INSIDER is a new series that aims to highlight exciting developments from the world of cancer research and clinical trials. These posts are written by our research laboratory heads and the opinions expressed in these posts are those of the contributing author.

By Prof Robin Anderson, Head of the Translational Breast Cancer Program and Metastasis Research Laboratory

October is Breast Cancer Awareness month.  As we reflect on the unexpected events of 2020 that have forced us to make drastic, but hopefully temporary changes in lifestyle, it is a good time to reflect on the remarkable progress made over the past 30 years in the treatment of breast cancer, thanks to medical research.

The current five-year survival rate in Australia, based on data from 2012 to 2016, is 91% for women and 85% for men.

These five-year survival rates have increased from the 1987-1991 period when they were 75% for women and 76% for men. The increase in survival has been more dramatic for women, assisted by the increasing public awareness of symptoms, free mammography since 1994 and, importantly, medical research.  Breast cancer is a rare disease in men and is likely to be diagnosed at a more advanced stage.

These dramatic increases in survival rates are the result of many years of research in cancer institutes around the world, gaining new knowledge about the basic biology of breast cancer and seeking more effective therapies.  Breast cancer treatment varies depending on the type of cancer that develops.  The most common type of breast cancer typically responds well to endocrine therapy as the cancer needs the hormone estrogen to keep growing.  If deprived of estrogen, the cancer dies.  Endocrine therapy has been the mainstay of this type of breast cancer for the past three decades and results in close to 100% survival after 5 years. However, a few of these cancers can recur after many years and are more challenging to treat.  Medical researchers have now discovered new cell cycle inhibitors (specifically inhibiting CDKs 4 and 6) that dramatically prolong progression free survival when used in combination with endocrine agents.

Another type of breast cancer is called HER2 amplified breast cancer, so called because it is driven by a gene called Her2.  In the early 1990’s, patients with this type of cancer had a life expectancy of only 3-5 years.  The discovery of an antibody that specifically blocks Her2 function by medical researcher and medical oncologist Dennis Slamon revolutionised the treatment and now nearly all Her2 positive patients survive beyond 5 years.

The third major subtype, the so called triple negative breast cancer, is the most challenging type to treat and is the focus of researchers at the ONJCRI.  These patients are treated with standard chemotherapy to which most respond well, but it is not uncommon for the cancer to return.  There is very active research at ONJCRI and at many other cancer research institutes around the world seeking better therapies for this type of breast cancer.  Many new experimental treatments are emerging, but will need to be tested in clinical trials to see if they really can improve the outcome of triple negative breast cancer patients.