Chemotherapy for breast cancer: Part 1 - How it works and when it's offered

Chemotherapy is an important part of the management of some breast cancers; and it may be given before or after surgery - depending on the type and stage of your cancer. This video explains how chemotherapy works, and when it is offered. When breast oncologists like myself talk about chemotherapy, we are talking about systemic anti-cancer treatments. That means they are designed to travel throughout the body, and kill cancer cells wherever they may be. Unlike surgery and radiotherapy, which are focused on treating one area, chemotherapy circulates through the bloodstream and treats the entire body. This is important as breast cancer can cause microscopic spread. These cancer cells are too small to be seen on a scan, and in time, they could cause stage 4 or metastatic recurrence. Chemotherapy is aimed at significantly reducing that risk. Not all breast cancers benefit from chemotherapy. For each patient, I consider all the available information and ask myself; does the biology of this cancer justify chemotherapy? As a result, treatment will be bespoke to your situation. More than ever before, we can identify patients who are most likely to need, or benefit from chemotherapy. So when chemotherapy is recommended, you can be confident this is based on multiple factors and the best clinical trial evidence, all tailored to your needs. So how does chemotherapy actually work? Cancer cells tend to divide more rapidly, and in a less organised manner than normal cells. Chemotherapy exploits this vulnerability, and different chemotherapy drugs work in different ways. When chemotherapy is given before surgery - it is called neoadjuvant treatment. There are a number of advantages to this strategy, and it's particularly helpful for triple-negative breast cancers - or the HER2-positive subtype. Neoadjuvant chemotherapy allows the tumour to shrink, allowing less extensive surgery; less complex surgical planning; and possibly better cosmetic results. One of the most important aspects of neoadjuvant chemotherapy is that the chemosensitivity of the tumour can be seen by its response. The ideal response is what we call a pathological complete response, or pCR; where the cancer has melted away by the time of surgery. This allows us to identify those patients who may benefit from intensifying treatment after surgery. If there is still residual cancer, a different drug can be used as a second chance to clear any remaining cancer cells. When chemotherapy is given after surgery, it is called adjuvant treatment; and the aim is to kill any microscopic cancer cells that may have been left behind. Unlike with neoadjuvant treatment, there is nothing to monitor, as the breast cancer has already been removed. Adjuvant chemotherapy is offered based on clinical trial evidence of efficacy, and benefit for your type of breast cancer. It is recommended for larger tumours, high grade cancers, and where there is spread to lymph nodes. The oestrogen and HER2 receptor status of the cancer also guides this decision. Not every patient with breast cancer needs chemotherapy. For hormone receptor-positive, HER2-negative cancers; genomic tests examine gene activity in the tumour to evaluate the biology, and potential behaviour of the breast cancer. Oncotype DX; EndoPredict; and Prosigna can help identify the aggressive cancers which would benefit most from treatment; and which patients could be spared chemotherapy. Decisions about chemotherapy are highly personalised and made together - taking into account your wishes; beliefs; and particular situation. To talk through what it might mean in your specific case; please get in touch with my team to schedule a discussion.