Personalising breast cancer treatment for better results
Future breast cancer treatments are evolving towards targeted therapies individualised for each patient’s condition.
Health Agenda magazine
The earliest recorded cases of breast cancer were noted in Ancient Egyptian papers dating from 1600BC. At that time, and right up until the mid-20th century when scientists discovered DNA, little was known about breast cancer and how to treat it.
Recently, as genetic profiling of the disease’s different forms has advanced, treatment has also changed. There is now an understanding that different cancers respond better to various treatments, rather than the one-size-fits-all approach used in the past.
Professor Alessandra Muntoni is the Director of Research Investment at the National Breast Cancer Foundation. She spoke with Health Agenda about this personalised approach to breast cancer treatment.
Is a more tailored approach to breast cancer treatment a recent development?
The last 20 years have completely changed the way breast cancer is thought about and treated. However, there are still some breast cancers that are not yet understood at the molecular level and have no specific treatments.
Breast cancer research is leading the way in understanding the complexities of the disease and many of the learnings can be applied to other cancer types.
Conventional breast cancer treatment can include surgery, radiotherapy and chemotherapy. Does a tailored approach use these treatments in different forms or does it use different therapies entirely?
Tailored treatment, also called personalised medicine, precision medicine or targeted therapies, aims to treat people according to the unique characteristics of their illness. Targeted therapies for breast cancer are based on information about the genetically different subtypes of the disease.
It’s a complex disease comprised of many subtypes that are all different at a molecular level, which means they grow, adapt, behave and respond to treatment differently. Each subtype needs to be understood at a molecular level before treatments can be personalised to tumour and patient individually.
In breast cancer, personalised medicines work by targeting specific characteristics of the cancer cells, such as a protein that allows the cancer cell to grow in a rapid or abnormal way. For example, some breast cancers are fuelled by the female hormone oestrogen. Once this relationship was understood, researchers were able to develop a medication (commonly known as tamoxifen) that blocks the effect of oestrogen in the breast tissue so the tumour has no fuel to grow.
Being able to prescribe tamoxifen and the other targeted treatments is a key improvement from the past when we did not know about breast cancer subtypes, and the standard treatment for all women was chemotherapy.
Targeted treatments are more effective at killing cancer cells and less likely to harm healthy cells along with the cancer cells during treatment. Tailoring treatments can also involve radiotherapy, surgery and chemotherapy, depending on what is right for the patient and the tumour.
For example, chemotherapy might be used before surgery to shrink the size of the tumour so the surgery is not as invasive.
How would a woman and her doctor know whether she would be a candidate for a treatment other than chemotherapy?
Once a tumour has been biopsied and the results determined by a pathologist there can still be challenges for the treating doctor. These include how to select which patients are likely to benefit from chemotherapy and those who may be safely spared this toxic therapy.
Also, predicting which patients with pre-cancerous breast changes will go on to develop invasive carcinoma and those who don’t need surgery and or radiotherapy. Finally, how to identify novel treatment approaches for rare types of breast cancer.
The common feature among these issues is the ability to select the best treatment for individual patients. Molecular pathology is an emerging discipline which focuses on the study and diagnosis of disease by examining the molecules within organs, tissues or bodily fluids. This can play an important role in better understanding the genetic changes in breast cancers and using that information to help select the optimal treatment for each patient.
This is the subject under investigation by National Breast Cancer Foundation-funded Professor Sandra O’Toole from the Garvan Institute of Medical Research, who hopes to make diagnosis and selecting the right treatment easier and more accurate for doctors.
What does a patient need to know about their particular type of tumour?
Knowing what subtype of breast cancer they’re dealing with allows doctors to determine the specific needs of each individual, and to determine a treatment plan according to the molecular make-up of their tumour.
Tumour cells contain certain hormones and protein receptors which are naturally found in women’s bodies. For example, about 70 per cent of breast cancers test positive for hormone receptors, which means treatments can target those receptors and effectively reduce or kill the cancer cells.