Prognostic Significance of Tumor Deposits in Gastric Cancer Patients Who Underwent Radical Surgery

Background: To investigate the prognostic significance of tumor deposits (TDs) in gastric cancers patients who underwent radical surgery.

Methods: Clinicopathologic and prognostic data from 2998 gastric cancer patients who underwent R0 surgery with D2/D3 lymphadenectomy were retrospectively reviewed. A TD was defined as discrete foci of tumor found in the perigastric fat or in adjacent ligament away from the leading edge of the tumor and showing no evidence of residual lymph node tissue, but within the lymph drainage area of the primary carcinoma.

Results: TDs were detected in 17.8% of patients. TDs were more frequently observed in cancers of larger size, of Borrmann type 4, with lymphovascular invasion, deeper in depth of invasion, and with extended lymph node metastasis. Multivariate analysis confirmed the presence of TDs as 1 of independent factors predicting a poorer outcome. When stratified by pN category, significant differences in survival were observed between patients with and without TDs for those in pN0/pT1-3, pN1/pT3, pN2/pT1-3 and pN3/pT2-3 category, but not for those in pT4a and pT4b category. Moreover, for cancers in each pN category, the prognosis for patients with TDs in pT1-4a category was similar with that of those without TDs in pT4a category, but significantly better than that of those with or without TDs in pT4b category. A revised pT category and a revised pTNM system were proposed, in which all the cancers with TDs in pT1-4a category were incorporated into those without TDs in pT4a category according to the pN category. Further analysis revealed the revised pT category and the revised pTNM system had better homogeneity, discriminatory ability, and monotonicity of gradients than the American Joint Committee on Cancer (AJCC) pT category and the AJCC pTNM system, respectively, representing optimum prognostic stratification.

Conclusion: TDs significantly correlated with gastric cancer patients' survival. It might be more suitable for TDs to be treated as a form of serosal invasion. Consequently, en bloc resection of the primary carcinoma is crucially important, and adjuvant chemotherapy should always be considered if TDs have been detected.