Multivariable-adjusted Cox regression analysis of ipsilateral and contralateral invasive breast cancer in women aged 49–75 years at DCIS diagnosis (DCIS diagnostic period 1989–2004). Age was the primary time scale, time since DCIS diagnosis (0–5, 5–10, and ≥10 years) the secondary time scale, and DCIS treatment a time-varying covariable (DOCX 22 kb