AMSTERDAM – Patients with metastatic renal cell carcinoma (mRCC) who experience disease progression in one or more metastatic sites while on treatment with a targeted therapy may still benefit from staying on the same drug rather than switching to another following locoregional treatment, results of a retrospective study suggest.
Among 55 patients with RCC, those who continued on the same targeted therapy after locoregional treatment of a site of progression had significantly longer post–first oligoprogression overall survival (PFOPOS) than patients who had been switched to another targeted agent, reported Della De Lisi, MD, from the University of Rome and colleagues.
“Locoregional treatments represent an option for oligometastatic mRCC treated with targeted therapy. Continuing the same systemic treatment after radical locoregional treatment in one or more metastatic site[s] appear[s] to be an independent predictive factor of better outcome in this subset of patients. Bone oligoprogressive mRCC showed similar better outcome[s].” they wrote in a poster presented at an annual congress sponsored by the European Cancer Organisation.
One option for patients with mRCC with slow or limited metastatic progression is locoregional therapy with radical intent, with the goal of achieving a complete response. When a patient’s disease progresses while on a targeted agent such as sorafenib (Nexavar) or sunitinib(Sutent), he or she may be switched to a different agent, but there is a lack of data on outcomes with this strategy, the authors said.
To see whether sticking with the same therapy or switching to another could be the wiser course, they took a retrospective look at outcomes for 55 patients with mRCC who had disease progression after at least 6 months of a first-line therapy in one or more sites treated radically with locoregional therapy.
The majority of patients (52 of 55; 94.5%) had clear-cell histology tumors. Slightly more than half (31 patients, 56.4%) had good risk disease according to the Memorial Sloan Kettering Cancer Center kidney cancer risk prediction tool, and 23 (41.8%) had intermediate risk. The risk category was not calculable for the one remaining patient.
In all, 36 patients (65.5%) did not have evidence of metastasis at diagnosis. All patients had oligoprogression in a single site. The most common metastatic sites were to lung in 15 patients, bone in 10, kidney in 8, brain in 4, and liver in 4 (other sites not listed).
Forty-eight patients received sunitinib in the first line, five received pazopanib (Votrient), and two received sorafenib. Locoregional therapy at the site of progression was radiotherapy in 25 patients (45.5%), surgery in 25, and cryoablation or thermoablation in 5.
The majority of patients (48; 83.6%) remained on the same tyrosine kinase inhibitor (TKI) after locoregional therapy, while 7 were switched to another agent. Of this latter group, four patients were switched to a different TKI, and three were started on a mammalian target of rapamycin (mTOR) inhibitor.
For all patients, the median PFOPOS was 37 months. However, comparing patients who continued the same therapy after locoregional treatment with those who switched, the investigators found a significant survival advantage to sticking with the same therapy, with a median PFOPOS of 39 months, compared with 11 months for patients who were switched to another agent (P = .014)
Other factors contributing to improved survival were good vs. intermediate risk score (39 vs. 29 months; P = .036), metastases to bone vs. viscera (median PFOPOS not reached, vs. 31 months; P = .045), and Fuhrman grade 1 and 2 vs. grade 3 and 4 (57 vs. 37 months; P = .021).
Switching therapies after first progression was an independent risk factor for poor prognosis in a multivariate analysis (hazard ratio 6.280, P = .007).
An analysis of progression-free survival (PFS) after first oligoprogression showed an overall PFS of 14 months. There were no statistically significant differences in terms of post-progression PFS between patients who stayed on the same therapy or were switched, however (15 vs. 7 months, P = .207).
The study was sponsored by participating institutions. The authors reported no conflicts of interest.