DFS after first nephrectomy predicts OS in localized renal cell carcinoma
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Post-nephrectomy recurrence appeared associated with shorter survival among patients with intermediate-high or high-risk renal cell carcinoma, according to study results presented at International Kidney Cancer Symposium.
“To the best of our knowledge, [this] study is the first to assess the association between DFS and OS among patients with intermediate-high risk and high-risk renal cell carcinoma [after] nephrectomy using real-world patient-level data,” Naomi B. Haas, MD, professor of medicine at Hospital of University of Pennsylvania, and colleagues wrote.
“Patients ... with recurrence [after] nephrectomy had an approximately three times increased adjusted risk [for] death compared with those without recurrence [after] nephrectomy following each landmark point,” researchers added. “Additionally, DFS and OS [after] nephrectomy were found to be significantly and positively correlated.”
Haas and colleagues used the SEER-Medicare database from 2007-2016 to conduct a retrospective observational study that assessed the association between DFS and OS among patients aged 65 years or older with newly diagnosed, completely resected renal cell carcinoma after first nephrectomy. All patients had intermediate-high (pT2N0Grade4/pT3N0) or high-risk (pT4N0/pTanyN1) disease.
The analysis included 643 patients (mean age, 75 years) who met inclusion criteria.
Researchers grouped patients into two cohorts based on whether they developed recurrence after initial nephrectomy (yes, n = 269; no, n = 374). Most patients were men (recurrence cohort, 64.7%; no-recurrence cohort, 57.8%) and 85% of patients in each cohort were white.
Investigators defined recurrence as first additional nephrectomy, first diagnosis of metastatic disease or initiation of systemic treatment for advanced renal cell carcinoma.
Investigators calculated OS from the index date, as well as from three landmark points — 1 year, 3 years and 5 years — after initial nephrectomy.
Mean follow-up was 25 months for the recurrence cohort and 35.2 months for the no-recurrence cohort.
In the overall study population, investigators reported median DFS of 4.44 years and median OS of 8.61 years. Patients who experienced disease recurrence achieved significantly shorter median OS than those whose disease did not recur (2.5 years vs. not reached; adjusted HR = 6; 95% CI, 4.2-8.5).
Those who developed recurrence by each landmark point achieved shorter subsequent OS than those who did not develop recurrence (1 year after initial nephrectomy, 2.4 years vs. 9.7 years; 3 years after, 4.5 years vs. not reached; 5 years after, 5.7 years vs. not reached; P < .001 for all).
A higher percentage of patients who did not develop recurrence achieved 5-year survival after each of the corresponding landmark points (1 year after initial nephrectomy, 70.1% vs. 37%; 3 years after, 72.8% vs. 42.3%; 5 years after, 78.6% vs. 53.2%).
Patients who developed recurrence by all three landmark points after initial nephrectomy had increased risk for death compared with those who did not develop recurrence (1 year after, adjusted HR = 3.5; 3 years after, adjusted HR = 3; 5 years after, adjusted HR = 2.7; P < .001 for all).
Kendall’s tau rank correlation model revealed a statistically significant correlation between DFS and OS (tau =0.7; 95% CI, 0.65-0.74).
Patients who developed recurrence after nephrectomy also incurred significantly higher mean monthly health care costs, paying an additional $4,924 per month in all-cause medical costs and $1,387 more in pharmacy costs than those who did not develop recurrence (P < .001).
Researchers acknowledged study limitations, including use of SEER-Medicare data — which may not reflect outcomes in a younger patient population — and the fact they inferred recurrence from database codes rather than using clinical data to make direct determinations.
“These findings demonstrate that in SEER, longer DFS is prognostic of longer OS among patients with renal cell carcinoma following initial nephrectomy,” Haas and colleagues concluded. “[The results] suggest that DFS can be useful as a predictor of OS in the renal cell carcinoma adjuvant setting when OS data are immature.”
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Haas NB, et al. Abstract E38. Presented at: International Kidney Cancer Symposium; Nov. 5-6, 2021; Austin, Texas.
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