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.

Evaluation of Molecular Positive Margins Using Surrogate P53 and Retinoblastoma Protein Expression and Correlation with Surgical Outcomes in Oral Squamous Cell Carcinoma

BACKGROUND p53 mutation and Rb over-expression have been extensively studied in oral squamous cell carcinoma (OSCC) but their clinical relevance with respect to excision margins is still controversial. The purpose of the study was to determine the expression of molecular markers (p53& Rb) for predicting early locoregional recurrence in oral cancer. METHODS Histopathological specimens of 93 patients of oral cavity squamous cell carcinoma were subjected to p53 mutation and Rb protein testing in tumour and at the closest negative margin on H &E using immunohistochemistry. The expression of p53 and Rb in tumour tissue and at excision margin was correlated with clinicopathologic parameters recurrence and survival over a 2 year follow up period. RESULTS p53 mutation expression in tumour tissue was associated with increased recurrence (22.5 % versus 11.3 % P = 0.13) and mortality (17.5 % versus 5.6 % P = 0.056). p53 expression at margins is also associated with higher recurrence and mortality. Rb overexpression in tumour tissue is not significantly associated with recurrence (15 % and 16.4 %). Rb overexpression at margins had higher recurrence (40 %; P = 0.627) and higher mortality (60 %) in comparison to Rb negative cases (16.4 %versus 6.8 % respectively). CONCLUSIONS Clinical and routine histopathological assessments of margins remain the standard method of prognosticating and planning adjuvant treatment. Determination of molecular positive margins using p53 & Rb in oral cancer may aid in identifying patients at high risk of development of recurrence despite negative pathological margins. KEYWORDS Rb, Margin, P53, Recurrence.

Adjuvant radiotherapy in recurrent pleomorphic leiomyosarcoma of spermatic cord: A case report and literature review

Pleomorphic leiomyosarcoma of spermatic cord is a very rare urologic disease, so there are no clear guidelines. The mainstay of treatment is surgery with wide excision margins. The role of adjuvant treatments, such as Chemotherapy (CHT) or Radiotherapy (RT), is not clear, due to the few data available in the literature. However, adjuvant treatments could be considered in patients with a high risk of local recurrence: R1 status after surgery and highgrade histology. We report the case of 68-year old man affected by recurrent pleomorphic leiomyosarcoma of spermatic cord right, who, in five years, underwent many surgical treatments for local recurrence, and also adjuvant CHT. The last surgery shows positive margins. Therefore, the patient receive adjuvant RT on the surgical bed and right inguinal nodes with a dose of 54 Gy in 27 fractions and VMAT technique. The treatment was well tolerated, the follow-up at 12 months is negative for local recurrence and show absence of toxicity. However a long-term follow-up is necessary to confirm the efficacy of radiotherapy on outcomes and especially on local control. Keywords: pleomorphic leiomyosarcoma; recurrence; positive margins; adjuvant radiotherapy

1644 Trainee Perspective in Sarcoma Care

Aim Soft tissue sarcomas (STS) are rare and aggressive tumours. Appropriate multidisciplinary management requires robust knowledge of best practice and understanding of current guidelines. Plastic surgery trainees must therefore be proficient in the assessment, investigation, and treatment of patients with STS. We aimed to evaluate trainee education, confidence, and competence in managing patients with STS. Method All plastic surgery trainees in Wales completed an online questionnaire and written assessment. This was designed by the lead for STS and TPD. Formal training, knowledge of national guidelines and excision margins for different types of STS and skin cancer was assessed using short answer questions. A five-point Likert scale was used to assess trainee confidence in STS and skin cancer management and follow-up. Volume and type of teaching in sarcoma and skin cancer was also quantified. Results Trainees received less sarcoma training and were less confident in STS assessment and follow-up, in comparison to skin cancer. More senior trainees or those with formal sarcoma training were more confident in skin cancer management (mean confidence rating 4.4 vs 2.2) and performed better in the written assessment of excision margins (mean score 100% vs 61.45%) Conclusions Trainees receive less training in sarcoma with a significant impact on their competence and confidence in sarcoma care. We believe this is consistent across the United Kingdom as evidenced by just two sarcoma webinars held during the COVID-19 pandemic. Formal national evaluation of sarcoma teaching should be carried out to inform ongoing efforts to improve educational resources on this important topic for trainees.

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.

309 Does Anaesthetic Type Effect Positive Excision Margin Rate for Non-Melanoma Skin Cancers?

Aim Australia has the highest incidence of Non-melanoma skin cancers (NMSC) in the world estimated to be 2448/100,000 population with the state of Queensland carrying the highest burden. Surgical excision is the primary treatment and makes up a large proportion of general surgical lists in regional Queensland where they are typically removed using either local anaesthetic (LA) alone, local anaesthetic and sedation (LAS), or general anaesthesia (GA). There is little in the literature to suggest if anaesthetic type effects the rate of involved margins. The purpose of this study is to establish if anaesthetic type impacts the rate of positive excision margins in regional hospitals in Queensland. Method A retrospective audit was performed, incorporating a total of 194 squamous and basal cell carcinoma lesions excised between October 2019 and October 2020 at two hospitals in regional Australia. Data was recorded for the type of anaesthetic used and the histopathology of the lesions including type of lesion and microscopic margin involvement. Results Of the 194 excised lesions 39 of them had involved margins (20.1%). The rate of involved margins under LA, GA and LAS were found to be 19.79%, 18.52% and 22.73% respectively. When comparing these modalities with each other: LA vs GA, LAS vs GA and LA vs LAS no significant difference was found in involved margins for excision of NMSC with p-values (&lt;0.05) of 1, 0.624 and 0.8225 respectively. Conclusions Modality of anaesthetic used for excision of NMSC does not affect the outcome of margin involvement.