The only reason I accepted his invitation to circle the dance floor is that his latest foray into temptation has to do with pluripotent stem cells, a highly interesting, extremely complex, and promising area of serious scientific investigation. But before I attempt to follow Dr Sears’ complicated dance routine, there’s another bit of news that I want to put before you. It is, in the considered opinion of Doc Gumshoe, one of the most important news items in the medical field to have emerged in quite some time.
What the results of the TAILORx trial might mean for thousands of women
The results of the trial have not actually been published yet. They were scheduled to have been presented at the American Society of Clinical Oncology (ASCO) a couple of days ago, but the news has trickled out and hit the front page of the New York Times. In a nutshell, it is this: for thousands of women with early stage breast cancer who would, following the current treatment guidelines, have been treated with chemotherapy, this form of treatment may not be necessary. And, given that chemotherapy is in its essential nature a highly toxic form of treatment, if it is possible to treat these patients without resorting to chemotherapy with no sacrifice to treatment outcomes, then by all means, chemotherapy should be avoided.
The trial, TAILORx, (Trial Assigning IndividuaLized Options for Treatment (Rx), was announced in 2006. Its initial objective was not specifically to evaluate the benefits of chemotherapy versus other forms of therapy, but to examine whether genes that are frequently associated with risk of recurrence for women with early-stage breast cancer can be used to assign patients to the most appropriate and effective treatment.
What the trial found was that in a significant percentage of women with early stage breast cancer, perhaps as high as 70%, chemotherapy provides no benefit whatever over drugs that inhibit the action of estrogen or prevent the body from generating estrogen. Tamoxifen and related drugs, termed endocrine therapy, are very widely used; even though these agents do have side effects, including a slight increase in the risk of developing uterine cancer, the side effects of endocrine therapy are quite mild compared with the side effects of chemotherapy. The almost inevitable side effects of chemo include extreme nausea and hair loss. Less frequent but more serious side effects include cardiac and nervous system damage, increased susceptibility to infectious diseases, and perhaps also increased risk of leukemia.
The trial evaluated nearly 10,000 women with early stage breast cancer who had genetic analyses of their cancers. Of these, about 70% had disease marked by the following characteristics: 1), early stage breast tumors measuring one to five centimeters; 2), that have not spread to the lymph nodes; 3) these tumors are sensitive to estrogens; 4), and do not demonstrate the presence of the HER2 protein; 5), finally, an intermediate score on a genetic test that estimates the activity of a group of genes that are known to predict cancer recurrence.
One group of women in this cohort, those with intermediate test scores, was randomly assigned to receive either hormone therapy alone or hormone therapy together with chemotherapy. After nine years of follow-up, the overall survival rates were 93.9% in the women who got hormone therapy alone, versus 93.8% in those women who were treated with the combined therapy regimen. The rates of survival free of any evidence of invasive cancer in those two groups were 83.3% versus 84.3%.
That one percent difference favoring the cohort of women who got the combined therapy suggests that there may be a very few women who get a tiny benefit from chemotherapy. The authors note that these women are substantially younger than the age at which women usually develop breast cancer, and that further study is necessary before arriving at any conclusion.
Based on the overall evidence, the conclusion of the authors as well as that of