How can you tell if your body is actively combating cancer or if it’s just the treatment itself making you feel worse? This is a common concern for those beginning immunotherapy. Unlike other treatments, it doesn’t produce immediate results. It requires patience, time, and careful monitoring. Yet, there are distinct indicators that immunotherapy is effective, and they might not always be what you anticipate.

Doctors monitor progress through scans, blood tests, and by observing changes in symptoms. Even if outwardly nothing seems different, the immune system might already be engaged in action on a deeper level. Let’s explore what to look out for and how to determine if immunotherapy is functioning effectively.

Understanding How Immunotherapy Works

Immunotherapy empowers your body to combat cancer on its own. This contrasts with chemotherapy, which destroys both healthy and cancerous cells. In immunotherapy, the medicine activates immune cells to better target cancer. Some of these cells attack cancer directly, while others bolster the body’s overall response system.

Medicines like Keytruda or Nivolumab boost your natural defense, but it’s not instant. Sometimes the tumor looks bigger before it shrinks. Or it may seem nothing is happening, but your immune system is preparing to fight back.

This is why it’s hard to say in the first week or two if it’s working. You need to wait, stay on the schedule, and follow your doctor’s checks.

5 Clear Signs Immunotherapy Is Working

Now let’s explore in more depth the specific ways you and your doctor may begin to notice that immunotherapy is helping. Understanding each sign gives a better idea of what’s happening inside the body and what to expect going forward.

1. Tumor Stops Growing

This is one of the most promising signs that immunotherapy is working. In many cases, the first noticeable change is that the tumor stops getting bigger. Even if it doesn’t shrink right away, halting its growth shows that the immune system is starting to control the cancer’s spread. 

This might be seen on an MRI or CT scan during a routine follow-up. If the size stays the same over weeks, doctors consider this a good signal.

2. Tumor Shrinks Over Time

With continued treatment, tumors may start to shrink slowly. Shrinkage can take time, and sometimes, the first scan may not show much difference. But after multiple doses, the size begins to reduce. 

This shrinkage means your immune system is attacking the cancer cells and breaking them down. It’s not always fast like chemotherapy, but it’s often more targeted and lasting.

3. No New Tumors Forming

Even if the current tumor hasn’t changed much, the absence of new growths is also a positive outcome. One of the goals of immunotherapy is to stop cancer from spreading. If follow-up scans show no new spots or affected areas, it means the medicine is holding the disease in place. 

Doctors watch closely for these developments to decide if the current treatment is effective or needs changes.

4. You Feel Better: Symptoms Start Improving

Often, the signs immunotherapy is working come not just from test reports but from how the patient feels. A drop in pain, easier breathing, better sleep, and an increased appetite all suggest the body is responding well. Cancer symptoms can become less intense. 

Some patients report a better mood and clearer thinking. These might seem small, but for someone in treatment, they mean a lot.

Energy levels might also pick up slowly. A person who felt exhausted before may be able to walk longer, sit up more, or do simple tasks without help. These changes are not always dramatic, but they show that healing might be starting internally.

5. Blood Markers and Lab Test Results Improve

Doctors often use blood tests to measure cancer markers or immune activity. If these numbers go down or stabilize, it’s another strong sign. Your white blood cell count might improve. Other markers linked to cancer progression may also drop. These are scientific proofs that something is working behind the scenes.

Lab improvements also include better organ function. For example, kidney and liver tests might come back more normal than before. These results show the body is tolerating the treatment and reacting positively.

Common Signs and Their Meaning

Why Regular Checkups Matter

Doctors use CT scans, MRIs, and blood tests to track changes. They also ask how you feel. Never skip a follow-up, even if you think nothing’s happening. Some changes can’t be felt but are visible on scans or in lab reports.

Also, don’t stop treatment on your own. If you feel worse, talk to your doctor. Some side effects mean the body is adjusting. Some mean you need help. Only tests and follow-ups can show the full picture.

Lifestyle Changes That Support Immunotherapy

While treatment works on one side, you can help your body on the other. Try to:

• Eat simple, whole foods
• Sleep on time
• Avoid infections
• Stay hydrated
• Reduce stress with meditation

These don’t replace treatment, but they give your body strength to handle medicine better.

Can Immunotherapy Stop Working After Some Time?

Yes, it happens. Cancer cells are smart and may find new ways to grow. That’s why even if the first signs immunotherapy is working show up, later they can disappear.

Doctors may change the medicine or add another drug. This combo may wake the immune system again. But it needs testing, tracking, and timing.

When Should You Call Your Doctor Immediately?

Call your doctor if:

• Pain gets worse suddenly
• Breathing becomes hard
• You feel dizzy or weak all day
• You get swelling or a bad rash

These may be side effects or other issues. They need checking right away.

Final Thoughts 

Seeing clear signs immunotherapy is working can take time, and the wait can feel frustrating. But remember—healing is rarely a straight path. From shrinking tumors to boosted energy levels, these signs may appear gradually, but each small improvement is a step in the right direction. Trust the process, stay engaged with your care team, and pay attention to your body’s signals. What may seem subtle today could be a powerful sign of progress tomorrow. When immunotherapy works, it can truly change everything.

Read Also: 11 Keytruda Side Effects And How to Deal With Them

FAQs

How many days does it take for immunotherapy to show results?

It usually takes a few weeks to a few months. Some people see early relief, others take longer. Stick with the plan and track progress.

Can immunotherapy cause tumors to grow first?

Yes, it can. This is called pseudo-progression. It means immune cells are gathering to fight, not that cancer is spreading.

What if there are no side effects at all?

That’s fine. Many people who get good results feel no side effects. Response isn’t linked to how sick you feel.

Can I do yoga or mild walking during immunotherapy?

Yes. Light exercise helps blood flow and reduces stress. Just don’t overdo it. Ask your doctor.

Should I keep working or take rest during treatment?

This depends on how you feel. Some people work part-time. Some take breaks. You must listen to your body and rest when needed.