Cancer-specific mortality differs significantly according to RCC subtype

By John Murphy, MDLinx
Published October 17, 2017

Key Takeaways

In patients undergoing nephrectomy for renal cell carcinoma (RCC), cancer-specific mortality rates can vary significantly by histologic type and subtype, according to a study from European researchers published in PLOS One

The researchers showed that patients with non-metastatic papillary RCC (pRCC) had a 24% reduced risk of cancer-specific death compared to patients with clear cell RCC (ccRCC). Also, pRCC type 1 patients had a 69% reduced risk of death compared to ccRCC patients, while pRCC type 2 patients showed no differences in cancer-specific mortality compared with ccRCC patients.

Given these findings, “There is urgent need to consider histopathological entities and their subtypes when assigning follow-up or targeted therapy for RCC patients,” wrote Nina Wagener, MD, of Mannheim Medical Center, Mannheim, Germany, and Sabine D. Brookman-May, MD, of Ludwig-Maximilians-University, Munich, Germany, and colleagues.

They noted that this was the largest international, multi-institutional study of non-metastatic and metastatic pRCC, pRCC type 1 and 2, and ccRCC with a long median follow-up. It involved clinical and pathologic data from 7,543 European and North American patients (mean age: 61.8 years) who underwent radical or partial nephrectomy for RCC, including 1,943 patients with pRCC and 5,600 patients with ccRCC. Median follow-up was 64.6 months.

After analyzing the data, the researchers showed that 5-year cumulative incidence rates for dying of non-metastatic cancer were 6.4% for pRCC versus 9.5% for ccRCC. And rates were 2.9% for pRCC type 1 versus 8.0% for pRCC type 2.

In metastatic disease, 5-year cumulative incidence rates were 64.9% for pRCC versus 73.9% for ccRCC. Differences were even more apparent between pRCC subgroups, with 5-year cumulative incidence rates of 20.9% for pRCC type 1 versus 68.0% for pRCC type 2.

“Our results are in line with the traditional hypothesis that pRCC is associated with a favorable prognosis compared to ccRCC,” the researchers wrote.

These results are not just of academic interest, they noted: “[O]utcome of pRCC versus ccRCC matters in daily clinical practice.”

For instance, patients with non-metastatic pRCC type 1 may require less follow-up compared to patients with ccRCC or pRCC type 2. And, a patient with a metastatic pRCC type 2 has a nearly equal risk of dying from this disease as one with a metastatic ccRCC.

“Consequently, this patient needs a therapy with equal efficacy as for ccRCC,” wrote Drs. Wagener, Brookman-May and colleagues. “On the other hand, a patient with a pRCC type 1 might need active surveillance with delayed systemic therapy.”

These recommendations exemplify the need for clinicians to consider the differences in histopathologic entities and their subtypes when selecting follow-up or targeted therapy for RCC patients, these researchers concluded.

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