You can do without chemotherapy

According to the results of a multicenter clinical trial on the selection of individualized therapy options (Rx) –Trial Assigning Individualized Options for Treatment (Rx), or TAILORx, chemotherapy is not needed by approximately 70% of women with the most common type of breast cancer – HER2-positive – without lymph node damage. Observations have shown that with such a diagnosis after surgical removal of the tumor, hormone therapy in combination with chemotherapy in most cases is no more effective than just hormone therapy.

As part of the Phase 3 clinical trial of TAILORx, launched in 2006, a molecular test evaluating the expression of 21 genes associated with breast cancer recurrence was used to select the optimal postoperative treatment protocol for women with early stages of HER2-positive breast cancer without lymph node damage. A total of 10,273 women with this type of disease participated in the study, who underwent therapy in 1,182 clinics in the USA, Australia, Canada, Ireland, New Zealand and Peru.

After inclusion in the study, the women's tumors were analyzed for the expression of 21 genes, on the basis of which risk coefficients (in the range of 0-100) for the development of relapse of the disease were calculated. Based on the results of earlier studies, women with the lowest risk (coefficient 0-10) received only hormone therapy, and women with the highest risk (coefficient 26 and higher) received a combination of hormonal and chemotherapy.

Women with intermediate risk coefficient values (11-25) were randomly divided into two groups, one of which received only hormone therapy, and the second received hormone therapy in combination with auxiliary chemotherapy.

Processing of the collected results showed that the values of the main criterion for evaluating the study – survival without signs of invasive disease, defined as the proportion of women without recurrence of the primary tumor, were comparable for patients of both groups. 5 years after the end of therapy, the survival rate without signs of invasive disease was 92.8% for women who received hormone therapy alone and 93.1% for women from the combination therapy group. After 9 years, these values were 83.3% and 84.3%, respectively. None of the differences are statistically significant.

Overall survival rates also turned out to be comparable for the two groups. After 5 years, the overall survival rate for the hormone therapy group was 98%, and for the combination therapy group – 98.1%. After 9 years, the corresponding figures were 93.9% and 93.8%.

The researchers also found that women with the lowest risk coefficient (1-10) who received only hormone therapy were characterized by a very low probability of relapse, which was only 3% for a 9-year period. This confirms the results of earlier studies. At the same time, it was found that in women with the highest risk coefficient (26-100), the incidence of long-term relapses was 13%, despite the combination therapy. This indicates the need to develop more effective methods of treating patients at high risk of relapse.

Based on all of the above, the authors concluded that in the early stages of HER2-positive breast cancer without lymph node damage, chemotherapy can be refused in about 70% of cases, namely:

• in women over 50 years of age with a relapse risk factor of 11-25 (45%);
• in women of any age with a relapse risk factor of 0-10 (16%);
• in women aged 50 years and younger with a relapse risk factor of 11-55 (8%).

At the same time, chemotherapy is advisable in the remaining 30% of cases:

• in women of any age with a relapse risk factor of 26-100 (17%);
• in women aged 50 years and younger with a relapse risk factor of 16-25 (14%).

New evidence suggests that chemotherapy does not benefit the majority of women at medium risk of relapse. They complement the results of TAILORx published in 2015, according to which the analysis of gene expression makes it possible to identify women with a low risk of relapse who can do without chemotherapy.

However, there is one controversial point. In a separate analysis of the results of observation of menopausal women and women under 50 years of age, who are in the upper part of the range of the middle part of the risk factor scale (16-25), the results showed that chemotherapy can still have a certain positive effect. To date, it is unclear whether this is due to the direct effect of chemotherapy or the suppression of the activity of the endocrine glands in the conditions of menopause induced by chemotherapy drugs. In any case, attending physicians should discuss the feasibility of chemotherapy with women of these subgroups.

Article by Joseph A. Sparano et al. Adjuvant Chemotherapy Guided by a 21-Gene Expression Assay in Breast Cancer is published in The New England Journal of Medicine.

Evgenia Ryabtseva, portal "Eternal Youth" http://vechnayamolodost.ru according to the National Cancer Institute: TAILORx trial finds most women with early breast cancer do not benefit from chemotherapy.