An analysis of conditional survival outcomes for patients with metastatic renal cell carcinoma (mRCC) has suggested that first-line therapy with a tyrosine kinase inhibitor (TKI) can result in improved survival odds over time.
Patients with mRCC treated with a TKI upfront had gradual increases over time in conditional overall survival estimates when compared with baseline survival predictions, a retrospective review has indicated.
Patients who survived at least 36 months after the start of therapy had an estimated 36-month conditional overall survival (OS) rate that was 7.3% higher than the predicted survival at the initiation of therapy, reported Seong Il Seo, MD, PhD, from Samsung Medical Center in Seoul, North Korea, and his colleagues.
The investigators also found that, while predictors of survival changed over time, previous metastasectomy was a key prognosticator of conditional overall survival throughout 36 months of follow-up, they reported in The Journal of Urology.
“To our knowledge, our data are the first to reveal the beneficial role of metastasectomy on conditional OS probabilities with time since an initial survival estimation, particularly in patients at intermediate and poor risk. [Conditional survival] estimates can be beneficial to counsel patients with mRCC about more practical prognoses and helpful to continuously adjust surveillance planning in these patients,” they wrote.
Conditional survival is an analytical method for providing more accurate estimates of how prognoses change over time when patients with aggressive metastatic disease, such as mRCC, are exposed to therapies such as nephrectomy or TKIs.
The investigators retrospectively reviewed records for 1,131 patients with mRCC in the Korean Renal Cancer Study Group database. They calculated conditional OS using a nomogram that indicated the likelihood that a patient would survive an additional number of years given that he or she had already survived a certain number of years. They also created a multivariate regression model to identify predictors of conditional survival over time.
They found that, at all survival times after the start of TKI therapy (6, 12, 18, 24, and 36 months), conditional overall survival gradually increased when compared with baseline survival estimates.
“While the actual overall survival rate decreased with time, the 36-month conditional overall survival rate was calculated as 7.3% higher in patients who had already survived 36 months compared to baseline estimations at the time of initial tyrosine kinase inhibitor treatment,” they wrote.
In the multivariate model, prognostic factors such as gender, pathologic T stage, and Heng risk classification became nonsignificant over time, but previous metastasectomy remained a significant independent predictor of survival after TKI therapy at all time points except for 18 months.
“This study largely corroborates previous data from the IMDC (International Metastatic Renal Cell Carcinoma Database Consortium), and it provides useful information on prognostication,” commented Adam B. Weiner, MD, of Northwestern University in Chicago, in a brief accompanying editorial.
The study was supported by a National Research Foundation of Korea research grant funded by the Ministry of Science and Information and Communications Technology and by a Korea Health Technology R&D Project grant through the Korea Health Industry Development Institute funded by the Ministry of Health and Welfare in South Korea. No conflicts of interest were reported.
SOURCE: Kang M et al. J Urol. 2018 June 22. doi: 10.1016/j.juro.2018.06.030.