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small but important study on the need to biopsy metastatic breast cancer lesions
20% of patients with suspected metastatic breast cancer had a change in clinical management as a result of biopsy--this is not currently the standard practice for metastatic disease,this study tending to imply that it SHOULD be
Note that the findings involved a small number of patients.
TORONTO, March 18 -- Biopsies of suspected metastatic breast cancer revealed a different hormone receptor status from the primary tumor in 40% of patients and changed clinical management in 20%, according to data from a small clinical series. Action Points
Her2 status differed between primary and metastatic lesions in 8% of cases, and the disease proved to be benign in 10%, Mark J. Clemons, M.D., of Princess Margaret Hospital, and colleagues reported online in Annals of Oncology.
The findings are potentially practice changing, Dr. Clemons said in an interview, because biopsy is not standard practice for metastatic breast cancer.
"In order to allow this to become a standard of care for patients with breast cancer worldwide, we are going to need more studies, but we also need physicians to begin to think about the fact that tumors can indeed change with time," said Dr. Clemons.
Preliminary results from an ongoing confirmatory study have been virtually identical to those of the initial study, he added.
Several retrospective studies have demonstrated discordant hormone-receptor status between primary and metastatic tumors in 15% to 40% of breast cancer patients. Her2 discordance has been reported in 7% to 26% of patients.
The discordance raises the possibility that some patients with metastatic breast cancer might receive suboptimal therapy in the absence of biopsy, Dr. Clemons and co-authors said.
To examine the issue prospectively, investigators performed biopsies of suspected metastatic breast lesions in 35 women, yielding 29 samples sufficient for analysis. Women with local recurrence were excluded from the study.
All samples were analyzed with respect to receptor status (estrogen/progesterone) and Her2 status and were compared with biopsy results from the patients' primary tumors.
Analysis of the 29 specimens showed that:
Three presumed metastatic lesions were benign and one patient had lymphoma
10 of 25 metastatic lesions had discordant receptor status compared with the primary tumors, loss of estrogen receptor positivity in three cases, and loss of progesterone receptor in seven
Two cases demonstrated a gain of Her2 overexpression
Six of the 29 patients with adequate biopsy specimens had changes in clinical management as a result of biopsy. The two patients who gained Her2 overexpression qualified for trastuzumab (Herceptin) or a clinical trial.
"For the four patients who had no evidence of metastatic breast cancer on biopsy, not only did their treatment plan change but also the biopsy results drastically changed their prognosis," the authors said.
The researchers acknowledged that their study was limited by its size, which would have made any subgroup analysis -- for type of adjuvant treatment, location of metastases, or disease-free interval -- unreliable.
However, they concluded, "tissue confirmation should be considered standard of care in patients with clinical and/or radiological suspicion of metastatic recurrence and lesions amenable to biopsy."
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