To fight cancer, doctors often resort to aggressive treatments that include surgery followed by secondary chemotherapies. This tactic works for many cancer types, but unfortunately not for kidney cancer. In a large, random, double-blind study, researchers at the University of Pennsylvania found that two commonly used anti-cancer drugs, sorafenib and sunitinib, were no more effective than placebos at preventing kidney cancer recurrence. The study has implications for drugs that should and shouldn’t be in a patient’s adjuvant therapy following surgery.
Kidney cancer accounts for nearly 4% of all new cancer cases every year. Although the cancer has a relatively modestly high five-year survival rate at 73.2%, the disease still claimed over 14,000 lives in 2015 alone. Typically, surgery to remove the cancerous growth in the kidneys is the best initial treatment. However, the surgery alone is ineffective at preventing relapse in patients. As such, doctors often prescribe adjuvant therapies, which are secondary anti-cancer treatments to maximize the effectiveness of the surgery.
In the case of kidney cancer, sorafenib (Nexavar, Bayer/Onyx Pharmaceuticals) and sunitinib (Sutent, Pfizer) are widely used in the hope of improving patient survival after surgery. The drugs are anti-angiogenic agents that inhibit the kinase known as vascular endothelial growth factor (VEGF). By inhibiting VEGF, the drugs block the growth of blood vessels that enable cancer to survive and proliferate.
While the drugs’ actions seem to fit with the goal of stopping the cancer, researchers found no difference in patient survival when treated with these drugs compared to when treated with placebos.
The double-blind, placebo-controlled, phase 3 trial included 1,943 patients from 226 study centers in the US and Canada. All patients were diagnosed with high-grade kidney cancer at stage T1b (tumor is larger than 4 cm but not larger than 7 cm across and is only in the kidney), and had undergone surgery to remove the non-metastatic cancer. They were then randomly assigned to the sorafenib group, the sunitinib group, or the placebo group for 54 weeks.
In analyzing survival rates between the three treatments after surgery, researchers found no significant differences: Median disease-free survival was 5.8 years with sunitinib, 6.1 years with sorafenib, and 6.6 years with placebo.
While the drugs did not reduce kidney cancer recurrence, the researchers found the drugs “did not appear to make the outcome of patients receiving them any worse,” said Naomi Haas, first study author.
The findings are similar to other trials that reported the ineffectiveness of the anti-cancer drug bevacizumab in the adjuvant setting in breast and metastatic colorectal cancers.
While these results seem discouraging, studies like these are important as they help doctors identify which drugs will and will not be effective for the patients. After all, given the toxicity and side-effects of chemotherapies, it is equally important to understand which drugs to not take, as well as which to take. Studies like this also give insight into how cancer recurrence occurs, and specific to kidney cancer, the pathways may not involve VEGF at all.
Additional source: EurekAlert!
