Christobel Saunders, University of Western Australia; Anthony Dowling, University of Melbourne; Rik Thompson, Queensland University of Technology, and Robin Anderson, Peter MacCallum Cancer Centre
Cancer is a collection of many hundreds of diseases. The common factor is that once-normal cells have undergone a series of mutations in their genes that has led to uncontrolled growth and an impaired ability to die when they normally should.
Cancers may also spread into other organs, forming secondary cancers, called metastases. When patients die of cancer, it’s usually due to these metastases.
Breast cancer is one of the most common cancers in the Western world, with 15,000 women (and about 70 men) diagnosed each year in Australia. Fortunately, with modern treatments, more than 90% of women with breast cancer go on to have a normal life expectancy, though the side effects of both the cancer and its treatment affect many aspects of their lives.
When detected, cancer can be classified into stages, based on how advanced the disease is in the body.
In breast cancer, the important factors include the aggressiveness of the cells (the grade) and specific proteins that they make. These proteins drive the growth of the tumour cells, including some that bind to female hormones such as oestrogen and growth-promoting proteins such as HER2. Whether a tumour has involved lymph nodes under the arm is also of great importance in assessing its likely potential to spread further.
These markers guide us closely in what drug treatments to consider but also suggest a “prognosis” – that is, how likely the cancer is to be cured or to come back.