Non-melanoma skin cancer options growing

Vienna, Austria - Until recently, physicians had few nonsurgical options for treating nonmelanoma skin cancer. That could be changing, however, as researchers learn more about photodynamic therapy (PDT) and newer pharmaceuticals, as well as new uses for older drugs.

In North America alone, managing skin cancer costs nearly $500 million annually.

Nevertheless, some modalities show promise against nonmelanoma skin cancers. PDT, for example, when combined with IV verteporfin (Visudyne, Novartis), has shown response rates between 70 percent and 90 percent, depending on the amount of light used, with good cosmesis at two years (Lui H et al. Arch Dermatol. 2004 Jan;140(1):26-32.).

Additionally, a multicenter randomized study comparing PDT plus topical methyl aminolevulinic acid (ALA/Metvix, PhotoCure) versus surgery found similar results in terms of clinical clearance at three months. But at 12 months, surgery achieved a 96 percent clearance rate; PDT, 83 percent. At 24 months, patients receiving PDT had a 10 percent recurrence rate versus only 2 percent with surgery (Rhodes LE et al. Arch Dermatol. 2004 Jan;140(1):17-23.).

"If one looks at the literature regarding PDT and skin cancer," Dr. Rivers says, "not many studies have been done. And the best promise in terms of lowest recurrence rate seems to be for BCC and maybe in situ SCC, but not for invasive SCC. So it would appear that PDT is inferior to surgical excision and Mohs surgery for BCC. And because there's a risk of metastatic disease in SCC, its use is limited there. At this time, PDT should be reserved only for those patients who cannot undergo surgical excision."

Electroporation Researchers also are testing electroporation, which temporarily increases cell membrane permeability (through injection of bleomycin into the tumor, followed by application of a short, high-voltage pulse directly into the tumor tissue.)

"To this point, this technique has been used primarily in unresectable head and neck cancers, primarily SCCs," he says. "It can be tissue-sparing and may prevent chemotherapy drug resistance. And it may be less expensive compared to conventional surgery. Also, there are some trials now going on for BCC of the skin which would suggest that it does have a benefit, although randomized phase 3 trials have not been done."

According to one published study of electroporation, researchers saw complete response in 51 of 56 BCC tumors of the treated skin (Heller R et al. Cancer. 1998 Jul 1;83(1):148-157.).

NSAIDs Nonsteroidal anti-inflammatory agents (NSAIDs) offer a similar dearth of data regarding nonmelanoma skin cancers.

"There's been some work done with these agents in colon cancer and familial polyposis," Dr. Rivers says. "And for actinic keratoses (AKs), we know there is one drug, diclofenac sodium in hyaluronic acid (Solaraze, Bioglan/Bradley), which can work. But there are no published studies at this time to support its use in BCC or SCC."

Among immune response modifiers, imiquimod has received approval for treating AKs.