RADIATION THERAPY INCREASES SOME CANCER RISK

Radiation therapy increases some cancer risk

Radiation treatment for breast cancer raises a woman's long-term risk for esophageal cancer, according to a study conducted by epidemiologists at Columbia-Presbyterian Medical Center.

Physicians should be especially alert to symptoms suggestive of esophageal cancer in patients who have received radiation treatment, said principal investigator, Habibul Ahsan, M.D., MMedSc, an assistant professor at the Center's Columbia School of Public Health. The report was published in the Annals of Internal Medicine.

The study was conducted by examining the records of more than 220,000 breast cancer patients diagnosed between 1973 and 1993. The group included both patients who received radiation therapy and those who did not.

Ten or more years after diagnosis, irradiated patients were roughly four to five times more likely to develop esophageal cancer than nonirradiated patients or women in the general population, according to the researchers.

This is the first study to link radiation therapy for breast cancer with an increased risk for esophageal cancer.

In an earlier study, the researchers demonstrated that breast-cancer irradiation raises one's risk for lung cancer. The risk was substantially higher among patients who smoked.

The same pattern may hold true with esophageal cancer, said Alfred Neugut, M.D., Ph.D., associate professor of clinical medicine and public health at Columbia-Presbyterian.

"In the lung cancer study, the effect of smoking turned out to be multiplicative," he stated. "That is, you ended up with 40 times the risk if you were both a smoker and had radiation therapy. With esophageal cancer, the combined effect of irradiation and smoking may turn out to be even more dramatic. We don't know that yet. We're just starting a study that will give us some answers in a couple of years."

The researchers also plan to analyze the effect of radiation dosage, alcohol consumption, and body mass index on the incidence of esophageal cancer.

"We believe that clinicians should be aware of the possibility of a second cancer in the esophagus should suspicious symptoms arise among long-term survivors, particularly those who received radiation therapy in the past and who smoke cigarettes or drink alcohol," concluded Drs. Ahsan and Neugut in their paper.

Esophageal cancer occurs in about one out of every 2,000 women with breast cancer.

Not surprisingly, the researchers stressed that their findings should not be taken as a criticism of radiation treatment for breast cancer. Instead, they called the incidence of esophageal cancer in breast cancer patients "trivial" and viewed it as an acceptable side effect of the already controversial therapy.

SOURCE: "Radiation Treatment for Breast Cancer Raises Risk for Esophageal," Columbia-Presbyterian Medical Center media release. Jan. 22, 1998.

The Chiropractic Journal.

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