PURPOSE: This study was designed to determine whether incidental splenectomy for 
iatrogenic injury affects long-term cancer-specific survival in patients having 
resection of an adenocarcinoma of the sigmoid or rectum.
METHODS: A retrospective case-matched review of patients undergoing surgery for 
colorectal cancer with incidental splenectomy between January 1, 1990 and 
December 31, 1999 was undertaken. Data were analysed for age, American Society 
of Anesthesiologists physical status, gender, disease stage, operation type, and 
outcome. These cases were matched with patients from the same center, of the 
same age and gender, with the same stage of disease and operation, who did not 
require a splenectomy at the time of their surgery.
RESULTS: Fifty-five patients were identified who had an iatrogenic splenectomy. 
Matched gender, stage, and American Society of Anesthesiologists-matched 
controls were identified. Follow-up from time of surgery to death or last 
follow-up ranged from 2 to 205 (median, 43) months. A Kaplan-Meier survival 
analysis using the Cox proportional hazards model to define the statistical 
significance found a significant difference between the groups favoring those 
without splenectomy (hazard ratio, 1.8; 95 percent confidence interval (CI), 
1-3.3; P=0.0399). Cancer-specific survival at five years was 70 vs. 47 percent 
and at ten years was 55 vs. 38 percent.
DISCUSSION: Patients with colorectal cancer who had splenectomy as a result of 
iatrogenic damage of the spleen while undergoing resection of the sigmoid or 
rectum for adenocarcinoma had a significantly worse prognosis.