News Release

Outpatient care of thyroid cancer patients poses minimal risk

Peer-Reviewed Publication

Washington University School of Medicine

St. Louis, May 3, 2000 - You're told you have thyroid cancer. The gland located just below your vocal cords needs to be surgically removed, preventing your body from producing hormones that elevate your mood and keep your metabolism vigorous. Two weeks later, when lack of thyroid hormones has you blue, you have to drink a radioactive cocktail and spend up to several days isolated in a hospital room in which the furniture, phone Ð and even the toilet seat Ð are covered in protective plastic.

Giving radiation treatment after surgery is thought to provide the best chance of survival Ð the irradiation aims to destroy remaining cancerous cells. The risk to household members if patients forgo a hospital stay can be relatively small, though, according to results published in today's issue of the Journal of the American Medical Association.

Researchers at Washington University School of Medicine in St. Louis sent 30 patients home soon after they drank a cocktail containing radioactive sodium iodide (131I). They determined that most of the patients' close contacts were exposed to about 20 times less radiation than the maximum the government allows.

"It's similar to the amount of radiation given during a chest or a shoulder X-ray," says Perry W. Grigsby, M.D., a professor of radiology and the paper's lead author.

After patients take the radioactive cocktail, iodine concentrates in the thyroid gland. Any excess iodine is excreted in urine, feces, sweat, saliva and exhaled breaths.

Since the 1940s, scientists have known that 80 percent or more of the radioactive isotope can be excreted from patients' bodies in the week or so after 131I treatment. For this reason, most doctors have favored hospitalizing thyroid cancer patients for one or more days as a safety precaution. It takes about eight days for half of the radioactivity of 131I to disappear.

The Nuclear Regulatory Commission (NRC) ruled in May 1997 that patients could be sent home after being treated with an 131I drink if other individuals, including household members, were not likely to be exposed to more than 500 millirem of radiation. However, exposure estimates have been based on computer models, making many doctors reluctant to try early discharge. Women with young children and other patients also expressed concern about exposing family members, Grigsby says.

To address such concerns, the Washington University researchers treated 30 patients with an average dose of 131I and sent them home a half hour later. The patients were told to keep their distance from with other household members for two days. In addition, they were advised to drink lots of fluids and take several showers a day to help get rid of excess iodine.

To monitor radiation exposure, the researchers gave the 30 patients and 65 members of their households matchbook-sized monitors that clip onto clothing. Study participants were told to wear the monitors around the clock for 10 days.

The monitors also were clipped onto the collars of 17 dogs and cats. And they were taped to a wall of four rooms in each house, including patients' bedrooms.

On average, the household members were exposed to 24 millirem of radiation during the 10 days - much below the NRC's 500 millirem limit. The highest total dose to a family member was 109 millirem, though one pet received 111 millirem.

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Grigsby PW, Siegel BA, Baker S, Eichling JO. Radiation Exposure From Outpatient 131I Therapy for Thyroid Carcinoma. The Journal of the American Medical Association. 283 (17) pp. 2272-2274, May 3, 2000.

The full-time and volunteer faculty of Washington University School of Medicine are the physicians and surgeons of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC Health System.


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