Mammograms should begin at 40 for women with an average risk of breast cancer and by 30 for high-risk women, say two groups of medics.
Their advice contradicts controversial guidelines from a US advisory panel.
The joint recommendations from the American College of Radiology and the Society of Breast Imaging take into account the success of annual mammography screening starting at age 40, say experts
According to lead study author Dr Carol Lee: "The significant decrease in breast cancer mortality, which amounts to nearly 30pc since 1990, is a major medical success and is due largely to earlier detection of breast cancer through mammography screening."
The recommendations serve in part as a rebuttal to guidelines issued in November by the US Preventive Services Task Force, which recommended against routine breast mammograms for women in their 40s to spare them some of the worry and expense of extra tests to distinguish between cancer and harmless lumps.
Those recommendations contradicted years of messages about the need for routine breast cancer screening starting at age 40, sparking a rebellion from breast cancer specialists who argued the guidelines would confuse women and result in more deaths from breast cancer.
"Amidst all the furore, the ACR and the SBI stand firmly behind their recommendation that screening mammography should be performed annually beginning at age 40 for women at average risk for breast cancer," Dr Lee and colleagues wrote in the Journal of the American College of Radiology.
The recommendations also cover the use of magnetic resonance imaging or MRI and breast ultrasound in women who are at high risk of breast cancer because they have mutations in the BRCA1 or BRCA2 genes or a family history of breast cancer.
In these women, breast mammograms should begin by age 30, but not before age 25, when the risk of radiation exposure from the mammograms begins to outweigh the benefits of screening.
Dr Phil Evans, of the University of Texas Southwestern Medical Center in Dallas, and president of the Society for Breast Imaging, said the guidelines were based on the latest clinical trial data.
"Where the data was not present, we looked at recommendations that reflect expert consensus opinion," he said.