Patients who have had cancer in the past are often excluded from clinical trials of these drugs, because they already have an elevated risk for getting the same or another form of cancer again. Doctors may avoid prescribing TNF blockers to these patients for fear of further increasing the risk. With more study in this area, Dr. Mariette says doctors may be comfortable prescribing these drugs to arthritis patients who have been cancer-free for at least five years. “We couldn’t entertain that five years ago,” he says.

Arthur Kavanaugh, MD, a rheumatologist and professor of medicine at the University of California, San Diego, says this latest analysis will not substantially change the way he prescribes TNF blockers for his RA patients.

“I discuss this with patients already. We discuss cancer a lot because it is such an important issue and it is a theoretical consideration with any medications that affect normal immune function,” Dr. Kavanaugh says. “When I discuss it with them, I say that we don’t know if there is an increased risk, but because it is possible, they need to accept the fact that there may be.”

He adds, “While data from controlled clinical trials is of great importance, it is not always possible to extrapolate to the broader population. For example, in a clinical trial, patients tend to be scrutinized more regularly and perhaps more thoroughly for safety issues, and as a result, things may be detected at an earlier stage than they may be in the clinic.”

Nevertheless, Dr. Kavanaugh says the additional data may help doctors and patients make informed decisions.

“Safety information is always important,” Dr. Kavanaugh says. “We try to bring as much information as possible, including data from analyses such as these, to the patients, and talk to them about the possibilities. In the end, patients want to know how likely is it that it will happen to them, and of course for an individual person it is not possible to predict.”