AT 52, DESIREE BASILA nurtured her lifelong passion for ballet. By day, she taught high school math and science in San Francisco. After school, she took ballet classes for up to four hours a night. “It gives you a certain relationship with your body,” Basila says. “My body was much more than something that just carried my head around.”

Her reliance on her body as a channel for artistic expression shaped how she responded to her cancer diagnosis in June 2007. Following an irregular mammogram, her care team referred her to a surgeon, who diagnosed her with ductal carcinoma in situ (DCIS). Because the lesion in her breast was so large, the surgeon urged her to schedule surgery to remove her breast rather than have a lumpectomy.

But the ballet dancer took a beat.

Basila searched PubMed, a free online database that provides summaries of published health science research, to find out as much as she could about her diagnosis. She learned DCIS is a noninvasive breast cancer contained within the milk ducts that has not spread into nearby breast tissue. Some 50% to 80% of DCIS cases never become invasive cancer. “Here I was thinking I had a disaster on my hands,” she says. “Then I realized no one knows which DCIS cases will progress to invasive breast cancer and which ones will just sit there.”

Because it’s difficult to predict which instances of DCIS will become invasive cancers, patients typically undergo a lumpectomy and radiation—unless the lesion is too big, as it was in Basila’s case, or there are multiple lesions. In these situations, mastectomy is recommended.

But as a dancer, Basila knew removing her breast could impair the use of her shoulder or throw off her center of gravity. That could force her to relearn how to turn and balance while dancing—and might even prevent her from practicing ballet ever again. Basila didn’t want to have a surgery that would fundamentally change her body for a diagnosis that might never cause her any harm.

Basila saw Shelley Hwang, a surgical breast oncologist at UCSF Helen Diller Family Comprehensive Cancer Center in San Francisco, for a second opinion. Hwang also recommended a mastectomy. Basila asked Hwang if she could forgo surgery. The doctor was reluctant, but after Basila asked, “What if I just don’t do anything?” and turned to leave the office, Hwang agreed to delay surgery if Basila enrolled in a trial.

In the small study, Basila and other participants took the hormone therapy tamoxifen and received regular scans to monitor their DCIS. After three months, the study called for participants to undergo a mastectomy, but Basila didn’t intend to if her disease remained stable. Three years later, a scan found the cancer had spread beyond the milk ducts. Basila had surgery to remove the cancerous growth outside the milk ducts, leaving the noninvasive portion of the lesion intact. More than 18 years since her diagnosis, Basila, now 71, still undergoes regular mammograms to monitor her DCIS, which has not progressed again.

By electing to monitor for symptoms or signs of growth on scans, physical exams or blood tests, some people with low-risk cancer may be able to delay or avoid surgery or the toxicity of chemotherapy and radiation. In some early-stage cancers, including prostate, bladder and thyroid cancers, research is finding that people who choose active surveillance live just as long as those who decide to have treatment right away. “If we can have the same outcomes with far fewer operations, I think that’s a really compelling finding,” says Hwang, who now leads the breast oncology program at Duke Cancer Institute in Durham, North Carolina.

What Is Active Surveillance?

Active surveillance, also called active monitoring, is a planned treatment approach in which early-stage or slow-growing cancer is closely monitored with regular tests—such as blood work, imaging or repeat biopsies—and curative treatment starts only if the cancer shows signs of progression. Patients who choose active surveillance may also take preventive medications, such as aromatase inhibitors or other endocrine therapies.

Not appropriate for most cancers, active surveillance is used in select cases—such as certain prostate, thyroid and bladder cancers and non-Hodgkin lymphomas—when the disease is small, has not spread to other parts of the body and is considered low risk. Even then, it is an option only for people who can adhere to a rigorous monitoring schedule. Outside this narrow group, delaying treatment could allow cancer to progress beyond a curable stage.

Active Surveillance Means Regular Monitoring

People who choose to delay active treatment are watched with testing and exams for signs of cancer growth.

When appropriate, active surveillance can help patients avoid or delay the side effects of surgery, radiation or chemotherapy and preserve quality of life while the cancer remains stable. But the approach isn’t right for everyone. Living with an untreated cancer can cause significant anxiety. Additionally, frequent testing can be burdensome, uncomfortable and costly, while patients who miss follow-up appointments might miss the signs of cancer growth, which can impact outcomes.

People eligible for active surveillance should carefully weigh these trade-offs and discuss the medical and psychological implications with their care team—and their loved ones—before deciding whether this approach is right for them. “Like anything else in medicine, this is a risk-benefit discussion with the patient and their physicians,” says Roger Li, a urologic oncologist at Moffitt Cancer Center in Tampa, Florida.

‘You Have Time’

Active surveillance is now regularly used as an approach to low-grade prostate cancer, but it wasn’t always so common.

When Bill Manning, of Fallbrook, California, now 73, was diagnosed with prostate cancer in June 2009, doctors told him the cancer was unlikely to grow or spread aggressively. Manning’s doctor suggested surgery and radiation, but Manning says he knew surgery could have “quite profound” side effects. “They have a huge impact on your quality of life,” says Manning, who is now executive director of Active Surveillance Patients International, a prostate cancer advocacy organization.

Like Basila, Manning educated himself about his diagnosis through books recommended by members of a support group he joined. He learned men with prostate cancer often experience sexual dysfunction, including impotence and low libido, after treatment. A 2013 study found that within 15 years of either surgery to remove the prostate or radiation, 87% to 94% of men have some degree of erectile dysfunction. Urinary incontinence, bowel dysfunction and radiation-induced bladder cancers are also common complications.

Learning about these potential impacts on his quality of life, Manning proactively sought out active surveillance, which he says his doctor “grudgingly accepted.”

Doctors now routinely discuss active surveillance for low-risk prostate cancers, which represent about half of all prostate cancers. This shift came after research found men with low-risk disease who didn’t have treatment lived just as long as those who had treatment. Twice a year, Manning undergoes a prostate-specific antigen test, a blood test that measures levels of a protein made by the prostate that can indicate the presence of cancer. He has also had more sensitive tests, such as ultrasounds and multiparametric MRIs, which render more detailed images of the prostate than standard MRIs.

“There’s been extreme overtreatment on guys that didn’t really need it,” Manning says. Men in the low-risk group “have time to put on the brakes, learn about the disease, learn about their options.”

Avoiding Treatment Complications

In cancer, the word “indolent,” which means slow growing, indicates the disease is not an emergency. Up to 40% of people with non-Hodgkin lymphoma have indolent disease, which means they are candidates for active surveillance. Many people with this type of cancer do not exhibit symptoms common in this disease, such as fatigue, fever or swollen lymph nodes. They may learn they have lymphoma when they receive abnormal blood test results despite feeling fine.

Since frequent blood tests can detect progression, doctors often recommend active surveillance for people with indolent non-Hodgkin lymphoma, but there’s no universal protocol. Some doctors may monitor patients with blood work and physical examinations, while others may order CT scans as well. According to Paolo Strati, a hematologist-oncologist at the University of Texas MD Anderson Cancer Center in Houston, patients at his institution typically undergo monitoring every six months for the first two years and annually after that. Scans tend to stop after 10 years.

But many people still choose to undergo treatment. “Some patients value not receiving any type of treatment. Others are concerned about keeping a cancer in their body,” Strati says. That concern, not clinical need, pushes many to pursue treatment.

Those who start treatment for indolent B-cell non-Hodgkin lymphoma often receive Rituxan (rituximab) by IV infusion once a week for four weeks and then every six months. This drug targets the CD20 protein found on the surface of B cells and activates the immune system. While this approach can kill cancer cells, it also can weaken the immune system and put patients at increased risk for serious infections and other illnesses. “Sometimes, for longer than a year after treatment, patients can be immunocompromised,” Strati says. “The benefit of avoiding treatment is to avoid these possible complications.”

In a clinical trial published in the Lancet in 2003, 309 people with asymptomatic, advanced-stage indolent non-Hodgkin follicular lymphoma—a type of cancer that had spread to multiple lymph nodes or beyond but was still considered slow-growing—received either immediate treatment with chemotherapy alone, which was the standard treatment at the time, or had active monitoring. Those in the active monitoring group who had disease progression could begin chemotherapy. After 16 years, people in both groups lived the same amount of time.

But, Strati says, anxiety is common during active surveillance. Sometimes, he explains, a person may have no pressing symptoms and potentially be able to forgo treatment, but they choose to receive it anyway because they’re more comfortable that way. “And that’s an acceptable approach,” he says.

Some people erroneously believe any treatment delay could raise their risk for more aggressive disease later, Strati says, but some cancers grow slowly by nature, and some may never need to be treated.

Surgery or Surveillance

Some people with early-stage bladder cancer that has a low chance of ever progressing outside the bladder may also choose active monitoring. This may allow them to avoid multiple bladder surgeries and the associated side effects, which can include urinary problems and sexual dysfunction.

“We know that these tumors tend to have recurrences, but they don’t progress on to disease that would threaten life,” Li says.

To determine candidates for active surveillance, physicians may use criteria endorsed by the International Bladder Cancer Group. These guidelines advise people with early-stage bladder cancer to consider monitoring their disease if they have five or fewer tumors, each smaller than 1 centimeter, and no history of high-grade disease. “This saves them the morbidity of multiple different resections that would require anesthesia and all the associated morbidities,” Li says.

Still, people with low-grade bladder cancer generally choose surgery. “There’s a perception that as long as they have tumors in their bladder, they’re exposed to risk of progression,” he says.

A Personal Choice

People who have low-risk cancer may differ in their tolerance for active surveillance and should carefully weigh the risks and benefits of both active monitoring and immediate treatment. One person with low-risk prostate cancer may decide to do active surveillance to avoid side effects of radiation, while someone with DCIS who has a large lesion may decide to have a mastectomy to avoid the fear of developing invasive cancer.

“I don’t think everyone with DCIS should have active monitoring,” Hwang says. “I think some women benefit from surgery more than others, and some don’t benefit at all.” The patients most likely to benefit from surgery, she explains, are those with extensive estrogen-negative, high-grade DCIS.

In the phase III COMET trial, published Dec. 12, 2024, in JAMA, Hwang and colleagues followed 957 women age 40 or older with hormone receptor-positive grade 1 or 2 DCIS. The women either had active monitoring, which involved breast imaging and physical examination every six months, or surgery with or without radiation. People in both groups could choose to take endocrine therapy. After two years, 5.9% of the women in the surgery group and 4.2% of those in active monitoring had developed invasive breast cancer.

“Twenty years ago, it was considered crazy, heresy or just dangerous to consider anything other than surgery for DCIS,” Hwang says. “But now we are having conversations about whether this could be an option.”

While emerging data demonstrate the safety of active surveillance for low-grade DCIS, the number of women who take this route has held pretty steady since Basila insisted on it all those years ago. A 2015 study found less than 2% of women with DCIS chose to forgo surgery at that time. Today, according to a 2021 report co-authored by Hwang, around 3% of women with DCIS, when given the choice, go for this option. While active surveillance may be a more frequent part of the conversation about DCIS, it’s not yet recommended in treatment guidelines, but that could change as more studies, like the COMET trial, evaluate active surveillance for people with low-risk DCIS.

Basila, who pushed for active surveillance for her DCIS, says that each person must make their choice based on their individual values and their tolerance for risk. “It remains true that quality of life means more to me than quantity,” she says.

Sonya Collins is a freelance health journalist based in Atlanta.