How to manage the side effects of Pembrolizumab in my aunt?

Question

Hello doctor,

My aunt is 58 and diagnosed with stage 4 lung cancer with small spots seen in the liver also. The doctor started Keytruda (Pembrolizumab) immunotherapy because the PD-L1 report was high. She has had two infusions so far, and her cough improved a little, but fatigue is still there.

How long does immunotherapy usually take to show clear results on scans?
Also, are there serious immune side effects we should monitor at home, like fever or breathing issues?

I am hearing about this type of treatment for the first time, so I am trying to understand how it works.

Kindly suggest.

Answer 1

Hello,

Welcome to icliniq.com.

I understand your concern about your aunt’s illness.

It is good that the doctors checked the PD-L1 (programmed death-ligand 1) level and started Pembrolizumab, because patients with high PD-L1 often respond better to this type of treatment. Immunotherapy usually takes some time before the effect becomes clearly visible on scans.

In most patients, doctors repeat a CT (computed tomography) scan after about two to three months of treatment (often after three to four cycles) to see whether the tumors are shrinking or at least remaining stable.

Sometimes symptoms like cough or breathing improve earlier, which can be an encouraging sign, but the scan is what confirms the response.

Fatigue is one of the most common effects during immunotherapy, and many older patients with lung cancer notice it, especially in the first few cycles. It does not always mean the treatment is failing.

At home, it is important to watch for certain immune-related side effects. These treatments can sometimes cause the immune system to attack normal organs.

A few things to watch for include new or worsening breathlessness, persistent cough, unexplained fever, severe diarrhea, yellowing of eyes or skin, severe skin rash, or unusual weakness. If any of these appear, the treating doctor should be informed promptly so they can evaluate her.

Otherwise, the main follow-up usually involves regular clinical review and periodic CT scans to monitor how the disease is responding to the treatment.

I hope this helps.

For more queries, reach out to me anytime. I am happy to help you.

Thank you.