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Background: The addition of radiation therapy (RT) to surgery in retroperitoneal sarcoma (RPS) remains controversial. We examined practice patterns in the use of RT for patients with RPS over time in a large, national cohort., Methods: Patients in the National Cancer Database (2004-2017) who underwent resection of RPS were included. Trends over time for proportions were calculated using contingency tables with Cochran-Armitage Trend test., Results: Of 7,485 patients who underwent resection, 1,821 (24.3%) received RT (adjuvant: 59.9%, neoadjuvant: 40.1%). The use of RT decreased annually by < 1% (p = 0.0178). There was an average annual increase of neoadjuvant RT by 13% compared to an average annual decrease of adjuvant RT by 6% (p < 0.0001). Treatment at high-volume centers (OR 14.795, p < 0.0001) and tumor > 10 cm (OR 2.009, p = 0.001) were associated with neoadjuvant RT. In contrast liposarcomas (OR 0.574, p = 0.001) were associated with adjuvant RT. There was no statistically significant difference in overall survival between patients treated with surgery alone versus surgery and RT (p = 0.07)., Conclusion: In the United States, the use of RT for RPS has decreased over time, with a shift towards neoadjuvant RT. However, a large percentage of patients are still receiving adjuvant RT and this mostly occurs at low-volume hospitals., (© 2024. The Author(s).)

Background: Surgery and radiation therapy remain the standard of care for patients with high-grade extremity soft tissue sarcoma that are >5 cm. Radiation therapy is time and labor-intensive for patients, and social determinants of health may affect adherence. The aim of this study was to define demographic, clinical, and treatment factors associated with the completion of radiation therapy and determine if preoperative radiation therapy improved adherence compared to postoperative radiation therapy., Methods: The cohort included patients in the National Cancer Database with high-grade extremity soft tissue sarcoma >5 cm without nodal or distant metastases who received limb-sparing surgery and radiation therapy with microscopically negative R0 margins. Multivariable logistic regression analyses identified factors associated with radiation therapy sequencing and adherence (defined as completion of 50 Gy preoperative radiation therapy or at least 60 Gy postoperative radiation therapy). A multivariable Cox Proportional Hazards model assessed overall survival., Results: Among 2,145 patients, 47.1% received preoperative radiation therapy (n = 1,010), and 52.9% (n = 1135) received postoperative radiation therapy. A greater proportion of patients treated with preoperative (77.2%) versus postoperative radiation therapy (64.9%, P < .0001) received the recommended dose. More patients with private insurance (49.8% vs 35.3% Medicaid vs 44.9% Medicare, P = .011) and patients treated at an academic medical center (52.6% vs 47.4%, P < .001) received preoperative radiation therapy. Patients who received preoperative radiation therapy had lower odds of receiving insufficient doses of radiation therapy (odds ratio 0.34 [95% CI 0.27-0.47]). Neither radiation therapy adherence nor sequencing were independent predictors of overall survival., Conclusions: Patients who received preoperative radiation therapy were more likely to complete therapy and receive an optimal dose than patients treated with postoperative radiation therapy. Preoperative radiation therapy improves adherence and should be widely considered in patients with high-grade extremity soft tissue sarcoma, particularly in patients at risk for not completing therapy., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Based on the NCCN Guidelines for Soft Tissue Sarcoma (STS), treatment of extremity STS (ESTS) includes radiation therapy (RT) and surgical resection for tumors that are high-grade and >5 cm. ​​The aim of this study was to describe the association between neighborhood socioeconomic status (nSES), concordance with NCCN Guidelines recommendations, and outcomes in patients with ESTS., Methods: Patients with ESTS diagnosed from 2006 through 2018 were identified in SEER registries. The analytic cohort was restricted to patients with high-grade tumors >5 cm without nodal or distant metastases who received limb-sparing surgery. Patient demographics and tumor characteristics associated with receipt of RT were analyzed using adjusted regression analyses. Kaplan-Meier curves and adjusted accelerated failure time models were used to examine disparities in cancer-specific survival., Results: Of 2,249 patients, 29.0% (n=648) received neoadjuvant RT, 49.7% (n=1,111) received adjuvant or intraoperative RT, and 21.3% (n=476) did not receive RT. In adjusted analyses, lower nSES was associated with lower likelihood of receiving RT (odds ratio, 0.70 [95% CI, 0.57-0.87]; P<.001). Low nSES was associated with worse cancer-specific survival (hazard ratio, 1.19 [95% CI, 1.01-1.40]; P=.04). Race and ethnicity were not significant predictors of receipt of RT or cancer-specific survival in the fully adjusted models., Conclusions: Patients from lower nSES areas were less likely to receive NCCN Guideline-recommended RT for their ESTS and had worse cancer-specific survival. Efforts to better define and resolve disparities in the treatment and survival of patients with ESTS are warranted.

Volumetric modulated arc therapy (VMAT) is a frequently employed and guideline-recommended radiotherapy (RT) modality for extremity soft tissue sarcomas (eSTS). Prior studies have demonstrated that significant tumor volume changes during treatment result in loss of target volume coverage with highly conformal techniques such as VMAT, but few solutions exist to these issues aside from adaptive replanning. Here, we describe a related but novel phenomenon in which relatively minor changes in surface volume contour (whether due to daily setup uncertainty, edema of peritumoral tissue, or progression or pseudo-progression of tumor volume itself) can result in unexpected subcutaneous hotspots. This phenomenon is of significant clinical concern given the known association between skin dose and major wound complications during preoperative RT for eSTS. By evaluating daily cone-beam CT (CBCT) images from thirteen eSTS patients treated with VMAT RT, we identify daily surface contour changes (range: 2 mm-15 mm, median: 8 mm) which are frequently below conventional adaptive replanning thresholds. When applied under experimental conditions, these external contour changes did not have major impacts on target volume coverage (range: 30.2%-91.2%, mean: 72.5%) but did result in unexpected hotspots of 125.8% on average (range: 110.0%-142.2%) in the subcutaneous tissues. To mitigate this issue, we develop a methodology for VMAT treatment planning using flash PTV and virtual bolus (VB) to produce robust treatment plans that are more resistant to target volume changes, surface contour changes, and setup uncertainties than conventional planning methods. With this methodology, robust plans were equivalent to standard plans at baseline, but, after incorporation of surface volume changes, both maintained target volume coverage (p < 0.001) and prevented development of subcutaneous hotspots (p < 0.001) better than standard plans. As such, this treatment planning methodology may facilitate development of robust VMAT treatment plans that minimize development of subcutaneous hotspots and preserve target volume coverage in the context of routine volumetric changes during preoperative RT., (Copyright © 2023 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.)

Background and Objectives: Radiotherapy (RT) enables conservative surgery for soft tissue sarcoma (STS). RT can be delivered either pre-operatively (PreRT) or postoperatively (PORT), yet in some patients, neither approach is fully satisfactory (e.g., urgent surgery or wound healing risk prevents PreRT, yet PORT alone cannot cover the entire surgical field). We hypothesized that, in such situations, low-dose PreRT (LD-PreRT) would decrease the risk of intraoperative tumor seeding and thus permit PORT to a reduced volume (covering the high-risk tumor bed but not all surgically manipulated tissues)., Methods: We identified a single-institution retrospective cohort of 78 patients treated with LD-PreRT (10-30 Gy), resection, and PORT between 1980 and 2018., Results: At a median follow-up of 8.2 years, 8-year overall survival (OS) was 65.9%, disease-free survival (DFS) 50.5%, and local control (LC) 76.7%; in 45 patients with extremity/superficial trunk (E/ST) STS, 8-year LC was 80.9%. Both before and after propensity score adjustment, there were no differences in OS, DFS, or LC between this cohort and a separate cohort of 394 STS (221 E/ST-STS) patients treated with surgery and PORT alone., Conclusions: In patients for whom neither PreRT nor PORT alone is optimal, LD-PreRT may prevent intraoperative tumor seeding and enable PORT to a reduced volume while preserving oncologic outcomes., (© 2021 Wiley Periodicals LLC.)