Perianal Paget's: Preserving Performance Status with Photons. A Case Series of Three Women with Extramammary Paget's Disease Treated with Primary Radiotherapy
Faculty and Abstracts
Purpose: Extramammary Paget’s Disease (EMPD) is a rare cutaneous malignancy of the skin with a high concentration of apocrine glands, most commonly affecting the anogenital region of postmenopausal women. Like Paget’s Disease of the breast, EMPD presents with eczematous lesions often leading to a misdiagnosis of inflammatory dermatosis, delaying diagnosis and treatment. Both dermal invasion and lymphatic spread can occur, with over 30% of cases complicated by an associated malignancy. The standard of care has historically been surgical excision; however, positive resection margins and local recurrences are common due to the irregular shape and multifocal nature of the disease, with potential disfigurement and morbidity including the need for urinary and bowel diversions. There is very little published literature regarding definitive non-surgical, organ-sparing management for EMPD. The prior reports offer few details regarding treatment technique or refer to patients previously treated with outdated modalities. The purpose of this study is to report on our treatment technique and outcomes with 3 consecutive women treated with definitive RT using VMAT.
Methodology: We retrospectively reviewed the medical documentation and treatment records of 3 women treated at one institution for EMPD of the perianal area between 2018 and 2023 including work-up, treatment plans, toxicity and outcomes. We describe our treatment techniques and these patients in depth, including both short- and long-term outcomes for definitive treatment with RT.
Results: The 3 women were aged 69-83 years and all presented with eczematous perianal skin lesions with subsequent histopathological confirmation of EMPD. All women underwent systemic evaluation including pelvic imaging and endoscopy to rule out associated malignancy. Based on multi-disciplinary discussion, surgery would have required permanent colostomy, and they were each recommended for organ-preservation with primary RT. All 3 were treated with VMAT to a dose of 54-60Gy to the region of visible EMPD and 45Gy to the elective pelvic nodes. All women completed treatment as prescribed. Acute toxicities included grade 2-3 dermatitis, cystitis, anorectal pain, and diarrhea. Chronic toxicities included RT related skin changes and changes in bowel habits. Four- and five-year follow-up of two of the women show no clinical or pathological evidence of disease. The third woman is 6 months from completion of her radiotherapy, with no clinical signs of disease.
Conclusions: EMPD is rare, frequently misdiagnosed, and often a harbinger of invasive disease, requiring a high index of suspicion and low threshold to biopsy concerning anogenital lesions. Following diagnosis, it is essential to evaluate for advanced or associated malignancies. Excision remains first line when negative margins and organ preservation are possible. RT is well tolerated and an effective method of treatment, and should be considered for the elderly, medically inoperable, and for those whom surgery may be disfiguring or affect quality of life.
