Clinical And Pathological Features Of Breast Cancer In Patients With Systemic Sclerosis: Preliminary Data From The Sclero-Breast Study

Background:Systemic Sclerosis (SSc) is a rare and life-threatening connective tissue disease characterized by vascular dysfunction, specific autoimmune abnormalities and fibrosis of the skin and internal organs. Previous studies have shown a 1.5-fold increase in cancer risk in SSc patients compared with the general population, including breast cancer (BC). The relationship between BC and SSc has long been discussed but past research has been contradictory and inconclusive on this topic.Objectives:The aim of our project was to analyze clinical and pathological characteristics of BC developed by SSc subjects and possible correlations with scleroderma features. Here we present the preliminary data from the Sclero-Breast study.Methods:Our observational retrospective multicenter study enrolled 33 SSc women with a personal history of BC identified at two Rheumatology/SSc Units in the north of Italy between January 2017 and December 2019 (lc/dcSSc 23/9, 1 unknown; mean age at SSc onset 57 years, range 32-73). All patients underwent general and instrumental assessment: smoking habits; presence of skin ulcers, calcinosis, teleangectasia; presence of gastro-intestinal and kidney involvement; interstitial lung disease (at HR-CT); pulmonary function tests; ECG abnormalities; echocardiographic assessment of pulmonary arterial hypertension (PAH); videocapillaroscopic pattern; autoantibody profile; exposure to immunosuppressive and vasoactive therapies; status at last follow-up evaluation and cause of death. Clinical and pathological characteristics of BC were also evaluated: age at diagnosis; menopausal status; histotype; hormone receptor status; MIB1, HER2 expression; clinical and pathological stage at diagnosis; metastatic sites; type of loco-regional treatment (surgery and radiotherapy); type of systemic treatment (neoadjuvant/adjuvant chemotherapy and endocrine treatment); other cancers and time from diagnosis of the first disorder to the second one.Results:A total of 54.5% of subjects developed BC before SSc (median interval of 5 years), whereas 45.5% of patients developed BC after SSc (median delay of 8 years). 54.5% of patients showed interstitial lung disease and the cause of death of the 6 deceased subjects was PAH. A significant association (p<0.05) was observed between the use of immunosuppressive therapy and diffuse skin extension, negative ACA, positive Anti-Scl-70 and interstitial lung disease, but not with BC status. 93.1% of patients were diagnosed with an early-stage tumor, 70.8% of invasive carcinomas with a low MIB-1, 8.3% with a tubular histotype, while 42.8% presented with a Luminal A-like tumor. 66.6% underwent breast conserving surgery and 55.5% RT after surgery. 40% of patients developed interstitial lung disease after RT and 20% dcSSc.Conclusion:According to our preliminary data, SSc patients developed BC at good prognosis, suggesting a de-escalation strategy of cancer therapies. On these grounds, a proper screening is mandatory in order to allow for early cancer detection in SSc patients. Further investigations on larger numbers of patients are needed. First of all, they would further clarify the intriguing relationship between BC and SSc. Secondly, they would help to explore the common biological and molecular pathways at the basis of these two disorders, with the aim to improve BC diagnosis and prognosis and to personalize oncological targeted treatments in this subset of fragile patients.Disclosure of Interests:None declared