Radiation Therapy After Surgery in Treating Women With Phyllodes Tumor of the Breast

A Prospective Study of Adjuvant Radiation Therapy After Resection of Borderline and Malignant Phyllodes Tumors

PURPOSE: This phase II trial studied how well radiation therapy works after surgery in treating women with phyllodes tumor of the breast.

RATIONALE: Radiation therapy uses high-energy x-rays to damage tumor cells. Radiation therapy following surgery may be effective in treating patients with phyllodes tumor of the breast.

OBJECTIVES:

• Determine the local recurrence rate in women with phyllodes tumors of the breast previously treated with local excision with negative margins and are now treated with adjuvant radiotherapy.
• Determine the survival rate in patients treated with this regimen.

METHODS: Within 12 weeks after prior local excision or breast reexcision, patients underwent adjuvant radiotherapy 5 days a week for a total of 28 treatments. Patients were then followed every 6 months for 10 years.

DISEASE CHARACTERISTICS:

1. Histologically proven phyllodes tumors of the breast with borderline or malignant grade, defined as 1 of the following:

   1. Borderline, defined as 5-9 mitoses/10 high power fields (HPF), pushing or infiltrating margins, 2+ atypia
   2. Malignant, defined as 10 or more mitoses/10 HPF, predominantly infiltrating margins, usually 3+ atypia with occasional 2+ atypia

2. Must have been excised with breast-conserving resection and no positive margins

3. Local recurrence of a previously excised phyllodes tumor allowed if the recurrence is in the area of the prior excision

4. No prior breast carcinoma or ductal carcinoma in situ in the ipsilateral breast

5. Hormone receptor status: Not specified

PATIENT CHARACTERISTICS:

1. Age: 18 and over

2. Sex: Female

3. Menopausal status: Not specified

4. Performance status: Not specified

5. Life expectancy: Not specified

6. Hematopoietic: Not specified

7. Hepatic: Not specified

8. Renal: Not specified

9. Other:

   1. Not pregnant
   2. Negative pregnancy test
   3. Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

1. Biologic therapy: Not specified
2. Chemotherapy: Not specified
3. Endocrine therapy: Not specified
4. Radiotherapy: No prior radiotherapy to the ipsilateral breast
5. Surgery: See Disease Characteristics