Starting tomorrow, all Maryland physicians who treat breast cancer will be required to offer their patients detailed and understandable explanations of treatment options before actual surgery is performed or treatment undertaken.

Maryland thus becomes the 15th state to protect women from a once common nightmare: being sedated for a biopsy and waking up to find that a breast has been removed.

Under the Maryland "informed consent" law, women will have the right to have a diagnostic biopsy separated from any second surgical or medical procedure, thereby providing an opportunity to explore alternative treatments -- a lumpectomy with radiation rather than a mastectomy, for example.

The law was passed in 1986 and signed by then-Gov. Harry Hughes, but Maryland physicians were given a one-year grace period to become acquainted with its provisions. Virginia already has such a law, but the District does not.

The law requires that a brochure, prepared by the Maryland Medical and Chirurgical Faculty -- the state medical society -- be given to each breast cancer patient and that its provisions be explained in lay language by the physician. Each patient is asked to sign a receipt confirming that she has received the brochure; the receipt is then returned to the state Department of Health and Mental Hygiene.

Because of the opposition of many Maryland physicians to such a law, the medical association and state health officials first attempted to accomplish its purposes on a voluntary basis. Some 65,000 brochures and forms were distributed, but only 81 receipts were ever returned. Many physicians who had been opposed to legislation subsequently withdrew their objections.

Under the new law, physicians face censure or loss of license if they fail to comply.