In a nutshell
This study investigated the risk factors for recurrence in breast cancer patients treated with mastectomy without radiation therapy. The study concluded that by using these risk factors, a subgroup of patients could be defined as being at a high risk for recurrence and most likely to benefit from post-mastectomy radiotherapy (PMRT).
Some background
Post-mastectomy radiotherapy (PMRT) is radiotherapy (high-energy radiation to kill cancer cells by damaging DNA) received after a mastectomy (removal of the breast). PMRT has been shown to reduce the rate of locoregional recurrence (LRR) in high-risk patients. LRR is the return of the cancer at, or near, the original cancer site. Cancer can return and spread to the lymph nodes. N0 refers to cancer that has not spread to nearby lymph nodes and N1 refers to cancer that has spread to 1 to 3 underarm lymph nodes.
PMRT has been recommended for breast cancer patients who have tumors that are greater than 5 cm in size. However, the usefulness of PMRT in breast cancer patients with tumors less than 5 cm in size or with 3 or fewer involved lymph nodes (N0 or N1) remains unclear.
Methods & findings
This study investigated the risk factors for LRR in N0 and N1 breast cancer patients with tumors less than 5 cm who underwent a mastectomy but not radiotherapy. The study examined the records of 390 women, 307 with N0 and 83 with N1 breast cancer. The women had undergone total mastectomy but did not receive radiotherapy. The patients were followed for 5.6 years to look at the risk factors of LRR.
In N0 patients there were two risk factors for LRR identified – being less than 50 years of age at diagnosis and not receiving chemotherapy after surgery. The 5-year LRR free survival rates were 100% for patients without either risk factors, 96.4% with one of the risk factors and 86.7% with two of the risk factors.
In N1 patients, a hormone receptor negative tumor (tumor does not depend on hormones such as estrogen or progesterone for growth) was a risk factor for LRR. The 5-year LRR free survival rates were 100% for hormone receptor positive cancer and 92.3% for hormone receptor negative cancer.
The bottom line
The authors concluded that PMRT may be of benefit for N0 patients aged less than 50 years and who were not treated with chemotherapy, and for N1 patients with hormone receptor negative cancer.
The fine print
There were a limited number of patients in the N1 group, which may have limited statistical power.
What’s next?
Discuss your treatment options with your doctor.
Published By :
PLOS ONE
Date :
Dec 21, 2015
