MedWire News: Some women with a rare type of breast cancer called phyllode breast cancer benefit from radiation therapy after surgery to reduce their risk of recurrence, US study results show.

Phyllodes tumours are breast tumours that develop in the connective tissue of the breast and are much rarer than those that develop in the ducts or lobules.

Most women with phyllodes tumours receive either breast-conserving surgery or mastectomy (removal of the entire breast), but few also receive radiation therapy as it is thought their risk of recurrence is minimal.

"Typically these tumours are treated well by surgery alone," explained lead researcher Dr Richard Pezner, from the City of Hope National Medical Center in Duarte, California. "However, local recurrences are not uncommon."

To identify subgroups of women with phyllodes tumours who may benefit from radiation therapy to reduce their risk of recurrence, Dr Pezner and team studied data on 478 women with this type of breast cancer who received either breast-conserving surgery or mastectomy at 130 hospitals between 1964 and 2005.

They found that the risk of recurrence was 15% greater in women with tumours larger than 2 cm who received breast-conserving surgery and women with tumours larger than 10 cm who received mastectomy, compared with women with smaller tumours.

The team also found that women with larger tumour sizes and those who experienced recurrence tended to have a shorter life expectancy than other women.

Writing in the International Journal of Radiation Oncology Biology Physics, Dr Pezner and colleagues conclude: "Based on our data... radiation therapy should be evaluated for Patients with malignant phyllodes tumours of the breast if they underwent lumpectomy for tumours at least 2 cm in size or mastectomy for tumours at least 10 cm in size."

They add: "This may be especially important because our study showed that local recurrence impacted on survival rates."