Early initiation of locoregional treatment (LRT) of an intact primary tumor (IPT) in women with de novo stage IV metastatic breast cancer does not appear to prolong survival or improve health-related quality of life (HRQoL) compared with systemic therapy alone, according to a new study (Abstract LBA2). Seema A. Khan, MD, of the Northwestern Memorial Hospital, presented these findings during the ASCO20 Virtual Scientific Program Plenary Session.
Approximately 6% of patients with newly diagnosed breast cancer present with stage IV disease and an IPT, Dr. Khan said. Although retrospective studies suggest that the use of LRT for IPTs may improve prognosis, Dr. Khan explained that these studies were biased, as they typically enrolled younger women who had smaller tumors, estrogen receptor–positive disease, and a lower metastatic burden. Other randomized studies have provided conflicting results in regard to the survival benefit of LRT in women with metastatic breast cancer and an IPT.
The clinical trial conducted by Dr. Khan and colleagues registered a total of 256 patients with a stage IV diagnosis of an intact primary invasive carcinoma of the breast who previously completed 16 or more weeks of treatment with optimal systemic therapy (OST), which was based on the patient’s tumor biologic profile as well as age and menopausal status (NCT01242800).
Patients who did not experience disease progression during OST were randomly assigned to either LRT for the IPT (125 patients) plus OST or no LRT (131 patients). The patients randomly assigned to the no-LRT group continued their systemic therapy regimens. Early local therapy paralleled guidelines for the treatment of women with nonmetastatic breast cancer, Dr. Khan explained, and included complete tumor resection with free surgical margins as well as postoperative radiotherapy, per standard of care. The median age of those randomly assigned to each group was approximately 56.
During a median follow-up period of 53 months (range, 0 to 91 months), the investigators observed 121 deaths and 43 locoregional progression events in the overall cohort. The 3-year overall survival rates for OST plus LRT and OST alone were 68.4% and 67.9%, respectively (HR 1.09, 90% CI [0.80, 1.49]; log-rank p = 0.63). There were no differences between the two treatment groups in regard to overall survival among women with an HER2-positive tumor subtype (HR 1.05, 95% CI [0.49, 2.24]) or a hormone receptor–-positive and HER2-negative tumor subtype (HR 0.94, 95% CI [0.59, 1.51]). In 20 women with the triple-negative tumor subtype, survival was worse in the early local therapy arm (HR 3.50, 95% CI [1.16, 10.57]).
There was no difference between treatments in terms of progression-free survival (p = 0.40), with 89 patients in each randomly assigned treatment arm experiencing disease progression or death during follow-up. Patients randomly assigned to OST alone experienced a significantly higher 3-year rate of locoregional recurrence/progression compared with the LRT-plus-OST arm (25.6% vs. 10.2%; HR 0.37, 95% CI [0.19, 0.73]; Gray test p = 0.003). Although the OST-plus-LRT treatment regimen was associated with significantly worse HRQoL at 18 months after random assignment, there was no difference between the two groups for this endpoint at 6 months (p = 0.64) or 30 months (p = 0.74).
Discussant Julia R. White, MD, of The Ohio State University Comprehensive Cancer Center, said that there currently exists an ongoing debate about the optimal treatment of patients with de novo metastatic breast cancer. Dr. White noted that the study by Dr. Khan et al is now the fourth trial that addresses LRT for the primary tumor in de novo metastatic breast cancer.
“Despite LRT in this setting improving local control, primary surgery did not significantly improve quality of life for patients with de novo stage IV breast cancer,” Dr. White said.
Dr. White said that always performing primary tumor surgery for de novo stage IV breast cancer is not currently supported by data from Dr. Khan et al or from other previous trials. The research data do indicate, however, that primary tumor surgery in this patient population can sometimes be performed.
“The rationale for that is that patients can sometimes have locoregional symptoms or progression that occur that are going to need surgical approaches for palliation,” Dr. White said.
Although the study by Dr. Khan et al suggests that LRT does not significantly prolong survival or improve (H quality of life in patients with metastatic breast cancer, Dr. White noted that this therapy should be reserved for patients who become symptomatic or experience progression locally.
Although the study by Dr. Khan and colleagues suggests that LRT does not significantly prolong survival or improve health-related quality of life in patients with metastatic breast cancer, Dr. White noted that this therapy should be reserved for patients who become symptomatic or experience progression locally.
She added that other data indicate “there may be a role for routine LRT for de novo oligometastatic breast cancer in combination with systemic therapy plus ablative therapy of all metastases to secure long-term no evidence of disease or cure,” but this needs to be confirmed in ongoing trials.
— Brandon May
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου