Partial nephrectomy reduces mortality not related to renal cancer?
Matched pair analysis comparison with radical nephrectomy.
Scopo del lavoro
To evaluate survival not related to renal cell carcinoma in patients undergoing partial
nephrectomy (PN), compared to those who underwent radical nephrectomy (RN).
Materiali e metodi
Retrospective evaluation of an institutional database that stores the data of more than
2200 patients undergone surgery for kidney cancer.
For the present study, the records of patients metastatic at diagnosis or with follow up
judged as insufficient (<24 months) have been exluded. Thus, 1478 patients have been
enrolled, 491underwent PN, 987 RN.
It was then generated a propensity score for the variable "intervention" (PN vs RN) that
combined the following factors: sex, age, presence of diabetes, presence of
cardiovascular disease, Charlson score, histology (benign vs malignant), TNM stage,
grading . It has been made a 1:1 matching between patients undergoing respectively PN
and RN with the closer propensity score. The non-cancer-related survival has been
analised.
Risultati
2 groups were generated, each of 389 patients who underwent PN and RN, homogeneous
with the desired characteristics (see table pts: patients).
There were 37 (9.5%) and 39 (10.0%) deaths due to causes not related to renal cell
carcinoma in patients receiving respectively PN and RN (p = 0.904), with a latency of 6.2
vs 6.8 years after surgery (p = 0.585). Survival free of death from causes unrelated to
renal carcinoma at 5 years was comparable (94.7% RN vs 94.2% PN, p = 0.414), as well
as that related to renal cell carcinoma (98.0% PN vs 96.1% RN, p = 0.075 ). The factors
that showed a significant correlation with mortality from causes unrelated to renal
carcinoma were male sex (HR 2.100 [95% CI 1184-3723], p = 0.011), age (continuous
variable, HR 1.056 [1031-1082 ], p <0.001), Charlson score> = 2 (HR 2.637 [1633-4259], p
<0.001), but not the type of surgery (RN vs PN, HR 1.060 [0860-1702], p = 0.809).
Discussione
The evidence that PN may exert a protective effect on mortality not-related to renal cell
carcinoma arises from USA population studies, which suffer from some well known biases
related to lacking of data in cancer registries, or from studies on surgical series, which
often compare groups very heterogeneous due to the selection biases relted to the
selection of the cases to be submitted to PN rather than RN.
The present study, aims at balancing several factors associated with non-cancer-related
mortality, but also others associated with cancer-related mortality to reduce the influence
that these factors may exert on the analysis.
The data in the present study cannot confirm a survival advantage in patients receiving
PN.
Conclusioni
The non-cancer-related mortality in patients with renal cell carcinoma seems to be
influenced more by gender, age and comorbidities of the patient, than from the kind of
operation.