Worries that widespread screening for breast and cervical cancers can yield limited benefit and lead to unnecessary harm prompted decisions by two medical organizations to recommend less preventive testing. The American College of Obstetricians and Gynecologists announced revised recommendations for Pap tests, saying young women should begin getting the cervical-cancer screening test at a later age and at less frequent intervals than previously recommended. The news followed breast-cancer guidelines announced last week by a federally funded task force that created an uproar by saying women could wait until they are older to begin routine mammography screenings and have them less frequently than currently recommended. Critics said the changes may have been driven by efforts to control healthcare costs. Both organizations denied that notion, and rejected assertions they timed their announcements to coincide with the healthcare debate in Congress.