A single institution's long-term follow-up of patients with pathological complete response in locally advanced rectal adenocarcinoma following neoadjuvant chemoradiotherapy.

Purpose: This paper aimed to study the long term follow-up of patients with primary rectal adenocarcinoma receiving neoadjuvant chemoradiotherapy who obtained a pathological complete response (pCR) and identify factors predicting complete response.

Methods: Retrospective review of notes, histology, pre-operative full blood count and imaging of patients with primary rectal adenocarcinoma diagnosed in our institute from 2000 to 2012 from a prospectively maintained database were used. SPSS version 22.0 was used for statistical analysis.

Results: Three hundred eighty patients diagnosed with primary rectal adenocarcinoma were identified, 277 received neoadjuvant chemoradiotherapy followed by curative resection. Forty-six patients obtained a pCR (ypT0N0) with no local recurrence and two metastatic recurrences on follow-up. Patients with a pCR have a significantly improved overall survival and disease-free survival compared to a non-pCR (150.0 and 136.1 vs 77.5 and 84.7 months, p = 0.001). On univariate analysis, increased tumour height above anal verge, low lymph node yield, high pre-operative haemoglobin and a low neutrophil-lymphocyte ratio are significant factors identifying a pCR. Multivariable analysis of the above factors confirmed tumour height above anal verge as significant in obtaining a pCR.

Conclusion: Patients with rectal adenocarcinoma who develop a pCR following neoadjuvant chemoradiotherapy have improved overall and disease-free survival. We have identified distance from anal verge, low lymph node yield, high pre-operative haemoglobin and low neutrophil-lymphocyte ratio as significant predictors of developing a pCR.