The Impact of Radiation Therapy on Obstetric Complications in Cancer Survivors

Abstract

<h3>Purpose/Objective(s)</h3> Long-term side effects of radiation therapy (RT) include fibrosis, poor wound healing and hormonal dysfunction. These may potentially deleteriously affect obstetric outcomes amongst female cancer survivors, but there is minimal data. We hypothesized that previous RT treatment would be associated with increased maternal and fetal complications. <h3>Materials/Methods</h3> We utilized the Nationwide Inpatient Sample (NIS) Healthcare Cost and Utilization Project, containing discharge data from 1,050 hospitals in 44 states, a 20% stratified sample of hospitals in the US. Inclusion criteria were women with a previously specified cancer diagnosis, now hospitalized for a birth between 2015 and 2017; there were no exclusion criteria. The incidence of maternal (i.e., organ failure, infections, transfusions) and obstetric (including eclampsia, abruption, fetal distress) complications was compared between those who had / had not previously received RT. Categorical variables were compared using chi-square test. In addition, composite endpoints of ‘any maternal complication' and ‘any fetal complication' were analyzed, with predictors assessed using logistic regression. <h3>Results</h3> A total of 3215 patient hospitalizations were included in the study, of whom in 135 the mother had previous received RT. Median age – 31 years, 69% white, no sig. difference between those who did / did not receive RT. Cancer type was unevenly distributed between the two groups – RT patients had mostly lymphoma (36%), thyroid (25%) and breast (23%) cancer, whereas non-RT patients had thyroid (26%), melanoma (19%), breast (11%) and cervix (10%). Background maternal medical conditions: heart disease (OR 23.1, <i>P</i> < 0.001) and thyroid disease (OR 1.6, <i>P</i> < 0.04) were more common amongst those who had received RT. Regarding maternal medical complications, respiratory failure (OR 6.6, <i>P</i> < 0.01), and mechanical ventilation (OR 11.5, <i>P</i> = 0.01) were all more common in the ‘received-RT' group. Regarding obstetric complication, none were associated with previous RT (of note, there were fewer cesarean sections in the previous RT group). On multivariate analysis for the composite endpoint ‘obstetric complications' age (HR 1.02, <i>P</i> < 0.001), exposure to chemotherapy (HR 1.47, <i>P</i> = 0.01) and diabetes mellitus (HR 1.99, <i>P</i> = 0.06, borderline) were associated with poorer outcomes; there was no association with previous RT. On multivariate analysis for composite endpoint ‘maternal complications', no single covariate was associated with a worse outcome. <h3>Conclusion</h3> Previously RT was associated with an increased risk of maternal respiratory medical complications at time of delivery. Conversely and reassuringly, previous RT was not associated with increased fetal complications at delivery. Out data legitimize current trends to minimize cardiac radiation exposure in young women, and provide guidance for the optimal medical care of cancer survivors at time of delivery.