Report from the Evaluation Indicators Working Group: Guidelines for Monitoring Breast Screening Program Performance - Second Edition

Appendix C - Glossary

Asymptomatic

A woman who does not report symptoms and appears without signs of disease at screening.

Cancer

Includes both invasive and ductal carcinoma in situ (DCIS) of the breast.

Diagnosis

The first pathologic or cytological diagnosis of cancer, last known biopsy for benign cases, or last intervention prior to a recommendation to return to screening or return for early recall1.

Ductal carcinoma in situ

(DCIS) a non-invasive tumour of the breast, arising from cells that involve only the lining of a breast duct. The cells have not spread outside the duct to other tissues in the breast.

Fine-needle aspiration biopsy

A needle is inserted into the lesion and material drawn out using a syringe. The material can be stained and the cells examined in a laboratory to determine whether they are benign or malignant.

Incident cancer

Cancer detected by a program screen after the initial screen.

Initial screen

The first Canadian screening program screen provided to a woman.

Interval cancer

Any invasive breast cancer diagnosed in the interval following a “normal” screening result and before the next scheduled screening examination.

Invasive cancer

Cancer cells invading beyond the basement membrane of the milk duct or lobule. A ductal carcinoma in situ component may also be present in cases of invasive cancer.

Open biopsy

Surgical removal of a breast mass under local or general anesthesia for subsequent microscopic examination by a pathologist.

Post-screen cancer

A cancer detected outside the program within 24 months of a negative screening episode.

Prevalent cancer

The proportion of the population with cancer at a given point in time.

Screen

Can comprise mammography, or both clinical breast examination and mammography, delivered by a program.

Screening episode (completed)

Defined for normal screens as the date of the last screen; for abnormal screens, the date of tissue diagnosis if biopsy is performed, and the date of the last test before a return to screening or before the recommendation for repeat diagnostic imaging. A “negative screening episode” can include all follow-up, provided that the end result is negative.

Re-screening

Subsequent screening, according to policy, after initial screening under the program. This includes women who miss a scheduled round of screening.

Screen-detected cancer

Cancer detected as a result of a positive test with histological confirmation attributed to the screening findings of the program.

Tissue biopsy

A biopsy which provides breast tissue for histopathologic examination (does not refer to fine-needle aspiration biopsy which provides only cells). Includes both core and open biopsies.

Total person-years at risk

Within a 12 or 24-month period after a negative screening episode, women are considered at risk for post-screen detected cancer. Women contribute a count in the denominator for each year or fraction of a year within the period of interest before a post-screen detected cancer or the next regular program screen.