But observational study finds "very low risk" for other cancer survivors Women with cardiac damage from radiation or chemotherapy are at increased risk of congestive heart failure (CHF) during and after pregnancy, a retrospective study found. In a single-center cohort of 78 cancer survivors exposed to potentially cardiotoxic therapies seen at a high-risk pregnancy center, there were 13 women with a history of cardiotoxicity, but only the four with a reduction in left ventricular ejection fraction (LVEF) to under 50% after completion of cancer therapy had any of the adverse cardiovascular outcomes looked for during pregnancy -- cardiac death, acute coronary syndrome, sustained arrhythmia, or CHF. All four of these cases were CHF, for an incidence of 31% during pregnancy or shortly after delivery among the 13 women with cardiotoxicity, reported Paaladinesh Thavendiranathan, MD, MSc, of the University of Toronto, and colleagues in the Journal of the American College of Cardiology. These findings should reassure female cancer survivors without prior history of cardiotoxicity "that they are at a very low risk of developing CHF during pregnancy," the researchers concluded. But for those who do have cardiotoxicity, the one-in-three rate of problems means they likely "should receive close cardiac surveillance during pregnancy at a center with expertise in cardiac disease in pregnancy," the group wrote. That conclusion for closer monitoring drew agreement from Javid Moslehi, MD, of Vanderbilt School of Medicine in Nashville, who was not involved in the study. Moreover, the paper "really adds significantly to what is a growing recognition that once you get cancer therapy, subsequently, you may accrue other risk factors that come on that may predispose you to the ultimate clinical presentation, which is heart failure," he told MedPage Today. Previous studies have found CHF prevalence ranging from 0% to 5.4% around pregnancy among women with a history of cancer, which Thavendiranathan's group chalked up to limitations in study design, such as lack of cardiac assessment pre- and post-pregnancy, the inclusion of events prior to and after pregnancy, and the use of self-reported data on peripartum CHF. Their study, though, "examines outcomes in consecutive pregnancies of cancer survivors, adjudicates outcomes based on clinical criteria, and provides information for pre-conception counseling," Thavendiranathan and co-authors wrote. Over a 10-year period, the investigators evaluated a total of 78 consecutive cancer survivors seen at a high-risk pregnancy clinic for 94 pregnancies, of which four were twin pregnancies. While all received potentially cardiotoxic cancer treatments in childhood or as young adults, 55 women had anthracycline-based chemotherapy while 23 got non-anthracycline chemotherapy or radiation therapy only. Notably, there were no differences comparing women with CHF and women without CHF during pregnancy in the age at cancer diagnosis (28 versus 25, P=0.790), age at pregnancy (35 versus 34, P=0.680), cancer type, or exposure to anthracyclines (75% versus 79%, P=0.840). Women with CHF during pregnancy were more likely to have had: Cardiotoxicity before pregnancy (100% versus 12%, P=0.007) Left ventricular systolic dysfunction at the first antenatal visit (75% versus 8%, P=0.004) Cardiac medication use (50% versus 8%, P=0.026) While Moslehi called the study "thought-provoking," he cautioned that findings might change somewhat if looked at prospectively in a larger population. Thavendiranathan disclosed relationships with the Canadian Institutes of Health Research. Moslehi disclosed relationships with: Novartis, Pfizer, Bristol-Myers Squibb, Takeda/Millennium, Ariad, Acceleron, Vertex, Incyte, Rgenix, Verastem, Pharmacyclics, StemCentRx, Heat Biologics, Daiichi Sankyo, Regeneron, Myokardia, Ipsen, Deciphera, Redux Therapeutics, AbbVie/Abbott, Janssen/J&J, Amgen, and FDA. — LAST UPDATED 10.15.2018