Wednesday, November 17, 2010

Respect for Radiation: X-rays and Cancer Risk in PJS

This patient-view report is on x-rays and radiation and Peutz-Jeghers syndrome. In our discussions of tests, we seldom mention, and never discuss, medical radiation and x-rays in PJS. There's hope for the future. The PillCam  or Video Capsule Endoscopy doesn’t involve radiation. Magnetic Resonance exams for the small bowel and breast are alternatives to small bowel series and mammography. Hopefully, new techniques and equipment for detection of polyps, tumors and cancers will be evolved before any of us totals 100 x-ray exams. Hopefully, new treatment methods will cure cancers without the side effects and after-effects of current treatments. And most hopefully, cancer prevention will be a priority not just for those of us with mutations, but for all of us sharing this planet.

In the PJS Online Support Group we discuss many types of cancer risk factors including smoking, diet, hormones, chemicals, lack of activity, viruses (HPV in cervical cancer), and just having PJS. As usual, I'm writing from the patient point-of-view. You should discuss any of these ideas with your doctor. Background research for this report includes many medical articles, information from several websites, and half a dozen books on x-rays and medical radiation. If you are interested in the topic and want some references, see the links below.

What most strikes me is that x-rays and radiation are powerful forces that can help or hurt. Used wisely, they can reveal the insides of our bodies to others and cure cancer. Used unwisely, they can cause cancer, birth defects and other medical problems. In the USA x-rays and medical radiation are regulated by law so that they provide the lowest possible dose for the best possible results. But, experts do not agree about cancer risk from radiation in the general population (people without PJS). They do agree about risk to fetuses and caution that pregnant women abstain from x-rays unless necessary to save the mother and/or child's life. But estimates of cancer risk from radiation range from "there is no absolute proof that radiation causes cancer" to "there's no absolute proof that any dose of radiation is safe and doesn't cause cancer". Most authors and scientists agree that there are some risks including cancer from radiation/x-rays but that the benefits exceed the risks. Many state that only medically necessary x-rays be given and that doctors carefully monitor their patients' x-rays to prevent excess radiation exposure.

I'm concerned about x-rays and radiation in PJS folks for two reasons: our greatly increased risk for cancer over the general population and the high number of x-rays, including CT scans, we're likely to have during our lives.

Our risk of cancer is many times higher than that of people in the general population because we have a germline mutation in a tumor suppressor gene. Because of the mutation, we have less protection against growing both benign and cancerous tumors. Cancer-causing events in life like the risk factors listed above plus aging cause additional mutations to the PJS gene. Mutations that we are born with are called germline mutations and are distributed throughout every cell of our bodies. Mutations that occur during life are called somatic mutations, can occur anywhere throughout the body and are often organ or region-specific. Somatic mutations are usually noticed by the person's body and destroyed (apoptosis). Sometimes damage escapes notice or there's too much or the person's body can't deal with it and a mutated cell survives, accumulates more damage, becomes a cancer, multiplies and is finally noticed because of symptoms or signs. Symptoms are what we feel -- something that's gone wrong -- a lump, a pain, weight loss, bleeding between periods. Signs are what the medical expert can find, often with tests including x-rays.

Okay, we're born with an increased risk of cancer. Then we carry these bodies through life, exposing them to one risk after another. We do our best to avoid excess risk, but sometimes it's difficult to know what's risky and what's not, especially when just being alive and aging is a risk. We might wonder about radiation risk from x-rays, but credit them with our lifesaving diagnosis of PJS. We don't want to "look the gift horse in the mouth" and question their use in our children or us. We trust our doctors to order only necessary tests, but because PJS is so rare, our doctors probably follow specialist guidelines. Using those specialist guidelines, let's figure out a baseline of x-rays, based on current guidelines in a hypothetical PJS person who lives to age 70.

From the 2001 Johns Hopkins PJS booklet:

* From age 12 small bowel series every other year
29 exams times 6 mSv = 174 mSv
(a CT exam is 15-30 mSv)

* From age 25 CT scan every one to two years
23 exams times 15 mSv = 345 mSv
45 exams times 15 mSv = 675 mSv

* From age 25 mammogram annually
45 exams times .4 mSv = 18  mSv

Lifetime total 537 mSv to 867 mSv for females
Or  519 mSv to 849 mSv for males

Unfortunately, things seldom go as planned. Accidents and injuries often lead to additional x-rays. X-rays to extremities (arms and legs) are generally safe, but those to the torso can accumulate. In PJS people, extra x-rays are ordered because symptoms occur between scheduled exams or something suspicious on one exam requires a follow-up. If a problem is found, more x-rays are taken. Chest x-rays are given for upcoming surgery. A cancer diagnosis requires more tests to determine the extent of disease. Then more scans during treatment to gauge treatment effectiveness. Then follow-up scans for years to be sure cancer hasn't recurred. And many cancers are treated with radiation to the area where tumors are/were. Given that many people with PJS have multiple cancers, these scenarios are multiplied. So our baseline estimates of 519 mSv to 867 mSv are on the low end of what we can expect to receive, if we are able and willing to follow these guidelines. And if the technology and guidelines don't improve during our lifetimes.

I bet you're wondering what an mSv (millisievert) is and how it's related to cancer. Radiation is all around us all the time. It's in the sun, soil, atmosphere, our food and our bodies. Naturally occurring radiation is estimated to be between 1.5 and 3.6 mSv per year per person. So, our hypothetical PJS person is already getting 105 mSv to 252 mSv during his/her estimated 70-year life span. The Food and Drug Administration has a good entry explaining radiation risk and CT scans at  They note that some Japanese survivors of the atomic bomb with doses of 5 to 20 mSv at one time demonstrated a small but increased radiation-related excess relative risk for cancer mortality. Again, experts disagree about how much radiation is likely to cause cancer. It's most likely that cancer-causing events interact with one another synergistically to cause cancer.

Our increased risk for cancer because of a germline mutation that gives us PJS multiplied by a large number of x-rays and medical radiation may further increase our risk of cancer. There is no need to refuse necessary x-rays. Most of our members know from personal experience that x-rays lead to diagnosis lead to treatment lead to resolution of symptoms. They don't cure PJS or even treat it directly, but they are invaluable for finding out what is wrong where so that proper steps can be taken. These are powerful tools to help us heal. It's up to us to use them wisely.

There are many ways to reduce radiation exposure that require only attention and communication. All require talking to doctors and radiation technicians, but those are the people who want to help you stay healthy, so they have an interest in doing the right thing.

Here are some ideas to consider:

Get only medically necessary x-rays:
         * Watch for duplicate x-rays, especially when going to a new doctor. Make sure your x-rays are sent to your new doctor. Even if they are a few years old and you need new films, they can help the radiologist by providing a then-and-now comparison.
         * If your polyps are small and slow growing based on scopes and previous x-rays, maybe you can wait longer between exams. Have this discussion with your doctor.
         * Your confidence in x-rays for polyps might be low because polyps have been missed in the past, discuss this with your doctor.
         * Ask, is an x-ray the best exam for this problem? Perhaps you can substitute another type of exam and get adequate results. Discuss capsule endoscopy (pill camera) instead of a small bowel series. Or an endoscopic ultrasound instead of an abdominal CT scan. Or an x-ray instead of a CT scan. Magnetic resonance enterography may replace barium follow-through x-rays and the PillCam.
         * Don't assume you need x-rays. Talk with your doctor first. Remember, adhesions can cause obstructions that feel similar to polyps. And heavy periods as well as GI bleeding can cause anemia. If you insist on an x-ray, you'll probably get one. In the USA doctors are more afraid of medical malpractice suits for missed diagnoses than radiation overexposure.

Keep track of all the x-rays you've received:
         * Talk with your doctor about your total number of x-rays and future plans. Make sure that your doctor is keeping track of your radiation exposure too. The FDA has an x-ray record card at the link below.
         * If you move or change doctors, take your x-rays with you. They're your property (in the USA). If the hospital or clinic won't release them to you directly, make sure they've been sent to and received by your new doctor.

Technical Details:
         * Adjustments can be made to x-rays and CT scans. If you are small, ask for an adjustment.
         * Ask to have the smallest necessary area screened.
         * Shielding is available for different areas of the body including reproductive organs and breasts.
         * Machines vary in radiation dose per test. Older machines generally expose patient to higher levels of radiation. Example: Mammograms were often 3.0 mSv, now are 0.4 mSv. Ask about the facility and the machines in use.

Special considerations for females:
         * Breasts are one of the most radiation sensitive areas of the body. Increased risk of breast cancer was found in women who had x-rays for scoliosis as children. There are many ways to protect your breasts. Ask for shielding, especially during the small bowel series: they're examining your GI tract, not your breasts. Chest x-rays can be taken from the back to the front, rather than the usual front to back, reducing radiation to breast
         * If you are pregnant or want to get pregnant, have your x-rays and polyp removal before conception. Ask if your ovaries can be shielded. It isn't possible in some tests, but worth discussing with your doctor. Also, if you are having radiation treatment for a pelvic area cancer and want to bear children later, be sure to discuss this with your doctor. It may be possible to tuck the ovaries outside the radiation field and save their fertility.        

Special considerations for males:
         * Shielding for testicles is available. Ask about it.

Special considerations for children:
         * Children are more sensitive to x-rays because their cells are rapidly dividing, they are smaller than adults and have a longer life expectancy.
         * Settings on machines are for adults, not children. Ask for individualized settings for weight and size on both x-rays and CT scans.

There's hope for the future. The PillCam  or Video Capsule Endoscopy doesn’t involve radiation. Magnetic Resonance exams for the small bowel and breast are alternatives to small bowel series and mammography. Hopefully, new techniques and equipment for detection of polyps, tumors and cancers will be evolved before any of us totals 100 x-ray exams. Hopefully, new treatment methods will cure cancers without the side effects and after-effects of current treatments. And most hopefully, cancer prevention will be a priority not just for those of us with mutations, but for all of us sharing this planet.

Best to all,
Links for those interested in learning more:

Johns Hopkins PJS Booklet

NIH takes step to assess any possible risk associated with low-dose radiation exposure

UC Davis radiology expert leads published review of radiation exposure risks from medical tests

AAPM statement on radiation dose

Radiation Exposure in X-ray and CT Examinations

Food and Drug Administration - CT scan

FDA x-ray record card

Health Physics Society
Medical and Dental Issues
(check out their links too)

X-Rays and Health Project

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