I have a long personal and professional interest in breast cancer. My mother and her mother both died of breast cancer. My mother's struck when she was 48. When her cancer recurred, 19 years after her mastectomy (no chemotherapy), it clearly had a mind of its own. It grew first slowly then quickly, gradually eroding her quality of life and becoming progressively more indifferent to oncologists' treatment plans. She died peacefully, with our family at her bedside, well attended in the hospice room at Ashland Community Hospital.

Doing the math, I realized that what I wanted for myself and for my daughter was not an early-detection or treatment plan. What I wanted was the strength of my mother's immune system during those 19 years she fended off a recurrence. She had great secondary resistance to her cancer. I wanted to learn all I could about optimal primary prevention, inspired by her secondary prevention. I wasn't the only one at risk here: Almost every woman I know has some worry about breast cancer.

Except for my 87-year-old godmother who somehow knows she won't get breast cancer, most women find breast cancer ultimately terrifying. Realistically, statistically, we all should be more worried about heart disease and stroke, but cardiovascular disease seems more predictable. Breast cancer touches the least and the most likely among us. We sigh and make dinner for friends, hoping their recovery is speedy and that our own time never comes.

I followed every lead I could find about breast cancer prevention. Every study, every mention of a study — if it mentioned reduced relative risk for breast cancer, I was on it. All well and good, but — as a physician, in my early 40s, with a young daughter and mammogram recommendations all around — do I sign up for screening? Why did I even hesitate?

I was an undergraduate at UC Berkeley and studied medicine at UC San Francisco. Not only had I been encouraged to hold a healthy skepticism about any medical claim until proven otherwise, but I also followed footsteps trod by John Gofman, a scientist and physician whose work culminated in his controversial pronouncement that there is no safe dose of ionizing radiation and that the primary hazard of such X-rays is an increased risk of cancer. Mammograms are X-rays using ionizing radiation.

I put the question to a local radiologist, wondering about the hazards of such radiation to the breast. He reassured me that the radiation dose of mammography was so low it was negligible. I paused just long enough for him to suggest that I could wait a year — next year's new mammography machines would reduce the dose of radiation by 90 percent. Hunh? Why reduce it if it's safe?

I went ahead with the mammograms, and had about five from my mid 30s to late 40s. At the last mammogram, the technician came back and nicely, but with some concern (hers increased mine), set me up for some additional focused views. It seems that some calcifications on a previous mammogram (which in retrospect looked very worrisome), had completely disappeared! Nothing. Zip. Gone.

Strange occurrence? Dodged a bullet? Mistake in reading? I don't know, but the episode influenced my thinking about cancer in general. I am neither alone nor in the mainstream, but I see cancer as a generalized disease process that is more or less controlled by the immune system. There are indeed some highly malignant cancers, such as inflammatory breast cancers and some melanomas, that wield irresistibly fatal forces. There are other cancers that conceivably arise, then linger or regress, and the host's lifespan is not affected, if the host's immune system can take and hold the upper hand. The patient survives, sometimes with, sometimes without, the help of conventional medical intervention.

My scheme is more simplistic than the multifaceted view of cancer, summarized by Gina Kolata in the New York Times ("Behind Cancer Guidelines, Quest for Data," Nov. 23.) What is behind the new screening guidelines is a view of cancer that accounts for its wildly different pace in different people. Sometimes it's lethal, sometimes it's controllable and "» sometimes it's harmless. Harmless. The scientists balance that recognition with the truth that, to some extent, both mammograms (ionizing radiation) and medical treatments (chemotherapy) are harmful. Thus they struggle to make sense of screening guidelines.

I, meanwhile, delight in researching prevention: primary prevention, secondary prevention, whatever — how do you not get or not succumb to breast cancer?

Deborah Gordon, M.D., is fully trained in family practice and specializes in classic homeopathy and preventative medicine in Ashland, where she has lived for 23 years.