Breast Cancer on the Run in October: (Day 27) Oncotype and the New Genetics
OCTOBER 27: ONCOTYPE AND THE NEW GENETICS
THANK YOU. THAN YOU. THANK YOU, GOD. THANK YOU, DOCTOR. THANK GOD I DON’T HAVE TO DO CHEMOTHERAPY…. A decade ago there were few women who would echo these sentiments. Most women who were diagnosed with breast cancer ended up needing chemotherapy after surgery.
The efficacy of adjuvant chemotherapy (chemotherapy given after surgical removal of the cancer) had been established in the early 1980s. We have chronicled the move towards more aggressive and varied regimens through the next three decades.
The old criteria used to enter a patient into an adjuvant chemotherapy protocol was rigid and depended on establish factors like tumor differentiation, tumor size, and lymph node involvement. It was hard not to qualify.
There was also an uneasy feeling among some that the advantages conferred on the patient taking adjuvant chemotherapy were real, but not that substantial. Perhaps not everyone needed it or reaped advantages from it.
Occurring in parallel at this time was a look into the human genome and the genetic issues that lead to the development of breast cancer. We were learning how to access genetic material and learn from it.
Equally as important was a treasure trove of information and pathological material from thousands of breast cancer patients that had been entered into large data bases over the years and that could be newly evaluated. This material was available to study based on the new genetics.
Out of this came a new system to determine whether a patient needed chemotherapy based on the genetic make up of the tumor. Each person developed their own unique breast cancer based on certain genetic criteria. Not all breast cancer of a certain differentiation, size,and lymph node involvement were the same. Some were more or less aggressive based on criteria other than those used beforehand.
Oncotype DX was the test developed to determine whether a patient with invasive breast cancer would benefit from chemotherapy or not based on the biology of that individual patient’s tumor. Many patients were found not to need chemotherapy. This has been well established in trials with over 50,000 patients.
The new Oncotype DCIS (DCIS-early, stage 0 breast cancer) is a test based on a patient’s genetic information to determine the risk of their DCIS or an invasive cancer developing in 10 years. Although this test cannot predict the benefit of radiation therapy, it does provide information on individual risk for a future event.
The significance of Oncotype is far reaching. We are now treating patients as individuals and the breast cancer they develop as being as individual as they are themselves. Treatment should then be personalized.
This is real progress.