Clinicopathological characteristics of rectal carcinoids.

Purposes: Carcinoids are heterogeneous neuroendocrine tumors with malignant potential. The rectum is the third most common location for gastrointestinal carcinoids. We assessed the clinicopathological characteristics of rectal carcinoids.

Methods: A retrospective study of 203 patients treated for rectal carcinoids at the Asan Medical Center, Seoul, Republic of Korea from 1991 to 2007.

Results: The patients were on average 51 (18-83) years old. The male-to-female ratio was 1.48:1. Over half (62.1%) of the patients were asymptomatic. The most frequent symptoms in the symptomatic patients were abdominal pain (11.1%) and hematochezia (10.7%). Local excision was applied to 92.1%, low anterior resection to 4.9%, and biopsy only to 3.0% of total patients. Initially, 4.4% presented with distant metastasis. Distant metastasis rates for tumors < or =1 cm, >1 to < or =2 cm, and >2 cm were 1.7% (3/177), 15.0% (3/20), and 50.0% (3/6), respectively. In the follow-up period, three patients showed recurrences. The size, lymphovascular invasion, perineural invasion, and T and N stages were associated with distant metastasis. The overall 5-year survival rate was 94.0%. The TNM stage and presence of lymphovascular invasion were associated with lower survival.

Conclusions: The chance that a rectal carcinoid will develop distant metastases increases as the tumor increases in size, lymphovascular invasion or perineural invasion is present, and T and N stages increase. The TNM stage and presence of lymphovascular invasion were associated with lower survival. Treatment plan should be chosen carefully considering above factors.