Surveillance safe for some mRCC patients

The largest analysis of active surveillance for metastatic renal cell carcinoma (RCC) presented to date shows that a proportion of patients can be safely observed without need to start systemic therapy right away.

The median time on active surveillance exceeded 14 months for patients starting systemic therapy at least 6 months after diagnosis in the study, based on patients with metastatic RCC in the Canadian Kidney Cancer information system (CKCis).

Overall survival was significantly longer in the 863-patient active surveillance cohort as compared to a group of 848 patients receiving immediate treatment, according to investigator Igal Kushnir, MD, a medical oncology fellow at Ottawa Hospital Cancer Centre in Ottawa, ON. The study was presented at the American Society of Clinical Oncology annual meeting in Chicago.

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According to Dr. Kushnir, these new findings corroborate and strengthen the conclusions of a Lancet Oncology study (2016; 17:1317-24) and a presentation from the 2018 ASCO annual meeting that suggested the benefit and safety of selective active surveillance in smaller cohorts.

Surveillance now ‘supported with robust evidence’

“It’s something that is easier to endorse, because now it’s supported with robust evidence, and we can reassure the patient that it’s safe,” Dr. Kushnir said in an interview with Urology Times.

When exactly to utilize active surveillance still relies on the “art of oncology,” said Dr. Kushnir, who noted he and co-authors looked further and couldn’t find an obvious clinical marker-such as histology, International Metastatic RCC Database Consortium (IMDC) risk criteria, or metastatic burden-that predicted the benefit of the approach in the CKCis cohort.

Continue to the next page for more.Nevertheless, patients can probably be selected for active surveillance based on the rate of disease change seen in early serial imaging, according to Dr. Kushnir.

“Our guess is that if you have a patient that has no symptomatic disease, no pending visceral crisis, and the overall burden of disease is not high, it’s probably safe to defer treatment to at least the next serial imaging. If the growth kinetics on the next imaging are quite low, then probably this patient can be assigned to active surveillance,” said Dr. Kushnir, who worked on the study with M. Neil Reaume, MD, and co-authors.

To assess the outcomes and safety of active surveillance versus immediate systemic treatment, Dr. Kushnir and colleagues identified patients in the CKCis database diagnosed with metastatic RCC between 2011 and 2016.

They classified active surveillance as either starting systemic treatment at least 6 months after a diagnosis of metastatic RCC, which included 370 patients, or never starting systemic therapy at all, provided overall survival was greater than 1 year (to exclude patients likely not receiving treatment due to poor prognosis), which included 493 patients.

Among the 370 patients who did start systemic treatment 6 or more months after the active surveillance period, the median time on active surveillance was 14.2 months, with a range of 6 to 71 months, Dr. Kushnir reported.

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The 5-year probability of overall survival was 70.2% for the active surveillance cohort versus 32.1% for the immediate treatment group (p<.0001). After adjusting for age and IMDC risk criteria, both overall survival and time to treatment failure were significantly greater in the active surveillance patients who later started systemic treatment, as compared to those who had immediate treatment, according to his report.

Taken together, these findings suggest a significant number of patients can be safely observed for a long period of time, sparing both medical and financial toxicities associated with systemic therapy for a median of more than a year, Dr. Kushnir said.

“After a median follow-up of 41 months, still 57% of patients on active surveillance never received systemic therapy, which is quite significant,” he added.

Dr. Kushnir has stock or other ownership interests with Teva Pharmaceutical Industries Ltd. Several of his co-authors also reported disclosures; for a full list, go to bit.ly/CKCisdisclosures.