Limited Role for Routine Restaging After Neoadjuvant Therapy in Locally Advanced Rectal Cancer.

Background: Although many patients with locally advanced rectal cancer undergo restaging imaging after neoadjuvant chemoradiotherapy and before surgery, the benefit of this practice is unclear. The purpose of this study was to examine the impact of reimaging on outcomes.

Materials And Methods: We performed a retrospective analysis of consecutive patients with stage 2 and 3 rectal adenocarcinoma treated with neoadjuvant chemoradiotherapy between May 2005 and April 2018. Patient and disease characteristics, imaging, treatment, and oncologic outcomes were compared between those who underwent restaging and those who went directly to surgery. Predictors of outcomes and cost effectiveness of restaging were determined.

Results: Of 224 patients, 146 underwent restaging. Six restaged patients had findings leading to a change in management. There was no difference in freedom from recurrence (P = 0.807) and overall survival (P = 0.684) based on restaging. Pretreatment carcinoembryonic antigen level >3 ng/mL (P = 0.010), clinical T stage 4 (P = 0.016), and pathologic T4 (P = 0.047) and N2 (P = 0.002) disease increased the risk of death, whereas adjuvant chemotherapy decreased the risk of death (P < 0.001) on multivariate analysis. Disease recurrence was lower with pelvic exenteration (P = 0.005) and in females (P = 0.039) and higher with pathologic N2 (P = 0.003) and N3 (P = 0.002) disease. The average cost of reimaging is $40,309 per change in management; however, $45 is saved per patient when downstream surgical costs are considered.

Conclusions: Imaging restaging after neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer rarely changes treatment and does not improve survival. In a subset of patients at higher risk for worse outcome, reimaging may be beneficial.