Long term effects of hypofractionated prone intensity-modulated radiation therapy after breast conservation surgery in patients with breast cancer

The study evaluated long-term outcomes of combining hypofractionated intensity-modulated radiation therapy (H-IMRT) with prone-positioning in patients after conservation surgery for breast cancer. The authors found that this combination safely controlled cancer locally without affecting regional lymph nodes.

Adjuvant radiation is given as additional therapy in patients with conserved breast cancer. Breast conservation (BC) refers to removing the tumor only, without whole breast surgery. At prone-position (PP) patients lie with their chests down and backs up. H-IMRT contains few high-intensity radiation doses to precisely destroy any remaining cancer cells without harming surrounding tissues. H-IMRT at PP as an adjuvant recently showed benefits with minimal toxicities in patients after BC. However, its long-term effects are unclear.

The study included 489 patients who had breast conservation surgery. All patients were then treated with adjuvant H-IMRT at PP. 155 of them were followed up for 52 months on average after radiation.

Local recurrence (LR) means the return of cancer in the same place where it first started. All patients survived for 5 years without any LR. 98.2% of patients survived without cancer’s spread to regional lymph nodes in 5 years. 6 patients developed cancer in distant organs during this time.

Breast discomfort was the most common long-term side effect. It occurred in 21.3% of patients. Occasional and mild breast pain happened in 20% of patients. 1.3% of patients required analgesics for moderate breast pain. 11% had new pain after radiation.

Mild soft-tissue fibrosis (STF; scar tissue forming) occurred in 12.3% of patients. It was the second most common long-term effect. No patient faced inflammation and fibrosis in lungs, rib fracture, or heart disorders, as late side-effects. Cosmetic changes in breasts due to treatment were described as minimal by all patients. 9 (5.8%) patients developed another type of cancer. after a minimum of 5 years.

The study concluded that H-IMRT at PP after breast conservation surgery was beneficial to control breast cancer locally and prevent its spread to regional lymph nodes and was well tolerated.

This was the largest study evaluating the long-term effects of this combination. It also looked back in time to analyze patients’ records.