Background: The aim of this study was to determine the prognostic value of peritumoral deposits (PTDs) in colorectal cancer (CRC).
Methods: A total of 695 patients with pT3/T4 CRC (1980 to 1999) were reviewed. Tumor deposits located ≥2 mm from the front of the direct spread in the primary tumor were evaluated as PTDs.
Results: PTDs were observed in 111 patients (16.0%). The incidence of PTDs increased according to increasing N stage: 7% for N0, 22% for N1, and 39% for N2 (P < .0001). Five-year disease-specific survival was 85.0% in patients without PTDs and 59.5% in those with PTDs (P < .0001). Multivariate analysis showed that PTDs affected disease-specific survival independent of T and N stages. A significant prognostic impact of PTDs was similarly observed in another cohort comprising 474 patients with pT3/T4 CRC (2000 to 2005). The κ values among 8 observers were .70 for PTDs and .32 for the conventional growth pattern.
Conclusions: PTDs have considerable prognostic relevance and offer improved judgment reproducibility in assessing the invasive margin of CRC.
Keywords: Colorectal cancer; Growth pattern; Invasive margin; Peritumoral deposits; Prognosis.
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