The Surgical Treatment of Renal Cell Carcinoma

Nationwide Trends, 2012–2021

Renal cell carcinoma (RCC) is one of the 15 most common forms of cancer in Germany in terms of incidence and mortality (1). Since RCCs are not sufficiently sensitive to either chemotherapy or radiotherapy and around 60% are diagnosed at an early stage, surgical resection is considered the mainstay of treatment. Over the last two decades, two essential changes with oncologically equivalent outcomes have emerged, which are reflected in the guidelines: the trends towards nephron-sparing and minimally invasive surgery. Partial nephrectomy (PN) has become the gold standard for T1 tumors, given that preserving as much functional renal parenchyma as possible is of great importance for the risk of chronic kidney failure and cardiovascular events. Moreover, laparoscopic and robot-assisted surgery appear to reduce morbidity (2). The aim of this investigation was to map the trend in case numbers and complication rates in Germany over a 10-year period from 2012–2021 on the basis of large patient numbers with treatment-related data from the German statutory health insurance (SHI) and to assess whether there have been corresponding shifts in surgical numbers.

Methods

Using nationwide pseudonymized inpatient billing data and master data from individuals insured with the German statutory health insurance provider AOK (Allgemeine Ortskrankenkassen), we identified RCC cases with radical nephrectomy (RN) or PN in patients aged over 18 years from 2012 to 2021 (exclusion criteria: surgery with cardiopulmonary bypass, malignant neoplasm of the renal pelvis/ureter, renal and ureteral calculi, previous kidney transplantation). Comorbidities were recorded using the definitions of the Elixhauser Comorbidity Score. All cases were grouped according to open, laparoscopic, and robot-assisted (da Vinci) surgery. Endpoints included mortality (in-hospital or within 90 days), transfusions (30 days), reinterventions (30 days), and general complications (30 days). For the descriptive analysis, percentages and medians with interquartile range (IQR) were used. Trends over time were examined with Cuzick’s test. For the risk-adjusted comparison of PN and RN, logistic regression models (generalized estimating equations with logit link, exchangeable correlation structure, and robust standard errors) were used, and surgical technique, age, sex, and comorbidity were taken into consideration. All analyses were performed using STATA (Version 18.0).

Results

A total of 43 936 AOK cases from 543 hospitals were included (PN: 22 030, 36.4% females, median age: 66 (IQR: [57–74]); RN: 21 906, 39.6%, 69 [60–77]). The exclusion criteria applied to 1484 cases. Between 2012 and 2021, the annual case number fell by 15.5% from 4684 to 3960. At the same time, the percentage of PN rose from 41.0% to 57.4% (p [trend] < 0.001). Open surgical procedures went down from 85.6% to 53.9% (PN) and from 78.5% to 65.0% (RN), respectively. In the case of PN, this was in favor of robot-assisted surgery (2021: 36.9%), whereas for RN, the percentage only increased to 12.7% in the final years considered here and still lagged behind classical laparoscopic surgery (2021: 22.4%) (Table 1). RN cases had comorbidities more frequently compared to PN cases: for example, metastases (15.1% versus 2.1%), other tumors (18.8% versus 6.5%), and kidney failure (19.6% versus 14.0%).

Table 1

Case numbers and percentages according to surgical technique over time

PN patients showed lower mortality and transfusion rates, but more reinterventions (total complications: 26.4% [PN] versus 32.7% [RN]). Following risk adjustment for surgical technique, age, sex, and comorbidity, there was no significant difference in the total rate of complications (Table 2).

Table 2

Endpoints

Discussion

This study is the first to show the trend in oncological kidney surgery in Germany based on a large patient population from hospitals providing all levels of care, and reveals shifts in favor of nephron-sparing and minimally invasive surgery in the period from 2012 to 2021. The decline in the total number of surgeries may well be associated with the decline in age-standardized disease rates since 2010 (1), a more critical approach to establishing the indication for cytoreductive nephrectomy, as well as an increase in active surveillance and local ablative therapies for small tumors (2). The analysis is limited to AOK insurees, who account for around a third of the German population. While there are differences to the total population in terms of age and sex distribution and comorbidity (3), these can be controlled for through risk-adjustment. A limiting factor is, in particular, the lack of TNM stage and tumor characteristics such as location and size in the SHI billing data, meaning that these data do not permit a fully risk-adjusted comparison, and different complication rates may reflect, in part, the complexity of individual cases rather than the limitations of a surgical technique. German cancer registry data show that the stages at initial diagnosis shifted only slightly upwards during the study period (stage T1 + T2: 2011/12: 74% [males] and 77% [females], 2019/20: 67% and 68%, respectively), and two thirds continue to be diagnosed at the localized stage. Therefore, there is a critical discussion to be had regarding the fact that open surgery remained the predominant approach for RN and PN in 2021, given that the guideline recommendations of the European Association of Urology (EAU) had already defined laparoscopic RN back in 2010 as the treatment standard for patients with not partially resectable ≤ T2 tumors (2). In comparison, registry data in the United Kingdom show a percentage of minimally invasive oncological renal procedures in 2017 of 80.9% (4), and US registry data a percentage in 2019 of 78.4% (5). One can expect the numbers for partial nephrectomy and minimally invasive surgery to increase further in the future. In order to investigate whether these trends improve quality of care, studies with data linked to surgical technique, complications, and oncological parameters from a variety of sources are needed.

Jens-Uwe Stolzenburg*, Clara Steiner*, Claus Fahlenbrach, Christian Gilfrich, Christian Gratzke, Christian Günster, Elke Jeschke, Gralf Popken, Jan Roigas, Hanna Leicht

Conflict of interest statement
The authors declare that no conflict of interests exists.

Manuscript submitted on 29 July 2024, revised version accepted on 29 October 2024.

Translated from the original German by Christine Rye.

Cite this as
Stolzenburg JU, Steiner C, Fahlenbrach C, Gilfrich C, Gratzke C, Günster C, Jeschke E, Popken G, Roigas J, Leicht H: The surgical treatment of renal cell carcinoma—nationwide trends, 2012–2021. Dtsch Arztebl Int 2025; 122: 109–10. DOI: 10.3238/arztebl.m2024.0234

References

1. Robert Koch Institut: Krebs in Deutschland. www.krebsdaten.de/Krebs/DE/Content/Publikationen/Krebs_in_Deutschland/krebs_in_deutschland_ node.html (last accessed on 15 October 2024).

2. EAU Guidelines Office, Arnhem, The Netherlands: EAU Guidelines on Renal Cell Carcinoma. https://uroweb.org/guidelines (last accessed on 15 October 2024).

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