September 21, 2009 (Berlin, Germany) — Surgical removal of the primary tumor in patients with metastatic breast cancer — which is not currently standard practice — could greatly improve survival. According to data from 1 study presented here at the 15th Congress of the European CanCer Organization and the 34th European Society for Medical Oncology (ESMO) Multidisciplinary Congress, tumor removal was associated with a doubling of overall survival.
"Removing the tumor was associated with a 40% reduction in mortality," said study author Jetske Ruiterkamp, MD, a surgical resident at the Jeroen Bosch Hospital in Den Bosch, the Netherlands.
The median survival of patients who underwent surgery was substantially longer than those who did not (31 months vs 14 months). "The 5-year survival rates were 24.5% for patients who had their tumor removed, compared with 13.1% for those who didn't," explained Dr. Ruiterkamp during a press briefing. This 5-year survival difference was highly significant (P < .0001).
In the Netherlands, 1 of 9 women are diagnosed with breast cancer, and of this cohort, 3% to 10% have distant metastases at the time of their diagnosis. Generally, advanced-stage breast cancer is treated palliatively, and the primary tumor is removed only if it is symptomatic, Dr. Ruiterkamp said.
However, recent data suggest that removing the primary tumor could have a beneficial effect on outcome and extend survival. In a retrospective study, Dr. Ruiterkamp and colleagues analyzed the impact that surgical resection had on patient survival, after accounting for potential confounders such as age and associated comorbidities.
A total of 15,769 women were diagnosed with breast cancer in the south of the Netherlands between 1993 and 2004. Of this group, 728 patients had distant metastases at their initial diagnosis, representing 5% of all breast cancer patients in that region of the country. Approximately 40% of the patients with advanced-stage disease had undergone surgical removal of the primary tumor.
The researchers conducted stratified analyses to compare surgically and nonsurgically treated patients in subgroups that were defined by factors such as age, T-classification, comorbidity, and the number of metastatic sites. In addition, a multivariate analysis was performed to evaluate the independent contribution that surgery might have had.
The multivariate analysis showed surgery to be an independent prognostic factor for overall survival, after adjustment for age, period of diagnosis, T-classification, comorbidity, number of metastatic sites, use of locoregional radiotherapy, and use of systemic treatments.
Currently, the researchers are reviewing medical charts of selected patients and looking at factors such as the type of surgery that was performed, information about surgical margins, and whether lymph node dissection had taken place. This information will help find a biologic explanation for these results, she said.
"When we do the chart review, maybe we can also find out the reasons for having the surgery," she added.
Although these results are interesting, José Baselga, MD, president of ESMO, pointed out that surgical removal of the primary tumor is not commonly done in this patient population. "That is the bias of the study," he told Medscape Oncology when approached for independent comment.
The primary tumor is usually removed for 1 of 2 reasons, he said. "One is if the tumor is causing complications and the second is if the patient asks for it to be removed. In the latter case, the woman may be doing well and would like to remove the tumor."
It might be that the primary tumor continues to launch cells into circulation, so the surgery is a self-sealing of the primary tumor, he added. "However, these data alone are not going to lead to a change in current practice. Randomized clinical trials are needed."
Dr. Ruiterkamp agreed. Even multivariate analysis showed that surgery is an independent factor in overall survival. A randomized controlled trial should be performed to see if surgery really has any benefit, she concluded.
15th Congress of the European CanCer Organization (ECCO 15) and the 34th European Society for Medical Oncology (34th ESMO) Multidisciplinary Congress: Abstract 5005. Presented September 21, 2009.
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Cite this: Removal of Primary Tumor in Metastatic Breast Cancer May Prolong Survival - Medscape - Sep 21, 2009.