Mohs micrographic surgery SWAG network service Update May 2016 Dr Adam Bray Consultant Dermatologist Dermatological & Mohs surgeon Bristol

Bristol Mohs service Since Feb 2015 Approximate waiting list 3 months once seen (less for eyelids) Second Mohs surgeon Dr Pawel Bogucki Excellent links with local Plastic surgery, Oculoplastics, and Maxillofacial  Southmead Hospital, North Bristol NHS Trust (NBT) Any interested clinicians are welcome to arrange a visit for their professional development

Referrals Please write to me stating: ‘Referral for Mohs surgery, Dermatology department’: Southmead Hospital, North Bristol Trust NBT.outpatientbookings@nhs.net

Bristol Mohs service 110 cases treated (now usually 4 per week) Mainly Bristol Also Bath, Swindon, Cheltenham & Gloucester First 81 cases analysed Defect size mean = 29mm Tumour size mean = 22mm 91% reconstructed by Dermatology (rest Plastics, and Oculoplastics) Almost all on the same day 3 all day GA combined cases (Plastics, Oculoplastics, Mohs) Combined Oculoplastic list for eyelid cases every 1-2 months

What needs Mohs? Tumours that can be easily excised with a sufficiently wide margin to guarantee cure without significantly affecting the repair do not need Mohs. A 'rule of thumb' is as follows: - Can I confidently excise the tumour with the recommended clinical margin & repair optimally? - If not, Mohs (or other margin controlled surgery) should be considered

On the SWAG website

Possible Indications for Mohs (in order of strength) Poorly defined borders Anatomical location: ‘H-zone’ (high risk of recurrence) Sites where sparing tissue highly important Recurrent Incompletely excised Infiltrative/Morphoeic Large (>2cm) Immunosuppressed/Gorlin syndrome N.B. Mohs is usually used for head and neck BCC, but other sites and tumours can be considered. N.B. Strongly consider Mohs for recurrent or incompletely excised tumours, unless straightforward to take generous deeper layer, or skin margins of 6-10mm+ (for recurrences) or 4-6mm+ (for positive margins) as recommended for standard excision/pathology.

Situations where Mohs is difficult If a GA is unavoidable If bone is involved (but Mohs can still be useful to clear skin) Consider other margin controlled surgery e.g. ‘spaghetti technique’ The “spaghetti technique”: An alternative to Mohs surgery or staged surgery for problematic lentiginous melanoma (lentigo maligna and acral lentiginous melanoma). J Am Acad Dermatol. Elsevier Inc; 2011 Jan 1;64(1):113–8.

Summary of Key Mohs Benefits Maximum cure rate Healthy tissue sparing potential Fast results

What needs Mohs? Avoid intra-operative frozen section analysis Consider Mohs over delayed repair Why? The pathology is FAR more accurate Avoid intra-operative frozen section analysis Why? Shown to be VERY inaccurate

False-negative rate of intraoperative frozen section margin analysis for complex head and neck nonmelanoma skin cancer excisions M. D. Moncrieff, A. K. Shah, L. Igali, J. J. Garioch Volume 40, Issue 8, pages 834–838, December 2015

A. Because they were not fully removed Mohs Micrographic Surgery Q. Why are tumours incompletely excised? A. -Because they are difficult to see -Because they grow unpredictably Q. Why do tumours recur? A. Because they were not fully removed

Mohs: Horizontal Sections Mohs Micrographic Surgery Mohs: Horizontal Sections

RCT: Smeets et al; Lancet 2008 Mohs Micrographic Surgery RCT: Smeets et al; Lancet 2008 Cure Rates Optimal Standard Excision +- Mohs Mohs Micrographic Surgery Comment Primary BCC 96% 98% 1. Not just high risk BCC (e.g. 1cm nod nose). 2. 30% lost to FU. 3. More complex tumours in Mohs group. 4. ‘Standard’ Group not standard. 5. All incompletely excised tumours had re-excision or Mohs. Recurrent BCC 88% 5 year follow-up

2 Large Prospective Case Series Mohs Micrographic Surgery 2 Large Prospective Case Series Malhotra R et al. The Australian Mohs database, part II: periocular basal cell carcinoma outcome at 5-year follow-up. Ophthalmology 2004; 111:631–6. Periocular 819 patients Cure rates: Primary 100%; Recurrent 92% Leibovitch I et al. Basal cell carcinoma treated with Mohs surgery in Australia II. Outcome at 5-year follow-up. J Am Acad Dermatol 2005; 53:452–7. 3370 patients Cure rates: Primary 98.6%; Recurrent 96%

Discharge to GP or referrer Referral ?BCC Curettage & electrodessication or Cryotherapy (usually in clinic) Clinic FU Clinic or phone FU or letter Derm/plastics appt Diagnostic biopsy Discharge to GP Topical treatment Excision Clinic FU Clinic or phone FU or letter ECT Clinic or phone FU or letter Radiotherapy Discharge to GP MDT meeting Discharge to GP or referrer Radiotherapy assessment FU Mohs surgery FU Mohs assessment clinic or phone FU or letter Discharge to GP or referrer

BSDS UK Mohs Standards 2012 New (first) UK quality standards document Mohs Micrographic Surgery BSDS UK Mohs Standards 2012 New (first) UK quality standards document Training standards Usually a 1 year post-CCT advanced skin cancer surgery fellowship 100 varied cases Participation in further 250 cases Curriculum being ratified by SAC/RCP/GMC Workload 120-200 cases per Mohs surgeon per year 400 cases per training unit

Thanks for listening

Referrals Please write to me stating: ‘Referral for Mohs surgery, Dermatology department’: Southmead Hospital, North Bristol Trust NBT.outpatientbookings@nhs.net

What needs Mohs? Tumours that can be easily excised with a sufficiently wide margin to guarantee cure without significantly affecting the repair do not need Mohs. A 'rule of thumb' is as follows: - Can I confidently excise the tumour with the recommended clinical margin & repair optimally? - If not, Mohs (or other margin controlled surgery) should be considered

End

The Mohs procedure explained

Pathology – nodular BCC Mohs Micrographic Surgery Pathology – nodular BCC

Pathology – Micronodular BCC Mohs Micrographic Surgery Pathology – Micronodular BCC

Pathology – Infiltrative BCC Mohs Micrographic Surgery Pathology – Infiltrative BCC

BCC Spread Beyond Clinical Margins Mohs Micrographic Surgery BCC Spread Beyond Clinical Margins BCC Type Clinical Excision Margin Around Tumour Complete Clearance Rate (not cure) <20mm & Well-defined 3mm 85% 4mm - 5mm 95% Morphoeic 66% 5mm 82% 13mm – 15mm >95% Determined by Mohs pathology. Breuninger H, Dietz K. Prediction of subclinical tumor infiltration in basal cell carcinoma. J Dermatol Surg Oncol 1991; 17:574–8. Kimyai-Asadi A, Goldberg LH, Peterson SR et al. Efficacy of nar- row-margin excision of well-demarcated primary facial basal cell carcinomas. J Am Acad Dermatol 2005; 53:464–8. Telfer N, Colver G, Morton C. Guidelines for the management of basal cell carcinoma. Br J Dermatol. 2008 Jul. 1;159(1):35–48.

Standard Pathology Standard protocol Usually 4-6 x3mm slices 5 micron shaves from each slice Usually <5% of margins seen Standard Pathology

Standard Tumour Pathology - NBT Mohs Micrographic Surgery Standard Tumour Pathology - NBT Bread-loafing 3mm slices Shaves taken from each Tips separate: shaved off broad end If tumour found, tips rotated and shaves taken from sharp end Saves going through whole specimen No standardisation

Mohs Micrographic Surgery Standard Pathology

The Mohs Excision – Cross Section Mohs Micrographic Surgery The Mohs Excision – Cross Section PRESSURE DOWNWARDS SQUASHED FLAT UNDERSIDE OF SPECIMEN 100% OF MARGINS ON 1 PLANE Superficial Peripheral Margin Deep Margin Deep Peripheral Margin

Mohs: Flattening the specimen Mohs Micrographic Surgery Mohs: Flattening the specimen