A matched pair analysis of five-fraction stereotactic body radiation therapy versus protracted conventional radiation therapy in patients receiving chemotherapy for locally advanced pancreatic cancer.

2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 444-444
Author(s):  
Antony Koroulakis ◽  
Petra Prins ◽  
Andrew Gabrielson ◽  
Chris Silveri ◽  
Andrew Hwang ◽  
...  

444 Background: Stereotactic body radiation therapy (SBRT) is a novel treatment modality for unresectable, locally advanced pancreatic cancer (LAPC). SBRT delivers high doses of radiation over a shorter duration, with minimal acute toxicities, compared with conventional radiation therapy (CRT) using intensity modulated radiation therapy (IMRT) or 3D conformal techniques (3D-CRT). Few studies have compared outcomes between SBRT and CRT techniques. We conducted a retrospective matched pair analysis of LAPC patients receiving chemotherapy and either SBRT or CRT to assess local control (LC), progression-free survival (PFS), and overall survival (OS). Methods: We retrospectively analyzed 28 patients with LAPC who were treated between August 2006 and August 2014 with 5-FU- or gemcitabine-based chemotherapy combined with CRT (45–56 Gy over 25–28 fractions) or SBRT (25–30 Gy over 5 fractions). Fourteen patients treated with CRT were matched with 14 patients treated with SBRT for age (< 65 vs. ≥ 65 years); nodal staging (N0 or N1); and chemotherapy type (gemcitabine-based or 5-FU-based, administered either concurrently or as induction therapy). Tumor response was assessed using RECIST and all outcomes were calculated from the date of diagnosis. The Log Rank test of Kaplan-Meier curves was used for statistical analyses. Results: Median follow-up time was 11 months (mo). The median duration of LC, PFS, and OS for the entire cohort was 11, 8, and 14 mo, respectively. Median duration of LC was 10 mo for CRT and 11 mo for SBRT (p > 0.05). Median PFS was 8 mo for both groups (p > 0.05). The median OS times were 12 mo for SBRT and 16 mo for 3D-CRT/IMRT (p > 0.05). Conclusions: In this small matched-pair analysis, LAPC patients treated with chemotherapy had similar outcomes following 5 fractions of SBRT as compared with a protracted course of CRT. Given the shorter treatment duration with SBRT, further study is warranted with increased cohort sizes and stratification by other patient and disease characteristics.

2021 ◽  
Vol 39 (3_suppl) ◽  
pp. 410-410
Author(s):  
Emanuel Boyer ◽  
Russell Palm ◽  
Jessica M. Frakes ◽  
Sarah E. Hoffe ◽  
Mokenge Peter Malafa

410 Background: Outcomes remain poor for those diagnosed with unresectable pancreatic cancer. SBRT and IRE have independently demonstrated high rates of local control and minimal toxicity for patients with locally advanced pancreatic cancer (LAPC). Data is limited regarding safety and efficacy in the sequential use of both therapies. Materials and Methods: A single institution retrospective matched cohort analysis was performed for patients with non-metastatic pancreatic cancer treated with induction chemotherapy and SBRT followed by IRE, compared with patients of the same cohort who did not receive IRE. Patients were paired based on age, tumor stage, GTV D95, CA19-9 prior to SBRT, and chemotherapy type to mitigate selection bias in surgical candidates. Overall survival (OS), progression free survival (PFS), freedom from local failure (FFLF) and freedom from distant failure (FFDF) were the primary outcomes compared via Kaplan-Meier survival analysis with log-rank methods. Results: From July, 2014 to February, 2020 17 patients received SBRT followed by IRE. These patients were matched with 17 patients who received SBRT from January, 2012 to March, 2019. Most patients received neoadjuvant FOLFIRINOX (82.4%) and were AJCC 8 stage III (79.4%). Median age of the overall cohort was 65.5 years and 50% were male. Median dose delivered to 95% of gross tumor volume was 32.61 Gy, and median pre SBRT CA19-9 value was 70.5 U/mL. There were no statistically significant differences in matched characteristics between the two cohorts. Among the SBRT+IRE, the median time between IRE and SBRT was 66 days (range:49-467 days). The median OS, PFS, FFLF, and FFDF for IRE+SBRT vs. SBRT alone from SBRT was 10.8 vs 15.1 months, 9.6 vs. 15.3 months, 15.7 vs. 15.3 months, 15.9 vs. 14.4 months respectively (all P > .10). 11 patients in the entire cohort experienced toxicity as a result of their radiation therapy (35%), with one G3 GIB and one patient experiencing G3 abdominal pain. Among the 17 patients who underwent IRE, nine patients experienced toxicity (53%). Most of these events were G3, with two G4 intestinal bleeds. There was zero mortality in the 90 day period post operatively. Conclusions: In a retrospective cohort,non-selective delivery ofIRE afterSBRT demonstrated no oncological benefit for patients with unresectable pancreatic adenocarcinoma compared to only SBRT. Compared to historical experiences of IRE alone, there was no increase in overall toxicity with the combination of SBRT and IRE. The optimal timing, sequencing, and indications for IRE and SBRT in LAPC remain unknown and are best assessed prospectively. [Table: see text]


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