Risk of second primary cancer after breast cancer treatment

Technological advances in both diagnosis and treatment of breast cancer lead to early detection and better treatment management. Consequently, the population of long-term survivors is on the rise. The risk of developing second cancers among breast cancer survivors was shown to be higher than that for the general population. The aim of this work was to review the literature on the risk of second primary cancer (SPC) after breast irradiation. Pubmed search of population-based studies on SPC after breast irradiation was conducted and the findings (in terms of Standardised Incidence Ratio) were collated and discussed. Several studies confirmed the link between breast tumour irradiation and risk of SPC, showing a small, but valid risk. There are, however, confounding factors that can either underestimate or overestimate risks: misclassification of tumour status, genetic inheritance, smoking, environmental factors, and the lack of accurate data in cancer registries. While isolating these potential triggers might be difficult, this approach would allow better discernability between radiotherapy-related risks and those generated by other factors. It is also important to evaluate the current status of treatment-related late effects and to lower such risks by minimising the dose delivered to normal tissues.