For patients with earliest stage of breast cancer, how much treatment is enough?

After a breast biopsy at age 40, Rawan Kajo was given two options: Surgeons could remove one breast, or both.

Kajo, a pharmacist living in Doylestown, Pennsylvania, didn't like either choice. What had been found in one breast was a calcification, not a tumor – essentially a risk factor for future cancer.

"If it was a tumor, I wouldn't give it a second thought," she said about the surgery. "But we're doing this aggressive treatment to eliminate a risk that might never end in a real problem."

For years, that's been the challenge for patients diagnosed with ductal carcinoma in situ, what's sometimes called "Stage zero" breast cancer. DCIS, which is often driven by hormones, is defined as the presence of abnormal cells inside a milk duct.

About 20% to 30% of hormone-positive DCIS has the potential to become invasive cancer, with the remaining 70% to 80% not at risk, said Dr. Laura Esserman, Kajo's doctor and a surgeon and breast cancer oncology specialist at the UCSF Breast Care Center.

Even with the standard care – surgery and radiation, and often hormonal therapy – women have about a 15% chance of getting another cancer or DCIS on either side. But because it's been impossible to identify who was in danger, every DCIS was treated the same.

That's starting to change.

Recent studies are finding genetic and other differences between harmless calcifications and DCIS that will turn dangerous.

The same treatment doesn't make sense for everyone because "all breast cancers aren't the same," Esserman said. "There's a big span from ultra-low risk to very fast-growing."

Some doctors see DCIS as more of a warning sign than a dangerous tumor: something to be addressed, but not requiring the aggressive approach used for actual tumors.

The goal is to "right size" treatment, said Dr. Freya Schnabel, a breast cancer oncologist at NYU Langone in New York.

"We don't want to overtreat, but we also for sure don't want to undertreat and give away this wonderful gift that we got of making this non-life-threatening diagnosis," Schnabel said.

Not all breast cancers are the same

Before mammography, only about 3% of tumors were diagnosed as DCIS because they were too hard to spot without the imaging technology, Esserman said. Now, about a quarter of breast cancers are diagnosed as DCIS.

Such early diagnosis can save lives, but can also harm people who are treated unnecessarily, including stoking unwarranted fear.

As many as 1 in 4 patients diagnosed with breast cancer during routine mammography may have DCIS that doesn't need aggressive treatment. In women who have surgery for DCIS, 25% to 68% may end up with persistent, difficult to treat pain at the surgical site, even with a lumpectomy.

Esserman believes it's important to focus aggressive treatment on those who really need it, and reduce treatment in those who will be just fine without it.

Tens of billions of dollars are spent annually "applying all those resources to everyone uniformly, without thinking about it," she said.

Instead, it makes sense to first figure out who carries high-risk genetic modifications that make them more likely to have dangerous tumors. And even among those without concerning mutations, there are signs that some people are at higher risk than others, she said.

About 10% to 15% of people carry the highest risk, and more resources could be spent on them by reducing costs for those at the lowest risk, she said.

"Probably the bottom 10%, 20%, 30% of people can do way less," Esserman said. "We have the capacity to do these things and tailor what we do based on all that we've learned in the last few decades."

Options don't always make things easier for DCIS patients

Right now, patients may be offered options, but not much data, on which to base their decision, said Dr. Susan Domchek, a breast cancer specialist at Penn Medicine in Philadelphia.

"It can put a lot of pressure on patients to make complex medical decisions," she said. "When the risks are smaller, the options increase."

People bring their own lived experiences into the decision-making process, Domchek said. One might have seen a family member or close friend die of cancer and therefore want to be as aggressive as possible, while another might have had a serious complication from a prior surgery and be eager to avoid another operation.

Individual risk hasn't always been well communicated to patients, Domchek said. DCIS is "a risk factor that needs to be managed carefully. It's not being ignored," she said. "But it's not the same having as node-positive breast cancer. And it's not all one bucket."

Ongoing studies could help determine who can be treated less aggressively than others.

"We're having to rethink and trying to de-escalate some of the treatments, because we realize we're overtreating," said Dr. Kelly Hunt, a surgical oncologist at The University of Texas MD Anderson Cancer Center in Houston. "In many cases, what we're finding is some of these very low-grade DCIS lesions will not progress."

Unfortunately, the differences aren't apparent on a mammogram, said Dr. Baṣak Dogan, director of breast imaging research at UT Southwestern Medical Center.

Higher risk DCIS is generally associated with symptoms such as discharge from the nipple or a palpable mass, as is a change in size or shape of a growth over time. With a large DCIS, it can be hard to get a biopsy that's representative of the whole growth, so she'd be inclined to treat it as higher risk.

Dogan doesn't agree with the term "overdiagnosis." She thinks it's important to find the DCIS, "but we can do less with what we find." If she were a patient with DCIS, she would want to know that she had it and would want to have the choice to be followed carefully or to be treated.

There's also a cultural difference, she said, with Americans more likely to want aggressive treatment than people in her native Turkey.

The best approach "fits the patient's cultural preference, their lifestyle and what they want to do with their body, also taking into account disease’s biological behavior."

When less treatment is just as good

Not everyone needs surgery or radiation, and studies are beginning to identify who can benefit from less.

Currently, radiation is given to most people with DCIS because traditional factors can't distinguish those at risk.

A recently published study looked at 1,000 DCIS patients in the U.S., Australia and Sweden treated with radiation and breast-conserving surgery. They were broken down into low risk, elevated risk and residual risk categories using a unique test that combines response to hormones and growth signals as well as information about the patient's age, their tumor's size and whether it was taken out with clean edges.

For the 37% deemed low risk, there was no difference in overall recurrence risk between those who got radiation and those who didn't, said an author on the study, Dr. Chirag Shah, who directs clinical research in the Department of Radiation Oncology at the Cleveland Clinic. "The low-risk patients probably don't derive a benefit from radiation," he said.

In the "elevated" group, which accounts for about 43% of patients, radiation cut the likelihood of recurrent or invasive cancer, he said, so it was clearly beneficial for them.

In the third group, which accounted for about 20% of the total, even after radiation, 15% had a recurrence in the breast and 7% developed invasive recurrences.

"We need to think about new therapies for those patients," he said.

In his own clinic, Shah discusses with the patient whether to use the test. In those found to have a low risk, he recommends omitting radiation therapy.

He gives patients information about their likely risk and lets them decide "what they value as part of shared decision making," he said. Two people with the same risk on paper may make different decisions based on their personal experience.

If a patient opts for radiation, he assures them the treatment has fewer side effects than it used to, and many women can receive radiation therapy for just five days instead of the previous five to seven weeks of daily treatment. Shah said some women he treats have so few side effects they wonder if they are really receiving radiation.

Shah hopes that within five years, such risk stratification can become mainstream, "with patients understanding their risk rather than the general DCIS population's risk."

Surgery not always a given

Surgery, too, may not be necessary for everyone with DCIS.

In a trial of 1,200 women diagnosed with DCIS, half are receiving either surgery, radiation and hormonal therapy, and half repeat imaging with or without hormones. They will then be followed for at least two years to see whether their tumors progress.

Most people do well with surgery, Hunt said, but they can have bad reactions to anesthesia or antibiotics or other problems.

"While we expect good outcomes, we don't always see a perfect outcome in every case," Hunt said.

If everyone just gets surgery, doctors will never learn whether it's actually necessary, Esserman said. She's leading a trial, which Kajo joined, to look at using just endocrine therapy – drugs like low-dose tamoxifen or aromatase inhibitors – rather than surgery.

If a DCIS mass hasn't changed after three months on such hormonal therapy, "it probably needs to come out," Esserman said. But for many women, hormone treatment may be enough to prevent a DCIS from turning dangerous.

Learning how to stratify DCIS can be used as a tool to avoid more advanced cancers.

"DCIS is an opportunity. It is a proving ground," Esserman said. "It's way to say: Here's someone who's at risk for breast cancer, how much risk and for what? And what can I do to reduce that risk?"

For Kajo, so far, the endocrine therapy has been a good alternative.

The day Kajo joined Esserman's trial, she began taking a low dose of the drug tamoxifen used to prevent and treat breast cancer. Instead of the usual 20 mg dose, she started taking 5 mg. Kajo hates the tamoxifen. It makes the first two days of her period almost unbearable with cramps. But it's worth it to her to potentially avoid surgery.

Three months after starting the drug, an MRI scan showed her calcifications were clearing. Three months after that, they "looked way better than three months before," Kajo said. She's getting ready to go back for a mammogram and MRI to see what's happened in the year since.

That's key, Esserman said. Women with DCIS shouldn't be left alone, but watched carefully to ensure that their breasts aren't changing and that there's no sign of a burgeoning tumor.

Kajo admits she's a bit anxious about what the new scans find, but she believes putting off surgery was the best choice for her and her family.

"With treatments and DCIS, it's all fear-based," she said.

Most people choose aggressive care, Kajo said, because they're too afraid of what might happen if they don't – even if such treatment isn't necessary.

That's why she's speaking out. "if I can help one person to think they have hope in this journey," she said. "I know how stressful this can be and how scary this is."

Contact Karen Weintraub at kweintraub@usatoday.com.

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This article originally appeared on USA TODAY: Breast cancer treatment studied for 'stage zero' patients with DCIS