Obesity is an adverse factor on laparoscopic radical nephrectomy for t2 but not t1 renal cell carcinoma

The impact of body mass index on oncological and surgical outcomes of patients undergoing nephrectomy: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis to evaluate the impact of body mass index (BMI) on oncological (primary) and surgical (secondary) outcomes of patients who underwent nephrectomy, as obesity or high BMI is a known risk factor for renal cell carcinoma (RCC) and predictor of poorer outcomes.

METHODS

Studies were identified from four electronic databases from database inception to 2 June 2021, according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement. The review protocol was registered in the International Prospective Register of Systematic Reviews with the identification number: CRD42021275124.

RESULTS

A total of 18 studies containing 13 865 patients were identified for the final meta-analysis. Regarding oncological outcomes, higher BMI predicted higher overall survival (BMI >25 vs BMI <25 kg/m2 : hazard ratio [HR] 0.70, 95% confidence interval [CI] 0.58-0.85), cancer-specific survival (BMI >25 vs BMI <25 kg/m2 : HR 0.60, 95% CI 0.50-0.73; BMI 25-30 vs BMI <25 kg/m2 : HR 0.46, 95% CI 0.23-0.95; BMI >30 vs BMI <25 kg/m2 : HR 0.50, 95% CI 0.36-0.69), and recurrence-free survival rates (BMI >25 vs BMI <25 kg/m2 : HR 0.72, 95% CI 0.63-0.82; BMI 25-30 vs BMI <25 kg/m2 : HR 0.59, 95% CI 0.42-0.82). Those with a lower BMI fared better in surgical outcomes, such as operation time and warm ischaemic time, although the absolute difference was minimal and unlikely to be clinically significant. There was no difference between groups for length of hospital stay, intraoperative or postoperative complications, blood transfusion requirements, and conversion to open surgery.

CONCLUSION

Our study suggests that a higher BMI is associated with improved long-term oncological survival and similar perioperative outcomes as a lower BMI. More research into the underlying biological and physiological mechanisms will enable better understanding of the effect of BMI, beyond mere association, on post-nephrectomy outcomes.

Impact of perinephric fat volume and the Mayo Adhesive Probability score on time to clamping in robot-assisted partial nephrectomy

The aim of this study is to evaluate the association of perinephric fat volume (PNFV) and the Mayo Adhesive Probability (MAP) score with time to clamping (TTC) in robot-assisted partial nephrectomy (RAPN). The study subjects consisted of 73 tumors in 72 patients who underwent transperitoneal RAPN at a single cancer center between February 2020 and July 2022. Clinical characteristics including R.E.N.A.L. nephrometry score, MAP score and PNFV were evaluated in a multivariate analysis in relation to TTC, which was classified into two groups based on median TTC. PNFV and MAP score were analyzed separately. PNFVs were measured by SYNAPSE VINCENT^® by a single expert urologist. Median TTC was 67 (range: 36-119) min. Spearman's rank correlation analysis indicated that a significant correlation was observed between PNFV and MAP score with a value of 0.81 (p < 0.0001). Univariate analysis revealed that R.E.N.A.L. nephrometry score ≥ 7 (p = 0.036), posterior tumor location (p = 0.033), MAP score ≥ 3 (p = 0.02) and PNFV ≥ 250 ml (p = 0.02) were significant factors for prolonged TTC. In a multivariate analysis including PNFV (analysis 1), R.E.N.A.L. nephrometry score ≥ 7 (OR 3.54, p = 0.018) and PNFV ≥ 250cm³ (OR 3.94, p = 0.010) were independent factors for prolonged TTC. Similarly for MAP score (analysis 2), R.E.N.A.L. nephrometry score ≥ 7 (OR 3.54, p = 0.018) and MAP score ≥ 3 (OR 3.94, p = 0.010) were independent factors for prolonged TTC. Both MAP score and PNFV may have a significant impact on TTC.

Preoperative factors affecting the operative outcomes of laparoscopic nephrectomy

OBJECTIVES

Laparoscopic radical nephrectomy is the standard surgery for localized renal cell carcinoma. Both tumor and patient factors affect the difficulty of laparoscopic radical nephrectomy. Obesity is a major factor influencing technical difficulty in surgical procedures. This study examined preoperative tumor and patient factors affecting the operating time.

METHODS

The data of 123 patients who underwent laparoscopic radical nephrectomy at our institution between January 2014 and December 2018 were retrospectively analyzed. The operating time was determined based on the median pneumoperitoneum time. Surgical procedures with a pneumoperitoneum time of ≥130 min were defined as having prolonged pneumoperitoneum time. Multiple logistic regression analyses were performed to identify the preoperative factors affecting the prolonged pneumoperitoneum time, and risk stratification was performed based on these factors.

RESULTS

Multiple logistic regression analyses revealed that a total number of renal pedicle blood vessels ≥3 and a visceral fat volume ≥3000 cm³ were associated with prolonged pneumoperitoneum time of laparoscopic radical nephrectomy. Based on the multivariate analysis results, these factors were considered individually, and the cohort was stratified into three risk groups: low (0 point), intermediate (1 point), and high (2 points) risk groups. The pneumoperitoneum time was significantly prolonged as the number of risk factors increased.

CONCLUSIONS

We developed a risk stratification model using preoperative factors to predict the prolonged pneumoperitoneum time of laparoscopic radical nephrectomy, which can help select suitable cases that are appropriate for each surgeon's skill level.