Mohs repair method impacts risk for healing complications following radiation therapy

Key takeaways:

• Free flap (38.7%), split thickness graft (30%) and local flap (12.5%) repairs caused most complications.
• Complications included osteoradionecrosis, dehiscence/necrosis, infections and a need for revision.

ORLANDO — Certain Mohs surgery repair types raised the risk for healing complications following adjuvant radiation therapy, according to a presentation at the American Society for Dermatologic Surgery Annual Meeting.

“As we know, adjuvant radiation therapy reduces the risk of locoregional recurrence in completely resected, high risk cutaneous squamous cell carcinoma at stage T2b and T3 by over 55%,” Lindsey M. Voller, MD, a third-year dermatology resident at Stanford University, said during her presentation. “The time to radiation therapy is an important consideration as delays in radiation can be associated with high rates of local recurrence. However, starting radiation before complete wound healing can compromise the integrity of the repair and lead to wound complications.”

According to Voller, data on the association between adjuvant radiation therapy following Mohs surgery and the risk for healing complications are limited. In her presentation, Voller discussed findings that showed the type of repair used during Mohs significantly influences the risk for healing complications following adjuvant radiation therapy, whereas other factors do not.

The retrospective chart review included 127 cutaneous squamous cell carcinomas that were treated with adjuvant radiation therapy following Mohs excision. Of the included patients, 72.4% were aged 70 years or older, 83.5% were men and 92.9% had tumors on the head and neck.

Comorbidities among the cohort included diabetes (29.1%), obesity (28.3%), immunosuppression (26%), smoking (14.2%) and prior radiation therapy to the site (6.7%).

Results showed no significant associations between healing complications and gender, comorbidities, site or defect depth, although the complication group had a significantly larger mean defect diameter (113.7 mm vs. 64.3 mm; P = .001).

On the other hand, different repair types were linked to higher rates of complications, with free flap (n = 31), split thickness graft (n = 10) and local flap (n = 48) repairs causing complications in 38.7%, 30% and 12.5% of the patients treated, respectively.

Full thickness graft (n = 10), linear repair (n = 23) and secondary intention/tissue substitute (n = 5) were associated with very few to no complications, with only 10%, 4.3% and 0% of patients treated, respectively, reporting an issue.

The most common complications among flap repairs included dehiscence/necrosis (35.5%), infection (22.6%) and osteoradionecrosis (19.4%). Among split thickness grafts, the most common complications were dehiscence/necrosis (30%), osteoradionecrosis (20%) and revision need (20%). Patients who received local flap repairs also experienced, though to a lesser degree, dehiscence/necrosis (10.4%), revision need (6.3%), infections (2.1%) and osteoradionecrosis (2.1%).

“A significant association was identified between repair type and healing complications using a Fisher’s exact test,” Voller said. “However, when this test was employed to compare each category to a linear closures utilized test control, only free flaps had a significant association with healing complications.”