Treating rare cancers: Nontraditional therapies may work for unusual lesions

Key Points

As director of dermatologic surgery at the Mount Sinai School of Medicine, New York, and because of his interest in rare skin cancers, Dr. Spencer found a number of rare skin conditions in his exam room when other doctors couldn't identify or treat the problem.

"That's not always a great position to be in, because the rare conditions tend to be ones hard to resolve," Dr. Spencer tells Dermatology Times.

"The first thing you want to do when you make a diagnosis of extramammary Paget's is to send the patient to a medical oncologist to make sure they don't have an internal malignancy, too," Dr. Spencer says.

He says extramammary Paget's disease arises in three scenarios:

"In about 20 percent of patients," he says, "extramammary Paget's is associated with an internal malignancy. The internal malignancy needs to be treated with chemotherapy or surgery, or whatever is the accepted treatment for that specific cancer."

Extramammary Paget's is treated as a separate entity, with the traditional approach being a large excision, such as a radical vulvectomy, a procedure that leaves much to be desired, Dr. Spencer says.

"This is a very difficult procedure, which leaves a huge wound often left to heal by second intention. Needless to say, this can be very uncomfortable and require weeks to months of woundcare.

"But probably the biggest drawback is that it has a very high local recurrence rate - up to 40 percent in some series - and can return even after very large genital surgeries."

Looking for a better solution, Dr. Spencer started using an alternative therapy - the nightly application of imiquimod.

"We know imiquimod works on other superficial skin cancers, so it was worth a try. We apply imiquimod nightly for two months, with about a two-week rest after one month. It is remarkably unpleasant. Putting this drug on a mucous membrane every night is very uncomfortable and inflammatory," Dr. Spencer says.

The results, however, are promising. "I've treated nine cases of extramammary Paget's with topical imiquimod as the primary therapy. We are a couple of years out now, and have had only one recurrence. One out of nine is very good," he says.

Dr. Spencer thinks the imiquimod is working better than the surgery because the disease may extend far beyond what can be seen.

"You can't cut out what you can't see, whereas the medicine can hit a very broad area," he says.

There is not a large volume of data to support Dr. Spencer's choice of treatment, but he says in the case of rare skin cancers, it's not unusual for dermatologists to find themselves in uncharted territory.

Because of their position as the experts on skin, they need to realize they might have to step outside of normal boundaries for the benefit of their patients, he says.

"Doctors need to be willing to consult the literature, and then be open to innovation when they come across a puzzling condition, because there is not necessarily an easy answer. With rare conditions, there is not usually going to be a lot of experience or big studies, so much of what we know is going to be anecdotal," Dr. Spencer says.

He also cautions dermatologists not to be overly anxious to pigeonhole unusual-appearing skin lesions. He contends that doctors would see more rare cases if they simply recognized them.

"I think there are probably more rare conditions out there that cross our desks if we are open to seeing them, and not pass them off as something benign and common.

"Certain practices tend to see more rare conditions, because they appreciate them and notice them, rather than writing them off as common conditions," Dr. Spencer says.