NEW YORK: Mammography is less accurate at spotting breast cancer if a woman has had the disease before, according to a US government-funded study. Breast cancer survivors are more likely to develop new tumors than women without a history of breast cancer, but little is known in detail about screening for survivors. The study, published in the Journal of the American Medical Association and based on information from the largest mammography registry in the United States, showed that screening does help detect breast cancer in survivors -- but not often enough. “These findings and additional studies that are likely to be stimulated from this report should lead to improved (radiology routines),” said Robert Smith of the American Cancer Society, in a statement. The study, led by Les Irwig of the University of Sydney in Australia, was the joint work of US and Australian researchers, who compared nearly 120,000 mammograms – half from breast cancer survivors, half from those without a comparable history of breast cancer. Within a year of screening, 655 tumors were found in survivors, compared to 342 in the other women.