Maureen Lengel, 52, has been through a lot since being diagnosed with arthritis in her teens: several surgeries, including hip replacements, and an assortment of other treatments for rheumatoid arthritis. Lymphoma is the last thing she needs is to worry about. Along with the many difficulties of rheumatoid arthritis, cancer worries lurk in her mind.

"I know that people with RA have a higher risk of developing cancer," says Lengel, who keeps up on the latest news related to her disease by reading, sharing and discussing information with her doctor. The worry first set in for Lengel in the mid-1980s, when she realized the methotrexate she was taking for RA was the very same drug her friend’s mother was receiving for breast cancer. She did a little research and learned that higher doses of the drug kill abnormal cells in cancer treatment, whereas the lower doses used for RA merely quench the abnormal behavior of cells.

"Whether it is the disease itself or the drugs people take for it that increase the risk, I've seen articles on both sides of the story," she says. "Some say RA drugs may not raise cancer risk, but there are also articles that link cancer, specifically lymphoma, to one of the drugs I’m taking now. Naturally I am concerned."

So are many of the patients that Lengel’s rheumatologist, Mary Chester Wasko, MD, sees at the University of Pittsburgh Medical Center. Trying to help them sort out the facts isn’t always easy.

"The RA and cancer connection is such a worry of so many patients," says Dr. Wasko. "They read about studies that are highlighted in the press and then wonder why their doctors can't give them a straight answer. It is not that we’re trying to be elusive, it is just that many of the studies have limitations that make interpreting the results difficult."

We asked top experts to clarify the connection between cancer and rheumatoid arthritis – lymphoma in particular. Like Lengel, share this information with your doctor and have an open discussion about your own risks.

Cancer and RA: same system opposite effects

"RA is not cancer – let's be clear about that – but RA has some features that resemble cancer, so treatment we would normally think of as oncolytics have application to RA," says Gary S. Firestein, MD, chief of the Division of Rheumatology, Allergy and Immunology at the University of California, San Diego. Kinship at the cellular level makes such treatment crossovers possible, he says.