A new study on breast cancer entitled “Breast Cancer Laterality Does Not Influence Survival in a Large Modern Cohort: Implications for Radiation-Related Cardiac Mortality” was published on the International Journal of Radiation Oncology • Biology • Physics (Red Journal) by Dr. Charles E. Rutter, from the Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut, and colleagues.
The research team evaluated the relevance of tumor laterality on overall survival after radiation therapy in a modern cohort of patients from the National Cancer Database (NCDB), since previous radiation therapy for left-sided breast cancer that included cobalt and orthovoltage radiotherapy, had been correlated with an elevated probability of cardiac mortality.
The NCDB is a collaborative project of the Commission on Cancer of the American College of Surgeons and the American Cancer Society and contains data, without any of the patient identification, from approximately 70% of newly diagnosed cancers in the U.S.. The NCBD is much larger than the Surveillance, Epidemiology and End Results (SEER) database, and contains data that include histopathologic and specific treatment information, such as protocol of therapies, dose, technique and type of target.
The study analyzed 344,831 patients diagnosed with ductal carcinoma in situ (DCIS) or invasive carcinoma of any histological subtype, and received external beam radiation therapy after breast-conserving surgery from 1998 to 2006. Left and right breast tumors were present, respectively, in 50.7% (174,956) and 49.3% (169,875) of patients. All subjects were followed-up on average for 6.04 years and subset analyses were performed in patients with extended follow-up of 10 years or more.
The results demonstrated that tumor laterality (left-side vs. right-side) does not seem to increase the probability of death, when using radiation therapy in this cohort of patients, therefore cardiac mortality is not so frequent as previously described.
“The delivery of radiation therapy for breast cancer is markedly different today than it was several decades ago when the association between breast radiation, cardiac disease and cardiac death was observed. Treatment planning and more advanced treatment techniques and technologies have reduced the risk to the heart,” Dr. Rutter, MD said in an ASTRO press release.
“This study demonstrates that the advances in breast radiation oncology have made treatment safer, and should reduce patients’ fears of cardiac risk and impact on their overall health after they complete their cancer treatment.” he concluded.