Clinicopathological characteristics of rectal carcinoids

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. A retrospective study of 203 patients treated for rectal carcinoids at the Asan Medical Center, Seoul, Republic of Korea from 1991 to 2007. 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 a parts per thousand currency sign1 cm, > 1 to a parts per thousand currency sign2 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. 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.