Abstract Presenting Author Email: alona.courtney@imperial.ac.uk Research question Is there significant variation in the management of mastitis and breast abscesses between different hospitals in the UK and Ireland? Background and Aim Lactational mastitis affects a third of breastfeeding women, 11% of whom develop breast abscesses. Non-lactational mastitis affects 5-9% of women. Management of mastitis includes alleviation of milk stasis and antibiotics. Ultrasound-guided needle aspiration is the recommended method of treatment for breast abscesses. Despite guideline recommendations, there is evidence suggesting significant variation in practice, particularly concerning antibiotic prescribing, rates of incision and drainage and length of inpatient treatment. Considering that the majority of breast surgeons are no longer participating in the on-call roster and the acute presentation of primary breast infections, we hypothesise that such variation in practice indeed exists across the UK and Ireland, where patients are treated by non-breast specialist general surgeons. The aim of the MAMMA study is to describe the current practice in the management of mastitis and breast abscesses in the UK and Ireland and to provide recommendations for best practice. Design Patients: Inclusion criteria: all female patients over the age of 16 with symptoms of mastitis or breast abscess. Exclusion criteria: 1) male patients, 2) underlying breast cancer, 3) breast surgery within 90 days of presentation, 4) breast implant in situ on the ipsilateral side. Intervention / Comparator (or main explanatory variable in an observational study): The following guidelines will be used as audit standards: 1) WHO Mastitis Guidelines 2000, 2) GAIN Guidelines on the Treatment, Management & Prevention of Mastitis 2008, 3) ABM Clinical Protocol #4: Mastitis 2014, 4) NICE Clinical Knowledge Summaries: Mastitis and Breast Abscess MAMMA: Mastitis And Mammary abscess Management Audit Outcomes: Phase 1 will increase our understanding of the patient treatment pathways and ease of access to specialist breast services for patients with mastitis and breast abscesses. Phase 2 will collect prospective, real-time data on the management of mastitis and breast abscesses nationwide. Specifically, MAMMA will enable us to gather precise evidence on antibiotic prescribing, rate of operative versus radiological management, waiting time to ultrasound scan, rate of inpatient versus outpatient treatment, length of hospital stay and the rate of follow-up by breast surgeons. This highquality data will be instrumental in updating guidelines and help to standardise the management of mastitis and breast abscess across the UK and Ireland. Study design The study will be carried out in 3 phases with the support of a national trainee collaborative: 1) national practice survey, 2) prospective audit, 3) prospective re-audit. All acute hospitals that manage patients with mastitis and breast abscess will be invited to participate. All participating centres will be required to register this audit as per local protocol. All study data will be collected and managed using REDCap electronic data capture tool. Team and Infrastructure MAMMA National trainee collaborative will be established with the assistance of the Mammary Fold Academic and Research Committee and other regional research collaboratives. It will be the driving force behind this project. The trainee collaborative will be overseen by the MAMMA Steering Committee, convened from key stake-holders from a variety of medical and surgical specialties, allied health care professionals and patient representatives, who are directly involved in the management of patients with breast infections. MAMMA Study Management Group (SMG) will be responsible for audit management, data analysis, dissemination of results and drafting of publication. Regional trainee leads will represent each HEE region in the UK and Ireland and will be responsible for recruitment and coordination of local collaboratives; they will be directly accountable to the SMG. Local trainee collaboratives will consist of a local lead, maximum of two collaborators and one data validator. Further information is available on www.mammastudy.com.