As many as one in three women over 40 never had a mammogram or did not have one in more than two years, in a study published in the American Cancer Society journal Cancer. Many women have one or two mammograms then fail to return for regular screenings, the researchers found.

Unreliable Surveys

Campaigns to increase mammogram use have had limited success. Patricia A. Carney, PhD, of the Dartmouth Medical School and colleagues compared data from the New Hampshire Mammography Network (NHMN) to get a more accurate understanding of patterns of mammography use in that state.

For example, previous New Hampshire studies indicated that overall use of mammograms by women 50 years and older ranged from 65-82 percent. However, those studies relied on single community healthcare facility use or self-reporting surveys, which are prone to poor patient recall.

Carney's team found that 36 percent of women 40 and older in New Hampshire either had never had a mammogram or had not had one in over 27 months. Women over 80 were less likely than younger women to receive screening.

Lapses in Routine Screening

Only 65 percent of the women who got mammograms during their lifetime received routine screening within the recommended one to two year interval. The remaining 35 percent had one or two screening mammograms and did not return with 27 months.

"Routine mammography screening may be occurring less often than believed when survey data alone are used," Dr. Carney and her colleagues conclude. The researchers call for further study to explore the reasons women do not return for additional screening after having just one or two mammograms.