Studying drug exposure when disease is measured through accurate identification of an incident case: application to breast cancer in pregnancy (ConcePTION breast cancer demo)

Study type

• Study type:
  Non-interventional study
• Scope of the study:
  Disease epidemiology

  Drug utilisation

  Effectiveness study (incl. comparative)

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Anatomical Therapeutic Chemical (ATC) code:
  (L01D) CYTOTOXIC ANTIBIOTICS AND RELATED SUBSTANCES

  CYTOTOXIC ANTIBIOTICS AND RELATED SUBSTANCES

  (L02) ENDOCRINE THERAPY

  ENDOCRINE THERAPY
• Medical condition to be studied:
  Breast cancer female

  Breast cancer stage I

  Breast cancer stage II

  Breast cancer stage III

  Breast cancer stage IV

Population studied

• Age groups:
  Adults (18 to < 46 years)

  Adults (46 to < 65 years)
• Special population of interest:
  Pregnant women
• Estimated number of subjects:
  2965

Study design details

• Main study objective:
  Our aim is to improve methods for developing measurements of medication exposure in hospital settings. This drug utilisation study will describe patterns of medication use in pregnancy associated breast cancer (PABC) and in breast cancer in non-pregnant women. We will also assess whether time at diagnosis and timing of medication use in pregnancy impacts maternal survival and pregnancy outcomes.
• Outcomes:
  Maternal overall and 5-year relative survival in woman with PABC vs non-PABC patients. Mode of delivery and the following pregnancy outcomes (termination of pregnancy, live birth, stillbirth, preterm birth, small for gestational age SGA) in women with PABC and non-PABC.
• Data analysis plan:
  Descriptive analysis of cancer therapies used to treat breast cancer over the course of a pregnancy (prior to, during, after pregnancy) and during pregnancy (1st, 2nd or 3rd trimester) will be provided. 5-year relative survival analyses will be carried out using e.g. Cox proportional hazard regression and flexible parametric models to elucidate the complex associations between time-since-conception, medication exposure, breast cancer incidence and survival and to control for important confounders. Effects will be presented as relative risk estimates with CI describing the precision of the estimate (95% CI).