Phyllodes Tumor Partial Breast Radiation Study

In 2008 a research study conducted by Dr. Barth involving 46 women determined that whole breast radiation therapy performed after a lumpectomy of borderline and malignant phyllodes tumors decreases rate of recurrence. None of the 46 participants developed a local recurrence.

Based on information we have learned from research studies, we recommend whole breast radiation therapy for women with malignant and borderline phyllodes tumors after they receive a lumpectomy.

New methods for delivering breast radiotherapy are being developed that allow radiation to be delivered solely to the site of the surgical resection. This is called partial breast radiation. The main advantage of partial breast radiation is that it simplifies treatment for the patient. Radiation is delivered twice a day for 5 days, rather than 5 days per week for 6 weeks. The main concern is that partial breast radiation might miss other sites of breast cancer in the breast receiving the radiation.

Evidence is accumulating from research studies that partial breast radiation therapy after surgical removal of the more common type of breast cancer, invasive ductal carcinoma, the breast results in rates of local recurrence that are comparable to those seen after whole breast radiation therapy.

In contrast to patients with invasive ductal cancers of the breast, it is very rare for patients to have phyllodes tumors that appear in more than one area of the breast. Review of research data determined that cancer recurrences seen in patients with phyllodes tumors that had undergone lumpectomies were almost always at the original tumor site. Therefore, partial breast radiation is likely to be as effective as whole breast radiation therapy after resection of malignant phyllodes tumors.

The purpose of the study is to determine what the chances are that a phyllodes tumor will recur in the breast when the breast is treated with partial breast radiation therapy after a lumpectomy.


Eligibility Criteria:
Inclusion Criteria:

* Histologic proof of phyllodes tumor of borderline or malignant grade, as first defined by Pietruszka and modified by Azzopardi and adopted by the World Health Organization (1,2,17):

  * Borderline malignant: 5-9 mitoses/10 HPF, pushing or infiltrating margins, 2+ (moderate) stromal cellularity and atypia.
  * Malignant: 10 or more mitoses / 10 HPF, predominantly infiltrating margins, usually 3+ (severe) stromal cellularity and atypia but occasionally 2+.
* The tumor has been excised with a breast-conserving resection and there is no tumor seen at any of the margins of the resection.
* No prior breast carcinoma or ductal carcinoma in situ in the ipsilateral breast. Patients with a local recurrence of a previously excised phyllodes tumor are eligible if the recurrence is in the area of the previous excision.
* No history of irradiation of the ipsilateral breast.
* No evidence of other areas worrisome for cancer on physical examination and mammography of the ipsilateral breast.
* Age \>18 years.
* Informed consent.
* Documentation that either:

  1. the patient's medical insurance company has certified that they will pay for the cost of radiation therapy treatments, or
  2. a letter from the patient indicating that they explicitly understand the costs of radiation therapy and that the sponsor (Principal Investigator) of this study will not be held responsible for these costs.

Exclusion Criteria:

* Histologically positive margins.
* Breast carcinoma or ductal carcinoma in situ in the ipsilateral breast.
* A history of irradiation to the ipsilateral breast.
* Pregnancy. A urine pregnancy test will be performed on each fertile premenopausal female prior to entry into the study. Patients with childbearing potential must employ effective contraception during the radiation therapy.
* A radiation planning CT scan which demonstrates a target lumpectomy cavity that is not clearly delineated or a target lumpectomy cavity/whole breast reference volume \> 30%.
* Unacceptable radiation therapy quality assurance parameters, as defined in Section 5 of the protocol.