LOS ANGELES — Citing an effort to hold down costs, health insurance giant Blue Cross wants doctors in California to report conditions it could use to cancel new patients' medical coverage, it was reported Tuesday. The state's largest for-profit health insurer is sending physicians copies of health insurance applications filled out by new patients, along with a letter advising them that the company has a right to drop members who fail to disclose "material medical history," the Los Angeles Times reported on its Web site.