Women who are 65 years of age and older account for a significant proportion of newly diagnosed breast cancer cases. Many organizations recommend annual mammograms in this age group. As of January 1, 1998, Medicare started reimbursing for annual screening mammograms for women ages 40 years and older; in addition, the deductible was waived for screening mammograms [ corrected]. A recent recommendation was made to lengthen the screening interval in this age group because of the slower growth rates of breast tumors in this age group. Field and associates evaluated the significance of the screening interval in women age 65 and older who were diagnosed with breast cancer.

Women at least 65 years old who were enrolled in a breast screening program and had been diagnosed with breast cancer were studied retrospectively. Women who had been diagnosed with breast cancer within six to 30 months after a normal mammogram and normal findings on physical examination of the breasts were included in the study group. All mammography films were reviewed by two radiologists who specialized in breast imaging. The diameter of invasive tumors was measured. All patients were divided into four groups based on severity of disease, which included tumor size and presence or absence of metastatic disease. Screening intervals were defined as annual if performed within 18 months or less and as biennial if performed between 19 and 30 months.

A total of 119 patients qualified for the study. The size of invasive tumors was smaller in the annual screening group when compared with tumor size in the biennial screening group. Also, the severity of disease and the incidence of axillary node metastatic disease was significantly less in the patients who received annual screening mammograms. More patients presented with palpable breast masses in the biennial screening group.

The authors conclude that an annual mammography screening interval would be appropriate in patients 65 years of age and older. They state that they found significantly smaller tumors, less severe disease and less axillary lymph node involvement in women who underwent annual screening. Women who underwent screening at a longer interval had a higher incidence of more advanced breast cancer. Discovering breast cancer at an earlier stage of development increases the chance of long-term survival.