Not Every Cancer Requires Instant Therapy, Experts Explain

Why Some Cancers Aren’t Treated Right Away

For most people, hearing the word “cancer” creates an urgent desire to start treatment immediately. Yet for certain slow-growing cancers, doctors may advise watching and waiting instead of rushing into surgery, chemotherapy or radiation.

In some situations, aggressive treatment can cause more harm than good — especially when the tumor is unlikely to affect a patient’s lifespan or quality of life in the near term. This strategy, often called “watchful waiting” or “active surveillance,” relies on close monitoring rather than immediate intervention.

Fox News medical contributor Dr. Marc Siegel noted that many cancers will never become life-threatening, but that doesn’t mean people should avoid screening or diagnosis. Knowing what you’re dealing with, he said, allows for more nuanced decisions, including the option of observation.

“Information is power,” he emphasized. “How you act on that information is where medical judgment and the art of medicine come in.”

Below are examples of cancers where, in carefully selected low-risk cases, doctors and research suggest that delayed treatment may be appropriate. Every decision, however, must be made individually with a physician.

1. Low-Risk Prostate Cancer

Prostate cancer can range from very aggressive to extremely slow-growing. Some tumors require rapid treatment, but others may never cause serious problems.

Sanoj Punnen, M.D., a urologic oncologist at Sylvester Comprehensive Cancer Center in Miami, said that for most low-risk prostate cancers — often described as Gleason 6 or grade group 1 — his team usually recommends surveillance rather than immediate surgery or radiation.

The Gleason score measures how abnormal prostate cancer cells appear, from 6 (least aggressive) to 10 (most aggressive).

“For higher-grade tumors, like Gleason 8, 9 or 10, we believe they can progress quickly and increase the risk of metastasis, so we push for treatment,” Dr. Punnen said. “For low-risk tumors, we think the danger is small, so we focus on observation.”

That observation is active, not passive. Patients are followed with PSA blood tests, MRI scans and occasional biopsies to make sure the tumor isn’t changing.

2. Ductal Carcinoma in Situ (DCIS)

Ductal carcinoma in situ, sometimes referred to as stage 0 breast cancer, involves abnormal cells confined to the milk ducts. Because the cells have not invaded nearby tissue, DCIS is often viewed as a very early-stage or precancerous condition.

For women with low-risk DCIS, some research suggests that careful monitoring can be as safe in the short term as immediate surgery. A 2024 Dana-Farber Cancer Institute study found that women who chose active surveillance had similar quality of life, mental health and symptom progression over two years as those who underwent standard surgical treatment.

The study’s lead author said the results indicate that active monitoring is a reasonable short-term option for managing low-risk DCIS, while longer follow-up is still needed to confirm long-term safety.

Other studies have also reported that low-risk DCIS patients did not see higher rates of invasive cancer after two years of close observation. Even so, each patient should review personal risk factors and preferences with a breast cancer specialist before choosing a “watch and wait” approach.

3. Indolent (Slow-Growing) Lymphomas

Non-Hodgkin lymphoma affects the lymphatic system, including lymph nodes, spleen, thymus, bone marrow and related tissues. Some lymphomas are fast-growing and require immediate treatment, but indolent lymphomas can progress slowly and cause minimal symptoms.

The American Cancer Society notes that certain follicular lymphomas may be safely monitored without treatment at first. Guidelines from the National Comprehensive Cancer Network support watchful waiting for asymptomatic, slow-growing cases to avoid chemotherapy or immunotherapy side effects until treatment is clearly needed.

The Lymphoma Research Foundation describes “active surveillance” as a common approach after diagnosis or relapse in selected patients. Treatment begins when lymphoma-related symptoms appear or when tests show the disease is advancing.

Aggressive lymphomas, on the other hand, generally demand prompt therapy.

4. Chronic Lymphocytic Leukemia (CLL)

Chronic lymphocytic leukemia is one of the most common leukemias in adults. It begins in lymphocytes (white blood cells) in the bone marrow, then spreads to the bloodstream and sometimes to lymph nodes, the liver and the spleen.

CLL frequently grows slowly, and many people have no symptoms for years. Because of that, researchers have studied whether early treatment offers any advantage.

Several trials have shown that starting therapy right after diagnosis does not necessarily help patients live longer compared with careful observation. In some cases, the side effects of treatment may outweigh potential benefits during the early, symptom-free stage.

At the 2023 European Hematology Association Congress, a study presented by Petra Langerbeins, M.D., reported that early targeted treatment for asymptomatic CLL did not prolong overall survival compared to placebo. Her takeaway: in the era of modern targeted drugs, “watch-and-wait” remains the standard for patients with early, symptom-free CLL.

5. Low-Grade Endometrial Cancer in High-Risk Patients

Endometrial cancer, which arises in the lining of the uterus, is usually treated first with surgery to remove the uterus, fallopian tubes and ovaries.

However, not all patients are good surgical candidates. The American Cancer Society notes that in older adults, frail individuals or those with serious health conditions, doctors may advise delaying or avoiding surgery because the risks are too high.

For patients who want to preserve fertility or who have significant medical problems, hormone therapy may be used instead of immediate surgery. This strategy is generally reserved for tumors that are low-grade, small in volume and slow-growing.

6. Some Early Kidney Cancers

Small kidney tumors, often 3 centimeters or less, and certain benign lesions can also be monitored instead of removed right away.

According to the American Urological Association, active surveillance is an option for some patients with small, localized kidney masses, especially older adults or people with major health issues that make surgery riskier.

Guidelines emphasize shared decision-making that weighs the potential benefits of surgical removal against the chance that a patient may never be harmed by the tumor, especially in the context of other serious illnesses.

Data from the Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) Registry showed that patients who chose active surveillance had cancer-specific survival of 99% or higher — essentially the same as those who had immediate treatment.

7. Small Papillary Thyroid Cancers

Papillary thyroid cancer, the most common type of thyroid malignancy, can sometimes be very small and slow-growing. Tumors 1 centimeter (10 mm) or less are known as microcarcinomas.

Long-term studies of patients whose tiny papillary thyroid cancers were monitored rather than removed found that over 10 to 20 years, fewer than 10% showed meaningful growth, only about 5% developed lymph node spread and there were no thyroid cancer deaths in the carefully followed group.

Reflecting this evidence, the American Thyroid Association now recommends active surveillance as an option for very low-risk microcarcinomas.

The Takeaway: “Watch and Wait” Is Not One-Size-Fits-All

Although many patients with low-risk or slow-growing tumors can safely delay treatment, that approach is not appropriate for every cancer or every person.

Cancer behavior varies widely, and so do a patient’s age, overall health, genetics and comfort level with risk. What is safe for one individual could be dangerous for another.

Anyone facing a cancer diagnosis should have an in-depth discussion with their oncologist or specialist about all options, including the potential benefits and risks of both early treatment and active surveillance.

In selected situations, careful monitoring with regular checkups and tests can be a medically sound, lower-impact strategy. But that choice must always be guided by expert advice and tailored to the patient’s specific circumstances.