Credit improvements in therapy rather than diagnosis at an earlier stage for improved survival of renal cell carcinoma in recent years, investigators say.
A review of records on nearly 263,000 patients diagnosed with renal cell carcinoma (RCC ) from 2004 through 2015 showed that better 5-year overall survival (OS) in later years was likely attributable to better treatments rather than an uptick in detection of cancers at an earlier stage, a trend known as “stage migration,” reported Hiten D. Patel, MD, of the Brady Urological Institute at Johns Hopkins Medicine in Baltimore, and his colleagues.
“While survival has improved over time when considering all RCC patients, the primary benefit was observed in advanced RCC (stage III–IV), with 5-year survival increasing from 9.8% in 2004 to 13.2% in 2010 for patients with distant metastatic disease. The results indicate that stage migration no longer contributes to improvements in survival for RCC, and additional gains reflect improvements in advanced treatment options,” they wrote in European Urology Oncology.
Dr. Patel and colleagues noted that the incidence of RCC has been on the rise worldwide for nearly 3 decades because of both environmental risk factors and improvements in medical imaging that have resulted in an increase in incidental cancers.
“Data from the National Cancer Database (NCDB) indicated an increase in the proportion of patients presenting with cT1 RCC from 40% before 1993 to 60% through 2004. However, it is unknown if clinical stage migration has continued into recent years, which has implications for patient outcomes,” they wrote.
To try to answer this question, they sifted through data on 262,597 patients diagnosed with RCC from 2004 through 2015 at more than 1,500 facilities covered by the U.S. National Cancer Database.
They found that, up to 2007, there were statistically significant trends toward more frequent diagnosis of clinical stage I disease (70% of cases) and less frequent diagnoses of stage III (8%) and stage IV (11%; P less than .001 for all comparisons). From 2008 through 2015, however, the respective rates stabilized.
They also noticed a trend throughout the study period for decreased size of localized tumors at diagnosis, with a mean decrease of 0.22 cm for stage I lesions, and 1.24 cm for stage II tumors.
When they looked at 5-year overall survival by Kaplan-Meier analysis, they saw that it improved from 67.9% in 2004 to 72.3% in 2010. As noted before, most of the benefit was attributable to gains in survival among patients with stage III or IV disease.
In multivariable Cox proportional hazard models, diagnosis in recent years was a statistically significant predictor of improved survival, even after adjustment for stage distribution. In addition, receipt of systemic therapy was associated with improved survival, with a hazard ratio of 0.811 (P less than .001).
The authors acknowledged that a limitation of the findings is the reliance on the NCDB, which includes data on most cancer diagnoses in the United States, but is not a population-based sample.
No study funding source was reported. Dr. Patel and coauthors reported having no conflicts of interest to disclose.
SOURCE: Patel HD et al. Eur Urol Oncol. 2018 Sep 25. doi: 10.1016/j.euo.2018.08.023.