Mammography detects early-stage breast cancer among women over 40

Routine mammography in women aged 40 years and older is associated with detection of breast cancer at an earlier stage, thus allowing a wider range of treatment options, according to a report in Cancer published July 28th online.

Some reports have demonstrated a 20% to 30% reduction of breast cancer mortality with mammography screening, the authors explain, but these results remain controversial, and other benefits of regular mammography screening have not been demonstrated in a large population of women. Dr. Gary Freedman and colleagues from Fox Chase Cancer Center in Philadelphia, Pennsylvania compared the breast cancers of women 40 years and older according to whether they had no previous mammography (Group 1, 192 women), underwent mammography less than once yearly (Group 2, 695 women), or underwent mammography once yearly or more often (Group 3, 704 women). Early-stage T1 disease was least likely to be diagnosed among women in Group 1 — those without previous mammography (32%) — the authors report, but was more likely in Group 2 (50%) and Group 3 (56%). More frequent mammography was also associated with a lower likelihood of T2 tumors and locally advanced T3/T4 tumors, the results indicate. Similarly, the frequency of larger tumor sizes diminished with an increased frequency of mammography screening. Lymph nodes were positive in more than twice the proportion of Group 1 patients (17%) as in Group 2 or Group 3 patients (7%), the researchers note. The differences in tumor features contributed to the greater likelihood of breast-conserving surgery among women in Groups 2 and 3 (61%) than among women in Group 1 (41%), the report indicates. Mastectomy was recommended for more women in Group 1 (41%) than in Groups 2 (30%) and 3 (27%). Similar differences were seen when the analysis was restricted to women aged 40 to 49 years.]”This is a study that confirms the widely held belief that frequent (yearly) mammography confers many benefits,” Dr. Freedman told Reuters Health, “such as detection of breast cancer with early tumor size and stage and the possibility of more often being eligible for breast conservation. The study implies that women also may need chemotherapy less often because of more noninvasive tumors and invasive tumors 1 cm or less.” Dr. Freedman concluded that these results support annual screening mammography in women over age 40. “The study implies that survival should be better in those with frequent screening because of the earlier tumor stages,” he noted.However, he added, “The study will not end the controversy over a mortality benefit from the randomized prospective trials.”(Source: Cancer 2003: doi:10.1002/cncr.11605: Reuters Health: July 28, 2003: Oncolink)