Clinical significance of metastatic tumor deposit foci in rectal cancer in the lateral pelvic lymph node area

• Published in: International journal of clinical oncology Vol. 28; no. 10; pp. 1388 - 1397
• Main Authors: Yamai, Daisuke, Shimada, Yoshifumi, Nakano, Masato, Ozeki, Hikaru, Matsumoto, Akio, Abe, Kaoru, Tajima, Yosuke, Nakano, Mae, Ichikawa, Hiroshi, Sakata, Jun, Nagai, Takahiro, Ling, Yiwei, Okuda, Shujiro, Watanabe, Gen, Nogami, Hitoshi, Maruyama, Satoshi, Takii, Yasumasa, Wakai, Toshifumi
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01.10.2023; Springer Nature B.V
• Subjects: Cancer Research; Classification; Clinical significance; Colon cancer; Colorectal cancer; Lymph nodes; Lymphatic system; Medical prognosis; Medicine; Medicine & Public Health; Metastases; Metastasis; Oncology; Original Article; Rectum; Surgical Oncology; Survival; Tumors; Lateral pelvic lymph node dissection; Tumor deposit; Rectal cancer; Lateral pelvic lymph node area; Low rectal cancer
• ISSN: 1341-9625; 1437-7772
• DOI: 10.1007/s10147-023-02391-1

Background Although previous studies have demonstrated that tumor deposits (TDs) are associated with worse prognosis in colon cancer, their clinical significance in rectal cancer has not been fully elucidated, especially in the lateral pelvic lymph node (LPLN) area. This study aimed to clarify the clinical significance of TDs, focusing on the number of metastatic foci, including lymph node metastases (LNMs) and TDs, in the LPLN area. Methods This retrospective study involved 226 consecutive patients with cStage II/III low rectal cancer who underwent LPLN dissection. Metastatic foci, including LNM and TD, in the LPLN area were defined as lateral pelvic metastases (LP-M) and were evaluated according to LP-M status: presence (absence vs. presence), histopathological classification (LNM vs. TD), and number (one to three vs. four or more). We evaluated the relapse-free survival of each model and compared them using the Akaike information criterion (AIC) and Harrell’s concordance index (c-index). Results Forty-nine of 226 patients (22%) had LP-M, and 15 patients (7%) had TDs. The median number of LP-M per patient was one (range, 1–9). The best risk stratification power was observed for number (AIC, 758; c-index, 0.668) compared with presence (AIC, 759; c-index, 0.665) and histopathological classification (AIC, 761; c-index, 0.664). The number of LP-M was an independent prognostic factor for both relapse-free and overall survival, and was significantly associated with cumulative local recurrence. Conclusion The number of metastatic foci, including LNMs and TDs, in the LPLN area is useful for risk stratification of patients with low rectal cancer.