Evaluation of Volumetric Response Assessment From SABR for Renal Cell Carcinoma (RCC).

PURPOSE: SABR is increasingly used to treat renal cell carcinoma (RCC). However, the optimal method to assess treatment response is unclear. We aimed to quantify changes in both volume and maximum linear size of tumors after SABR and evaluate the utility of the 2 approaches in treatment response assessment. METHODS AND MATERIALS: We retrospectively studied patients with RCC treated with SABR at our institution between 2013 and 2020. All available follow-up computed tomography scans were aligned, and tumors were contoured on all scans. Volume and maximum linear size were measured at each follow-up, relative to these measurements at the time of computed tomography simulation. RESULTS: Twenty-four patients with 25 tumors were included. Median follow-up was 32 months (range, 16-67). Nineteen tumors (76%) had 30% volumetric response at a median time of 7 months after SABR, and 12 tumors (48%) had 30% decrease in maximum linear size at a median time of 16 months. Eighteen tumors (72%) decreased in volume on first follow-up scan and continued to shrink, and 5 tumors (20%) displayed transient growth after SABR (average 24% increase in volume). Compared with T1a tumors, T1b or larger tumors were more likely to have transient growth (8% vs 33%; P = .16) and had higher average relative volume 24 months after SABR (0.47 vs 0.8; P = .022). CONCLUSIONS: Volume measurement results in more pronounced and earlier change compared with linear size measurement when assessing response to SABR. These findings may provide guidance when assessing treatment response for patients with RCC treated with SABR.

Overall and chemotherapy-free survival following stereotactic body radiation therapy for abdominopelvic oligometastases.

INTRODUCTION: Limited data establish the efficacy and safety of SBRT in the abdominopelvic (AP) space, where SBRT delivery is challenging due to the proximity of radiosensitive luminal gastrointestinal (GI) organs. The aim of this study was to assess clinical outcomes in patients with AP OM treated with SBRT. METHODS: Eligible patients were those with OM (defined as metastases in ≤3 total sites) in the AP space (excluding liver) treated with SBRT. Descriptive statistics and Kaplan-Meier estimates of (LC), progression-free survival (PFS), overall survival (OS) and chemotherapy-free survival (CFS) were performed. RESULTS: Fifty-one patients with 58 AP OM received SBRT between 2011 and 2015. Median follow-up was 21.9 months. All SBRT treatments were delivered in 5 fractions with a median dose of 35 Gy (25-40 Gy). Progression post-SBRT occurred in 38/51 patients (75%), with a median PFS of 4.9 months (95% CI: 2.5-7.5), and 2-year PFS of 29%. Rates of 2-and 4-year LC were 74% and 69%, respectively. Median OS was 42.6 months (95% CI: 31-55). Oligometastatic progression occurred in 21/38 patients, and of those, 48% (10/21) received further SBRT. Resulting 2- and 4-year CFS were 47% and 37%, respectively (median 15.1 months). Nineteen patients (37%) experienced a grade 1 or 2 acute toxicity. One grade 3 (acute) toxicity was observed. No grade 4 or 5 toxicities were detected. CONCLUSIONS: SBRT to AP OM was associated with sustained LC, excellent OS and minimal toxicity. The use of SBRT allowed for prolonged CFS and the salvage of limited-burden distant failures.

Radical chest wall resection and hyperfractionated accelerated radiotherapy for radiation-associated angiosarcoma of the breast: A safe and effective treatment strategy.

Radiation-associated angiosarcomas (RAS) of the breast are vascular tumors arising in a previous radiation field for primary breast cancer. They occur rarely but confer a high probability of local recurrence (LR) and poor prognosis. A wide range of treatment strategies exists due to limited evidence, and although resection is the definitive treatment, LR rates remain high. It has been suggested hyperfractionated accelerated radiotherapy (HART) has the potential to prevent LR. The sarcoma group at the Juravinski Cancer Centre (JCC) reports our experience of nine patients treated with radical resection and adjuvant HART. This is one of the largest reported cohorts we are aware of to receive this treatment. The JCC pathologic data base was reviewed between the year 2006-2015 for patients with RAS. Patients who received radical surgery and immediate HART were eligible. Patients underwent radical chest wall resection and en bloc mastectomy. Radiotherapy was then delivered to 4500 cGy in 45 fractions three times daily using parallel opposed photon beams and electron patching, or volumetric modulated arc therapy. Primary outcome was recurrence-free survival in months, and records were reviewed for descriptive reports of toxicity. We compared our results to other institutions experience with surgery alone or other adjuvant therapies. Median follow-up was 19 months (range 3-41 months). One of nine patients developed LR and developed metastasis, one died of other causes, and seven are alive with no recurrent disease. There were seven reports of mild skin toxicity during treatment. One patient developed chronic wound healing complications which eventually resolved and one patient developed asymptomatic radiation osteitis of a rib. On the basis of our experience at the JCC, we recommend treatment with radical chest wall resection and adjuvant HART to prevent recurrence in RAS patients. As demonstrated in our patients, the large normal tissue volume irradiated is tolerable with in combination with small fraction sizes, and no major toxicities were seen. Further investigation into adjuvant therapy regimens and prospective studies are required to reach consensus on optimal treatment for this disease.