A Study of Partial Breast Radiation Therapy after Lumpectomy for Malignant Phyllodes Tumors of the Breast
I am a cancer surgeon at Dartmouth-Hitchcock Norris Cotton Cancer Center in Lebanon, New Hampshire. I care for many patients with breast cancer, and am particularly interested in an unusual form of breast cancer: phyllodes tumors.
We recently completed a study which showed that treating the whole breast with radiation therapy after excising malignant phyllodes tumors is very effective: none of the 46 patients so treated had the tumor recur in their breast. Now we have begun a second study to see if focusing the radiation on just part of the breast-around the site where the tumor was removed, rather than radiating the entire breast-is equally effective in preventing the recurrence of phyllodes tumors.
Phyllodes tumors 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 metastasize (spread) to other parts of the body
- Borderline phyllodes tumors metastasize in 2-4% of patients
- Malignant phyllodes tumors metastasize in 10-35% of patients
Phyllodes tumors can be treated with mastectomy, and the chance that the tumor will come back along the chest wall is low. What happens when phyllodes tumors are excised by a lumpectomy, thereby preserving the breast? To answer this question, I gathered together all medical reports that described patients with borderline or malignant phyllodes tumors who had been treated with a lumpectomy with "negative margins," that is, no tumor cells were seen at the edge of the lumpectomy specimen when the edges were looked at by a pathologist under the microscope. We found that after lumpectomy alone, 20-25% of patients develop recurrent phyllodes tumors in their breast.
Based on these reports, the risk of a borderline or malignant phyllodes tumor returning if only a lumpectomy is performed is too high. 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 led us to conclude that lumpectomy 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, while at the same time preserving the breast? Radiation therapy is one possibility. Radiation therapy has clearly been shown to markedly decrease the chance that the more common form of breast cancer, invasive carcinoma, will recur, and is standard treatment after lumpectomy.
In 1998 we began a study whereby women with borderline or malignant phyllodes tumors were treated with a lumpectomy with negative margins and then received radiation therapy to their whole breast. The results of this study were published in August 2009 in the medical journal Annals of Surgical Oncology (Volume 16, pages 2288-2294). Forty-six women were treated at thirty different institutions around the United States. Thirty patients had malignant phyllodes tumors and sixteen had borderline malignant phyllodes tumors. All of the patients have been followed for at least two years after surgery and half of the patients have been followed for at least five years, and no one of the patients has developed a recurrent phyllodes tumor in their breast.
The whole breast radiation treatments in our study were given once per day, five days per week, for six weeks. We have now started a second study that focuses the radiation therapy just on the part of the breast surrounding the site where the tumor was removed, i.e., partial breast radiation therapy. This is more convenient for patients because this treatment is given twice a day for only five days. In our review of medical papers that described recurrences after lumpectomy as the only treatment for phyllodes tumors, all were very close to the site where the tumor was initially removed. Since it is extremely unlikely that one would develop a recurrent phyllodes tumor in a different part of the breast, we feel that it is very reasonable to do a study to see if just partial breast radiation therapy is as effective as radiating the whole breast.
How can I be evaluated for participation in this study?
To be considered for participation in this research study, you need to have a borderline or malignant phyllodes tumor that has been completely excised from your breast within the past 3 months. All treatment is given nearby your home. Start by contacting Tanya Perry, the research coordinator for this study, at:
Phone: (603) 650-6056
Fax: (603) 650-7799
Also, feel free to contact me, the Principal Investigator of this study, at:
Dr. Richard Barth
Department of Surgery
Dartmouth-Hitchcock Medical Center
Lebanon, NH 03756
Phone: (603) 650-9479
Fax: (603) 650-8608
The full text of the original study, "A Prospective, Multi-Institutional Study of Adjuvant Radiotherapy After Resection of Malignant Phyllodes Tumors," is available for download (PDF, 225 KB).