Cancer Before, During and After Pregnancy

Background: The occurrence of cancer during pregnancy is uncommon with an incidence rate of ∼1 in 1000 pregnancies. The rate of pregnancy-associated cancer is increasing and this is partly caused by a trend in delaying child bearing to an older age. Aim: With little data in the UK concerning the number of women diagnosed with cancer during pregnancy, the purpose of this study was to compare incidence of cancer in pregnant women to the general female population. Methods: Cancer registry data for England were linked to hospital activity data to establish pregnancy-associated cancers. For this study, women aged 15 to 44 years diagnosed with a malignant cancer between 2012 and 2014 and a pregnancy or delivery code 1 year before or up to 1 year after diagnosis were defined as pregnant women. Age-standardized and age-specific incidence rates of cancer in pregnant women and the general female population in England were compared by 5-year age-group, geographic region of residence, income deprivation quintile and stage of cancer diagnosis. Results: A total of 3272 pregnancy-associated cancers were identified in 2,503,174 pregnancies. The age-standardized incidence rate (ASIR) of cancer in pregnant women was 48% higher than the equivalent ASIR of cancer in the female population aged 15-44 nationally (173 vs 117 per 100,000). This trend of higher incidence of cancer among pregnant women persisted for most regions, ages and stages, and was particularly high in the most deprived quintile. The most common cancers diagnosed around the time of pregnancy were breast (n = 784), melanoma of skin (n = 504), cervical (n = 498), hematologic (n = 286), ovarian (n = 240) and colorectal (n = 188). Comparing the ASIR of cancer in pregnant women with the female population, by site, rates were over 30% higher for breast cancer (55 vs 41 per 100,000 respectively) and around double those for melanoma (26 vs 13 per 100,000). Conclusion: The higher rates of pregnancy-associated cancers compared with the general female population may be due to frequent obstetric examinations which increases the chances of cancer detection. Further work using a more robust maternity dataset would be required to ascertain timing of cancer diagnosis in relation to delivery.