All Positives May Not Be the Same in Pancreatic Cancer: Lessons Learned From the Past.

Abstract

To the Editor: We read the article “The Role of Radiotherapy in Resected R0/R+ Pancreatic Cancer” Lutsyk et al1 with great interest. The authors retrospectively evaluated the role of adjuvant chemoradiotherapy in 134 localized pancreatic cancer patients operated at their centers. In the study, the margin status was classified as negative and positive with former being R0 and latter including both R1 and R2 resections. We think that the inclusion of R2 patients to the study could falsely augment the the benefit of chemoradiotherapy in the favor of R0 group considering the poor prognosis in the R2 resected patients. R2 resection in pancreatic cancer has not been shown to provide a survival advantage.2,3 The survivals of R2 resected patients are similar to those of patients who were not operated.4 Although, the authors noted similar outcomes fort he R1 and R2 resected patients, the survivals of R1 and R2 resections were not available in the manuscript. This lack of survival difference could simply be due to sample size issues and this issue should be further explained. In this study, it was found that survival was longer (21 vs. 16 mo, P= 0.006) in patients receiving chemoradiotherapy in patients with R+ resection. Chemoradiotherapy is generally applied 5 to 6 months after surgery. Since chemoradiotherapy is applied 5 to 6 months after surgery, it does not affect mortality in the first 6 months. In order to clearly see the contribution of chemoradiotherapy on survival and to exclude perioperative mortality, it is useful to reanalyze by removing those who died within the first 6 months, similar to the studies in the literature.5 We want to ask whether a similar analysis was done in the study group. In conclusion, chemoradiotherapy in pancreatic cancer has been a topic of debate in > 2 decades with studies inheriting selection bias and inadequate subgroup analyses. We think that prospective studies conducting with modern chemotherapy regimens and strict protocols can control the confounders and better delienate the role of chemoradiotherapy in pancreatic cancer.