Use of Postoperative PET/CT in Altering Management in Adjuvant Head and Neck Radiation Therapy

PURPOSE/OBJECTIVE(S)

Routine clinical practice does not include postoperative positron emission tomography (PET)/CT prior to postoperative radiation therapy (PORT) for head and neck cancer. Besides logistical challenges in obtaining postoperative PET/CT within six weeks after surgery, interpreting PET/CT findings in the postoperative setting can also be difficult. However, given the potential for residual or rapidly recurrent disease, postoperative PET/CT may help identify the need for additional diagnostic evaluation or alter adjuvant therapy. There are limited data evaluating the utility of postoperative PET/CT prior to PORT for head and neck cancer. We sought to evaluate the use and clinical relevance of postoperative PET/CT prior to PORT.

MATERIALS/METHODS

In this retrospective, single-institution cohort study, we identified patients with head and neck cancer between 2013 and 2020 who received a postoperative PET/CT prior to PORT. We extracted electronic medical record data supplemented with manual chart review to collect patient and disease-related information. We measured the rates of additional diagnostic workup and treatment alterations as a result of postoperative PET/CT findings.

RESULTS

The cohort included 29 patients who received a postoperative PET/CT prior to PORT. The mean age at diagnosis was 60.8 years (standard deviation: 15.0 years) and 20 (69.0%) were male. Regarding primary site, 10 (34.5%) were oropharynx, 7 (24.1%) were salivary gland, and 6 (20.7%) were oral cavity. The mean time from surgery to postoperative PET was 40.9 days (standard deviation: 27.7 days), and the mean time from postoperative PET/CT to start of PORT was 22.4 days (standard deviation: 20.3 days). A total of 9 (31.0%) patients experienced a change in management as a result of the PET/CT findings. Six (66.7%) patients received a biopsy. All 9 patients had a change in their radiation treatment plan, either dose escalation, target change, or in one case, converting to palliative dosing. Six (66.7%) patients were recommended addition of chemotherapy as a result of additional workup, with 4 (44.4%) of those patients ultimately receiving chemotherapy. Three (33.3%) patients underwent re-resection prior to PORT.

CONCLUSION

In patients with head and neck cancer who received postoperative PET/CT prior to PORT, a meaningful proportion underwent additional diagnostic evaluation and/or experienced an alteration in adjuvant therapy as a result of the imaging findings. Interestingly, all patients with abnormal postoperative PET findings had changes in their radiation treatment plan, including at least boosting gross disease for patients in whom re-resection or chemotherapy was not pursued. Future work will seek to expand this cohort through 2022 when postoperative PET/CT became more routine at our institution and include oncologic outcomes. Additional studies are needed to identify appropriate candidates for postoperative PET/CT and determine the clinical impact of postoperative PET/CT.

Association of Provider Zip Code Sociodemographic Characteristics with Radiation Therapy Modality Use in the Medicare Population

PURPOSE/OBJECTIVE(S)

Variations in healthcare delivery by provider and patient-level characteristics have been well studied in the US health system as a whole, though these patterns are not as well defined in radiation oncology. We evaluated the association of provider zip-code level sociodemographic characteristics with variations in radiation therapy (RT) modality use.

MATERIALS/METHODS

We used the Centers for Medicare & Medicaid Services (CMS) Physician and Other Supplier Public Use File, CMS Physician Compare, and National Neighborhood Data Archive databases to link non-facility based radiation oncologists and their submitted Medicare charges in 2020 with sociodemographic information of the provider's zip code. We selected radiation oncologists who submitted for any of the following RT treatments: proton RT (PRT), stereotactic body RT (SBRT), intensity modulated RT (IMRT), 3D conformal RT (3DCRT), and brachytherapy (BT). Sociodemographic covariates included predominant race/ethnicity of area (Black, White, or Hispanic), percentage of population earning above $75,000 annually, provider rurality (metropolitan vs non-metropolitan), and predominant education level attained of area (Bachelor's degree vs no Bachelor's degree). We measured the association of these covariates with the use of different RT modalities with multivariable logistic regression.

RESULTS

We identified 1,126 radiation oncologists for analysis. PRT was more likely to be used by providers in areas with a predominantly Black population compared with providers in areas with a predominantly White or Hispanic population (Black as reference, White odds ratio (OR) 0.11; 95% CI 0.05-0.24; Hispanic OR 0.23; 95% CI 0.08-0.56). IMRT was more likely to be used by providers in areas with a predominantly White or Hispanic population compared with providers in areas with a predominantly Black population (White OR 3.40; 95% CI 1.63-6.78; Hispanic OR 2.46; 95% CI 1.04-5.97). SBRT was less likely to be used in non-metro areas compared with metro areas (OR 0.28, 95% CI 0.12-0.56). The annual income measure was not associated with any RT modality. Providers in areas with predominantly Bachelor's degree attained were more likely to use PRT (Bachelor's degree as reference, OR 0.34; 95% CI 0.17-0.64) and less likely to use SBRT (OR 1.53; 95% CI 1.04-2.26), IMRT (OR 2.04; 95% CI 1.20-3.48), and 3DCRT (OR 1.52; 95% CI 1.04-2.22). No covariates were associated with BT use.

CONCLUSION

We identified notable variations in RT delivery with multiple sociodemographic factors. A predominantly Black population was associated with a higher likelihood of PRT use, and BT use was not associated with any sociodemographic covariate. These findings might reflect reduced barriers to care afforded by the universal healthcare setting of Medicare or ongoing improvements in RT delivery with respect to previously identified health disparities. Additional work is needed to further elucidate these patterns of RT use and determine if they represent effective care.

Association between health-care system and prostate cancer mortality for African American men with localized and metastatic prostate cancer

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Background: African American (AA) men with prostate cancer (PC) present with more advanced disease and have worse survival than comparable non-Hispanic White (White) men. Recent studies suggest that receiving care within an equal access setting may attenuate these disparities. We hypothesize that AA men receiving care within the Veterans Health Administration (VHA) will have improved outcomes compared to AA men receiving care in the general population as assessed by the Surveillance, Epidemiology, and End Results (SEER) database. Methods: We identified AA men diagnosed with PC between 2004 and 2015 in the VHA and SEER. For comparisons of covariate distributions across subgroups, we used the chi-squared test with continuity correction. We analyzed the cumulative incidence (with 95% confidence intervals (CIs)) of PC specific mortality (PCSM) in the VHA and SEER. Additionally, multivariable Cox proportional hazards models controlling for demographic information were performed. Results: The cohort included 85,409 AA men (VHA: 27,415, SEER: 57,994). Median follow-up was 4.79 years in the VHA and 5.16 years in SEER. In the VHA, AA men were more likely to present with localized disease (VHA 94.7% vs SEER 86.4%, p < 0.001) and less likely to have metastatic disease (3.2% vs 4.3%, p < 0.001). The 5-year cumulative incidence of PCSM was lower for patients in the VHA (VHA: 3.8% [CI: 3.5-4.1%] vs. SEER: 5.0% [CI: 4.8-5.2%], p < 0.001). The PCSM difference was largest in men with metastatic disease. In metastatic patients, cumulative incidence of PCSM at five years was significantly lower in the VHA (VHA 52.5% [CI: 48.0-56.5%] vs. SEER 64.8% [CI: 62.3-67.1%], p < 0.001). In contrast, AA men with localized disease had similar PCSM in the VHA and SEER (VHA 2.4% [CI: 2.2-2.6%] vs. SEER 2.6% [CI: 2.4-2.7%], p = 0.09 at five years). On multivariable analysis, VHA system was associated with lower PCSM [Hazard Ratio (HR): 0.91, p < 0.001]. There was a significant interaction between VHA system and distant metastases at diagnosis [p < 0.001] indicating larger differences in PCSM by healthcare system in metastatic patients as compared to localized patients. VHA system was associated with reduced PCSM in metastatic patients [HR 0.84, p < 0.001] but not in localized patients [HR 0.96, p = 0.13]. Conclusions: AA men in the VHA had a significantly lower incidence of PCSM than those in the SEER database, especially for those who presented with distant metastases at diagnosis. Future work should examine how cost and access to care affect disparities in outcomes for AA men.

Cost-effectiveness of ipilimumab versus high-dose interferon as an adjuvant therapy in resected high-risk melanoma

BACKGROUND

Adjuvant ipilimumab was found to improve the overall survival and reduce toxicity compared to high-dose interferon (HDI) in patients with resected, high-risk melanoma. However, the cost of ipilimumab is substantially higher than HDI. This study evaluates the cost-effectiveness of ipilimumab as an adjuvant treatment in melanoma from a healthcare perspective.

METHODS

We designed a Markov model simulating resected, high-risk melanoma patients receiving either ipilimumab or HDI. Transition probabilities, including risks of survival, disease progression, and toxicity, were ascertained from clinical trial data. Costs and quality of life measurements (health utilities) were extracted from the literature. Incremental cost-effectiveness ratios (ICERs), defined as incremental costs divided by incremental quality-adjusted life-years (QALYs), assessed cost-effectiveness. ICERs <$100,000/QALY were deemed cost-effective. We measured model uncertainty with one-way and probabilistic sensitivity analyses.

RESULTS

In our base case model, ipilimumab increased costs by $107,100 and increased effectiveness by 0.43 QALY, yielding an ICER of $392,600/QALY. Our model was moderately sensitive to the costs of ipilimumab, though the cost of ipilimumab would need to decrease by 44% for ipilimumab to become cost-effective compared to HDI. The model was not sensitive to survival, toxicity, or other costs. Probabilistic sensitivity analysis showed that HDI would remain the cost-effective treatment option 96.2% of the time at a willingness-to-pay threshold of $100,000/QALY.

CONCLUSIONS

Adjuvant ipilimumab increases the survival and decreases the toxicity compared to HDI in resected, high-risk melanoma patients, though this would not be considered cost-effective due to the high price of ipilimumab.

Transoral robotic surgery for human papillomavirus-associated oropharynx squamous cell carcinoma: Recurrence and survival in the Veterans Affairs health system

6054

Background: Most transoral robotic surgery (TORS) literature comes from single and multi-institutional studies at tertiary-care academic intuitions. Long-term outcomes for patients with HPV-mediated oropharyngeal squamous cell carcinoma (HPV-OPSCC) treated with upfront TORS in other hospital settings across the United States are largely unknown. We present long-term recurrence and survival outcomes from a novel Veterans Health Administration (VHA) longitudinal dataset that includes patient-level data. Methods: Retrospective analysis of national VHA patients with p16-positive OPSCC diagnosed between January 2010 and December 2016, treated with TORS primary tumor resection with neck dissection. Outcome measures included: Cancer-specific survival (CSS), progression free survival (PFS), overall survival (OS), recurrence, extranodal extension (ENE), positive surgical margin (PSM), and adjuvant therapy regimen. Results: One hundred sixty-one patients were included of whom 29 (18%) were low-risk [0-1 metastatic lymph nodes, negative margins]; 45 (28%) intermediate-risk [close surgical margins, 2 to 4 metastatic nodes, LVI or PNI, pathologic T3 or T4 tumor]; and 87 (54%) high-risk [PSM, ENE, and/or ≥ 5 metastatic nodes]. ENE was present in 41% of cases and 24% of cases had positive surgical margins. Median follow-up was 5.6 years (95% CI 3.0-9.3). The 5-year CSS rates for low, intermediate, and high-risk groups were: 100%, 90.0% (95% CI 75.4-96.1%), and 88.7% (78.3-94.2%). On univariable analysis, pathologic factors associated with inferior CSS were: pT3-T4 tumor category (HR 3.81, 95% CI 1.31-11; p = 0.01), presence of more than four metastatic lymph nodes (HR 3.41, 95% CI 1.20-11; p = 0.02), and ENE (HR 3.53, 95% CI 1.06-12; p = 0.04). Close or PSM were not associated with CSS (HR 0.67, 95% CI 0.21 – 2.14; p = 0.50). In the low-risk group, 48% avoided adjuvant therapy and although there were five recurrences, none died from cancer. The intermediate-risk group was treated with adjuvant radiation in 64% of cases, and chemoradiation in 29% of cases; and there were five locoregional recurrences and three distant recurrences. Adjuvant chemoradiation was used in 68% of high-risk cases. Of the seven total patients with distant recurrences, six died of their disease. Conclusions: Our findings in this national cohort of Veterans with HPV-OPSCC demonstrate that TORS followed by adjuvant therapy yields favorable survival outcomes. Tumor-category, ENE, and more than four nodal metastases were the strongest adverse features in our data, and surgical margins did not have a significant impact on survival. Further investigations with large cohorts and prospective clinical trials are needed to elucidate the true oncologic implications of high-risk features and to identify patients best suited for de-intensified treatment.

PSA velocity to predict clinical progression in African American and non-Hispanic White patients with low-risk prostate cancer undergoing active surveillance

196

Background: The utility of prostate-specific antigen velocity (PSAV) to predict clinical progression in patients with localized prostate cancer (PC) on active surveillance remains unclear, and in African American (AA) patients on active surveillance remains undefined. Methods: We performed a cohort analysis using the national US Veterans Affairs Informatics and Computing Infrastructure (VINCI). We identified 5296 patients diagnosed with localized prostate cancer (PC) from 2001 to 2015 managed with active surveillance. Follow-up extended through March 31, 2020. We defined low-risk PC as ISUP grade group 1 (GG1) clinical tumor stage ≤ 2A, and PSA level ≤ 10 ng/dl; and active surveillance as no definitive treatment within the first year after diagnosis with at least one additional staging biopsy after diagnostic biopsy. The primary outcome was grade progression on repeat biopsy/prostatectomy defined as GG2 or GG3. The secondary outcome was incident metastases. Cumulative incidence functions and multivariable Cox proportional hazards models were used to test associations between PSAV and outcomes. Results: The final cohort included 3919 Non-Hispanic White patients (NHW) (74%) and 1377 AA (26%) patients. GG2 progression on repeat biopsy occurred in 2062 (38.9%) patients, with a cumulative incidence (CI) of 43.2 % and GG3 progression occurred in 728 (13.7%) patients, with a CI of 18% at seven years. Fifty-four (0.8%) patients developed metastases, with a CI of 1.4% at ten years. In unadjusted analyses, compared to NHW patients, AA patients were significantly more likely to progress to GG2 (52.8% vs 39.8%, p<0.001), and GG3 (22.2% vs 16.8%, p=0.01). On MV analysis, PSAV was a significant predictor of GG2 (HR 1.32 [1.26-1.39]), GG3 (1.5 [1.40-1.62]), and metastases (1.38 [1.10-1.74]). A significant interaction term between race and PSAV indicated the need for different PSAV thresholds for AA and NHW men. Based on maximally selected rank statistics, optimal thresholds for separating outcomes were different in AA vs NHW men. (0.44 vs. 1.18). Conclusions: In this analysis of PSAV in low-risk prostate cancer patients on AS—to our knowledge, the largest to date for AA patients—we observed that PSAV is a robust predictor of upgrading on restaging biopsy as well as metastasis. Compared to NHW patients, AA patients were more likely to progress at lower values of PSAV and therefore merit close follow-up on active surveillance protocols.

Effect of healthcare system on prostate cancer-specific mortality in African American and non-Hispanic white men

23

Background: Disparities in prostate cancer-specific mortality (PCSM) between African American and non-Hispanic White (White) patients have been attributed to biological differences; however, recent data suggest poorer outcomes may be related to barriers to medical care from the healthcare system in which patients receive care. We sought to evaluate potential drivers of disparities by comparing outcomes between African American and White men in the Surveillance, Epidemiology and End Results (SEER) national cancer registry and a relatively equal-access healthcare system, the Veterans Health Administration (VHA). Methods: We identified African American and White patients diagnosed with prostate cancer between 2004-2015 in the SEER and VHA databases. We analyzed metastatic disease at diagnosis with multivariable logistic regression, and PCSM with cumulative incidence analysis and sequential competing-risks regression adjusting for disease and sociodemographic factors. Results: The SEER cohort included 306,609 men (57,994 [18.9%] African American and 248,615 [81.1%] White) with a median follow-up of 5.3 years (interquartile range [IQR] 2.6-8.1 years), and the VHA cohort included 90,749 men (27,412 [30.2%] African American and 63,337 [69.8%] White) with a median follow-up of 4.7 years (IQR 2.4-7.6 years). In SEER, African American men were significantly more likely to present with metastatic disease (African American 4.3% versus White 3.0%, p< 0.001; multivariable odds ratio [OR] 1.25, 95% confidence interval [CI] 1.19-1.32, p< 0.001), whereas in the VHA, African American men were not significantly more likely to present with metastatic disease (African-American 3.2% versus White 3.3%, p= 0.26; multivariable OR 1.07, 95% CI 0.98-1.17, p= 0.12). In SEER, the 8-year cumulative incidence of PCSM was significantly higher for African American compared with White men (6.9% versus 5.1%, p< 0.001), whereas in the VHA, African American compared with White men did not have a significantly higher 8-year cumulative incidence of PCSM (5.5% versus 5.4%, p= 0.93). African American race was significantly associated with an increased risk of PCSM in SEER (univariable subdistribution hazard ratio [SHR] 1.39, 95% CI 1.33-1.45, p< 0.001), but was not significantly associated with PCSM on uni- and multivariable regression in the VHA. When adjusted for disease characteristics at diagnosis in SEER, disease extent, PSA, and Gleason score contributed to 85% of the risk of PCSM for African American men (adjusted SHR 1.06, 95% CI 1.02-1.12, p= 0.008). Conclusions: Racial disparities in PCSM were present in a national cohort, SEER, but not as pronounced in a relatively equal-access healthcare system, the VHA, potentially due to differences in metastatic disease at diagnosis among African American and White men between cohorts. These findings may be attributable to reduced barriers to care in the VHA.