The influence of body mass index on the cost of radical prostatectomy for prostate cancer.

Objective: to evaluate the impact of obesity on the costs of robotic-assisted (RALP), laparoscopic (LRP) and open retropubic radical prostatectomy (RRP).

Patients And Methods: the charts of 629 patients who underwent RP (262 RALP, 211 LRP and 156 RRP) between September 2003 and April 2008 at our institution were reviewed. Clinical and pathological data were collected, including age, American Society of Anesthesiologists score, body mass index (BMI), tumour stage, complications and length of stay. Direct and component costs (anaesthesia, laboratory, operating room service, radiology, room and board, pharmacy and surgical supplies) were obtained. Differences in costs were evaluated using three BMI categories (<25, normal weight; 25-<30, overweight; and ≥30 kg/m(2) , obese).

Results: of 629 patients, 136 (21.6%) had normal weight, 320 (50.9%) were overweight, and 173 (27.5%) were obese. Clinical and pathological characteristics were similar in the three BMI categories of the entire cohort. The median direct cost was higher for obese patients (P= 0.035). On further stratification by type of RP, costs were higher amongst obese than the other groups undergoing LRP (median US$5703 vs $5347; P= 0.002) and RRP (median $4885 vs $4377; P= 0.004). In patients who underwent RALP there were no significant differences in direct costs (median $6761 in obese vs $6745 in non-obese; P= 0.64).

Conclusion: obesity influenced the costs in patients who underwent LRP and RRP, mainly due to increased operating room service and anaesthesia costs in obese patients. RALP can be performed with no additional financial burden in obese patients.