The Science at the Root of Treating Breast Cancer

Wednesday, 29 May, 2019

"Let me start by telling you that breast cancer is a whole family of disease and not just one", opens Consultant Histopathologist, Dr Marie Staunton. "There is more than just one type and we've learned to recognise their respective features and traits and tally these with whether they will respond well to treatment or will be very aggressive in nature".

She continues, "Our work is rooted in the science of cancer and this allows us to provide robust confirmations of a diagnosis, to predict the future behaviour of a tumour and to advise of its likely biological response to drug treatments. Nowadays, tissue samples are predominantly taken by core biopsy by radiologists under local anaesthetic. But thirty years ago, all patients would have had to have a general anaesthetic followed by open surgery to extract a tissue sample. It can still be necessary to have surgery in certain cases but nowadays, 99% of people with cancer receive a diagnosis non-operatively using core biopsy.

The analysis of these tissue sample shapes much of what will happen next in a breast cancer patient's treatment regime. We bring all this information to the weekly multi-disciplinary team meetings and together with all the other clinicians, nursing staff and allied health professionals, we help to shape and define an individualised treatment plan for each patient.

Following surgery, a sample of the excised tumour will be sent to us again. We will analyse it to ensure - in the case of lumpectomy - that the clearance margins are safe. If not, we may recommend to the surgeon that the patient be recalled for further surgery.

The information tells us about the biological aggressiveness of the tumour and the liklihood of future recurrences. Apart from information about prognosis the pathologist also gives predictive information beneficial in planning the patient's treatment, such as likely response of the tumour to hormone therapy. We also test for certain mutations such as the Her-2 gene (which in suitable patients allows targeted therapy with designer drugs). All of this is conveyed to the medical oncologist who will be treating the patient.

Histology also determines the need for lymph node surgery in patients. In the past, a diagnosis of breast cancer would have automatically resulted in the surgical removal of all of the lymph nodes, often leaving patients with nerve damage in the arm and lymphodoema. Now, through biopsy of the sentinel or first lymph node, we check to see if it is cancer free. If it is, we can presume there has been no spread of the cancer and this will rule out the need for surgery", Dr Staunton concluded.

Pre-operative histology - confirming diagnosis

Core biopsy samples taken by the radiologists following imaging are examined by histology to confirm whether the sample is benign or malignant. 99% of patients with cancer will get a confirmed diagnosis in this way and histology will also reveal the grade and the subtype of the cancer. It will also dictate the clearance margin for lumpectomy i.e how much surrounding tissue the surgeon should remove, to reduce the risk of recurrence. All these findings form the basis of the histopathology report and will be discussed at the multidisciplinary team meeting. It will shape the course of an appropriate treatment plan for the patient before their cancer diagnosis has even been revealed to them.

Post-operative histology - predicting future behaviour

Following surgery, samples of the excised tissue will again be sent for examination. At this point the pathologist will be looking for various prognostic and predictive markers. Some tumours are hormone responsive and their recurrence can be blocked by drugs which can have a significant improvement on survival. Other drugs target specific mutations in breast cancer and these too are identified by histology or tissue analysis. This information helps guide the Medical Oncologist in prescribing chemotherapy and identifying the patients who have been cured and so do not need chemotherapy.

Photo by Richie Stokes.