Elevated visceral obesity quantified by CT is associated with adverse postoperative outcome of laparoscopic radical nephrectomy for renal clear cell carcinoma patients

Abstract

Purpose: To examine the association between CT measures of visceral obesity and short-term postoperative outcomes in renal clear cell carcinoma (RCCC) patients.

Methods: In this retrospective study, 76 patients treated with unilateral laparoscopic radical nephrectomy for stage I-III renal cancer were classified as obese or non-obese by preoperative CT-based measures of adiposity [obese: visceral fat area (VFA) > 100 cm², BMI ≥ 28 kg/m²]. Clinical variables, Fuhrman grade, operation time, estimated blood loss (EBL), postoperative complications, postoperative stay, drainage time and hospitalization expenses were compared between the two groups.

Results: Viscerally obese patients significantly had higher Fuhrman grade than the non-obese (p = 0.018). The operation time of obese patients by VFA or BMI was more than the non-obese (171.6 ± 68.9 vs. 140.8 ± 35.5 min, p = 0.012 and 197.2 ± 67.2 vs. 153.2 ± 57.7 min, p = 0.013, respectively). And obese patients by VFA or BMI tended to have more EBL than non-obese (132.0 ± 120.7 vs. 83.8 ± 53.4 ml, p = 0.018 and 215.3 ± 165.0 vs. 92.5 ± 68.8 ml, p = 0.013, respectively). Viscerally obese patients by VFA (not BMI) were more likely to develop postoperative complications as compared to patients classified as non-obese: VFA (26.9 vs. 4.2%, p = 0.045) and BMI (33.3 vs. 16.4%, p =0.265). Furthermore, obese patients by VFA (not BMI) were more likely to have longer postoperative stay: VFA (8.7 ± 2.5 vs. 7.5 ± 1.4 dollars, p = 0.013) and BMI (9.1 ± 2.9 vs. 8.1 ± 2.1 dollars, p = 0.209). Obese patients expensed more than non-obese: VFA (7570.9 ± 2674.3 vs. 6368.8 ± 1289.8 dollars, p = 0.040) and BMI (8390.8 ± 2929.7 vs. 6896.3 ± 2159.1 dollars, p = 0.029).

Conclusions: Elevated visceral obesity by VFA is associated with increased surgical complexity, postoperative morbidity, postoperative stay and hospitalization expenses for RCCC patients and may be superior to BMI for renal cancer outcome assessment. VFA may be a useful index for the evaluation and calculation of RCCC aggressiveness.

Keywords: Computed tomography; Postoperative outcome; Renal clear cell carcinoma; Surgical complications; Visceral obesity.