Women who are treated with radiotherapy tailored to their individual breast cancer risk have a low chance of disease recurrence, suggest findings presented March 24 at the 15th European Breast Cancer Conference (EBCC15) in Barcelona, Spain.
In her presentation, Fleur Mauritz, MD, from the Maastricht Radiation Oncology Institute in the Netherlands, discussed results from a 10-year study showing that fewer than 3% of women experienced locoregional recurrence when treated with radiotherapy following chemotherapy and surgery.
“The results of our study show that tailoring the extent of radiotherapy according to how well the chemotherapy has worked to treat cancer in the lymph nodes, leads to very low and reassuring recurrence rates in the breast and surrounding area,” Mauritz said in a statement.
Two recent studies suggest that locoregional radiation therapy can be tailored to some breast cancer patients who were treated with primary systemic treatment. However, these studies followed women over the course of five years, with Mauritz pointing out that long-term results are lacking.
She and colleagues led a prospective registry study called the Radiotherapy After Primary Chemotherapy (RAPCHEM) study, which followed women for 10 years. This study evaluated the long-term safety of tailoring locoregional radiation therapy to the nodal response after initial treatment, focusing on locoregional recurrence rate, recurrence-free interval, and overall survival.
The study included 848 women who were treated at 17 cancer centers in the Netherlands between 2011 and 2015. Each woman had a small breast tumor with signs of cancer spread in one, two, or three lymph nodes.
The researchers categorized the women into low-, intermediate-, and high-risk groups following chemotherapy and surgery. Women at low risk were given radiotherapy to the breast if their surgery removed the tumor (or no radiotherapy if they had their breast removed). Women with intermediate risk had signs of cancer in only one to three lymph nodes and were treated with radiotherapy to the breast area without irradiating the nearby lymph nodes. And high-risk women had signs of cancer in four or more lymph nodes and were treated with radiotherapy to the breast area and the lymph nodes in the surrounding area.
Of the total number of women, 24 (2.9%) had a recurrence in the breast, chest wall, or lymph nodes without signs of cancer spread elsewhere in the body. By risk group, 2.4% of low-risk women, 3.2% of intermediate-risk women, and 2.8% of high-risk women developed a recurrence.
The 10-year recurrence-free interval and overall survival were 79.2% and 83.0%, respectively. Both measures achieved significant differences when the low-risk group was compared to the intermediate- and high-risk groups, and when the intermediate-risk group was compared to the high-risk group.
Mauritz said this is the first study to show the benefits of tailoring radiotherapy for this group of patients over a 10-year period.
“We know that radiotherapy reduces the risk of breast cancer recurrence, especially when patients have had surgery to remove a tumor, rather than the whole breast, and when there are signs of cancer in the lymph nodes,” she said in a statement.
She added that the team will next study risk factors for breast cancer recurrence and where cancer recurs to help refine radiotherapy.