Negative Prognostic Impact of Tumor Deposits in Rectal Cancer

Objective: To investigate whether tumor deposits (TDs) in rectal cancer are associated with increased recurrence risk and decreased survival. Background: Tumor deposits (TDs) are considered a risk factor for recurrence after colon cancer resection, and the presence of TDs prompts adjuvant chemotherapy. The prognostic relevance of TDs in rectal cancer requires further exploration. Methods: All patients treated with abdominal resection surgery for rectal cancer in Sweden between 2011 and 2014 were eligible for inclusion in this retrospective cohort study based on prospectively collected data from the Swedish Colorectal Cancer Registry. The primary endpoint was local recurrence or distant metastasis. Secondary outcomes were overall and relative survival. Results: Five thousand four hundred fifty-five patients were identified of which 3769 patients were analyzed after exclusion. TDs were found in 404 (10.7%) patients, including 140 (3.7%) patients with N1c-status. In TD-positive patients, local recurrence and distant metastasis rates at 5 years were 6.3% [95% CI 3.8–8.8%] and 38.9% [95% CI, 33.6–43.5%] compared with 2.7% [95% CI, 2.1–3.3%] and 14.3% [95% CI, 13.1–15.5%] in TD-negative patients. In multivariable regression analysis, the risk of local recurrence and distant metastasis were increased; HR 1.86 [95% CI, 1.09–3.19; P =0.024] and 1.87 [95% CI, 1.52–2.31; P =<0.001], respectively. Overall survival at 5 years was 68.8% [95% CI, 64.4–73.4%] in TD-positive patients and 80.7% [95% CI, 79.4–82.1%] in TD-negative patients. pN1c-patients had similar outcomes regarding local recurrence, distant metastasis, and survival as pN1a-b stage patients. TD-positive pN1a-b patients had significantly worse outcomes whereas TDs did not affect outcomes in pN2a-b patients. Conclusion: This study suggests that TDs have a negative impact on the prognosis in rectal cancer. Thus, efforts should be made to diagnose TD-positive rectal cancer patients preoperatively.