for clinicians and policy makers interpreting observational comparative effectiveness research in oncology.

Patterns of Care and Outcomes of Adjuvant Chemoradiation for Node-Positive Pancreatic Adenocarcinoma

PURPOSE

The literature has been conflicting on the superiority of adjuvant chemoradiation over chemotherapy for node-positive adenocarcinoma of the pancreas following definitive surgery. We aimed to evaluate the patterns of care and outcomes of these two treatment options using the National Cancer Database (NCDB).

METHODS

Patients diagnosed with non-metastatic, node-positive adenocarcinoma of the pancreas from 2006 to 2014 who received oncologic resection with negative margins were identified in the NCDB. Patient- and clinical-related factors were compared between those who received adjuvant chemotherapy alone (aC) versus adjuvant chemoradiation (aCRT). Univariable and multivariable logistic regression was performed to assess for predictors of adjuvant chemoradiation use. The Kaplan-Meier method was used to assess overall survival (OS) and Cox regression analysis was used to assess impact of covariables on OS.

RESULTS

There were 3609 patients who met the study criteria, of which 2988 (82.8%) received chemotherapy alone and 621 (17.2%) who received chemoradiation. Median follow up for living patients was 33.8 months (IQR 22-51). On multivariable logistic regression, those who received treatment in more recent years of diagnoses (OR 0.21-0.37, p < 0.001) were less likely to receive aCRT over aC. Two-year OS for those who received chemo alone was 44.9% and for chemoradiation was 42.6% (p = 0.169). This finding was sustained on multivariable survival analysis (HR 0.99, p = 0.867).

CONCLUSIONS

Adjuvant chemotherapy alone for adenocarcinoma of the pancreas is the predominant treatment of choice among US hospitals. There was no overall survival benefit noted in those who were treated with adjuvant chemoradiation.

Optimal adjuvant radiotherapy dose for stage I, II or III Merkel cell carcinoma: an analysis of the National Cancer Database

BACKGROUND

We performed an analysis of the National Cancer Database to determine optimal doses of conventionally-fractionated adjuvant radiotherapy for patients with stage I/II or III Merkel cell carcinoma.

METHODS

The cohort included 2735 patients with resected Merkel cell carcinoma of the head and neck, trunk or extremities receiving radiotherapy. Exclusion criteria included doses of radiotherapy <30 or >80 Gy, or dose per fraction >200 or <180 cGy. Recursive partitioning analysis and spline models were used to select dose thresholds. Multivariable Cox regression was performed to validate thresholds with respect to overall survival.

RESULTS

Recursive partitioning analysis models defined a threshold of 57 Gy for stage I/II Merkel cell carcinoma, above which 3-year overall survival rate was decreased (P < 0.0001). The 3-year overall survival rate for patients receiving 50.0-57.0 Gy (81.2%) was greater compared to doses of 30.0-49.9 Gy (75.3%) or >57.0 Gy (70%, P < 0.0001). Doses > 57.0 Gy were associated with an increased hazard of death (1.31, confidence interval 1.07-1.60) with respect to doses of 50.0-57.0 Gy. Doses < 50.0 Gy for stage III Merkel cell carcinoma were associated with worsened 3-year overall survival (P < 0.0001) and increased hazard of death (2.01, confidence interval 1.43-2.82) with respect to doses between 50.0 and 57.0 Gy.

CONCLUSIONS

Our results support doses of 50-57 Gy for most patients with stage I/II Merkel cell carcinoma receiving conventionally-fractionated adjuvant radiotherapy. In contrast to a prior National Cancer Database analysis, our results suggest doses ≥ 50 Gy should be strongly considered for patients with stage III Merkel cell carcinoma regardless of anatomic subsite.

Immune status and the efficacy of radiotherapy on overall survival for patients with localized Merkel cell carcinoma: An analysis of the National Cancer Database

BACKGROUND

Immunosuppressed (IS) patients with Merkel cell carcinoma (MCC) have worse outcomes compared to immunocompetent (IC) patients, and it is unclear if adjuvant radiotherapy (RT) is beneficial for these patients. We sought to determine the effect of immune status on adjuvant RT efficacy regarding overall survival (OS) for patients with localized MCC.

METHODS

This was an observational study of National Cancer Database (NCDB) identifying patients with stage I/II or III MCC with known immune status diagnosed from 2010 to 2014. The median follow-up time was 29 months. OS was described using Kaplan-Meier methods and compared for subgroups by immune status and adjuvant RT using log-rank tests, multivariable Cox regression and interaction effect testing.

RESULTS

A total of 2049 IC and 255 IS patients were included. Adjuvant RT was associated with decreased hazard of death for stage I/II MCC (HR 0.65, CI 0.54-0.78) adjusting for factors including immune status. Interaction effect testing did not demonstrate a significant difference in the effect of adjuvant RT on OS between IC and IS status in either stage I/II or III MCC (both P values > 0.05).

CONCLUSIONS

In this observational study, adjuvant RT was associated with decreased hazard of death for patients with stage I/II MCC regardless of immune status. Adjuvant RT should be considered for both IS and IC patients with localized MCC.

Extrapulmonary small cell carcinoma: Prognostic factors, patterns of care, and overall survival

BACKGROUND

Extrapulmonary small cell carcinoma is a rare malignancy with scarce data. Treatment paradigms extrapolate from pulmonary small cell carcinoma and single institution studies. We analyzed the epidemiology, patterns of care, prognostic factors, and overall survival (OS) of EPSCC patients.

METHODS

The cohort included EPSCC. Patients with <2 months follow-up, unknown demographic/treatment variables were excluded. Descriptive statistics were performed to characterize the cohort. Kaplan-Meier methods were used to estimate OS. Cox proportional hazard modeling was done to analyze the influence of prognostic variables on OS.

RESULTS

5747 patients were included. Median OS was 1.2 years. Head and neck (HR: 0.60, 95% CI 0.53-0.67, p < 0.0001) and breast (HR: 0.69, 95% CI 0.53-0.89, p = .0046) were associated with improved OS; gastrointestinal (HR: 1.19, 95% CI 1.09-1.29, p < .0001) worse OS; and gynecologic (HR: 1.04, 95% CI 0.92-1.17, p = .5660) showing no difference, all compared to genitourinary (reference). Surgery was associated with improved overall survival (HR: 0.84, 95% CI 0.79-0.91, p=<.0001). Chemoradiation showed a decreased HR (HR: 0.91, 95% CI 0.83-0.99, p = .0363) when compared to chemotherapy alone (reference).

CONCLUSION

EPSCC occurs throughout the body with poor survival. Anatomic subsite was predictive for survival. Surgical resection may improve survival. Concurrent chemoradiation appears to improve survival over chemotherapy alone.

Effect of omission of surgery on survival in patients aged 80 years and older with early-stage hormone receptor-positive breast cancer

BACKGROUND

Surgery is increasingly being omitted in older patients with operable breast cancer in the Netherlands. Although omission of surgery can be considered in frail older patients, it may lead to inferior outcomes in non-frail patients. Therefore, the aim of this study was to evaluate the effect of omission of surgery on relative and overall survival in older patients with operable breast cancer.

METHODS

Patients aged 80 years or older diagnosed with stage I-II hormone receptor-positive breast cancer between 2003 and 2009 were selected from the Netherlands Cancer Registry. An instrumental variable approach was applied to minimize confounding, using hospital variation in rate of primary surgery. Relative and overall survival was compared between patients treated in hospitals with different rates of surgery.

RESULTS

Overall, 6464 patients were included. Relative survival was lower for patients treated in hospitals with lower compared with higher surgical rates (90·2 versus 92·4 per cent respectively after 5 years; 71·6 versus 88·2 per cent after 10 years). The relative excess risk for patients treated in hospitals with lower surgical rates was 2·00 (95 per cent c.i. 1·17 to 3·40). Overall survival rates were also lower among patients treated in hospitals with lower compared with higher surgical rates (48·3 versus 51·3 per cent after 5 years; 15·0 versus 19·7 per cent after 10 years respectively; adjusted hazard ratio 1·07, 95 per cent c.i. 1·00 to 1·14).

CONCLUSION

Omission of surgery is associated with worse relative and overall survival in patients aged 80 years or more with stage I-II hormone receptor-positive breast cancer. Future research should focus on the effect on quality of life and physical functioning.

Immune status and the efficacy of adjuvant radiotherapy for patients with localized Merkel cell carcinoma of the head and neck

PURPOSE

Immunosuppressed (IS) patients are at increased risk for developing Merkel cell carcinoma (MCC) with worsened outcomes compared to immunocompetent (IC) patients. We sought to determine the effects of immune status on the efficacy of adjuvant RT regarding OS for patients with stage I, II or III (localized) MCC of the head and neck.

METHODS/PATIENTS

The National Cancer Database was queried for patients with resected, localized MCC of the head and neck with known immune status. Kaplan-Meier methods were used to describe OS. Log-rank tests, multivariable Cox regression models and interaction effect testing were used to compare OS by subgroup categorized by patient and treatment factors including immune status and adjuvant RT receipt.

RESULTS

A total of 892 (89.6%) IC and 104 (10.4%) IS patients with MCC of the head and neck were included. Adjuvant RT was associated with improved 3-year OS rate for both IS patients (49.4% vs. 35.5%, p = 0.0467) and stage I/II IC patients (72.4% vs. 62.9%, p = 0.0092). Adjuvant RT was associated with decreased hazard of death (HR 0.77, 95% CI 0.62-0.95). Interaction effect testing did not demonstrate a difference in the efficacy of adjuvant RT on OS between IC and IS status (p = 0.157).

CONCLUSIONS

In this NCDB analysis, adjuvant RT was associated with decreased hazard of death for patients with localized MCC of the head and neck regardless of immune status and should be considered for both IS and IC patients.

Adjuvant external beam radiotherapy for surgically resected, nonmetastatic anaplastic thyroid cancer

BACKGROUND

EBRT in resected, nonmetastatic anaplastic thyroid cancer (ATC) remains undefined. We evaluated patterns/outcomes with EBRT and chemotherapy in this setting.

METHODS

This retrospective analysis included patients identified from the National Cancer Database with nonmetastatic ATC from 2004 to 2014 who underwent non-palliative resection.

RESULTS

Our analysis included 496 patients, including 375 who underwent adjuvant EBRT (among whom 198 received concurrent chemotherapy). The median age was 68 years. On MVA, EBRT was associated with sex (OR 0.5, 95% CI 0.3-0.8, P = .002) and income (OR 2.2, 95% CI 1.4-3.3, P < .001). EBRT was associated with longer OS on UVA (12.3 vs 9.1 months, P = .004) and MVA (HR 0.7 [CI 0.6-0.9], P = .004). Concurrent chemoradiation was associated with longer OS on UVA (14.0 vs 9.1 months, P = .003) and MVA (HR 0.6 [CI 0.5-0.8], P < .001).

CONCLUSION

Adjuvant EBRT is associated with longer OS in resected, nonmetastatic ATC, with additional improved survival with concurrent chemotherapy.

Short delay in initiation of radiotherapy for patients with glioblastoma-effect of concurrent chemotherapy: a secondary analysis from the NRG Oncology/Radiation Therapy Oncology Group database

Background

We previously reported the unexpected finding of significantly improved survival for newly diagnosed glioblastoma in patients when radiation therapy (RT) was initiated later (>4 wk post-op) compared with earlier (≤2 wk post-op). In that analysis, data were analyzed from 2855 patients from 16 NRG Oncology/Radiotherapy Oncology Group (RTOG) trials conducted prior to the era of concurrent temozolomide (TMZ) with RT. We now report on 1395 newly diagnosed glioblastomas from 2 studies, treated with RT and concurrent TMZ followed by adjuvant TMZ. Our hypothesis was that concurrent TMZ has a synergistic/radiosensitizing mechanism, making RT timing less significant.

Methods

Data from patients treated with TMZ-based chemoradiation from NRG Oncology/RTOG 0525 and 0825 were analyzed. An analysis comparable to our prior study was performed to determine whether there was still an impact on survival by delaying RT. Overall survival (OS) was investigated using the Kaplan-Meier method and Cox proportional hazards model. Early progression (during time of diagnosis to 30 days after RT completion) was analyzed using the chi-square test.

Results

Given the small number of patients who started RT early following surgery, comparisons were made between >4 and ≤4 weeks delay of radiation from time of operation. There was no statistically significant difference in OS (hazard ratio = 0.93; P = 0.29; 95% CI: 0.80-1.07) after adjusting for known prognostic factors (recursive partitioning analysis and O6-methylguanine-DNA methyltransferase methylation status). Similarly, the rate of early progression did not differ significantly (P = 0.63).

Conclusions

We did not observe a significant prognostic influence of delaying radiation when given concurrently with TMZ for newly diagnosed glioblastoma. The effects of early (1-3 wk post-op) or late (>5 wk) initiation of radiation tested in our prior study could not be replicated.

Strengths and limitations of large databases in lung cancer radiation oncology research

There has been a substantial rise in the utilization of large databases in radiation oncology research. The advantages of these datasets include a large sample size and inclusion of a diverse population of patients in a real-world setting. Such observational studies hold promise in enhancing our understanding of questions for which evidence is conflicting or absent in lung cancer radiotherapy. However, it is critical that investigators understand the strengths and limitations of large databases in order to avoid the common pitfalls that beset observational analyses. This review begins by outlining the data variables available in major registries that are used most often in observational analyses. This is followed by a discussion of the type of radiotherapy-related questions that can be addressed using such datasets, accompanied by examples from the lung cancer literature. Finally, we describe some limitations of observational research and techniques to mitigate bias and confounding. We hope that clinicians and researchers find this review helpful for designing new research studies and interpreting published analyses in the literature.

Immortal Time Bias in National Cancer Database Studies

PURPOSE

In studies evaluating the benefit of adjuvant therapies, immortal time bias (ITB) can affect the results by incorrectly reporting a survival advantage. It does so by including all deceased patients who may have been planned to receive adjuvant therapy within the observation cohort. Given the increase in National Cancer Database (NCDB) analyses evaluating postoperative radiation therapy (PORT) as an adjuvant therapy, we sought to examine how often such studies accounted and adjusted for ITB.

METHODS AND MATERIALS

A systematic review was undertaken to search MEDLINE and EMBASE from January 2014 until May 2019 for NCDB studies evaluating PORT. After appropriate exclusion criteria were applied, 60 peer-reviewed manuscripts in which PORT was compared with postoperative observation or maintenance therapy were reviewed. The manuscripts were reviewed to evaluate whether ITB was accounted for, the method with which it was adjusted for, impact factor, year of publication, and whether PORT was beneficial.

RESULTS

Of the 60 publications reviewed, 23 studies (38.3%) did not include an adjustment for ITB. Most studies that did adjust for ITB employed a single landmark (LM) time (n = 31), 4 used a sequential landmark analyses, and 2 used a time-dependent Cox model. In 23 of 31 studies (74.2%) that did adjust for ITB via a single LM time, the rationale behind why the specified LM time was chosen was not clearly explained. There was no relationship between adjusting for ITB and year of publication (P = .074) or whether the study was published in a high-impact journal (P = .55).

CONCLUSIONS

Studies assessing adjuvant radiation therapy by analyzing the NCDB are susceptible to ITB, which overestimates the effect size of adjuvant therapies and can provide misleading results. Adjusting for this bias is essential for accurate data representation and to better quantify the impact of adjuvant therapies such as PORT.

Association of Timing of Adjuvant Therapy With Survival in Patients With Resected Stage I to II Pancreatic Cancer

IMPORTANCE

Surgery followed by adjuvant chemotherapy or chemoradiation is widely used to treat resectable pancreatic cancer. Although studies suggest initiation of adjuvant therapy within 12 weeks of surgery, there is no clear time interval associated with better survival.

OBJECTIVE

To evaluate the ideal timing of adjuvant therapy for patients with stage I to II resected pancreatic cancer.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included 7548 patients with stage I to II resected pancreatic cancer (5453 with adjuvant therapy; 2095 without adjuvant therapy) from the National Cancer Database from 2004 to 2015. Data were collected from January 2014 to December 2015 and analyzed from December 2018 to May 2019.

EXPOSURES

Adjuvant chemotherapy or chemoradiation at various time intervals.

MAIN OUTCOMES AND MEASURES

Overall survival (OS).

RESULTS

A total of 7548 patients (3770 male [49.9%]; median [interquartile range] age, 67 [59-74] years) were identified from the National Cancer Database. Among 5453 patients with adjuvant therapy, a Cox model with restricted cubic splines identified the lowest mortality risk when adjuvant therapy was started 28 to 59 days after surgery. Patients were divided into early (n = 269, adjuvant therapy initiated within <28 days), reference (n = 3048, adjuvant therapy initiated within 28-59 days), and late (n = 2136, adjuvant therapy initiated after >59 days) interval cohorts. Median (interquartile range) overall follow-up was 38.6 (24.6-62.0) months. Compared with the reference interval cohort on multivariable analysis, both the early cohort (hazard ratio, 1.17; 95% CI, 1.02-1.35; P = .03) and the late cohort (hazard ratio, 1.09; 95% CI, 1.02-1.17; P = .008) were associated with worse mortality. Similarly, the reference interval cohort had improved OS compared with the early cohort in 268 propensity-matched pairs (2-year OS, 52.5% [95% CI, 46.7%-59.0%] vs 45.1% [95% CI, 39.5%-51.6%]; P = .02) and compared with the late cohort in 2042 propensity-matched pairs (2-year OS, 51.3% [95% CI, 49.1%-53.6%] vs 45.4% [95% CI, 43.3%-47.7%]; P = .01). Patients who received adjuvant therapy more than 12 weeks after surgery (n = 683) had improved OS compared with surgery alone in both multivariable analysis (hazard ratio, 0.75; 95% CI, 0.66-0.85; P < .001) and 655 propensity-matched pairs (2-year OS, 47.2% [95% CI, 43.5%-51.3%] vs 38.0% [95% CI, 34.4%-42.0%]; P < .001).

CONCLUSIONS AND RELEVANCE

Patients with stage I to II pancreatic cancer who commenced adjuvant therapy within 28 to 59 days after primary surgical resection had improved survival outcomes compared with those with adjuvant therapy before 28 days or after 59 days. Patients who recovered slowly from surgery still benefited from delayed adjuvant therapy initiated more than 12 weeks after surgery compared with patients who underwent surgery only.

Patterns of care and outcomes of intensity modulated radiation therapy versus three-dimensional conformal radiation therapy for anal cancer

Background

Definitive chemoradiation is the standard of care for anal squamous cell carcinoma. Compared to three-dimensional conformal radiation therapy (3DCRT), intensity modulated radiation therapy (IMRT) is increasingly becoming the preferred technique in order to reduce treatment related toxicity. The objective of this study is to evaluate practice patterns and total radiation treatment times of two radiation modalities.

Methods

A total of 6,966 patients with non-metastatic squamous cell carcinoma of the anus who received definitive chemoradiation were queried from the National Cancer Database (NCDB) from 2004-2013. Logistic regression was performed to assess for predictors of IMRT receipt. The Kaplan-Meier method and multivariable Cox regression analysis was used to assess overall survival (OS).

Results

In total, 3,868 (55.5%) received 3DCRT and 3,098 (44.5%) received IMRT. Total radiation treatment time was <7 weeks for 54.3% of patients treated with 3DCRT versus 63.8% of patients treated with IMRT. On multivariable logistic regression, positive clinical nodes (OR =1.20, P=0.001) and treatment at an academic facility (OR =1.23, P<0.001) were associated with increased likelihood of receiving IMRT. The 5-year OS was 73.0% for 3DCRT and 73.9% for IMRT (P=0.315). On multivariable analysis, total radiation treatment time ≥7 weeks (HR =1.33, P<0.001) was associated with worse survival while radiation modality (3DCRT vs. IMRT) did not impact survival (HR =0.98, P=0.763).

Conclusions

IMRT has dramatically increased in utilization from 2% to 65% during the study time period. IMRT was less likely than 3DCRT to have prolonged radiation treatment times, which was associated with worse survival.

Exceptional Responders in Oncology: A Systematic Review and Meta-Analysis of Patient Level Data

PURPOSE

We aim to systematically review and analyze the available literature on "exceptional responders" in oncology. We hypothesize that survival or patients with an exceptional response may be predicted based on clinical factors.

MATERIALS AND METHODS

A PICOS/PRISMA/MOOSE selection protocol was used to find studies that reported oncology patients with an exceptional response. A total of 333 initial articles were screened, and 76 articles were included, accounting for 85 patients. The primary outcome was survival after exceptional response therapy (ERT). The secondary outcome was survival since diagnosis. Univariate and multivariate analyses were conducted for both outcomes with 17 covariates.

RESULTS

The median age was 52 years (interquartile range, 35-66 y), 51.8% were male individuals, 18 (21.2%) had lung cancer, and 1 patient (1%) met all National Cancer Institute criteria for exceptional response. The most common treatment resulting in exceptional response was a form of chemotherapy (49.2%) followed by targeted therapy (26.8%) and radiation therapy (7.7%). The median time from diagnosis to initiation of ERT was 7.92 months (interquartile range, 0-24.72 mo). On multivariate analysis of survival after initiation of ERT, there were no predictors of exceptional response. On multivariate analysis of survival since diagnosis, predictors of prolonged survival included time between diagnosis and ERT initiation (hazard ratio, 0.52; 95% confidence interval, 0.32-0.87; P=0.0124) and single prior surgery versus none (0.08; 95% confidence interval, 0.01-0.98; P=0.04853).

CONCLUSIONS

There were no clinically apparent patient or treatment factors that predicted favorable survival following ERT; instead, reporting of exceptional response appears to be biased.

Delineating the pattern of treatment for elderly locally advanced NSCLC and predicting outcomes by a validated model: A SEER based analysis

INTRODUCTION

Locally advanced nonsmall-cell lung cancer (LA-NSCLC) represented a highly heterogeneous group, with more than half of the patients aged ≥65 years at the time of diagnosis. However, the optimal treatment for elderly LA-NSCLC patients was still not defined.

METHODS

A total of 33530 elderly patients (≥65 years) diagnosed with LA-NSCLC from 2004 to 2014 were identified from Surveillance, Epidemiology, and End Results (SEER) database.

RESULTS

Locally advanced nonsmall-cell lung cancer patients aged 65-74 years were more frequently treated with chemoradiotherapy (CRT) (40%), while patients aged ≥75 years received more best supportive care (BSC) (36%). For age group of 65-74 years, patients who had surgery with or without (neo)adjuvant therapy had a median survival of 28 months, CRT 15 months, radiotherapy (RT) alone 6 months, chemotherapy alone 11 months, and BSC 3 months; while for patients aged ≥ 75 years, the median OS was 20, 13, 7, 9, and 2, respectively. Besides, independent clinicopathological factors were integrated into nomograms for OS and CSS prediction, C-indexes achieved 0.692 and 0.698, respectively. Importantly, the discrimination of nomogram was superior to that of the American Joint Committee on Cancer TNM classification (0.742 vs 0.572 for training set and 0.731 vs 0.565 for validation set).

CONCLUSION

For elderly patients with LA-NSCLC, the curative-intent treatment (surgery or CRT) conferred better survival compared to chemotherapy alone, RT alone and BSC. The proposed nomograms based on independent clinicopathological variables may be practical and helpful for precise evaluation of patient prognosis, and guiding the individualized treatment for elderly LA-NSCLC.

Effects of adjuvant radiation therapy on survival for patients with resected primary tracheal carcinoma: an analysis of the National Cancer Database

Objective(s)

To identify predictors for receiving adjuvant radiation therapy (RT) and investigate the impact of adjuvant RT on survival for patients with resected primary tracheal carcinoma (PTC).

Methods

The National Cancer database was queried for patients with PTC diagnosed from 2004 to 2014 undergoing resection. Patients who died within 30 days of resection were excluded to minimize immortal time bias. Kaplan–Meier methods, Cox regression modeling and propensity score weighted (PSW) log-rank tests were considered to assess the relationship between adjuvant RT and overall survival (OS). Logistic regression was performed to identify predictors associated with receiving adjuvant RT.

Results

A total of 549 patients were identified with 300 patients (55%) receiving adjuvant RT. Squamous cell carcinoma (SCC) was the most common histology with 234 patients (43%). Adenoid cystic carcinoma (ACC) was second most frequent with 180 patients (33%). Adjuvant RT was not associated with OS by multivariable Cox analysis or PSW log-rank test (P values > 0.05). Patients with positive surgical margins (odds ratio (OR) 1.80, confidence interval (CI) 1.06–3.07) were more likely to receive adjuvant RT than those with negative surgical margins. Patients with ACC (OR 6.53, CI 3.57–11.95) were more likely to receive adjuvant RT compared with SCC.

Conclusions

Adjuvant RT was not significantly associated with OS for patients with resected PTC in this analysis. Surgical margin status and tumor histology were associated with receiving adjuvant RT. Further investigations including prospective registry studies capturing radiation technique and treatment volumes are needed to better define which patients with resected PTC may benefit from adjuvant RT.