Sala M, et al. - Researchers assessed the survival and disease-free survival in different subtypes of interval cancers by breast density, accounting for clinical and biological characteristics. A higher risk of death was seen in women with true interval cancer in non-dense breasts than women with screen-detected cancers. It was advisable to routinely collect information on breast density, both for further tailoring of screening strategies and as a predictive factor for diagnosed breast cancers.

Methods

• Experts included 374 invasive breast tumors (195 screen-detected cancers; 179 interval cancers, classified into true interval, false-negatives, occult tumors and minimal-sign cancers) diagnosed in women aged 50-69 years undergoing biennial screening from 2000-2009, followed up to 2014.
• They categorized the breast density into non-dense (<25% dense tissue) and mixed dense breasts (≥25%).
• They generated the survival curves by the Kaplan-Meier method and compared by the log-rank test.
• To estimate the adjusted hazard ratios (aHR) and 95% confidence intervals (95%CI) for death and recurrences, Cox proportional hazard regression models were computed.
• They stratified all analyses by breast density.

Results

• Findings suggested that in younger women, interval cancers were detected at more advanced stages, in denser breasts and demonstrated a higher proportion of triple-negative cancers, especially among true interval cancers.
• As per data, women with interval cancer and non-dense breasts had an aHR for death of 3.40 (95%CI:0.92-12.62).
• The highest adjusted risk of death was seen in women with true interval cancers detected in non-dense breasts (aHR=6.55;95%CI:1.37-31.39).