Patterns of Disease Progression in Metastatic Renal Cell Carcinoma Patients Treated With Antivascular Agents and Interferon Impact of Therapy on Recurrence Patterns and Outcome Measures

BACKGROUND: The standard of care for patients with advanced renal cell carcinoma (RCC) has changed to favor targeted therapy over immunotherapy. Differences in patterns of progression between patients treated with these 2 modalities, and the impact of disease stabilization on outcome, were investigated. METHODS: Patients who progressed on first line antivascular therapy (AVT) or interferon were identified, and their medical records reviewed. RESULTS: A total of 162 patients met inclusion criteria for this analysis. Patients in the AVT group had better baseline performance status, fewer liver metastases, and more responses (CR + PR) compared with the interferon group. Both groups were equally likely to develop distant metastases; however, for patients in the AVT group, these new metastases were more likely to arise in the setting of controlled disease at baseline sites (18% vs 4%, P = .012). There was no difference in anatomic sites of progression between the 2 groups. Patients responding (CR + PR) to AVT trended toward longer progression-free survival (PFS) compared with patients with stable disease (SD) (P = .06). No difference between responders and SD was seen in the interferon group. CONCLUSIONS: Patients with RCC treated with antivascular therapy were more likely to progress at new sites in the setting of stable disease at baseline sites, suggesting that AVT may be more effective at controlling existing sites of disease than it is at preventing new metastases. Patients with SD on AVT had shorter PFS compared with responders (CR + PR). Whether this relationship extends to overall survival requires further study. Cancer 2009;115:1859-66. (C) 2009 American Cancer Society.