DESTIN, Fla. - When it comes to melanoma treatment, one of the most effective strategies - excision - is what dermatologists do best, Dr. Christopher J. Miller said.
"Getting the tumor out is the one thing we are good at [with melanoma]. And we have tools to be better at it," he emphasized.
Click here to watch a video interview on this subject with Dr. Christopher J. Miller.
Histostains, including melanoma antigen recognized by T cells 1 (MART-1), are one such tool. "These stains have revolutionized our ability to treat melanoma using frozen sections," said Dr. Miller, director of dermatologic surgery at the University of Pennsylvania in Philadelphia.
Dr. Miller said he hopes MART-1 staining will change a belief in dermatology that detection of residual disease is less accurate with use of frozen sections after Mohs surgery, compared with use of permanent sections after staged excision, also known as "slow Mohs."
"That is a dogma that is holding back the transition to using frozen sections," Dr. Miller noted at the annual meeting of the Alabama Dermatology Society.
There are data to indicate this is a safe practice, Dr. Miller said, including a large study of 625 patients with melanoma in the head and neck area, "an anatomic location with historically high recurrence and metastasis rates and poor survival rates." Mohs surgery using frozen sections resulted in complete melanoma removal in 97%, with 5-year local recurrence and metastasis rates, and disease-specific survival rates comparable to or better than those for historical controls (J. Am. Acad. Dermatol. 2005;52:92-100).
"And the proof is in the high cure rates all of us are getting with Mohs surgery using frozen sections and immunostains," he said.
"If you compare the frozen sections with MART-1 to the permanent sections with MART-1, we’re making the same calls," emphasized Dr. Miller.
Several studies support a finding that MART-1 imparts equivalence in terms of residual disease detection between frozen sections and permanent sections (Dermatol. Surg. 2009;35:207-13; J. Am. Acad. Dermatol. 2002;46:78-84).
With frozen sections, the Mohs surgeon (not a pathologist) checks for evidence of residual disease, results are immediate, and multiple stages of surgery can be performed on the same day. In contrast, slow Mohs requires that permanent sections processed in formalin be sent to a pathologist for evaluation. "And you have to coordinate a lot of logistics because you have to make sure the pathologist is ready to read these slides when they are available, and the patient is ready to come back right when you know your answer," Dr. Miller said. Typical turnaround time for pathology results is 24-48 hours.
Both Mohs with frozen sections and slow Mohs with permanent sections demonstrate excellent cure rates in studies, Dr. Miller said. Recurrences were in the range of 0%-2.6% in a review study (Cancer Control 2008;15:216-24).
"So they are both reliable methods in experienced hands," he noted. Importantly, both Mohs techniques permit examination of 100% of the excised margin for residual disease, Dr. Miller said. "That is what determines how certain you will be that the cancer is removed."
There are dermatologists who remain unconvinced about the benefits of frozen sections, Dr. Miller said. "I’d invite anybody to spend time with me treating these melanomas in my clinic. I’m sure I can convince them that with high-quality sections and attentive [histotechnicians] who are true experts in these stains, we can have stains that are of excellent quality that can give our patients the highest cure rates," he said in a follow-up interview.
Recognition that melanoma is a microscopic disease is important, Dr. Miller noted. "Let's accept we cannot see subclinical spread in every case. Twenty percent of the time we don’t get it all with what we think is an appropriate margin. Surgeons are having to go back for a second stage to remove tumor that wasn’t visible to them."
Dr. Miller's surgical approach to melanoma is Mohs with frozen sections. He supplements a standard hematoxylin and eosin (H&E) stain with a MART-1 immunostain for each patient. This strategy "has allowed me in multiple cases to detect melanocytes I probably would have missed had I used hematoxylin and eosin alone."
Dr. Miller also recommended an online tool that calculates the likelihood for survival from localized melanoma or regional metastatic disease based on clinical and patient characteristics. A blog posting on this easy-to-use tool is available.
For advice from Dr. Miller on the management of patients with thin melanomas, including why sentinel lymph node biopsies remain controversial in this population, watch a video interview.