A Study of Radiation after Lumpectomy for Phyllodes Tumors of the Breast
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by Richard J. Barth, Jr., M.D.
Associate Professor of Surgery
Chief, Division of Surgical Oncology
I am a cancer surgeon at the Dartmouth-Hitchcock Medical Center and the Norris Cotton Cancer Center in New Hampshire. I care for many patients with breast cancer, and am particularly interested in an unusual form of breast cancer, phyllodes tumors. About 9 years ago, when taking care of a patient with a malignant phyllodes tumor, I realized that most patients with such tumors have been treated with mastectomy. My patient preferred to find a way to effectively treat the tumor, yet also keep her breast. After some research, I began a study designed to determine if radiation therapy would be an effective way to prevent phyllodes tumors from recurring in the breast after the tumor is removed by a lumpectomy.
Some Background on Phyllodes Tumors
Phyllodes tumors (sometimes refered to as Cystosarcoma Phyllodes) of the breast are uncommon tumors which most often occur in young women (average age 40 years). Phyllodes tumors can be characterized based on their appearance under the microscope as benign, borderline or malignant. Benign phyllodes tumors rarely spread (metastasize) to other parts of the body, while borderline phyllodes tumors metastasize in about 4% of patients (1 of 25) and malignant phyllodes tumors metastasize in 22% of patients (about 1 in 5).
Phyllodes tumors can be treated with mastectomy, and the chance that the tumor will come back along the chest wall is low. But what happens when phyllodes tumors are excised by a lumpectomy, thereby leaving most of the breast intact? To answer this question, I gathered together all published studies that had described patients that had been treated with a lumpectomy for a phyllodes tumor and found that when all studies are combined, after a wide local excision (removal of the tumor plus a sizeable amount of normal breast tissue around the tumor), only 9% (16 of 186 patients) with benign phyllodes tumors recurred. However, nearly one third of patients with borderline phyllodes tumors (31%, 16 of 51 patients) recurred and 38%, 13 of 34 patients with malignant phyllodes tumors had the tumor recur in that same breast. After a local excision (where the tumor is removed with only a small rim of normal breast tissue around it), 21% (111/533) of benign tumors, 36% (16/44) of borderline tumors and 57% (26/46) of malignant phyllodes tumors recurred. This review of previous studies can be found in the journal Breast Cancer Research and Treatment, volume 57, pages 291-295, published in 1999.
Based on these reports, it seemed to us that the chance that a borderline or malignant phyllodes tumor is going to come back in the breast if only a lumpectomy is done is too high. No one wants the tumor to come back in the breast. Psychologically it is hard: you thought that you had taken care of this and now you have to deal with it again. Patients with recurrent phyllodes tumors will need to have more deforming surgery and possibly a mastectomy. Furthermore, in the process of coming back in the breast, some cells may break off from a malignant phyllodes tumor and spread somewhere else in the body. These considerations, and the knowledge of the results of previous published studies, led us to conclude that local or wide local excision of borderline or malignant phyllodes tumors (by itself) is unsatisfactory treatment.
What else can be done to try to lower the risk that the phyllodes tumor will recur in the breast, while at the same time preserving the breast?
Radiation therapy is one possibility. Radiation therapy has been clearly shown to markedly decrease the chance that the more common form of breast cancer (invasive carcinoma) will recur in the breast, and is standard treatment after lumpectomy. There are reports that radiation therapy has been used to successfully treat phyllodes tumors that have spread to other parts of the body and can not be surgically removed.
We therefore proposed a study whereby all women with borderline or malignant phyllodes tumors would be treated with a breast conserving resection (lumpectomy) and then receive radiation therapy. This study began in 1998. So far, 41 patients from around the country have been treated with lumpectomy and radiation therapy on this study. More than half of the patients have been followed for at least 4 years. So far, none of the 41 patients has developed a recurrent phyllodes tumor in their breast!
To be considered for participation in this clinical trial, you need to have a borderline or malignant phyllodes tumor that has been completely excised from your breast within the past 3 months. The microscopic slides of the tissue need to be sent to the Pathologist at Dartmouth who is part of this study, Dr. Wendy Wells, for her review. Patients who have had a carcinoma in the same breast or have already received radiation to that breast are not eligible. All treatment is given nearby your home.
