Supplementary Material for: Oestrogen receptor positive metastatic eccrine porocarcinoma: A case report and review of anti-oestrogen therapy in rare cancers.

Rare cancers, in aggregate, represent a significant burden of disease in oncology, and remain therapeutically challenging to manage due to a lack of clinical trials. Eccrine porocarcinoma is a rare cutaneous sweat gland malignancy for which there remains no standard approach to metastatic disease. We describe a patient diagnosed with metastatic disease, confirmed on bone biopsy; pathological analysis further revealed this was oestrogen receptor positive. She was commenced on the aromatase inhibitor letrozole and denosumab, and showed a significant clinical and radiological response on bone scan within 7 months. At the time of report, over 2-years since commencing letrozole, she remains well with no evidence of progression. Our experience adds to the literature suggesting anti-oestrogen therapy can have significant benefit in patients with ER positive non-breast cancer, and is in keeping with increasing interest in therapies agnostic to site of origin but guided by expression/mutation of oncogenic drivers.

罕见癌症整体而言在肿瘤学领域构成了沉重的疾病负担，且因临床试验匮乏，其临床治疗仍极具挑战性。小汗腺汗孔癌（Eccrine porocarcinoma）是一类罕见的皮肤汗腺恶性肿瘤，目前针对其转移性病变仍无标准治疗方案。本文报道1例经骨活检（bone biopsy）确诊为转移性疾病的患者，病理分析进一步证实其肿瘤为雌激素受体（oestrogen receptor）阳性。该患者接受了芳香化酶抑制剂（aromatase inhibitor）来曲唑（letrozole）联合地诺单抗（denosumab）的治疗方案，在治疗7个月后的骨扫描（bone scan）中显示出显著的临床及影像学应答。截至本文撰写时，距患者启动来曲唑治疗已超过2年，其病情仍维持稳定，无进展迹象。本次临床经验补充了相关文献证据，表明抗雌激素治疗（anti-oestrogen therapy）对雌激素受体阳性的非乳腺癌患者可带来显著获益，这也与当前日益受到关注的“以致癌驱动因子（oncogenic drivers）的表达或突变为指导、不依赖肿瘤起源部位”的治疗研究方向相符。