J Cancer 2018; 9(8):1466-1475. doi:10.7150/jca.23311

Research Paper

Survival Contradiction Between Stage IIA and Stage IIIA Rectal Cancer: A Retrospective Study

Shaobo Mo1,2*, Weixing Dai1,2*, Wenqiang Xiang1,2*, Ben Huang1,2, Yaqi Li1,2, Yang Feng1,2, Qingguo Li1,2✉, Guoxiang Cai1,2✉

1. Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai 200032, China;
2. Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China.
*Shaobo Mo, Weixing Dai, and Wenqiang Xiang contributed equally to this work.

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Citation:
Mo S, Dai W, Xiang W, Huang B, Li Y, Feng Y, Li Q, Cai G. Survival Contradiction Between Stage IIA and Stage IIIA Rectal Cancer: A Retrospective Study. J Cancer 2018; 9(8):1466-1475. doi:10.7150/jca.23311. Available from http://www.jcancer.org/v09p1466.htm

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Abstract

Background: When compared with patients harboring stage IIB and stage IIC disease, those with stage IIIA colorectal cancer have a better prognosis. We aimed to compare the cause-specific survival (CSS) of the patients with stage IIA rectal cancer with that of the patients with stage IIIA rectal cancer.

Methods: Data analyzed about patients with stage IIA and stage IIIA rectal cancer was from the US Surveillance, Epidemiology, and End Results (SEER) database. We then validated the results using data derived from Fudan University Shanghai Cancer Center (FUSCC).

Results: A total of 16,788 patients (13,551 staged IIA and 3,237 staged IIIA) were identified in SEER database. A multivariate analysis manifested that patients with stage IIIA disease were more likely to have a better CSS (HR 0.894, 95% CI 0.816-0.979, p=0.016) compared with patients with stage IIA rectal cancer. In the subgroup of patients whose number of lymph nodes harvested (LNH) <12, multivariate analysis signified that patients with stage IIIA disease were more prone to have favorable CSS (HR 0.805, 95% CI 0.719-0.901, p<0.001) compared with patients with stage IIA rectal cancer. In LNH≥12 subgroup, the Kaplan-Meier analysis revealed no significant difference between patients experiencing stage IIA and IIIA rectal cancer (p=0.618). Validation of data from FUSCC proved that patients with stage IIIA rectal cancer were more inclined to have better CSS (HR 0.407, 95% CI 0.187-0.885, p=0.019) in comparison to those with stage IIA rectal cancer. Specifically, in LNH<12 subgroup, the survival outcomes of stage IIIA patients were significantly better than that of the stage IIA patients (p=0.019), while there was no statistical significance between these two stages in the subgroup of patients with LNH≥12 (p=0.180).

Conclusions: Patients with stage IIA rectal cancer have poorer CSS than patients with stage IIIA rectal cancer, particularly when inadequate lymph nodes are harvested.

Keywords: rectal cancer, survival, stage IIA, stage IIIA, lymph node retrieval