Data presented Wednesday at the 2018 San Antonio Breast Cancer Symposium suggests that chemotherapy before surgery might improve the prognoses of patients with aggressive breast cancers, but the oncologist who led the study noted that therapies need to be tailored to individual patients to avoid overtreatment.
For patients with triple-negative breast cancer, considered more aggressive and difficult to treat than other forms, therapies meant to reduce the risk of recurrence often are added either before or after primary interventions.
"The focus of many breast cancer trials for several years has been on adding additional systemic therapies to reduce recurrence risk; however, adding therapies also leads to additional toxicity and overtreatment for many women," said Dr. Laura Spring, medical oncologist at Massachusetts General Hospital Cancer Center and instructor in medicine at Harvard Medical School.
This highlights the need for additional research to personalize the "right" amount of therapy for patients with breast cancer, she said.
Spring's retrospective study found that pre-surgery chemotherapy was associated with significantly lower recurrence risk and higher overall survival, leading researchers to believe that additional chemotherapy following surgery could be omitted in some cases.
Spring and her colleagues identified 27,895 patients in 52 eligible clinical trials from 1999 to 2016 and found that the reduced recurrence rate in patients who received chemo before surgery was comparable to that of those who received chemotherapy both before and after surgery.
Of patients with triple-negative breast cancer who received pre-surgery chemotherapy, 82 percent were less likely to see their cancer come back.
"The finding possibly reflects tumor biology," Spring explained.
The research by Spring and her colleagues was one of several studies on the treatment of triple-negative breast cancer presented at the symposium, which continues through Saturday at the Henry B. González Convention Center. The annual symposium, which dates to 1977, imparts state-of-the-art information on breast cancer research to academic and private researchers and physicians from over 90 countries.
Researchers from the Instituto Nacional de Enfermedades Neoplásicas, in Lima, Peru, found that if triple-negative breast cancer patients have post-surgery chemotherapy, it is best to complete it within 30 days of surgery.
“Patients with triple-negative breast cancer who delayed starting chemotherapy for more than 30 days after surgery were at significantly higher risk for disease recurrence and death compared with those who started the treatment in the first 30 days after surgery,” said Dr. Zaida Morante, medical oncologist with the Instituto Nacional de Enfermedades Neoplásicas.
Morante and her colleagues found in their retrospective study that patients who delayed chemotherapy past 30 days after surgery had a more than 90 percent increased risk for disease recurrence and death compared with those who started the treatment in the first 30 days after surgery. This risk is increased further if the chemo is given after 60 days.
"Our data show that it must be a priority for patients with triple-negative breast cancer to begin adjuvant chemotherapy within 30 days of completing surgery," said Morante. "After this period of time, the benefit of the chemotherapy is significantly diminished."