Background: The optimal timing of targeted therapy (TT) initiation for metastatic renal-cell carcinoma (mRCC) is not clear. We used a nationwide cancer registry to determine clinical and social factors associated with delayed TT and to evaluate the association of a delayed approach with overall survival (OS).
Patients and methods: We performed a retrospective observational study utilizing the National Cancer Data Base from 2006 to 2012 for patients diagnosed with mRCC (clear-cell histology) treated with cytoreductive nephrectomy and TT. Time to initiation of TT was defined as early (within 2 months), moderately delayed (2-4 months), delayed (4-6 months), and late (> 6 months).
Results: Of the 2716 patients included in the analysis, the median (interquartile range) time from diagnosis to initiation of TT was 2.1 (1.3-3.23) months. A total of 1255 patients (46.2%) had early TT, 1072 patients (39.5%) had moderately delayed TT, 284 patients (10.5%) had delayed TT, and 105 patients (3.9%) had late TT. Delay in TT initiation was not independently associated with OS in multivariable analysis. The time interval from diagnosis to TT initiation was not correlated with time from initiation of TT to death (r = 0.04, P = .08).
Conclusion: We found that delayed initiation of TT was not an independent predictor of worse OS. Although this study is subject to limitations of observation study design and selection bias, the results are consistent with the notion that in carefully selected patients, outcomes might not be compromised with initial observation.
Keywords: Kidney cancer; Surveillance; Systemic therapy; Tyrosine kinase inhibitor; Watchful waiting.
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