ATLANTA — Contrary to conventional belief, results of a new study suggest that surgical removal of the primary tumor can benefit women with stage IV breast cancer.
Although overall survival was unchanged at 5 years, there was a better progression-free survival for women who underwent local therapy of the primary tumor when initially presenting with metastatic disease, Roshni S. Rao, M.D., reported at a symposium sponsored by the Society of Surgical Oncology.
“This is important, because any time you can slow down the progression of the disease, it potentially gives other therapies a better chance at working,” Dr. Rao told this newspaper. “It's entirely possible that as medical therapy improves, the metastatic progression-free survival seen in these patients will translate into a survival benefit.”
The study joins a growing body of evidence that challenges traditional beliefs by suggesting that aggressive local therapy may prolong survival, said Dr. Rao, a breast-surgery fellow at the University of Texas M.D. Anderson Cancer Center, Houston.
Current treatment is generally directed at the sites of metastases, and the primary tumor is left intact. Surgery is undertaken only for palliation.
Only 3%-6% of American women diagnosed with breast cancer will be stage IV at presentation, but a staggering 50% of women internationally will present with metastatic disease, Dr. Rao said.
The retrospective, single-institution chart analysis included 224 women with stage IV breast cancer, including 142 patients who received systemic treatment without surgery and 82 who had surgery to remove the primary tumor and systemic therapy.
Of the surgical patients, 43 underwent mastectomies, and 39 had segmental resection.
All of the patients received hormonal therapy or chemotherapy within 3 months of diagnosis.
Both groups were similar in race, family and personal history of cancer, histology, tumor size, and estrogen- or progesterone-receptor status.
The surgical group was slightly younger than the nonsurgical group (49 years vs. 54 years); had one metastatic site (generally the liver); was more likely to receive chemotherapy than hormonal therapy as a first-line treatment; had a lower nodal stage (59 N0/N1 patients vs. 100); and was more likely to be Her2/neu positive (24 vs. 28 patients).
Initially, surgical patients demonstrated better survival than women who received systemic therapy alone. But this was not significant on final analysis, Dr. Rao said.
At 3 years, 119 of the 142 women (84%) in the nonsurgical group were alive, compared with 78 of the 82 women (95%) in the surgical group.
At final follow-up, there were 27 deaths in the nonsurgical group and 11 in the surgical group. Eleven patients who had surgical intervention at their primary site as well as their metastatic site had no evidence of disease during follow-up.
The only independent predictors of overall survival were having a single metastatic site and Her2/neu-negative status (hazard ratio 2.43 and 2.52, respectively).
Surgery and estrogen-negative status were the only independent predictors of metastatic progression-free survival (hazard ratio 0.47 and 0.6, respectively).