Testing cervical tumors before treatment for vulnerability to chemotherapy predicts whether patients will do well or poorly with standard treatment. The study supports the future possibility of personalized medicine for cervical cancer, which is normally addressed with a one-size-fits-all approach.
“Even though this is a small study, its strength is that it links a lab test of the tumor’s chemotherapy response to survival outcomes for the patients,” said lead investigator Julie K. Schwarz, MD, PhD, of Washington University School of Medicine in St. Louis, Missouri. “Very few cancers have been studied this way, and this is the first such report for cervical cancer.”
Since 1999, nearly all cervical cancer cases have been treated the same way: daily radiation therapy targeted to the tumor plus a weekly intravenous infusion of the chemotherapy drug cisplatin.
“We believe that radiation does the majority of the work with cervical cancer,” said Schwarz. “But a randomized trial published in 1999 showed that combining it with cisplatin chemotherapy improved survival outcomes.”
Even today, according to Schwarz, doctors have no way of knowing who will do well or poorly with the combined radiation and chemotherapy that every patient receives. Now, Schwarz and her colleagues have shown that the tumor’s response to chemotherapy, independent of radiation, may be a major deciding factor in whether a patient will do well with the standard treatment. Their study appeared in Gynecologic Oncology (2013; doi:10.1016/j.ygyno.2013.04.005).
“This is evidence that cisplatin is not just helping the radiation work better,” Schwarz said. “It is having some direct toxic effect on cancer cells that may be hiding elsewhere in the body, some place where the radiation is not hitting it, since we target the radiation so precisely to the main tumor. We think it would be beneficial for that drug to be selected appropriately for the patient’s individual tumor.”
The investigators tested tumors from 33 cervical cancer patients before their treatment began. They divided the patients’ tumors into three categories: responsive, intermediate response, and nonresponsive. The categories were based on how well cisplatin killed the tumor cells growing in a dish.
For tumors categorized as responsive, which were those cancer cells that cisplatin killed most easily, 100% of the patients were alive and disease-free after 2 years. For those that showed an intermediate response, 83% of the patients were alive and disease-free after 2 years. And for those tumors deemed nonresponsive, only 58% of patients had 2-year disease-free survival.
Cervical cancers can be divided into two main types based on how they look under a microscope, squamous cell carcinoma and adenocarcinoma. In patients with a diagnosis of the more common squamous cell carcinoma, disease-free survival at 2 years was even worse (46%).