Risk Factors of Developing a Second Malignancy Following Treatment of a First Primary Breast Cancer

Background: Breast cancer is the most prevalent cancer among Iranian women, and is the fifth cause of cancer-related death in Iran. Most studies have reported an overall excess of 20–30% chance for a second primary cancer to develop in individuals with a first breast cancer. In this study, we evaluated different factors might have a role in increasing the incidence of a second malignancy after a first primary breast cancer in Iran.

Methods: We considered 980 breast cancer patients from three cancer research centers in Tehran, Mashad and Isfahan from Sep 1995 till Sep 2010.

Results: Overall, 94 second primary neoplasms observed. This analysis showed the existence of a modest excess in several neoplasms occurring after breast cancer. Some treatment related factors, including radiotherapy or mastectomy, had statistically significant relation with development a secondary cancer. However, sub-analysis failed to prove such a relationship.

Conclusion: Therefore, we can concluded that the risk of developing a second cancer is more dependent on genetic and environmental factors that caused the first primary cancer, rather than being dependent on type of treatment and other factors mentioned in this study.