medwireNews: The use of targeted therapies for metastatic renal cell carcinoma (mRCC) could see patients surviving in excess of 2 years, suggest findings from the Institut Gustave Roussy in Paris, France.
But the researchers, led by Bernard Escudier, found that "the use of second and third lines of treatment appears to be lower than anticipated," despite sequential therapy currently being the standard of care.
In their analysis of all mRCC patients treated at the Institute from 2005 through 2009, 52% of 251 patients, aged an average of 60 years, received second-line therapy. Even among the 211 patients deemed eligible for second-line therapy due to progressive disease, the rate was only 62%.
Memorial Sloane Kettering Cancer Centre (MSKCC) classification significantly predicted the use of second-line therapy, with 73% of patients with a "good" MSKCC score receiving second-line therapy. This "appears to be the best factor for predicting which patients will be able to receive further lines of treatment," the researchers comment in the European Journal of Cancer.
However, the type of first-line therapy also significantly predicted a patient's likelihood of receiving second-line therapy. Patients taking bevacizumab were significantly more likely to receive second-line therapy (79%) than those taking sunitinib (59%) or sorafenib (52%).
"Whether this is due to treatment with [bevacizumab] or to patient selection bias remains questionable," say Escudier et al. "In the absence of randomized studies, there is no way to determine whether this is an ideal sequence."
Among the 251 participants, first-line treatment was sunitinib in 50.6%, sorafenib in 24%, and bevacizumab in 24%.
Over a median follow up of 20.2 months, the median overall survival of the patients was 25.8 months, ranging from 16.4 months for sorafenib-treated patients to 26.3 months and 32.5 months for sunitinib- and bevacizumab-treated patients.
Overall, 131 patients went on to receive second-line therapy. Of these, 22 (16%) had a partial response and 41% had stable disease. The median duration of response was 6.2 months and the median overall survival from the start of second-line therapy was 20.8 months for a tyrosine kinase inhibitor (sunitinib and sorafenib).
The percentage of patients who went on to receive third-line therapy was 56% for sunitinib-treated patients, 28% for sorafenib- and 65% for bevacizumab-treated patients.
"We still need to define how to use existing therapies optimally to provide maximal clinical benefit," say Escudier and co-workers.
"Being able to predict a patient's chance of receiving second line treatment might provide useful decision tools, especially when results from ongoing/planned prospective trials looking at cominations and sequencing of therapies, become available."
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