Women with small, lymph node negative triple negative tumors have excellent five-year outcomes when aggressively treated, according to a new retrospective study. Tumor characteristics were carefully evaluated to select the treatment regimens of study participants. A large minority of the women (33.5%) underwent mastectomy and many (58%) received chemotherapy. Given the generally poor prognosis of triple negative disease, it is heartening to see that this group of patients can have very favorable prognosis with currently available treatment.
Study participants were carefully selected
To select the study participants, the authors examined the records of 1,022 women with triple negative breast cancer who underwent breast cancer surgery between 1999 and 2006 at Memorial Sloan-Kettering Cancer Center, New York. Patients who received chemotherapy or other breast cancer treatment before surgery were excluded from the study. A total of 194 women who had lymph node negative tumors that measured 1 cm or less were included in the study. The median age at diagnosis was 55.5 years and the women were followed for a median of 73 months. About a quarter of the women had undergone BRCA testing: 19 had BRCA1 mutations, seven had BRCA2 mutations, and 23 did not have any BRCA mutation.
The women were divided into groups based on tumor size: T1mic (microscopic disease up to 0.1 cm in size); T1a (over 0.1 but no larger than 0.5 cm); T1b (over 0.5 but no larger than 1 cm). A total of 16 (8.2%) patients had tumors classified as T1mic, 49 (25.3%) had T1a tumors, and 129 (66.5%) had T1b tumors. The majority of the women (142; 73%) had poorly differentiated tumors (tumor grade 3: cells look abnormal and are fast-growing), however, they also tended to lack lymphovascular invasion (invasion of the cancer cells into the blood vessels or lymphatic channels) (170; 87.6%). Most of the tumors were detected by mammogram screening (134; 69%).
Patients received appropriate aggressive treatment
A total of 129 (66.5%) women underwent breast conserving treatment (typically, radiotherapy) and 65 (33.5%) women underwent mastectomy. A total of 113 (58%) of the women received chemotherapy and 123 (63%) received whole-breast radiation treatment. The women who were treated with chemotherapy had less favorable prognostic features, such as young age, T1b tumor, and poor tumor grade.
It is apparent that the women were treated aggressively based on the unfavorable outlook of triple negative breast cancer generally, as well as their specific tumor characteristics. Most women with small, single, lymph node negative hormone receptor positive (ER+/PR+) tumors are given breast conserving treatment and do not receive chemotherapy.
Disease free survival was 95% after five years
The five-year relapse-free survival rate was 95% for the entire study group, including both local recurrences (in the same breast, chest wall, or lymph nodes) and distant metastases. No differences were found in distant relapse-free survival rates between women with tumors up to 0.5 cm in size and those tumors between 0.5 and 1.0 cm. Survival was also similar for women who received chemotherapy and those who did not. This shows that treatment was effective in addressing the additional risk of relapse associated with tumors that were slightly larger or had other more aggressive features.
Please see our article on the latest research on triple negative prognosis for more information.