Background: Radiation dose escalation for locally advanced pancreatic cancer (LAPC) using stereotactic magnetic resonance (MR)-guided online adaptive radiation therapy (SMART) or computed tomography (CT)-guided moderately hypofractionated ablative radiation therapy (HART) can achieve favorable outcomes although have not previously been compared. Methods: We performed a multi-center retrospective analysis of SMART (50 Gy/5 fractions) vs. HART (75 Gy/25 fractions or 67.5 Gy/15 fractions with concurrent capecitabine) for LAPC. Gray’s test and Cox proportional regression analyses were performed to identify factors associated with local failure (LF) and overall survival (OS). Results: A total of 211 patients (SMART, n = 91; HART, n = 120) were evaluated, and none had surgery. Median follow-up after SMART and HART was 27.0 and 40.0 months, respectively (p < 0.0002). SMART achieved higher gross tumor volume (GTV) coverage and greater hotspots. Two-year LF after SMART and HART was 6.5% and 32.9% (p < 0.001), while two-year OS was 31.0% vs. 35.3% (p = 0.056), respectively. LF was associated with SMART vs. HART (HR 5.389, 95% CI: 1.298–21.975; p = 0.021) and induction mFOLFIRINOX vs. non-mFOLFIRINOX (HR 2.067, 95% CI 1.038–4.052; p = 0.047), while OS was associated with CA19-9 decrease > 40% (HR 0.725, 95% CI 0.515–0.996; p = 0.046) and GTV V120% (HR 1.022, 95% CI 1.006–1.037; p = 0.015). Acute grade > 3 toxicity was similar (3.3% vs. 5.8%; p = 0.390), while late grade > 3 toxicity was less common after SMART (2.2% vs. 9.2%; p = 0.037). Conclusions: Ablative SMART and HART both achieve favorable oncologic outcomes for LAPC with minimal toxicity. We did not observe an OS difference, although technical advantages of SMART might improve target coverage and reduce LF.

Introduction: The rate of isolated locoregional recurrence after surgery for pancreatic adenocarcinoma (PDAC) approaches 25%. Ablative radiation therapy (A-RT) has improved outcomes for locally advanced disease in the primary setting. We sought to evaluate the outcomes of salvage A-RT for isolated locoregional recurrence and examine the relationship between subsequent patterns of failure, radiation dose, and treatment volume. Methods: We conducted a retrospective analysis of all consecutive participants who underwent A-RT for an isolated locoregional recurrence of PDAC after prior surgery at our institution between 2016 and 2021. Treatment consisted of ablative dose (BED10 98–100 Gy) to the gross disease with an additional prophylactic low dose (BED10 < 50 Gy), with the elective volume covering a 1.5 cm isotropic expansion around the gross disease and the circumference of the involved vessels. Local and locoregional failure (LF and LRF, respectively) estimated by the cumulative incidence function with competing risks, distant metastasis-free and overall survival (DMFS and OS, respectively) estimated by the Kaplan–Meier method, and toxicities scored by CTCAE v5.0 are reported. Location of recurrence was mapped to the dose region on the initial radiation plan. Results: Among 65 participants (of whom two had two A-RT courses), the median age was 67 (range 37–87) years, 36 (55%) were male, and 53 (82%) had undergone pancreaticoduodenectomy with a median disease-free interval to locoregional recurrence of 16 (range, 6–71) months. Twenty-seven participants (42%) received chemotherapy prior to A-RT. With a median follow-up of 35 months (95%CI, 26–56 months) from diagnosis of recurrence, 24-month OS and DMFS were 57% (95%CI, 46–72%) and 22% (95%CI, 14–37%), respectively, while 24-month cumulative incidence of in-field LF and total LRF were 28% (95%CI, 17–40%) and 36% (95%CI 24–48%), respectively. First failure after A-RT was distant in 35 patients (53.8%), locoregional in 12 patients (18.5%), and synchronous distant and locoregional in 10 patients (15.4%). Most locoregional failures occurred in elective low-dose volumes. Acute and chronic grade 3–4 toxicities were noted in 1 (1.5%) and 5 patients (7.5%), respectively. Conclusions: Salvage A-RT achieves favorable OS and local control outcomes in participants with an isolated locoregional recurrence of PDAC after surgical resection. Consideration should be given to extending high-dose fields to include adjacent segments of at-risk vessels beyond direct contact with the gross disease.

Objectives: Adjuvant radiotherapy (RT) is commonly used after surgery for WHO grade 2 and 3 meningioma, but the role of patient-facility distance in RT receipt and dose/fractionation choice is not well defined. We examined whether travel distance was associated with receipt and type of adjuvant RT. Methods: We used the National Cancer Database to identify adults diagnosed between 2010 and 2020 with surgically treated WHO grade 2 or 3 meningioma and a CROWFLY distance ≤250 miles. Patients were categorized into 3 groups according to WHO grade and extent of resection: grade 2 with gross total resection, grade 2 with subtotal resection/biopsy, and grade 3 with any resection. Outcomes were receipt of adjuvant RT, SRS/HF-SRS versus fractionated EBRT among classifiable RT recipients, and overall survival. Results: Among 14,218 patients, 4063 (28.6%) received adjuvant RT. In multivariate models, the odds of RT receipt decreased with increasing distance, becoming statistically significant at 25 to <50 miles and remaining lower in more distant bins. Among 2767 classifiable RT recipients, greater distance was associated with higher odds of SRS/HF-SRS rather than fractionated EBRT. Distance was not associated with overall survival. Selected fine-bin estimates included OR =1.47 at 25 to <50 miles, OR =2.40 at 75 to <100 miles, and OR =3.08 at 150 to 250 miles. Conclusions: Greater patient-facility distance was associated with lower receipt of adjuvant RT and greater use of shorter stereotactic regimens among treated patients. These findings support geography as a predictor of both whether and how patients with higher-grade meningioma receive postoperative radiotherapy.