results from a national retrospective cohort study suggest.
The study found that, in patients with pathologically confirmed, localized T1/T2 MCC, “treatment with MMS was associated with an approximately 40% reduction in hazard of death compared with WLE,” reported John A. Carucci, MD, PhD, and colleagues in the department of dermatology at NYU Langone Health, New York. The results provide “preliminary data suggesting that treatment of localized, early-stage MCC with MMS may result in the most optimal patient survival outcomes for this aggressive form of skin cancer,” they added. The study was published online in JAMA Dermatology.
“Although data for keratinocytic nonmelanoma skin cancers have been definitive in demonstrating the advantage of peripheral and deep en face margin assessment over conventional WLE or NME [narrow-margin excision], the data for MCC, likely because of the disease’s rarity and limitations of available data sets, have been mixed,” they wrote.
Results from national studies published in the Journal of the National Cancer Institute and the Journal of the American Academy of Dermatology found no difference in survival among patients with localized MCC treated with WLE versus MMS. “However, these studies did not have confirmed pathologic node status, a substantial limitation considering that clinically node-negative cases of localized MCC have sentinel lymph node positivity rates ranging from 25% to 40%,” the authors noted.
To evaluate the association of the surgical excision modality and patient survival for pathologically confirmed localized T1/T2 MCC, Dr. Carucci and coauthors examined a cohort of 2,313 patients from the National Cancer Database with T1/T2 MCC diagnosed between Jan. 1, 2004, and Dec. 31, 2018, with pathologically confirmed, negative regional lymph nodes and treated with surgery. Their mean age was 71 years and 57.9% were male. Of the 2,313 patients, 1,452 underwent WLE, 104 underwent MMS, and 757 underwent NME.
The unadjusted analysis revealed that, compared with WLE, excision with MMS had the best unadjusted mean survival rates: 87.4% versus 86.1%, respectively, at 3 years, 84.5% versus 76.9% at 5 years, and 81.8% versus 60.9% at 10 years. Patients treated with NME had similar mean survival rates as those treated with WLE: 84.8% at 3 years, 78.3% at 5 years, and 60.8% at 10 years.
Multivariable survival analysis demonstrated that treatment with MMS was associated with significantly improved survival, compared with WLE (hazard ratio, 0.59; 95% CI, 0.36-0.97; P = .04).
“These data suggest that MMS may provide a survival benefit in the treatment of localized MCC, although further prospective work studying this issue is required,” the authors concluded. “Future directions may also focus on elucidating the benefit of adjuvant radiotherapy in localized cases treated with MMS.”
They acknowledged certain limitations of the study, including the fewer numbers of patients receiving MMS surgery, lack of randomization, and potential for selection bias.
In an interview, Travis W. Blalock, MD, director of dermatologic surgery, Mohs micrographic surgery, and cutaneous oncology at Emory University, Atlanta, who was asked to comment on the study, said that the field of MCC “has undergone rapid and robust transformation over the past 20 years. These changes encompass advancements in diagnosing the condition, identifying linked viruses, and developing systemic treatments.”
The study findings “imply that comprehensive assessment of histologic margins might offer advantages beyond minimizing scars, minimizing functional impact, and reducing the likelihood of local recurrence,” he said.
“It’s beyond doubt,” he added, that the study “furnishes us with yet another set of real-world insights that will undoubtedly influence patient outcomes. These insights serve to bring clarity to the ways in which we can deliver precisely targeted surgical treatment with durable outcomes for localized MCC.”
Patricia M. Richey, MD, director of Mohs surgery at Boston University, who was also asked to comment on the study, added that, because of the nature of the National Cancer Database, “the authors of this study were unfortunately unable to report disease-specific survival or immunosuppression status. That being said, the preliminary data presented are convincing and should result in us further exploring this topic, as well as readdressing and questioning related issues such as whether or not adjuvant radiotherapy is truly beneficial in cases with histologic clearance via Mohs.”
Dr. Carucci reported receiving grant funding from Regeneron for investigator-initiated basic research. No other author disclosures were reported. Neither Dr. Blalock nor Dr. Richey had relevant disclosures.