Prognostic value of tumor deposits in rectal cancer: A monocentric series of 505 patients

Background and Objectives It has been suggested that tumor deposits (TDs) may have a worse prognosis in rectal cancer compared with colonic cancer. The aim of this study was to assess TDs prognosis in rectal cancer. Methods Patients who underwent total mesorectum excision for rectal adenocarcinoma (2011-2016) were included. A case-matched analysis was performed to assess the accurate impact of TDs for each pN category after exclusion of synchronous metastasis. Results A total of 505 patients were included. TDs were observed in 99 (19.6%) patients, (pN1c = 37 [7.3%]). TDs were associated with pT3-T4 stage (P = .037), synchronous metastasis (P = .003), lymph node (LN) invasion (P = .041), vascular invasion (P = .001), and perineural invasion (P < .001). TD was associated with a worse 3-year disease-free survival (DFS) among pN0 (51.2% vs 79.8%;P < .001); pN1 patients (35.2% vs 70.1%;P = .004) but not among pN2 patients (37.5% vs 44.7%;P = .499). After matching, pN1c patients had a worse 3-year DFS compared with pN0 patients (58.6% vs 82.4%;P = .035) and a tendency toward a worse DFS among N1 patients (40.1% vs 64.2%;P = .153). DFS was worse when one TD was compared with one invaded LN (40.8% vs 81.3%;P < .001). Conclusion In rectal cancer, TDs have a metastatic risk comparable to a pN2 stage which may lead to changes in adjuvant treatment.