Accounting for less than 1% of all breast tumors, phyllodes tumors (PTs), which are “leaf-like” in appearance, are rare fibroepithelial tumors. They display a wide range of biological behaviors, ranging from fairly benign to highly aggressive.
PTs tend to resemble fibroadenomas, which are another type of benign breast tumor frequently found in young women. PTs, on the other hand, are found mostly in women between the ages of 40 to 60 years. These tumors rarely occur in men. In contrast to breast carcinoma, the lesion originates within the stroma of the breast (that is, the connective tissue).
PTs are often benign. However, complete tumor removal is still imperative, because they tend have high rates of recurrence. Removal usually involves the excision of the tumor as well as a wide margin of surrounding healthy tissue.
Tumors that are malignant may require more radical approaches, depending on the growth and stage of the cancer. Options for treatment of malignant lesions may include a combination of lumpectomy, mastectomy, radiation and/ or chemotherapy.
Although a hot topic of debate over the years, surgical therapy for PTs remains the mainstay. Moreover, despite the higher incidence of recurrence that is seen with breast-conserving surgery (BCS), studies have not shown any major differences between BCS and mastectomy with respect to outcomes. This is particularly true with respect to the overall survival and metastasis-free survival rates, which are more or less the same with both approaches.
Lumpectomy refers to the removal of phyllode tumors with up to 1 cm of healthy tissue, especially with borderline or malignant lesions. Tumors that are very large in relation to the size of the breast may require the removal of the entire breast removal, also termed mastectomy.
A “watchful waiting” approach may be employed for PTs that are benign and were excised supposing them to be fibroadenomas. These tumors have a low recurrence rate and good 5-year survival rates. PTs are considered to be “giants” once they have surpassed an (arbitrary) diameter of 10 cm. It is in these tumors that mastectomy is considered.
This is done if the breasts are small and the tumors have malignant characteristics, such as poorly-defined margins and abnormal stromal cells undergoing rapid divisions.
In order to reduce the chances of recurrence as much as possible, all visible PTs should be completely extirpated. This is important in the setting of possibly malignant tumors that may spread to nearby lymph nodes and adjacent tissues, requiring dissection of these structures.
Radiotherapy and chemotherapy
Approximately 10-15% of patients with PTs develop distant metastases. In order of frequency, the most common sites of spread are the lungs, bones and brain. The heart and liver are rarely involved. Metastatic tumors tend to have a very poor prognosis with very little chance of long-term survival. These patients are candidates for adjuvant radio- and chemotherapy.
The role of using these approaches, while uncertain in this situation, is indicated by some very promising results in other malignant soft tissue tumors (also called sarcomas).
While controversial, using adjuvant radiotherapy in patients with bulky tumors has shown some benefit. Radiotherapy uses high-energy rays that targets cancer cells and destroys them. This may be used after surgery to reduce the chances of tumor recurrence. It is usually done in a series of daily sessions during the work week, with a break on the weekends to allow the affected normal cells to recover.
The use of chemotherapeutic agents, such as cisplatin and anthracyclines, has been mentioned in several studies. However, they have not shown any real advantages in relation to long-term survival. Chemotherapy is not often used in the management of PTs, because they rarely spread outside the breast.
If the cancer has spread, chemotherapy is given over a period of 4 to 6 months, sometimes as a combination of multiple cytotoxic agents.
Reviewed by Dr. Liji Thomas, MD.