A Japanese survey of malignant disease in pregnancy.

Background: In recent years, the incidence of malignant disease in pregnancy has been increasing, but there are few large-scale surveys of malignant disease in pregnancy in Japan. The aim of this study was to survey malignant disease occurring during pregnancy in Japan.

Methods: Malignant disease in pregnancy was defined as diagnosis or treatment for malignant disease, except in situ carcinoma during pregnancy, or within 1-year postpartum. First, a primary survey questionnaire of the incidence of malignant disease in pregnancy and the number of deliveries over the course of 2014 was sent to 510 medical centers in Japan. Second, the survey questionnaires on the incidence of malignant diseases in pregnancy were collected and analyzed in detail.

Results: Of the 510 medical centers, 411 (81%) responded to the survey. There were 215,372 deliveries and 189 incidents (0.09%) of malignant disease in pregnancy. Of the 189 patients with malignancy, 157 detailed responses about the patients were received. The most frequently encountered cancer types were cervical cancer (36%), breast cancer (24%), and ovarian cancer (15%). During the 2 years after delivery, 15 patients (1 with breast cancer, 2 with ovarian cancer, 3 with hematologic malignancy, 4 with intestinal cancer, and 5 with others) died of the disease; most of them had advanced disease. In particular, 88% of the patients with intestinal cancers at diagnosis had advanced disease, and half of them died of disease.

Conclusions: In Japan, the most common malignancies in pregnancy in order of frequency are cervical cancer, breast cancer, and ovarian cancer. Early diagnosis and appropriate management of cancer during pregnancy are important for improving maternal and neonatal outcomes, because advanced diseases have a poor prognosis.