Clinical and Financial Implications of Positive Margins after Non-melanoma Skin Cancer Resection: A Longitudinal Evaluation
Bharat Ranganath, MD1, Robert Teixeira, MD1, Tyag Patel, BS1, Ramon Garza, MD2, Robert X. Murphy, Jr., MD1.
1Lehigh Valley Health Network, Allentown, PA, USA, 2PRMA, San Antonio, TX, USA.
The new paradigm of healthcare promotes the concept of "appropriateness of care", promoting the best outcomes while reducing inefficiency and wastefulness. Management of positive margins after non-melanoma skin cancer (NMSC) excision is debated in the literature. Excision of these tumors with frozen section occasionally yields the precarious scenario wherein a patient returns for follow-up and the final permanent pathology documents a positive margin. A decision must then be made whether to re-excise the area or to observe.
The authors previously reported preliminary results with two year follow up suggesting that re-excision of pathology-confirmed positive margins may be unnecessary under some circumstances. Our goal was to provide a longer follow-up and determine the rate of residual tumor in re-excised NMSC specimens after previous excision with positive margins, and to follow the outcome of patients who had positive margins but did not undergo re-excision.
An IRB-approved retrospective review was conducted to examine all patients with NMSC excision over a 15-year period. Of 1054 charts reviewed, 272 patients met inclusion criteria and fit into two groups: those who underwent initial NMSC excision with frozen section negative margins but were subsequently found to have positive margins by permanent evaluation and either (1) underwent re-excision for clearance of tumor (n=161) or (2) did not undergo further re-excision (n=111). Variables collected include demographics, previous skin cancer, tumor location, cancer subtype, excision measurements, and time between first and second excisions. For those patients with positive margins who did not undergo re-excision, charts were examined for evidence of "recurrence" and time to this recurrence.
Mean and median follow-up was 60 months (range 3-120 months).
83 of 161 patients (52 percent) with positive margins on initial excision had no evidence of residual cancer upon re-excision. Confirmation of residual tumor on permanent section was 48 percent. Gender, age, and location of lesions were not predictive of a positive re-excision. Patients with a previous history of basal cell carcinoma were more likely to have a true-positive margin after re-excision (p= 0.02). Larger re-excisions were more likely to harbor residual cancer (p=0.04).
For those patients with positive margins that did not undergo re-excision, only 7 of 111 patients (6.3 percent) had "recurrence" (clinically evident progression of disease at the initial site). Average time to develop this recurrence was 60 months. No patients died from NMSC progression.
Less than half of those with positive margins of NMSC had residual tumor within the specimens obtained at re-excision. Furthermore, only 6.3% of patients who declined resection after positive margins developed clinically evident progression of disease at 5 years.
Patients requiring larger re-excisions or who have a prior history of BCC are more likely to have residual cancer upon re-excision. Re-excision appears warranted for these patients and those with SCC. Observation may be more appropriate for some, such as elderly patients, high-risk surgical candidates, and those with small BCCs. Our study indicates that observation meets "appropriateness of care" standards for certain patients with positive margins on permanent pathology.
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