Prostate cancer seed implant — stay away from pregnant women?

Originally Published: May 8, 2009
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Dear Alice,

Is it true that if you have the seed implant for prostate cancer, the patient can not come in contact with any pregnant women?

Dear Reader,

While close contact is not advisable, pregnant women can safely stay within three feet of a "seeded" patient — a man with an internal prostate cancer treatment device that emits radiation — indefinitely. Radiation seed implants emit relatively low amounts of rem (the common unit of radiation) and don't pose a great risk to those around them, pregnant women included.

The prostate seed implant, a form of brachytherapy, is a treatment option for prostate cancer that involves strategically placing radioactive metal "seeds" into the prostate gland for a sustained dose of internal radiation. Typically the seeds are radionuclides of iodine-125, and a range of 60 to 150 seeds may be implanted in the prostate. This approach avoids radiation exposure to nearby organs, such as the bladder and the rectum, and can be a desirable option for those in treatment for prostate cancer.

Depending on the dose, or number of seeds, brachytherapy can cause a person to become mildly radioactive and some precaution may need to be exercised. With pregnant women, safety is all about distance. Pregnant women can be in the company of a man with an actively seeded-prostate at a distance of three feet without any danger. But pregnant women shouldn't sit next to, hug, or be intimate with a patient undergoing brachytherapy. Additionally, it can be dangerous for prostate seed implantees to hold children on their laps. Because children under age 18 are particularly at risk for radiation-related problems, it is best to limit time with children to one hour per day at a three feet distance during active treatment. After a month of treatment, the one-hour time limit can loosen up, but everyone should still abide by the three-feet rule while the seeds are active. Additionally, some men undergoing brachytherapy may be asked to avoid sex for the first 2 to 4 weeks of treatment. If you are receiving brachytherapy, your health care provider can give you more information about the dose you are on and whether you need to take specific precautions around children and pregnant women.

While it might seem quite scary for a pregnant woman to be in the company of a man with radioactive seeds, there is actually very little danger to the fetus in these circumstances. A pregnant woman can receive up to 0.5 rem of radiation while carrying her child without any risk. The prostate seed implants give off about 0.001 rem at a three-foot distance within one hour. In addition, about 0.001 rem per day is absorbed just from the ambient environment. When you do the math, this all adds up to almost no risk of excess exposure. For more information on pregnancy risk related to radiation, check out the Health Physics Society's page on Pregnancy and Radiation.

Playing it safe (at three feet) assures you are protecting your company and loved ones from any adverse effects of hidden radioactivity. Since brachytherapy dosages can differ, it's best to consult with your health care provider about specific precautions that will help protect your loved ones.

Alice