Genetic Test Shows Who Benefits From Chemo

Sept. 6, 2006 — -- Chemotherapy helps many cancer patients, but for some of them, it won't work and they'll only end up experiencing the sometimes toxic side effects the drugs bring on.

Doctors have long struggled to balance the potential risks and benefits of chemotherapy.

Now there might be a way to figure out which patients will benefit from a certain kind of chemotherapy before treatment begins, according to a new study published in this week's issue of the New England Journal of Medicine.

This discovery "is one of the most exciting new areas of study in oncology," said Dr. Eddie Reed, at the Centers for Disease Control and Prevention, in the study's accompanying editorial. "We may have a tool that can distinguish between patients who can benefit from platinum-based chemotherapy and those who cannot benefit from such a treatment."

This tool could save some patients from unnecessary exposure to a sometimes toxic treatment.

Researchers took tumor samples from 761 patients with non-small-cell lung cancers and looked for a gene called ERCC1.

ERCC1 is a piece of DNA that actually helps repair other pieces of damaged DNA. Every living creature -- from bacteria to mice to man -- has the ERCC1 gene.

Scientists believe this gene is essential for life, and all people and all cancer patients have this ERCC1 gene. Tumors have their own unique set of genes, however, so some tumors lack the ERCC1 gene.

Researchers found that if a tumor did not have the ERCC1 gene, it was more vulnerable to some chemotherapy treatments. Patients whose tumors did not have ERCC1 had a 35 percent reduced risk of death five years after chemotherapy.

If a tumor did have the ERCC1 gene, that tumor was more difficult for some chemotherapy drugs to kill. So chemotherapy treatment was no help for those patients.

The patients in this study were treated with platinum-based drugs such as cisplatin, carboplatin or oxaliplatin, so the finding only applies to this class of chemotherapy drugs. Researchers do not know if the ERCC1 gene reveals anything about whether other kinds of chemotherapy will work.