In fall 2015, stories began circulating that a study had shown that chemo wasn’t already required as part of breast cancer treatment. But after awhile, the conversation started to dwindle. That is until now. Today in Chicago, attendees of the annual meeting of the American Society of Clinical Oncology are hearing study findings that chemotherapy may no longer be required for all women diagnosed with breast cancer. The study, called TAILORx, was a team effort by the U.S. and Canadian governments, as well as several charitable organizations.
Chemo Found to Have No Impact on Early-Stage Breast Cancer Survival Rates
TAILORx began in 2006 and followed 6,800 women from age 18-75 who had received an early stage breast cancer diagnosis, defined as tumors that have not spread to the lymph nodes and range between 1-5 cm. The women must also have tested negative for HER2, a protein found to be a major contributor to breast cancer.
Study participants were blindly divided into 2 groups. Group 1 received both chemotherapy and endocrine-blocking drugs (such as Tamoxifen), while Group 2 was given only the endocrine-blocking drug. After 7 years, patients who received chemotherapy followed by an endocrine-blocking drug had the same rate of reoccurrence as the endocrine-blocking drug only group. After 9 years, 93.9% of patients were still alive in that group, while 93.8% were still alive in the group that also received chemo.
This finding could spare 60,000 U.S. women, or 70% of those previously recommended for chemo, from having to receive the treatment.
Typically Oncologists have determined the type of treatment after removing cancerous breast tumors and testing them using a genetic testing tool. The most commonly used genetic test is called Oncotype DX. The test rates a tumor from 0-100. Traditionally tumors that scored 0-10 were believed to not require chemotherapy, but Oncologists struggled with what type of treatment to recommend for patients whose tumor(s) scored between 11-25 (considered an ‘intermediate’ score). It is scores within this range that were targeted through the TAILORx study and were found to not require chemotherapy. Even more good news? The Oncotype Dx test is usually covered by insurance as part of a patient’s cancer diagnosis and treatment coverage.
As Always, There’s A Catch
Despite the overall finding that chemotherapy is not necessary for survival in most early-stage cases, the study found that some women 50 and under with an Oncotype Dx score of 16-25 still benefit from receiving the treatment. Study authors are unsure why, despite the women having the same clinical presentation as others who would not require chemo (18-75 years old, tumors between 1-5 cm, no lymph node activity, and HER2 negative). Although this news is disappointing, the upside is that the most common age for breast cancer diagnosis is 62, meaning the majority of future early diagnosis patients will benefit from the study’s findings.
Chemotherapy has always been the most dreaded part of treatment for cancer patients. The obvious side effects of fatigue, nausea, and hair loss are just a few of the significant potential downsides. More serious are the increased risks of leukemia and heart and nerve damage. To spare 70% of women from having to receive harsh treatment they do not need is incredible news.