CHICAGO—Patients with left-sided renal cell carcinoma (RCC) tumors are more likely to present with higher-stage disease and in general have worse cancer-specific survival (CSS) compared with patients who have right-sided RCC tumors, according to new study data presented at the 2019 American Urological Association annual meeting.

Investigators hypothesize that differences between left and right kidneys with respect to anatomic position, arterial blood supply, and venous and lymphatic drainage could explain the differences in outcomes between patients with left- and right-sided RCC, lead investigator Annemarie Uhlig, MD, of University Medical Center Goettingen in Goettingen, Germany, told Renal & Urology News.

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The study included 17,709 surgically treated adult patients with RCC in the Surveillance, Epidemiology and End Results (SEER) database and 41,967 in the German Centre for Cancer Registry Data (ZfKD) database. In the SEER and ZfKD datasets, left-sided tumors were significantly associated with a 19% and 15% increased risk of cancer-specific mortality, respectively, compared with right-sided tumors, after adjusting for multiple confounders, including sex, age at diagnosis, TNM status, and cancer grade, the investigators reported in a poster presentation.

Patients with left-sided RCC had higher T status and more often presented with node positive or metastatic disease.

In the SEER dataset, site-specific CSS differences were driven by whether lymphadenectomy (LAD) had been performed. Among patients who underwent LAD, investigators found no significant difference in laterality with regard to CSS, but in the absence of LAD, patients with left-side tumors had a significant 18% decreased CSS.

“Although the overall survival difference was only marginal, left-sided RCC in surgically treated patients tends to present at more advanced stage and has in general worse CSS, especially in patients without LAD,” the authors concluded. “Site-specific lymphogenic spread patterns might contribute to these findings.”

Dr Uhlig cautioned that “some of the effect we report can be due to residual confounding because you can never adjust for all the potential confounders.” The next research step would be pathologic examination of lymph nodes taken out at the time of surgery or to use computed tomography to try to discriminate positive from negative lymph nodes in patients with left-sided and right-sided tumors, she said.

If future studies confirm site-specific differences in outcomes, LAD protocols might be altered so surgeons may preferentially perform lymphadenectomies in patients with left-sided RCC, Dr Uhlig said.

Reference

Strauss A, Uhlig J, Lotz J, et al. Impaired survival among renal cell cancer patients with left sided tumor. Presented at the 2019 American Urological Association annual meeting held May 3-6 in Chicago. Abstract MP19-18.

This article originally appeared on Renal and Urology News