What harm can there be in taking a little extra "something" like a vitamin or herb when you have an illness as serious as cancer?

The answer is sometimes problems can occur for people with cancer who are supplementing their treatment with over-the-counter remedies.

There are some nontraditional treatments that may have serious side effects or may interfere with treatment for the cancer. And, if doctors don’t know about the different pills or other substances their patients are taking, they may not realize that the cancer treatment could be affected.

Heather A. Jones, MD, and colleagues from the University of Pennsylvania School of Medicine and the Veteran Affairs Medical Center in Philadelphia, found that many patients have taken a "don’t ask, don’t tell" approach with their doctors when it comes to unconventional medical therapy.

The researchers reported their findings in the journal Urology (Vol. 59, No. 2: 272-276).

The doctors asked 287 prostate cancer patients when they first came to the office what medicines they were taking, both those by prescription and over-the-counter.

Of the 84 patients with prostate cancer who were examined before starting radiation treatments, at first only six told the doctors that they were taking any type of unconventional therapy. But if the doctors asked very pointed questions, another 25 patients provided the information that they were taking nontraditional therapies.

For the most part, patients were taking large doses of vitamins A, E, and C. They were also taking herbal therapies that included garlic, saw palmetto, and selenium.

The researchers found that four out of 10 prostate cancer patients in this study were taking some form of unconventional therapy, and most of them did not tell the doctor up front when asked.

Experts say the jury is still out on whether certain vitamins and herbs are helpful in the treatment of prostate cancer. Jones said that an emphasis should be put on finding out whether these therapies could cause problems for patients, including the question of whether lab results are altered while patients are followed to gauge whether the treatment is working.

For example, Jones said there is some concern that antioxidants may interfere with radiation treatments. Shark cartilage use can cause elevation in liver function tests, an important tool in evaluating patients health status.

PC-SPES recently was taken off the market because it was altered with manufactured drugs that caused blood clots in the veins of the legs and swelling of breasts in men.

Jones said the purpose of telling the doctor about these unconventional therapies is to allow the patient and the doctor to talk about the risks and benefits of the vitamin or herb. This way, patients can make an informed decision about what is right for them. And, doctors can be on the lookout for problems that may have otherwise been ignored or not understood.