The reality is that Mohs surgery can and, at times, does fail. According to one expert, how the surgeon reacts to this challenge in terms of therapy is crucial to the patient's successful outcome.
The Mohs surgeon's reaction to the failed Mohs surgery is crucial. It is important to look ahead and keep a keen eye out for workable and, often, more aggressive solutions to the problem, according to one expert.
"In such cases, it is important to be and stay aggressive. My general rule with Mohs surgery is, one or two strikes and you're out.
According to Dr. Leffell, Mohs surgery is the best way to treat many nonmelanoma skin cancers, as cure rates can sometimes be as high as 98 percent. However, when Mohs surgery fails, the result can be chronic symptoms, multiple treatments, functional impairment and potentially fatal outcomes.
"If cancers recur after Mohs surgery and act aggressively, the surgeon has to make sure that he manages patient and family expectations. You have to realize that when you are dealing with a multiply recurrent skin cancer, you are dealing with a chronic situation, and you have to select treatment strategies that do not preclude options," Dr. Leffell tells Dermatology Times.
Predicting Mohs failure
Several factors can help predict Mohs failure, including a multiply recurrent cancer, a large tumor, a poorly differentiated cancer and perineural invasion, Dr Leffell says.
Some host or anatomical factors that may predispose Mohs failure are an infiltrative histology in the embryonic fusion plane; a squamous cell carcinoma (SCC) on the lip, ear or temple; widespread SCC or basal cell carcinoma (BBC); immunosuppression; and genetic factors, such as nevoid basal cell carcinoma syndrome.
Dr. Leffell says in the central-facial area, recurrent cancers can extend more deeply and be larger by the time they are actually diagnosed, which is likely due to the embryonic fusion plane.
There is a debate as to whether such fusion planes actually exist, anatomically. However, according to Dr. Leffell, most surgeons would agree that there is no question that central-facial cancers deserve special attention.
He says when Mohs surgery fails, it is important that the surgeon work in an interdisciplinary fashion with head and neck surgeons, plastic surgeons, radiation therapists and, occasionally, medical oncologists.
"Typically, Mohs surgeons work independently. If a patient has multiply recurrent cancers or multiple failures of Mohs surgery, you really need to engage in an interdisciplinary group effort to make sure that the patient receives the most intensive care possible," Dr. Leffell says.
Dr. Leffell says there are other unconventional therapeutic measures the surgeon could consider to prevent recurrences. For example, administration of Gleevec (imatinib mesylate, Novartis), a tyrosine kinase inhibitor, as well as intralesional interferon could be considered in cases that fail multiple surgeries and radiation.
Dr. Leffell describes two cases of multiply recurrent squamous cell carcinomas in which he injected interferon in the surgical margins for weeks to months after the surgical excision. No recurrence was noted with follow-up greater than five years in one of the cases.
Dr. Leffell hypothesizes that this therapeutic approach could possibly reduce the number of undiagnosed peripheral cells that are left over despite so-called "clear margins."
Radiation therapy has a central role in managing many difficult-to-treat nonmelanoma skin cancers, but its use must be considered in the context of potential recurrences and its impact on further therapeutic decisions.
According to Dr. Leffell, photodynamic therapy (PDT) is probably not going to be helpful in aggressive, poorly differentiated cancers. Currently, Dr. Leffell mainly uses PDT for actinic cheilitis.
He says some physicians have touted its effectiveness in treating BCC, but it should not be used to treat Mohs surgery failures.
"Maybe in the future, photodynamic therapy will be a solution for multiply recurrent lesions, but for the moment with the technology we have, I don't think it is advisable to employ PDT for a recurrent tumor," Dr. Leffell says.