Systematic review of added immunotherapy in traditional treatment for HER2 positive breast cancer patients

• This single-institution systematic analysis on seven studies shows that patients who had HER2 positive breast cancer benefitted more from dual immunotherapy alongside chemotherapy, compared to single immunotherapy or dual immunotherapy without chemotherapy. • Immunotherapy complemented the chemotherapy treatments synergistically in patients with HER2 positive breast cancer. • There was little information on the effectiveness of immunotherapy alone compared to surgical breast reconstruction techniques. Breast Cancer is one of the most prevalent cancers in the UK with a variety of subtypes. One of the more invasive and aggressive subtypes is known as ‘HER 2 positive’, referring to the overexpression of HER 2 receptors on cancer cells. Traditionally, surgical intervention alongside chemotherapy in these invasive subtypes is the preferred and recognised treatment. However, recent literature suggests newer immunotherapeutic agents approved by NICE could be beneficial to treat HER 2 Positive patients as an addition or even a substitute over traditional treatments. To perform a systematic review of added Immunotherapy in traditional treatment in HER2 Positive Breast Cancer Patients A literature search was conducted using four medical databases in 2022. These were PubMed, Scopus, EMBASE, and Web of Science. The inclusion criteria included Females aged 18 years and above diagnosed with HER2+ breast cancer using immunotherapy as the intervention comparing it with chemotherapy and looking at pCR and survival rates as the outcome. Exclusion criteria was also present excluding terms like ‘triple negative breast cancer’. The Joanna Briggs Institute (JBI) Checklists were used to assess the risk of bias of studies. After study selection processes, seven studies were used in this review. Five of the studies were randomised controlled trials and two of the studies were follow up studies. The randomised controlled trial results clearly showed a better pCR and survival rate for patients which had two immunotherapeutic agents compared to one, and patients who has chemotherapy alongside immunotherapy, compared to patients who only had immunotherapy. It was clear that two immunotherapeutic agents alongside chemotherapy was the most effective treatment for patients also producing the best pCR and survival rates. Limitations of studies included short follow up periods and lack of binding of participants in the trials.