Risk of secondary cancers in patients who have been treated for early stage breast cancer

This study aimed to examine the risk of developing a secondary cancer after breast conserving therapy for early stage breast cancer patients. This study found that patients who have been treated for early stage breast cancer do not have a significantly higher risk of secondary cancers. 

Women with early stage breast cancer, such as ductal carcinoma in situ (DCIS), have an excellent prognosis. However, effects from treatments, such as radiation, can appear years later. One possible risk is the development of a secondary cancer. A secondary cancer is one that occurs separate to the primary cancer, meaning it is not a metastases (spread) from the first cancer. The risk of developing secondary cancers in women treated for DCIS is not clear.

This study aimed to analyze the risk of developing secondary cancers after breast cancer treatment. This study included 755 women aged between 25-89 with stage I-II breast cancer or DCIS. These patients had breast-conserving surgery followed by radiotherapy between 1992 and 2001. Some also received chemotherapy or hormone therapy. Patients were followed for an average of 13.8 years.

The risk of developing secondary cancers over 15 years was 12.0%. The risk of developing any cancer in the general population is 12.1%. Chemotherapy, hormone therapy and high dose radiotherapy were not associated with a higher risk of secondary cancer. 

Compared to the general population, the risk of developing gynecological cancers or melanoma was higher in women with previous breast cancer treatment at 15 years after treatment. 

This study concluded that women who have been treated for early stage breast cancer do not have a significantly higher risk of secondary cancers overall.  

This is a study based in one institution and so could be biased in their selection of patients.