Salvage Radiotherapy in Isolated Locoregional Recurrence of Pancreatic Adenocarcinoma Post-Radical Surgical...

Isolated Locoregionally Recurrent Pancreatic Adenocarcinoma (ILRPA) accounts for 25-30% of recurrences after radical resection, yet the role of salvage radiation (RT) in this setting remains controversial due to limited data. We aimed to evaluate the impact of salvage RT on survival outcomes compared with non-salvage RT in patients with ILRPA. We retrospectively analyzed data of patients with ILRPA post-radical resection treated at our centre between 2012 and 2021. Patients were categorized into two cohorts based on whether salvage RT was administered post-recurrence. Patients who received a minimum of 30 Gy in 10 fractions (BED₁₀ ≥ 39 Gy) were included for analysis. The clinical characteristics, treatments, and outcomes were analyzed. The chi-square or Fisher's exact test for categorical variables and Student's t-test or Wilcoxon rank sum test for continuous variables were utilized for comparisons. The Kaplan-Meier method and log-rank test were performed to compare overall survival (OS) and progression-free survival (PFS) between the two groups. OS and PFS were calculated from the time of locoregional recurrence until event or loss of follow-up. Thirty-two patients were identified, with sixteen patients in each group. The patients and tumour characteristics were balanced between the two cohorts, except for chemotherapy, where the salvage RT group tended to receive palliative chemotherapy more than the non-salvage group (p = 0.007). The median radiotherapy dose received for the salvage RT cohort was 50.4 Gy (BED₁₀ = 59.5 Gy). Chemotherapy was restarted in 75% either before, after, or during radiation, and only in 31.25% of patients in the non-salvage group (p = 0.013). Patients who received salvage RT had statistically significantly better median OS and PFS than those who did not (25.2 vs. 8.4 months, p = 0.0006, HR 0.25, 95% CI (0.11-0.59)), (15.6 vs. 7.2 months, p = 0.0006, HR 0.26, 95% CI (0.11-0.58), respectively). Ten patients (62.5%) developed distant metastases (DM) at least 3 months post-recurrence in the salvage RT cohort compared to five patients (31.25%) in the non-salvage RT cohort (p = 0.08). In the salvage RT group, 10/16 patients (62.5%) maintained locoregional disease control post-RT. Salvage RT was associated with better OS and PFS in patients with ILRPA, highlighting its potential as an essential treatment modality. While salvage RT appears beneficial, confounding factors like chemotherapy disparities between groups necessitate further investigation in prospective cohorts.