Renal cell carcinoma following bariatric surgery.

Background: Obesity, hypertension, smoking, and amphetamine diet pills increase the risk for renal cell carcinoma (RCC). Obesity causes a four-fold increase. We report our 11-year experience with RCC after bariatric operations.

Methods: 5 patients with RCC were identified out of 2,287 bariatric surgical patients since 1993 on retrospective chart review.

Results: 4 of the 5 patients were females. At time of their bariatric operation, patients were age 29-52 (43.4) years, weighed 109-158 (129.8) kg, and BMI was 43-60 (49.4). All tumors were incidentally discovered 8-66 (27.4) months postoperatively when the patients weighed 54-94 (71.4) kg, with BMI 21-34 (26.6). Preoperative renal ultrasound obtained within 3 months of the bariatric operation was normal in 4; the other did not have a preoperative study. The latter patient had a vertical banded gastroplasty 12 years before and the RCC was discovered 5 1/2 years later during work-up for a revision. 3 had a distal gastric bypass and 1 underwent adjustable gastric banding. 4 of the patients had a radical nephrectomy and 1 underwent a partial nephrectomy. Tumors were 2.0-8.7 (4.4) cm in size, and all were clear-cell RCC without vascular or extrarenal involvement. None has had recurrence at 3-67 (30.8) months follow-up. 1 patient died from a stroke 18 months later.

Conclusion: Reversal of obesity following bariatric surgery does not eliminate risk for RCC. Preoperative and annual postoperative ultrasonography may be useful in identifying early stage RCC. Lesions that are not pure cysts must be evaluated with CT scans or MRI. Nephrectomy may be curative.