What Are the Indications That Immunotherapy Is Working? A Patient’s Guide

If you or a loved one is undergoing immunotherapy to combat cancer, you may be wondering how to know if it’s working. This treatment, which enhances your immune system to fight cancer, is a newer development that gives hope to many. However, immunotherapy differs from some therapies, where you notice immediate changes. It can act in ways that are not always recognizable at first. As one who has accompanied patients on this path, I want to tell you what to look for, what to anticipate, and how to remain hopeful as you track progress. Let me simplify it for you so you feel educated and empowered.

What Is Immunotherapy, and How Does It Work?

Immunotherapy is a cancer therapy that allows your immune system—the body’s natural guard against germs—to see and attack cancer cells. In most cases, cancer can evade your immune system, but immunotherapy is a wake-up call. Immunotherapy uses drugs, such as checkpoint inhibitors or CAR-T cell therapy, to stimulate your immune cells or teach them to detect and kill the cancer.

For instance, medicines like pembrolizumab (also known as Keytruda) inhibit the “off switches” cancer uses to evade surveillance, allowing your immune system to come into action. CAR-T therapy, however, harvests your immune cells, alters them in a laboratory, and reinstalls them to target the cancer directly. Depending on your type of cancer—like melanoma, lung cancer, or lymphoma—your physician will select the optimal strategy. It can be administered by IV or, in other situations, as a single-cell infusion.

How Can You Tell If It’s Working?

Immunotherapy is not always quick to reveal itself like chemotherapy or radiation can, which can quickly shrink tumours. Instead, weeks or months can pass before it’s noticeable, and everyone’s experience differs. Following are some things that could be signs it is working, as reported by patients and physicians:-

• Tumor Shrinkage Over Time – One of the most evident signs is when scans (like CT or MRI) show the tumour getting smaller. This might not happen immediately—sometimes it takes 2 to 6 months—but a gradual reduction is a good indicator. I’ve had patients with lung cancer who saw their tumours shrink after three months of treatment, giving them a big boost of hope.
• Fewer Symptoms of Cancer – If the immunotherapy is effective, you may experience fewer pains, improved breathing, or increased energy with the effects of the cancer decreasing. For example, a melanoma patient reported that her back pain dissipated after several cycles because the cancer lesions were shrinking. It is a subtle but significant adjustment.
• Stable Disease – Occasionally, the cancer doesn’t shrink but won’t grow any more. That “stable” situation can be a victory, as the immunotherapy keeps the cancer in check. One of my friends with kidney cancer was relieved that her scans didn’t indicate any new growth after months of therapy.
• Enhanced Blood Tests – Physicians routinely examine the blood for markers such as tumour markers (such as CEA in colon cancer). Should such levels be reduced, this would indicate that the tumour is being treated. The patient I am working on observed his PSA reading the s (in case of prostate cancer) diminish, an initial indication that the therapy worked.
• Feeling Stronger Overall – Some individuals feel improved in their daily lives—less fatigued, increased appetite, or capable of performing activities such as walking or cooking again. This is not a direct measurement, but it can indicate the burden of the cancer lifting. A patient with lymphoma once reported how she resumed gardening after a sudden burst of energy.

What About Unusual Reactions?

Immunotherapy may, on occasion, produce a peculiar reaction that may surprise you or your physician initially. Here’s what you should know:-

• Pseudo-progression – The tumour appears to grow, or new lesions develop on a scan before it gets smaller. This occurs because the immune system is killing the cancer, temporarily causing swelling. One melanoma patient I knew experienced this—her scan was initially worse, but three months later, the tumour was almost gone. Physicians may wait and observe with repeat scans to reassure.
• Slow Response – While quick-acting treatments act swiftly, immunotherapy may be slower. It could take 12 weeks or more before you notice changes. Just be patient, and your physician will keep an eye on you.
• Immune-Related Side Effects – If your immune system becomes more activated, you may experience new symptoms such as rash, joint pain, or fatigue. These can indicate that the treatment is working but requires attention. A patient with lung cancer I cared for developed a minor rash that resolved on cream, and her tumour reduced shortly thereafter.

What Might Suggest It’s Not Working?

While looking for positive signs is excellent, it’s also important to recognize when immunotherapy may not work. Inform your doctor if you see:-

• Tumour Growth – When scans indicate that the cancer is expanding despite therapy, it could suggest that the treatment is failing.
• Worsening Symptoms – Increased pain, weight loss, or shortness of breath could indicate that the cancer is advancing.
• Rising Markers – If blood tests show tumour markers rising, it’s a signal to reassess.
• New Cancer Spots – New areas of cancer on scans suggest the immune system isn’t keeping up.

If this happens, don’t lose hope—your doctor can switch to another therapy or adjust your plan. I’ve seen patients move to a different drug and find success after an initial setback.

How Do Doctors Track Progress?

Medical team of doctors keeps a close eye on how immunotherapy is working. Here’s what they might do to track progress:-

• Regular Scans – CT, MRI, or PET scans are performed regularly after a few months to keep eye on growth of tumour.
• Blood Tests – To look at tumour markers or immune cell activity.
• Physical Exams – To note any symptom changes or side effects.
• Patient Feedback – They’ll ask how you feel to get the whole picture.

These follow-ups assist your physician in determining whether or not to continue treatment, change it, or discontinue it. For instance, a patient with bladder cancer underwent frequent scans that revealed her tumour was stabilizing, which informed her treatment plan.

Tips to Help Your Journey

While waiting to find out if immunotherapy is effective, you can do things to feel your best:-

• Stay Connected – Tell your doctor or a support group how you feel. Hearing from others can calm fears.
• Eat Well – A healthy diet of fruits, vegetables, and protein can help your immune system.
• Rest and Move – Sleep plenty, but attempt light walks if possible—these can lift your mood and energy levels.
• Manage Side Effects -If you develop a rash or achiness in your joints, informs your doctor—they can offer creams or anti-inflammatory medication.

One of my patients discovered comfort in a weekly phone call with a friend who had undergone immunotherapy. It helped her remain upbeat while awaiting the scan results.

Questions to Ask Your Doctor

Don’t hesitate to ask your doctor if immunotherapy is effective. Write down your questions and have someone to assist you in listening. Below are some ideas:-

• How will we know whether this treatment is benefiting my cancer?
• How frequently will we monitor using scans or tests?
• What should I observe that could indicate it’s working or not?
• Is it a sign or an issue if my symptoms worsen?
• What happens if it breaks?

You may also inquire about meeting other patients. Their stories can provide comfort and insight, and patients become more confident after talking to someone who’s been in their shoes.

What to Expect Moving Forward

Immunotherapy can be a slow process, but its potential is exciting. Some patients see tumours shrink or disappear, while others maintain stability for years. I’ve had a patient with head and neck cancer who’s been cancer-free for over two years thanks to immunotherapy. Others might need to switch treatments if it doesn’t work, but each step brings new options.

The ride takes endurance, but your physician will manage you with periodic news. If this is a new treatment for you, remember that indications of success will come slowly, and what you notice—pain is gone, increased energy—may be as relevant as the pictures the scans show.

Conclusion

Immunotherapy is a crucial cancer-treating agent with a method – awakening your immune system to battle the condition. Tumour shrinkage, fewer symptoms, stable disease, improved blood markers, and overall well-being are all signs that it’s working—but it can take several weeks or months to notice these. Unusual side effects like pseudoprogression can occur, and your doctor will sort these out. If it’s not working, don’t worry—there are other options. Contact your care team, ask questions, and call on support to get through this. Immunotherapy brings hope; with proper monitoring, you can determine if it’s leading the way.

Tags: Chemotherapy , Immunotherapy , immunotherapy for cancer