Results that Stick
Despite the study limitations, Dr Msaouel said one finding he does expect to “hold true” is that the longer a patient survives with kidney cancer, the more likely he or she will survive later on. He added, “It’s good that what they found actually follows common clinical sense.”
Overall, the study authors found that for the entire SEER cohort, conditional survival leveled off as RCC patients lived longer. For instance, patients who survived 1, 2, 3, or 4 years continued to have a 91% probability of living an additional 2 years. By comparison, newly diagnosed patients have a lower 2-year survival rate of 83%.
A subgroup analysis of the SEER cohort revealed that patients with low-risk and high-risk RCC had only a modest increase in continued survival, but a considerable increase was seen for metastatic RCC patients. Specifically, the 2-year conditional survival for metastatic RCC patients who survived 1, 2, 3, 4, 5, and 6 years had a probability of 45%, 54%, 60%, 65%, 69%, and 73%, respectively. These prognoses were markedly higher than the 2-year overall survival rate of 27%, demonstrating the potentially superior prognostic accuracy of conditional survival.
“This [study] tells us sort of what we already know,” said Bradley McGregor, MD, clinical director, Lank Center for Genitourinary Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, during an interview with Cancer Therapy Advisor. “In my opinion it shows that for those patients who respond to their frontline therapy, the longer that response is, the better they’re going to do,” said Dr McGregor, who also was not involved in the study.
The utility of the absolute numbers for conditional survival, however, were called into question by experts. Citing the aforementioned limitations, Dr Msaouel said the numbers are not going to be “fully accurate.” Instead, the overall trend that survival probability increases as patients live longer could be communicated to metastatic RCC patients.
The authors of the study also found that for patients with low-risk RCC, the risk of death from noncancer-related causes was higher than death from cancer. Conversely, metastatic RCC patients were more likely to die from their cancer than other causes. By 8 years of survivorship, high-risk RCC patients had a higher risk of dying from noncancer-related causes than cancer itself, suggesting that these patients need additional surveillance beyond the traditional 5-year survival mark.
“In those with high-risk renal cell carcinoma, a lot of times our current surveillance approach goes to about 5 years,” said Dr McGregor. The findings suggest, he said, that 5 years may not be enough of a follow-up, and these patients potentially need to receive further surveillance beyond 5 years.
- Shao N, Wan F, Abudurexiti M, Wang J, Zhu Y, Ye D. Causes of death and conditional survival of renal cell carcinoma. Front Oncol. 2019;9:591.
- Hieke S, Kleber M, König C, Engelhardt M, and Schumacher M. Conditional survival: A useful concept to provide information on how prognosis evolves over time. Clin Cancer Res. 2015;21(7):1530-1536.
- Bristol-Myers Squibb. Bristol-Myers Squibb receives FDA approval for Opdivo (nivolumab), the only treatment to deliver significant overall survival in advanced renal cell carcinoma vs. a standard of care, in patients who have received prior anti-angiogenic therapy [news release]. Princeton, NJ: Bristol-Myers Squibb Company. Published November 23, 2015. Accessed August 5, 2019.