Critical appraisal:Winther JF, Boice JD Jr, Svendsen AL, Frederiksen K, Stovall M, Olsen JH 2008 2

Critical Appraisal

Article being appraised

Winther JF, Boice JD Jr, Svendsen AL, Frederiksen K, Stovall M, Olsen JH. Spontaneous abortion in a Danish population-based cohort of childhood cancer survivors. J Clin Oncol 2008 Sep 10;26(26):4340-6 Available from: http://www.ncbi.nlm.nih.gov/pubmed/18779621.

Applicable clinical question

Are cancer survivors at increased risk of complications during pregnancy, birth and breastfeeding?Are children of cancer survivors at increased risk of physical and developmental abnormalities?

Key Facts

Study Design

cohort study

Study aims:

To assess the risk of miscarriage and stillbirth among cancer survivors who received radiotherapy and subsequently became pregnant.

Number of Patients:

21125

1688 cancer survivors, 2737 sisters thereof, and 16700 comparison women in the population.

Reported outcome(s):

Rates of livebirths, stillbirths, and abortions (spontaneous, induced, ectopic and molar pregnancies).

Results of outcome(s):

No significant differences were seen between survivors and comparison women in the proportions of livebirths, stillbirths, or all types of abortions combined. Survivors, however, had a 23% excess risk for spontaneous abortion (proportion ratio [PR], 1.23; 95% CI, 1.0 to 1.5), related primarily to prior radiation treatments (PR, 1.58; 95% CI, 1.2 to 2.2) and especially high-dose radiotherapy to the ovaries and uterus (PR, 2.8; 95% CI, 1.7 to 4.7).

Comments on results:

Proportion ratios were calculated with sisters as the referent.

Includes an economic evaluation

no