WASHINGTON – Likening sexual assault in the Air Force's ranks to a cancer, the service's top officer resolved Wednesday to tackle the problem by screening personnel more carefully and putting an end to bad behaviors like binge drinking that can lead to misconduct.

But Gen. Mark Welsh, the Air Force chief of staff, underscored the challenge by telling a House oversight committee that the service recorded a disturbing number of reports of sexual assault last year even as it worked to curb misconduct in the wake of a sex scandal at its training headquarters in Texas. Dozens of young female recruits and airmen at Lackland Air Force Base near San Antonio were victimized by their instructors who sexually harassed, improperly touched or raped them.

Most difficult, Welsh said, is transforming a culture in which victims are often reluctant to report what happened because of guilt, shame or fear they won't be believed.