PurposeCurrent systemic treatment of targeted therapies, namely the vascular endothelial growth factor-antibody (VEGF-AB), VEGF receptor tyrosine kinase inhibitor (TKI) and mammalian target of rapamycin (mTOR) inhibitors, have improved progression-free survival and replaced non-specific immunotherapy with cytokines in metastatic renal cell carcinoma (mRCC).MethodsA panel of experts convened to review currently available phase 3 data for mRCC treatment of approved agents, in addition to available EAU guideline data for a collaborative review as the plurality of substances offers different options of first-, second- and third-line treatment with potential sequencing.ResultsSunitinib and pazopanib are approved treatments in first-line therapy for patients with favorable- or intermediate-risk clear cell RCC (ccRCC). Temsirolimus has proven benefit over interferon-alfa (IFN-α) in patients with non-clear cell RCC (non-ccRCC). In the second-line treatment TKIs or mTOR inhibitors are treatment choices. Therapy options after TKI failure consist of everolimus and axitinib. Available third-line options consist of everolimus and sorafenib. Recently, nivolumab, a programmed death-1 (PD1) checkpoint inhibitor, improved overall survival benefit compared to everolimus after failure of one or two VEGFR-targeted therapies, which is likely to become the first established checkpoint inhibitor in mRCC. Data for the sequencing of agents remain limited.ConclusionsDespite the high level of evidence for first and second-line treatment in mRCC, data for third-line therapy are limited. Possible sequences include TKI-mTOR-TKI or TKI–TKI-mTOR with the upcoming checkpoint inhibitors in perspective, which might settle a new standard of care after previous TKI therapy.
Docetaxel has shown promise for the treatment of hormone-refractory prostate cancer and has become the standard of care. The flare phenomenon is a known entity in androgen-deprivation therapy of advanced prostate cancer and it has also been described in palliative chemotherapy of hormone-refractory prostate cancer. The aim of this study was to evaluate the clinical impact of a prostate-specific antigen flare phenomenon in docetaxel-treated hormone-refractory prostate cancer patients. From December 2002 to August 2005, we treated 44 patients with hormone-refractory prostate cancer applying docetaxel-based regimens. Prostate-specific antigen levels were determined before therapy and weekly thereafter. Patients were divided into three groups: response (group 1), progression (group 2) and flare (group 3). Flare was defined as initially rising prostate-specific antigen under therapy, dropping thereafter to values below baseline. The groups were compared for overall survival by Kaplan-Meier analysis. We observed a prostate-specific antigen flare phenomenon in eight (18%) of 44 evaluable patients; 24 (54.5%) patients were primary responders and 12 (27.3%) experienced progressive disease. In group 3, prostate-specific antigen levels rose to 107-180% from baseline and then dropped to 21-68%. Kaplan-Meier analysis showed significantly better overall median survival for groups 1 (18 months, P=0.0005) and 3 (19 months, P=0.006) than for group 2 (7 months). Survival in groups 1 and 3 was comparable. Grade 3 and 4 toxicity was below 5% and equally distributed between the 3 groups. In our limited patient cohort, prostate-specific antigen flare phenomenon does not seem to be a clinically relevant issue in terms of overall survival. Thus, an initial rise of prostate-specific antigen under docetaxel therapy in hormone-refractory prostate cancer does not indicate therapeutic failure and should not lead to early withdrawal from therapy in the absence of clinical signs of progression.
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