Findings in a study published in the April 15, 2002, issue of the journal Cancer indicate that a delay of more than 20 weeks in diagnosing asymptomatic breast cancer-where a screening test first indicated a suspicious result-is associated with increasing tumor size and increasing risk of lymph node metastases.

Screening tests for breast cancer are useful because they can detect disease in women without symptoms. However, screening tests can also yield information that neither rules in nor rules out disease for the physician, leading to unnecessary and sometimes uncomfortable procedures in some women and long delays in diagnosis for others.

This new study by a team of Canadian researchers from the British Columbia Cancer Agency analyzed data in the Canadian Breast Cancer Screening Database of 4465 women with invasive breast cancer diagnosed within 3 years of a screening abnormality between 1990 and 1998.

Data was collected on the prognostic indicators of tumor size and axillary lymph node metastases, time interval between abnormal screening and pathological diagnosis of invasive breast cancer, and other information, including clinical index of suspicion, family history of breast cancer, and age at diagnosis.

The researchers found that delays of greater than 20 weeks from an initial "suspicious" screening to actual confirmation of the cancer were significant for worsening prognosis. Most women in the study were diagnosed between 4 to 12 weeks after the abnormal screen. They noted that in Canada, practice recommendations suggest prompt additional work-up for highly suspicious screening abnormalities and "early recall" within 6 to 12 months of low-risk abnormalities for repeat screening.

Comparison of high-suspicion versus low-suspicion screens indicated that women with highly suspicious screening abnormalities were eventually diagnosed with actual breast cancer sooner than women without highly suspicious screening abnormalities, at median 31 days versus 47 days, respectively. Highly suspicious screening abnormalities were more likely to have tumors greater than 10-mm, compared to all other screens (79.4% versus 55.9%, respectively) and more likely to have axillary lymph node metastases (33.9% versus 17.3%, respectively).

The authors concluded that prolonged delays from an abnormal breast screen to actual diagnosis of invasive breast carcinoma resulted in an increased likelihood of lymph node metastases and increased tumor size. "Irrespective of the cause, reducing delays may improve the prognosis for women and the effectiveness of breast screening programs," they wrote.

SOURCES:
Cancer, April 15, 2002;94:2143-2150
British Columbia Cancer Agency, (http://www.bccancer.bc.ca)