Tumor Deposits an Independent Prognosticator of DFS in Stage III Colon Cancer

Findings from a post hoc analysis of the phase 3 IDEA France trial suggest that tumor deposits are an independent prognostic factor for disease-free survival (DFS) in patients with stage III colon cancer (J Clin Oncol. 2020 Mar 13. Epub ahead of print).

“In the seventh edition of the American Joint Committee on Cancer TNM staging system for [colon cancer], the presence of [tumor deposits] is only considered in the absence of lymph node metastases,” state Jean-François Delattre, MD, Department of Medical Oncology, Assistance Publique–Hôpitaux de Paris, Hôpital Saint-Antoine, France, and colleagues, who posit that tumor deposits can affect prognoses in patients with colon cancer.

“In the era of personalized duration of histopathologic criteria-based adjuvant therapy, this could potentially lead to a decrease in the prognostic prediction accuracy,” they continued.

Using the phase 3 IDEA France study, the purpose of which was to compare 3 months versus 6 months of adjuvant therapy with fluorouracil, leucovorin, and oxaliplatin or capecitabine plus oxaliplatin, Dr Delattre et al conducted a post hoc analysis of all pathologic reports for patients with stage III colon cancer.

The main end point of the analysis was to determine the prognostic impact of tumor deposits on DFS. Another end point was the effect of tumor deposits on lymph node metastases count on pN restaging.

The link between tumor deposits and DFS was determined via a multivariable analysis.

Among 1942 patients with colon cancer, 184 (9.5%) had TDs, and DFS rates were similar between pN1a/b and pN1c subgroups. Patients with TDs had worse prognoses than those without TDs, with 3-year DFS rates of 65.6% (95% CI, 58.0%-72.1%) and 74.7% (95% CI, 72.6%-76.7%; P = .0079), respectively.

Tumor deposits were tied to a higher risk for recurrence or death (hazard ratio [HR], 1.36; P = .0201) according to multivariable analysis. Other adverse factors included

Notably, pT4 and/or pN2 disease (HR, 2.21; P < .001), 3 months of adjuvant treatment (HR, 1.29; P = .0029), and tumor obstruction (HR, 1.28; P = .0233) were also deemed to be adverse factors.

According to the findings, the 35 (2.3%) patients restaged as having pN2 disease DFS rates similar to those of patients initially classified as pN2.

“The presence of [tumor deposits] is an independent prognostic factor for DFS in patients with stage III [colon cancer]. The addition of [tumor deposits] to LNM may help to better define the duration of adjuvant therapy,” Dr Delattre and colleagues concluded.—Hina Porcelli