Utilization of short-course radiation therapy for patients with nonmetastatic rectal adenocarcinoma in the United States

Patterns of Care for Patients With Locally Advanced Rectal Cancer Treated with Total Neoadjuvant Therapy at Predominately Academic Centers between 2016-2020: An NCDB Analysis

Total neoadjuvant therapy (TNT) has emerged as the preferred approach for locally advanced rectal cancer (LARC), defined as T3/4 or any T with N+ disease. Our objective was to (1) determine the proportion of patients with LARC receiving TNT over time, (2) determine the most common method in which TNT is being delivered, and (3) determine what factors are associated with a greater likelihood of receiving TNT in the United States. Retrospective data was obtained from the National Cancer Database (NCDB) for patients diagnosed with rectal cancer between 2016 and 2020. Patients were excluded if they had M1 disease, T1-2 N0 disease, incomplete staging information, nonadenocarcinoma histology, received RT to a nonrectum site, or received a nondefinitive RT dose. Data were analyzed using linear regression, χ² test, and binary logistic regression. Of the 26,375 patients included, most patients were treated at an academic facility (94.6%). Five thousand three (19.0%) patients received TNT, and 21,372 (81.0%) patients did not receive TNT. The proportion of patients receiving TNT increased significantly over time, from 6.1% in 2016 to 34.6% in 2020 (slope = 7.36, 95% CI 4.58-10.15, R² = 0.96, P = .040). The most common TNT regimen was multiagent chemotherapy followed by long-course chemoradiation (73.2% of cases from 2016-2020). There was a significant increase in utilization of short-course RT as part of TNT from 2.8% in 2016 to 13.7% in 2020 (slope = 2.74, 95% CI 0.37-5.11, R² = 0.82, P = .035). Factors associated with a lower likelihood of TNT usage included age >65, female gender, Black race, and T3 N0 disease. TNT use in the United States has increased significantly from 2016-2020, with approximately 34.6% of patients with LARC receiving TNT in 2020. The observed trend appears to be in line with the recent National Comprehensive Cancer Network guidelines recommending TNT as the preferred approach.

Current Practice Patterns in Locally Advanced Rectal Cancer at Academic Institutions: A National Survey Among Radiation Oncologists, Medical Oncologists, and Colorectal Surgeons

PURPOSE

To assess the current treatment patterns in locally advanced rectal cancer (LARC) among radiation oncologists (RO), medical oncologists (MO), and colorectal surgeons (SR) specializing in gastrointestinal (GI) malignancies at academic institutions.

MATERIALS AND METHODS

An online survey consisting of 7 LARC clinical vignettes was distributed to GI specialists practicing at ACGME accredited academic institutions. Treatment paradigms consisted of long-course chemoradiation (LC-CRT) and short-course (SCRT) radiotherapy, chemotherapy (CHT), and surgery. The survey was open from January to April 2021.

RESULTS

Thirty-six RO, 14 MO and 21 SR (71/508 physicians) replied resulting in a response rate of 14.0%. For low rectal node positive tumors, 88.7% of primary recommendations incorporated TNT (73.1% LC-CRT, 26.9% SCRT). NOM was preferred by 41.3% if a clinical complete response (cCR) was achieved. The presence of high-risk features led 95.8% of physicians to employ TNT (79.4% LC-CRT, 20.6% SCRT). For a cT3N1-2 mid-rectal tumor without high-risk features, 85.9% would primarily recommend TNT (56.6% LC-CRT, 43.4% SCRT). For a cT4bN2a mid-rectal tumor without high-risk features, 97.2% of primary recommendations included TNT (76.9% LC-CRT, 23.1% SCRT).

CONCLUSION

Among academic RO, MO, and SR, the traditional regimen of LC-CRT, surgery, and adjuvant CHT is now infrequently recommended for LARC. TNT has been widely adopted for locally advanced node positive rectal tumors with variable patterns of care with respect to sequencing of CHT and RT. Fractionation with LC-CRT remained the majority. Non-operative management after a cCR in low rectal tumors has gained traction transforming LARC from a once classically perceived surgical disease.

The in-silico feasibility of dose escalated, hypofractionated radiotherapy for rectal cancer

Background and purpose

Short course radiotherapy (SCRT) has a low biological prescription dose. Rectal cancer has a dose response relationship and moderate α/β ratio (∼5). We hypothesise hypofractionated dose escalation has radiobiological advantages. We assessed in-silico dose escalation to the primary tumour using a simultaneous integrated boost (SIB) technique.

Materials and methods

Patients who had received 25 Gy/5# were enrolled. GTV was macroscopic tumour including lumen. CTVA was GTV + 10 mm. CTVB included elective nodes. PTV_Low was created from CTVF (CTVA + CTVB) + 7 mm. PTV_High (SIB) was GTV + 5 mm margin. OAR were as per RTOG guidelines. Each patient had 4 plans created at increasing dose levels (27.5 Gy, 30 Gy, 32.5 Gy and 35 Gy) to PTV_High. PTV_Low was 25 Gy/5#.5 test plans were created for each patient in Eclipse™ v15.5 and consisted of 2 VMAT full arcs (6 MV), Varian Truebeam (2.7). Planning objectives were set in the Photon optimiser (PO) and recalculated using Acuros v15.5. A priori feasibility was defined as 90% of plans achieving the planning objectives at 32.5 Gy dose level (EqD2 53.4 Gy).

Results

20 SCRT patients median age 70, F (n = 5), M (n = 15). Rectum level; low (n = 12), mid (n = 3) and upper (n = 5). 100 plans were analysed. Mean volume of PTV_High was 130 cm3 (SD 81.5) and PTV_Low 769.6 cm3 (SD 241.1). 100% plans complied with mandatory planning dose metrics for each structure at the 25 Gy/5# plan and each dose level.

Conclusion

Hypofractionated dose escalation to the primary tumour up to 35 Gy/5# is technically feasible in rectal cancer radiotherapy.

Nonoperative Management Following Complete Response in Rectal Cancer After Short-course Radiation Therapy and Consolidation Chemotherapy: Clinical Outcomes and Quality of Life Measures

PURPOSE

The purpose of his study was to report on a cohort of patients managed with nonoperative management (NOM) with a watch-and-wait strategy after achieving complete response (CR) to sequential short-course radiation therapy (SCRT) and consolidation chemotherapy.

METHODS

This was a retrospective study of patients treated SCRT and chemotherapy who achieved a CR and were managed with NOM. Bowel function was assessed with European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30, EORTC Quality of Life Questionnaire-Colorectal Cancer 29, and the low anterior resection syndrome (LARS) questionnaires. Endpoints included overall survival (OS), freedom from local failure (FFLF), freedom from distant metastasis, and disease-free survival (DFS).

RESULTS

Twenty-six patients met inclusion criteria. Seven (26.9%) patients developed local failure at a median of 6.8 months following CR, of which 5 were successfully salvaged. Median FFLF was not reached, with 6-month, 1-, and 2-year FFLF rates of 100.0%, 82.3%, and 71.3%. Median OS was not reached, with 6-month, 1-, and 2-year OS rates of 100%. Median DFS was not reached, with 6-month, 1-, and 2-year DFS rates of 100%, 95.0%, and 89.4%. Questionnaire response rate was 83.3%. Median LARS score was 27. Major, minor, and no LARS occurred in 3 (20%), 6 (40%), and 6 (40%) patients, respectively. There were no differences in questionnaire scores between patients who had the majority of their anal sphincter complex irradiated and those who did not.

CONCLUSION

NOM with a watch-and-wait strategy is safe and feasible in patients with locally advanced rectal cancer who achieve CR after sequential SCRT and chemotherapy, with evidence for good anorectal function.

Cost-effectiveness of Total Neoadjuvant Therapy With Short-Course Radiotherapy for Resectable Locally Advanced Rectal Cancer

IMPORTANCE

Short-course radiotherapy and total neoadjuvant therapy (SCRT-TNT) followed by total mesorectal excision (TME) has emerged as a new treatment paradigm for patients with locally advanced rectal adenocarcinoma. However, the economic implication of this treatment strategy has not been compared with that of conventional long-course chemoradiotherapy (LCCRT) followed by TME with adjuvant chemotherapy.

OBJECTIVE

To perform a cost-effectiveness analysis of SCRT-TNT vs LCCRT in conjunction with TME for patients with locally advanced rectal cancer.

DESIGN, SETTING, AND PARTICIPANTS

A decision analytical model with a 5-year time horizon was constructed for patients with biopsy-proven, newly diagnosed, primary locally advanced rectal adenocarcinoma treated with SCRT-TNT or LCCRT. Markov modeling was used to model disease progression and patient survival after treatment in 3-month cycles. Data on probabilities and utilities were extracted from the literature. Costs were evaluated from the Medicare payer's perspective in 2020 US dollars. Sensitivity analyses were performed for key variables. Data were collected from October 3, 2020, to January 20, 2021, and analyzed from November 15, 2020, to April 25, 2021.

EXPOSURES

Two treatment strategies, SCRT-TNT vs LCCRT with adjuvant chemotherapy, were compared.

MAIN OUTCOMES AND MEASURES

Cost-effectiveness was evaluated using the incremental cost-effectiveness ratio and net monetary benefits. Effectiveness was defined as quality-adjusted life-years (QALYs). Both costs and QALYs were discounted at 3% annually. Willingness-to-pay threshold was set at $50 000/QALY.

RESULTS

During the 5-year horizon, the total cost was $41 355 and QALYs were 2.21 for SCRT-TNT; for LCCRT, the total cost was $54 827 and QALYs were 2.12, resulting in a negative incremental cost-effectiveness ratio (-$141 256.77). The net monetary benefit was $69 300 for SCRT-TNT and $51 060 for LCCRT. Sensitivity analyses using willingness to pay at $100 000/QALY and $150 000/QALY demonstrated the same conclusion.

CONCLUSIONS AND RELEVANCE

These findings suggest that SCRT-TNT followed by TME incurs lower cost and improved QALYs compared with conventional LCCRT followed by TME and adjuvant chemotherapy. These data offer further rationale to support SCRT-TNT as a novel cost-saving treatment paradigm in the management of locally advanced rectal cancer.

Impact of postoperative radiotherapy on the outcomes of resected adrenocortical carcinoma-a real-world, population-based study

OBJECTIVE

To assess the impact of postoperative radiotherapy on the outcomes of resected adrenocortical carcinoma in a real-world setting.

METHODS

The Surveillance, Epidemiology, and End Results Research Plus database was accessed, and patients with resected non-metastatic adrenocortical carcinoma diagnosed 2010-2015 were reviewed. Kaplan-Meier estimates and log-rank testing were used to examine the impact of postoperative radiotherapy on overall and cancer-specific survival. Multivariable Cox regression analysis was used to explore factors associated with overall and cancer-specific survival.

RESULTS

A total of 294 patients were included in the final analysis, including 60 patients (20.4%) who received postoperative radiotherapy. Using Kaplan-Meier estimates, individuals who received postoperative radiotherapy have better overall survival (P = 0.002). Multivariable cox regression analysis showed that the following factors were associated with worse overall survival: older age (HR: 1.01; 95% CI: 1.00-1.03), male sex (HR for female sex versus male sex: 0.61; 95% CI: 0.43-0.85), and non-receipt of postoperative radiation therapy (HR: 2.29; 95% CI: 1.38-3.77). Systemic therapy was not associated with differences in overall survival (HR: 0.77; 95% CI: 0.54-1.10). Likewise, the following factors were associated with worse cancer-specific survival: male sex (HR for female sex versus male sex: 0.60; 95% CI: 0.41-0.88), non-receipt of postoperative radiation therapy (HR: 2.17; 95% CI: 1.27-3.70), and receipt of perioperative systemic therapy (HR: 0.67; 95% CI: 0.45-0.99).

CONCLUSION

Postoperative radiotherapy following resection of adrenocortical carcinoma is associated with better overall and cancer-specific survival.

Prognostic importance of circumferential resection margin in the era of evolving surgical and multidisciplinary treatment of rectal cancer: A systematic review and meta-analysis

BACKGROUND

Circumferential resection margin is considered an important prognostic parameter after rectal cancer surgery, but its impact might have changed because of improved surgical quality and tailored multimodality treatment. The aim of this systematic review was to determine the prognostic importance of circumferential resection margin involvement based on the most recent literature.

METHODS

A systematic literature search of MEDLINE, Embase, and the Cochrane Library was performed for studies published between January 2006 and May 2019. Studies were included if 3- or 5-year oncological outcomes were reported depending on circumferential resection margin status. Outcome parameters were local recurrence, overall survival, disease-free survival, and distant metastasis rate. The Newcastle Ottawa Scale and Jadad score were used for quality assessment of the studies. Meta-analysis was performed using a random effects model and reported as a pooled odds ratio or hazard ratio with 95% confidence interval.

RESULTS

Seventy-five studies were included, comprising a total of 85,048 rectal cancer patients. Significant associations between circumferential resection margin involvement and all long-term outcome parameters were uniformly found, with varying odds ratios and hazard ratios depending on circumferential resection margin definition (<1 mm, ≤1 mm, otherwise), neoadjuvant treatment, study period, and geographical origin of the studies.

CONCLUSION

Circumferential resection margin involvement has remained an independent, poor prognostic factor for local recurrence and survival in most recent literature, indicating that circumferential resection margin status can still be used as a short-term surrogate endpoint.

Phase II Trial of Neoadjuvant Bevacizumab with Modified FOLFOX7 in Patients with Stage II and III Rectal Cancer

LESSONS LEARNED

Neoadjuvant bevacizumab with modified FOLFOX7 without radiation failed to meet the goal of pathological complete response rate; however, the low number of recurrence and disease-free survival in this population, with predominantly stage III, is encouraging and worth further exploration. The racial distribution of the patient population, as well as a wait time of more than 4 weeks after last chemotherapy, may have contributed to the findings.

BACKGROUND

Combination chemotherapy in lieu of radiation in rectal adenocarcinoma is under exploration in multiple trials. We evaluated the efficacy of neoadjuvant FOLFOX + bevacizumab in patients (pts) with clinical stage II and III disease.

METHODS

Pts received six cycles of bevacizumab (5 mg/kg) and modified FOLFOX7 (oxaliplatin 85 mg/m² , leucovorin 20 mg/m² , and fluorouracil [5-FU] 2,400 mg/m² ). Surgical resection was performed 6-8 weeks after completion of treatment and upon confirmation of nonmetastatic disease. We employed a Simon two-stage design and required three pathological complete responses (pCR) in the first 18 pts, with a prespecified pCR rate of 25% before moving to the next stage.

RESULTS

Seventeen pts enrolled; 65% at stage III. Median age was 57 (35-79), 65% were male, 47% were Hispanic, 35% were white, and 18% were Asian. All pts but one completed six cycles of therapy. One pCR was observed (6%), and 11 of 17 (65%) pts had pathological downstaging. One patient experienced systemic recurrence and remains on treatment. Probability of disease-free survival (DFS) at 5 years is 0.94 (SE, 0.06).

CONCLUSION

The study failed to meet the required three pCRs in the first 18 pts. The DFS in this population is encouraging and supports the hypothesis that select pts with rectal cancer may be spared from radiation.

Pathologic Response and Postoperative Complications After Short-course Radiation Therapy and Chemotherapy for Patients With Rectal Adenocarcinoma

BACKGROUND

The role of neoadjuvant short-course radiation therapy (SCRT) in treating rectal adenocarcinoma is a topic of ongoing debate. Growing interest in total neoadjuvant therapy has spurred discussion on the optimal sequence of preoperative SCRT and chemotherapy.

PATIENTS AND METHODS

All patients receiving SCRT (5 Gy × 5 fractions) were identified. Details about preoperative treatments, radiation toxicities, and postoperative complications were collected. Patients were divided into 2 groups: those who underwent surgery within 14 days of completing SCRT and those with a longer delay. Outcomes compared included extent of pathologic response, margin-negative resection rate, acute radiation toxicities, and postoperative complications.

RESULTS

Fifty-seven patients with locally advanced or metastatic rectal cancer received SCRT between 2008 and 2018. Thirty-nine of 57 patients underwent definitive pelvic surgery with total mesorectal excision. There were no significant differences in tumor downstaging, radial margin status, or percent tumor viability between patients with immediate surgery versus delayed surgery. The delay group had higher rates of nodal downstaging (64.7% vs. 18.2%; P = .003). There were no differences in total or grade 3+ gastrointestinal radiation toxicity, postoperative complications, reoperation, readmission, and mortality between the 2 groups.

CONCLUSIONS

Though not yet common in the United States, SCRT has compared favorably with long course chemoradiation in multiple trials. Moreover, it is associated with greater efficiency and less disruption to chemotherapy. Our data show similar response and toxicity outcomes between the immediate and delay groups, suggesting SCRT is well-tolerated regardless of treatment sequence. Recently completed prospective trials may reveal the optimal preoperative treatment sequence.