Active Surveillance vs Treatment: How to Compare

This page is for people choosing between watching a cancer closely and treating it right away. It explains both approaches, who is offered each, and which warning signs need a call between visits.

Active surveillance means closely watching a cancer with scheduled tests, and starting treatment only if it changes. Immediate treatment means acting now to remove, kill, or shrink the cancer. Both are legitimate medical strategies. The right choice depends on how the specific cancer tends to behave.

Active surveillance is not "doing nothing." This page uses prostate cancer as its example, as NCI does. NCI says it often involves regular visits, digital rectal exams, PSA tests, and sometimes ultrasound and needle biopsies. NCI says the exact tests and timing are not set by controlled trials, so your team decides them. The goal is to catch early signs that the cancer is growing, not to ignore it. This differs from an older, looser approach called watchful waiting. That approach mainly aims to manage symptoms, rather than watch closely for growth.

Surveillance is typically offered for cancer that is found early, is expected to grow slowly, and is not causing symptoms. It is often considered for older patients, or when the cancer was found by chance during other testing. The appeal is simple. You avoid or delay the side effects of surgery or radiation while the cancer stays low-risk.

Immediate treatment is generally recommended for a faster-moving cancer. This applies when it is more likely to grow quickly, spread, or cause harm before a surveillance schedule would catch it. Surveillance test results can show the cancer is progressing. NCI says treatment to cure the cancer is started if it begins to grow.

Surveillance avoids or delays treatment side effects. But it means living with a known cancer, and committing to a strict testing schedule. Missing scheduled tests defeats the purpose of surveillance and raises real risk. Immediate treatment can bring more certainty. But it comes with the side effects of surgery, radiation, or other therapy right away. Some of these can be permanent.

Surveillance works only if new problems get reported between visits. Do not wait for the next scheduled test.

• Call 911 or go to the nearest emergency department if you suddenly feel short of breath, your heart is racing, you feel faint, or your skin looks very pale. Do not drive yourself.
• Call 911 or go to the nearest emergency department if you suddenly cannot pass urine at all, especially with a full, painful lower belly. Do not drive yourself.
• Call 911 or go to the nearest emergency department if back pain comes with new leg weakness or numbness, or you lose control of your bladder or bowels. Do not drive yourself.
• Call your care team right away if you see blood in your urine.
• Call your care team right away if you have new or worsening pain in your back, hips or pelvis that does not go away, or new trouble starting the flow of urine, emptying your bladder, or a weak "stop-and-go" stream.

Also call if you need to miss or move a scheduled test, so the schedule can be reset.

• Is my specific cancer a reasonable candidate for active surveillance?
• What exact tests, and how often, would surveillance involve?
• What result would mean it's time to switch to treatment?
• What are the risks of waiting, specifically for my case?
• If I choose treatment now, what are the expected side effects?

• National Cancer Institute — Prostate Cancer Treatment (PDQ) Patient Version
• National Cancer Institute — Active Surveillance for Low-Risk Prostate Cancer Continues to Rise
• National Cancer Institute — Side Effects of Cancer Treatment
• MedlinePlus — Breathing difficulty