The Impact of Tumor Deposits on Colonic Adenocarcinoma AJCC TNM Staging and Outcome

Abstract

The definition of tumor deposits (TD) in colonic adenocarcinoma has been modified in different editions of AJCC/TNM staging system. Studies have shown that the presence of TD is associated with advanced tumor growth and poor prognosis. Most of these data were obtained in patients with simultaneous lymph node (LN) metastases. Reports focusing on the impact of TD in patients without LN metastasis are limited. We retrospectively restaged all right-sided colonic adenocarcinoma over a 10-year period using criteria from the 5th, 6th, and 7th AJCC edition. We compared the number of tumor nodule interpreted as LN and TD in each edition, and evaluated the stage migration caused by TD definition change. We then assessed clinical significance of TD in AJCC 7th edition by comparing 5-year overall survival of N1c patients vs. other N category (N0, N1, N2) patients with similar T and M status. We showed that average number of tumor nodule interpreted as LN per case and number of cases with positive LN were significantly decreased with 7th edition compared to 5th/6th; however, numbers of cases with TD and <12 LN were significantly increased with 7th edition compared to 5th/6th. These changes, however, resulted in minimal effects on the final stage grouping. Our survival analysis showed that N1c patients had significantly worse survival compared to N0 patients. Although not statistically significant, the hazard ratios indicated that N1c group might have worse survival than N1 group and better survival than N2 group. Therefore, we conclude that TD predict patient outcome at least similarly to positive LN.

Prognostic value and characteristics of N1c colorectal cancer

“…examined right‐sided colonic adenocarcinomas only, showing significantly worse survival in N1c patients than N0 patients. This is comparable to the significantly worse DFS noted in colonic tumours in our study . Belt et al .…”

“…Furthermore, Jin et al examined right-sided colonic adenocarcinomas only, showing significantly worse survival in N1c patients than N0 patients. This is comparable to the significantly worse DFS noted in colonic tumours in our study [24]. Belt et al found more recurrences in TD-positive patients than TD-negative patients (65.1% vs 39.1%, respectively) [25].…”

Prognostic value of tumour deposit and perineural invasion status in colorectal cancer patients: a SEER‐based population study

“…We therefore speculate that TD may be associated with a risk of all‐cause death or cancer‐specific death at least similar to a positive lymph node in all N categories. This speculation is supported by a study on N0 cases, but not by others . In addition, TD is prognostically more important in CRC of lower N categories, as shown by the trend of higher TD‐associated HR in CRC of lower N categories.…”

Stage I‐III colon cancer patients with tumor deposits behave similarly to stage IV patients. Cross‐section analysis of 392 patients

“…Several studies demonstrated that patients with stage II but with TD behave similarly to stage III, but the evidence supporting this change are retrospective studies that classified TD as lymph node metastasis or based the TD definition on diameter . When a comparison between stage II cases with TD and cases with stage III (with lymph node metastasis) has been performed, there are no differences in survival …”