Small bowel obstruction in patients previously operated on for colorectal cancer.

OBJECTIVE

To find out the incidence, aetiology, and outcome of patients operated on for small bowel obstruction after previous operation for colorectal cancer.

DESIGN

Retrospective cohort study.

SETTING

District hospital serving a defined population, Norway.

SUBJECTS: 472 consecutive patients operated on for colorectal cancer, followed up for a median of 5.5 years (range 2.0-16.8) or until death; 351 had had a resection with curative intent, and 121 a palliative operation.

MAIN OUTCOME MEASURES: Incidence and aetiology of small bowel obstruction, postoperative mortality, and long term survival.

RESULTS

Small bowel obstruction necessitated operation in 36/351 (10%) after resection with curative intent, and in 5/121 (4%) after a palliative operation. The causes of obstruction were benign adhesions (n=21), local recurrence (n=17) and peritoneal carcinomatosis (n=3). One patient died of a myocardial infarction and six of cancer within 30 days of the operation for small bowel obstruction. The estimated median survival after the operation for small bowel benign obstruction was 1.9 years (SE=0.6) compared with 0.36 years (SE=0.04) for malignant obstruction (p=0.0007, logrank test). Late small bowel obstruction by adhesions was associated with higher blood loss during the primary operation (p=0.02). None of the 62 patients who took thiazide diuretics at the time of the primary operation later developed obstructive adhesions.

CONCLUSION

41/472 patients (9%) developed small bowel obstruction after the primary operation for colorectal cancer. The aetiology was benign in 21 and malignant in 20 patients. Survival after operation for the obstruction was far better with benign than with malignant obstruction.