With the advent of digital mammography and modern MRI scanning of the breasts, early breast cancer can now be detected in its “infancy” and quickly diagnosed. Modern treatment relies on a multimodality approach (surgeon, oncologist, radiologist, pathologist, etc) and the role of chemotherapy, hormone therapy, surgery and radiotherapy are discussed in the article.
This article is written by Dr Nick Plowman, MD, Senior Clinical Oncologist to St. Bartholomew’s Hospital, London.
With the introduction of modern imaging methods, mammography, ultrasound and MRI (this last being increasingly important for some patients), breast cancer is being detected at an earlier stage than ever before – this leads to increasing cure rates. Indeed, since screening became available on a population basis, pre-cancer (ductal carcinoma in situ – DCIS, and lobular carcinoma in situ – LCIS) and very early cancer (microinvasive cancer) have been detected much more frequently and pose a new set of interesting problems with regard to ‘how little’ therapy is needed to ensure cure.
When a more established breast cancer is detected by imaging, and proven (usually by fine needle aspiration cytology - FNAC), definitive/curative management is based on staging of the cancer (to what extent has it grown and spread) and, increasingly on cellular markers (detected by the histologist on analysis of the tumour or biopsy specimen) – hormone receptors, gene expression products and genetic signatures as detected by micro-array technology – all assisting in the decision on optimal management.
For early breast cancer, with no evidence of spread outside the breast, then limited surgery (conserving the majority of the breast) is safely performed – usually followed by breast radiotherapy. At the operation, armpit/axillary node sampling (taking the sentinel node that drains the area of the breast in which the tumour arose) is performed and followed by a larger axillary node dissection in node-positive patients for improved regional control rates. The information gained on the involvement or not of the axillary nodes is also of great importance with regard to future risk of relapse of the disease and assists the oncologist in the decision of subsequent management.
Axillary node-positive patients are usually advised to receive chemotherapy – intravenously administered drugs that kill cancer cells wherever they may be. Decisions on the need for such immediate post-operative chemotherapy (so-called adjuvant chemotherapy) are also based on the tumour’s size and histological grade (a microscopic assessment of aggressivity based on number of mitoses seen down the microscope etc.) and cellular markers such as mentioned above. By such means, the oncologist assesses the higher risk patients for whom adjuvant chemotherapy will have highly significant risk reduction potential for the future and lower risk patients for whom no further treatment is required or for whom anti-hormonal therapy may perform the same task.
The whole rationale of adjuvant therapy is that it is easier to cure cancer when there are only a few (relative term) cancer cells in the body than when there is full blown relapse – hence therapy is often given after an operation which by itself appears to have removed the only known site of disease.
Tumour cells that express hormone receptors (the proteins that are present in normal breast duct cells and sense and respond to oestrogen hormone and which are retained by some breast cancer cells) will respond to drugs targeted at either blocking these receptors (e.g. tamoxifen) or deprive the body of oestrogen (GnRH antagonists and aromatase inhibitors). These medications carry fewer side effects than chemotherapy and have an important role in the adjuvant therapy of patients with hormone receptor-positive disease and are given for up to five years after the diagnosis.
Larger or more extensive breast cancer (without overt spread beyond the breast and regional lymph nodes) may be treated by primary total mastectomy (sometimes with immediate reconstruction of the breast shape by subcutaneous prosthetic implant) or even primary chemotherapy to shrink the tumour down in size prior to operation. Such patients are more likely to receive all modalities of therapy – viz. chemotherapy, hormonal therapy, surgery, radiotherapy and nowadays the molecular agents. These last are of great interest. Where a breast cancer expresses a surface membrane protein called Her-2 (approximately 20% of cases) then this tumour is being driven to multiply in an above average, aggressive way by a particular oncogene. In the last few years, an inhibitor of Her-2 (trastuzumab) has been shown to further improve the results of adjuvant therapy in terms of long term disease survival (which we expect to equate with cure), and an orally active version of this therapy (lapatinib) is now becoming available.
It has now been unequivocally demonstrated that improved adjuvant therapy – wisely chosen and bespoke for individual patients and based on the risk characteristics of their tumour and its staging at presentation to the doctor – will increase the cure rate of this disease and it is therefore critical that this is assessed optimally at the outset.
Modern treatment relies on a multimodality approach (involving experts in surgery, radiology, histopathology, oncology and others). The team at The Oncology Clinic at 20 Harley Street in London has long-term experience in the field, introduced the specific aromatase inhibitors to Europe and has published widely in scientific medical journals on optimal therapy in breast cancer.