When Debbie Shuman heard the news about the tiny tumors found in her breast, she was “distressed but also grateful they were caught early.” Known as ductal carcinoma in situ (DCIS), the lesions had not yet broken through her milk duct, so they weren’t “invasive,” her doctor explained, but rather precancerous. Another sigh of relief. Shuman and her doctor decided on a lumpectomy, which in her case involved a second surgery to get a “clean” margin, or surrounding rim of normal breast tissue. Then, five weeks of radiation followed. “I’m pretty happy with the results,” she reports, and most nights she isn’t needled by fear of a recurrence.

A diagnosis like Shuman’s used to be rare. Not any more. Cases of DCIS have skyrocketed by roughly 200% since the Eighties. In fact, at many urban medical centers, nearly half of all breast cancers diagnosed through mammography and biopsies are DCIS, according to an NCI report. And young women are hardest hit: In one screening program, 43% of the tumors detected in women ages 40 to 49 years, and 92% discovered in thirty-something women, were DCIS. Is global warming or another sinister scourge of modernity to blame for this surge in cases? No, the only culprit here is a good one: mammography. Since its use has become widespread in recent years, mammography has enabled doctors to uncover these tiny lesions that appear as mere specks, or patterns of “microcalcifications,” on a mammogram.

A DCIS diagnosis may make women like Shuman feel they’ve escaped a worse fate. But it can also usher in a more vexing treatment decision than its grimmer cousins tend to force on patients. Here’s the conundrum: A DCIS tumor isn’t even strictly cancer, argue many experts, since it’s confined to the milk duct. What’s more, many of these tumors will stay dormant and never do any harm even if left completely alone. Only a small percentage of them actually do become malignant, usually over the course of several years. But the hitch is that there’s no crystal ball to distinguish the dangerous from the do-nothings.

In the face of this treatment dilemma, though, how are doctors generally responding? Are they quick to recommend a mastectomy, even if it might be overkill? Or do they lean toward breast-conserving therapy (BCT), with a lumpectomy followed by radiation? And how many are willing to trust the latest data and take a wait-and-see approach with certain tumors by doing a lumpectomy alone?

Many experts charge that doctors are performing far too many mastectomies. “DCIS is more often overtreated than undertreated in the U.S. today,” says William Wood, M.D., chairman of the department of surgery at Emory University School of Medicine in Atlanta. DCIS expert Karla Kerlikowske, M.D., professor in the departments of medicine, epidemiology and biostatistics at UCSF agrees, adding that “young women are having mastectomies ... without any assurance that losing their breasts will give them a survival advantage compared to BCT.” With a full thirty percent of women diagnosed with DCIS every year getting a mastectomy, it’s easy to see their point.

Fueling the debate is the finding that where a woman is treated seems to make a difference as well. Research shows that BCT is used less frequently at non-teaching hospitals, as well as in the south and southwest. But regional bias may spring as much from patients as it does from doctors. “I used to practice in California, and now I’m in Texas. The women here are more concerned about radiation and would prefer a mastectomy even when BCT would work. In California, the women generally seemed more comfortable with BCT,” notes breast surgeon Marilyn Leitch, M.D., medical director of the UT Southwestern Center for Breast Care at UT Southwestern Medical Center.

On top of that, it seems ironic that many doctors may feel more comfortable recommending BCT for early-stage breast cancer than for the precancerous condition of DCIS. Of course, it’s been since 1990 that the National Institutes of Health (NIH) declared BCT the treatment of choice for women with stage I and stage II disease. And this recommendation was based on a tremendous amount of research. No such formal recommendation has been made in the case of DCIS because an equivalent amount of evidence is not yet available to compare treatment options (though results from a few recent studies, including the large-scale National Surgical Adjuvant Breast and Bowel Project (NSABP), are promising to change that.)

But doctors’ greater comfort level with treating invasive cancer, compared to DCIS, may also stem from the very real challenges posed by DCIS. Not only is it hard to predict which lesions are potentially malignant, but it’s also frequently tougher to remove all of the tiny lesions, or microcalcifications, and achieve a “clean” margin. A surgeon often has an easier time cutting out a palpable lump and getting that safe margin of normal tissue around it. And some of the older stats on rates of DCIS recurrence would understandably spur both doctors and women to choose the safest, albeit most drastic, treatment possible.

With mastectomy, the recurrence rate hovers around 1%. But with lumpectomy followed by radiation, rates of recurrence have been as high as 13% or, in one recent study with a 10-year follow-up, as low as 2%. (In this same study, conducted by Dr. Melvin Silverstein at the Breast Center in Van Nuys, CA, lumpectomy without radiation had a recurrence rate of only 3%—a far cry from older research showing a recurrence rate of slightly more than 20% among women who had lumpectomy alone. Adding radiation usually halves the risk of recurrence, according to most research to date.) Further complicating matters, when the disease returns, it’s not always a DCIS diagnosis all over again. Sometimes, invasive cancer is in its place.

And let’s not forget that some women may be afraid to trust BCT even when it should work. “Some patients are far more troubled by a small possibility of recurrence than they are by the thought of losing their breast,” says Timothy J. Eberlein, M.D., director of the Cancer Center at Washington University School of Medicine in St. Louis. Plus, in the case of DCIS, some women—especially those with a superstitious bent—may feel so grateful about its early discovery that they fear they’re pushing their luck by choosing breast-sparing surgery.

The good news is that DCIS diagnosis and treatment is getting less troublesome these days. Recent breakthroughs in understanding and treating DCIS are helping doctors and patients make treatment decisions more easily, with fewer nagging doubts. First, experts have a better sense of trouble signs. Research has now shown that doctors can divine DCIS’ malignant potential from these factors: greater tumor size (i.e. greater than 2.5 cm in diameter); the so-called comedo type of DCIS; higher nuclear grade (more abnormality in the cell center); positive margins (failure to get a surrounding rim of normal tissue); and presence of necrosis (death of tissue cells). Experts at Memorial Sloan-Kettering Cancer Center in New York City just added another predictive factor to the mix: age. Women diagnosed with DCIS under age 40 were more than three times as likely to suffer a recurrence as patients between ages 40 and 69.

The other bright spot in DCIS research is treatment. A few large clinical trials are now under way to evaluate the effectiveness of lumpectomy alone as a treatment for DCIS patients whose tumors are deemed to have a “favorable prognosis”—meaning the red flags aren’t present. (For information on how to enroll in one of these trials, call the NCI at 800-4-CANCER.) Even more promising, recent findings from the most important ongoing study of breast cancer patients, the NSABP, show that women who opt for breast-sparing surgery now have one more therapy to add to their arsenal of protection: tamoxifen.

Women who took a five-year course of this drug on top of their BCT had only an 8% risk of suffering a recurrence, compared to a 13% risk for women who had the standard lumpectomy followed by radiation. What’s more, the tamoxifen was especially effective at preventing cancer from appearing in the same or opposite breast. The incidence of invasive cancers was down to 4% with the addition of tamoxifen, according to NSABP’s director Bernard Fisher, M.D, at Alleg-heny University of Health Sciences in Pittsburgh.

Though a DCIS diagnosis sends a woman to a strange, scary place, much as a diagnosis of invasive cancer does, at least she can now make her way down a clearer path. She and her doctor have more signposts to guide them and fewer blind spots and detours to thwart their journey to total recovery.