Excision Margin and Survival in Patients with High-Risk, Primary Cutaneous Melanoma: A Retrospective Study Based on Surveillance Epidemiology and End Result (SEER) Database

<b><i>Objectives:</i></b> The optimal excision margin of primary cutaneous melanoma greater than 2 mm in thickness is still a controversial topic. The aim of the present study was to compare the long-term survival between narrow and wide excision margins in the surgical excision of patients with high-risk primary melanoma. <b><i>Methods:</i></b> We chose the patients with primary melanoma of the skin thicker than 2 mm in The Surveillance, Epidemiology, and End Results database. Patients were divided into a narrow margin group (1–2 cm) and a wide margin group (&#x3e;2 cm) according to the resection margin information. The primary outcome was overall survival and disease-specific survival. <b><i>Results:</i></b> From 2004 to 2015, a total of 2,772 patients diagnosed as having melanoma of the skin were recruited into this study and were assigned to the narrow margin group (<i>n</i> = 1996) and the wide margin group (<i>n</i> = 776). A total of 1,098 patients died during the follow-up, and 681 of these were due to melanoma. There were 779 deaths in the narrow margin group and 319 deaths in the wide margin group (HR: 0.96, 95% CI: 0.84–1.10, <i>p</i> = 0.26). A total of 490 melanoma-specific deaths were reported in the narrow margin group and 191 were reported in the wide margin group (HR: 1.01, 95% CI: 0.85–1.19, <i>p</i> = 0.91). <b><i>Conclusions:</i></b> Wider excision margin greater than 2 cm did not provide any additional therapeutic benefits compared to narrow excision margin between 1 and 2 cm. A 2-cm margin is adequate and safe for high-risk primary melanoma of the skin thicker than 2 mm.

795 Adequacy of Surgical Excision Margins in Lentigo Maligna: An Audit

Aim The optimal excision margin for Lentigo Maligna (LM) lesions has been a frequent topic of debate. An audit was carried out to compare the excision margins used for LM excisions with current NICE guidelines, and to assess the adequacy of these excision margins. Method A retrospective study was carried out to analyse all excisions of LM lesions in 2018. 33 patients were identified from the plastic surgery departmental database. Patient demographics, the site and distribution of LM lesions, and any history of previous skin cancer were analysed. Patient electronic records, operative notes, and histopathological reports were examined to determine the number of excisions done for each LM lesion along with the peripheral and deep surgical excision margins, and the histological clearance achieved. Complete histological clearance was determined by the Multidisciplinary team for each lesion. Results 60 cases were identified. 60% of cases were located on the head and neck. The average peripheral surgical excision margin at first excision was 2.3mm. 55% of patients had a 2nd excision. The average peripheral surgical excision margin at 2nd excision was 5.4mm. 70.6% of cases achieved complete histological clearance at 2nd excision. 72.7% of lesions excised at 2nd excision with a 5mm or less surgical excision margin achieved complete histological clearance. Conclusions Taking &gt;5mm surgical excision margins did not increase the rate of complete histological clearance for Lentigo Maligna lesions.

1632 Improving Excision Margins in Skin Oncology

Aim There are 152,000 new non-melanoma skin cancer (NMSC) cases in the UK every year, and excision and reconstruction of basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) form a significant part of the clinical workload in plastic surgery. In this quality improvement project, we aimed to identify and improve our unit’s compliance of guidelines for excision margins for NMSCs. Method A retrospective audit was undertaken in June 2020 to determine compliance with British Association of Dermatology and local guidelines on excision margins for NMSCs. A repeat audit was undertaken in October 2020 following quality improvement interventions. Results The first audit cycle examined 66 lesions in total. Guidelines were met in 53% (BCCs) and 50% (SCCs) of lesions. 12% of lesions had unclear documentation of margins. 16 lesions had margins that were too small as according to the risk factors present. These findings were presented to the department, and a new operative note template specifically designed for skin oncology was launched. Key audit findings were displayed along with the guidelines on posters. A repeat cycle was undertaken in October 2020, which examined 52 lesions. Significant improvement was seen with 100% documentation, and excision margin guideline compliance rate of 71% (BCCs) and 79% (SCCs). Conclusions Adequate excision margins in skin oncology is vital to ensure complete excision and to minimise the risk of recurrence. Our project demonstrates significant improvement in excision margin compliance through the launch of a specific operative note template and information posters.

Histological Peripheral Margins and Recurrence of Melanoma In Situ Treated with Wide Local Excision

Background. The incidence of melanoma in situ (MIS) is increasing faster compared to invasive melanoma. Despite varying international practice, a minimum of 5 mm surgical excision margin is currently recommended in the UK. There is no clear guidance on the minimum histological peripheral clearance margins. Aim. This study compares the histological peripheral clearance margins of MIS using wide local excision (WLE) to the rate of recurrence and progression to invasive disease. Methods. A retrospective single-center review was performed over a 5-year period. Inclusion criteria consisted of MIS diagnosis, ≥16 years of age, and treatment with WLE with curative intent. Those patients with a recurrence of a previous MIS or with a reported focus of invasion/regression were also included. Clinicopathological data and follow-up were recorded. Results. 167 MIS were identified in 155 patients, 80% of which were lentigo maligna subtype. Of patients with completely excised MIS on histology (>0 mm), 9% had recurrence with a median time to recurrence of 36 months. Three (1.8%) cases recurred as invasive disease. Age, MIS site, MIS subtype, and histological evidence of foci of invasion/regression did not predict recurrence nor progression to invasive disease ( p > 0.05 ). The recurrence rate of MIS with a histological excision margin ≤3.0 mm was 13% compared to 3% in those with histology margins of >3.0 mm ( p = 0.049 ). Conclusion. A histological peripheral clearance of at least 3.0 mm is advocated to achieve lower recurrence rates. The follow-up duration should be reviewed due to the median recurrence occurring at 36 months in our cohort. Cumulative work on MIS needs to be collated and completed in a large multicenter study with a long follow-up period.