Genetic Variation Is Associated With Treatment-Related Side Effects

June 5, 2004

A new study finds an increased risk of severe digestive side effects in patients with a specific genetic variation who were treated with radiation and platinum-based chemotherapy for non-small cell lung cancer (NSCLC).

In this study, doctors treated 147 patients with radiation and either cisplatin (Platinol) or carboplatin (Paraplatin) and recorded the gastrointestinal (GI) side effects, such as nausea, vomiting, and inflammation or irritation of the esophagus (esophagitis). They also analyzed each patient's ERCC1 gene.

The investigators found that 30% of the patients who experienced more intense side effects had a variation in the ERCC1 gene. In comparison, only 14% of patients without this genetic variation experienced serious side effects.

"Our study raises interesting questions that will need to be validated in prospective trials before the results can be used in patient care," said lead investigator Rebecca Suk, MD, of Harvard University in Boston, Mass. "However, as we learn more about how genetic differences affect treatment outcomes for lung cancer, we hope to one day be able to select treatment based on individuals' genetic profiles."

Chemotherapy and radiation cause DNA damage in both healthy and cancerous tissues. In patients with a functional ERCC1 gene, the damage is repaired in the healthy tissue. The researchers hypothesized that in the patients with an alteration in the ERCC1 gene, the damage cannot be repaired, and as a result, these patients experience more severe side effects.

What This Means For Patients

Doctors are starting to understand why people have different reactions or responses to cancer treatment, and one of these reasons appears to be genetic. Once more of these studies are done in larger groups of people, doctors may someday be able to select treatment plans according to a patient's genes. This individual approach to cancer treatment, though, is still many years away.