Non-progressive breast carcinomas detected at mammography screening: a population study

Area of Science:

• Oncology
• Radiology
• Epidemiology

Background:

• Some breast carcinomas, particularly ductal carcinoma in situ, detected via screening may not progress to symptomatic disease.
• Determining non-progression is challenging but crucial for understanding screening efficacy.
• If all screening-detected tumors eventually become symptomatic, cumulative incidence would be similar with or without screening.

Purpose of the Study:

• To investigate if breast carcinomas detected by mammography screening in women aged 50-69 progress to clinical symptoms by age 85.
• To estimate the frequency of non-progressive tumors among screening-detected breast cancers.

Main Methods:

• Utilized 24-year follow-up data from the BreastScreen Norway program.
• Employed an extended age-period-cohort incidence model to estimate breast carcinoma incidence rates with and without screening.
• Calculated the difference in cumulative breast carcinoma rates at age 85 to determine the proportion of non-progressive tumors.

Main Results:

• An estimated 1.1% of participants were diagnosed with non-progressive breast carcinoma by age 85.
• This proportion of potentially non-progressive tumors represents approximately 15.7% of all breast carcinomas detected during screening.
• Confidence interval for non-progressive tumors was [95% CI 3.3, 27.1].

Conclusions:

• Findings suggest that a significant proportion of screening-detected breast carcinomas may be non-progressive.
• Nearly one in six breast cancers identified through mammography screening might not develop into symptomatic disease.
• This highlights the need for careful consideration in managing screening-detected breast cancers.