Peritumoral inflammatory infiltrate is not a prognostic factor in distal rectal cancer following neoadjuvant chemoradiation therapy.

Background: Peritumoral inflammatory response has been considered a good prognostic factor for colorectal cancer. However, this has not been evaluated in patients submitted to neoadjuvant therapy for distal rectal cancer. For this reason, we decided to study the effect of the presence of this pathological finding on disease recurrence and survival.

Methods: The peritumoral inflammatory infiltrate from recovered pathological specimens of patients operated after neoadjuvant therapy for distal rectal cancer was graded (positive or negative). Patients were compared according to the presence of peritumoral inflammatory response.

Results: Of the 168 patients, 63 (37%) patients had a peritumoral inflammatory response. The lack of peritumoral inflammatory response was significantly associated with the presence of mucinous component (13 vs 3%; p = 0.02). Five-year overall survival (91 vs 81%) and disease-free survival (57 vs 48%) were not significantly different between patients with and without peritumoral inflammatory response (p = 0.5 and 0.3, respectively).

Conclusions: Peritumoral inflammatory response is not a favorable prognostic factor in patients with distal rectal cancer after neoadjuvant chemoradiation therapy. Possibly, the immunosuppressive action of chemoradiation therapy may lead to a loss of function of the immunological response, which may represent a disadvantage of the neoadjuvant approach for the management of distal rectal cancer.