Skin cancer, particularly non-melanoma skin cancer (NMSC), remains a prevalent diagnosis in the United States and poses significant challenges in treatment. The National Comprehensive Cancer Network (NCCN) recommends complete excision, emphasizing the importance of preserving function and optimizing aesthetic outcomes. Mohs Micrographic Surgery (MMS) is considered the gold standard treatment reporting cure rates as high as 99-100%, but it requires specialized training. In our private plastic surgery center, we use two surgical techniques for NMSC treatment: traditional intraoperative frozen section analysis (IFSA) and our novel technique Modified Frozen Section Mohs (MFSM).
We conducted a retrospective chart review comparing the clinical outcomes of the IFSA versus MFSM performed by one plastic surgeon. The primary outcome was cancer recurrence and false negative rate, which was obtained by searching the pathology lab’s database for IFSA and MFSM procedures between January 2016 to July 2023. Secondary outcomes include defect size, number of stages, operative time, and complications. Chi-square and two-sample t tests were conducted for select variables.
There were 1598 IFSA procedures and 1714 MFSM procedures included in the final analysis. Baseline characteristics were similar across both groups. The pathology lab identified two recurrences in the IFSA group and zero recurrences in the MFSM group (99.9% and 100% cure rates, respectively; p=0.26). The false negative rate was 8/1598 (0.46%) for IFSA and 2/1714 (0.11%) for MFSM. The average number of stages to achieve clear margins was 1.15 for IFSA which was similar to MFSM at 1.17 stages (p=0.09). The average defect size for IFSA (2.13 cm2) was significantly higher than for MFSM (1.83 cm2) (p=0.003). The IFSA complication rate was 3.5%, which was higher than the 2.28% complication rate for MFSM (p=0.03).
Traditional IFSA and our novel MFSM are equally effective techniques for NMSC removal. Plastic surgeons can use either of these techniques to treat skin cancer with optimal cure rates without requiring Mohs training.
IFSA vs. MFSM Outcomes
| IFSA (1598 cases) | MFSM (1714 cases) | |
| Cure Rate (%) | 1596 (99.9%) | 1714 (100%) |
| Number of Recurrences | 2 | 0 |
| False Negative Rate (%) | 8 (0.46%) | 2 (0.11%) |
| Average Number of Stages | 1.15 | 1.17 |
| Defect Size (cm2) | 2.13 | 1.83 |
| Average Operative Time (minutes) | 48.5 | 49.4 |
| Complication Rate (%) | 3.5% | 2.28% |
