Organized Breast Cancer Screening Programs in Canada

1999 and 2000 Report

Appendix 3 - Glossary

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

Cancer
Includes malignant and ductal carcinoma in situ (DCIS) of the breast.

Diagnosis
The first pathologic or cytologic diagnosis of cancer, last known biopsy for benign cases, or last intervention before 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 technique used to differentiate cystic from solid lesions in the breast. A needle is inserted into the lesion and material drawn out using a syringe. If the material is solid, it can be stained and the cells examined in a laboratory to determine whether or not they are benign or malignant.

Incident cancer
Cancer detected by a program screen after the initial screen.

In situ
Refers specifically to 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.

Initial screen
The first Canadian screening program screen provided to a woman.

Interval cancer
Any invasive breast cancer diagnosed in the interval after 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.

Negative screening episode
A screening episode that concludes with normal findings, including program-initiated work-up that did not reveal any cancer.

Open biopsy
Surgical removal of a breast mass under local 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, 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.

Rescreening
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 histologic confirmation attributed to the screening findings of the program.

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.

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