Immunotherapy has changed the way of lung cancer therapy, offering hope to patients who may not respond well to traditional therapies. However, before starting immunotherapy, doctors perform several tests to ensure that it is safe and likely to be effective. These tests assess your overall health, cancer type, tumor markers, and possible risks. Here’s a detailed guide to the key investigations:
1. Basic Blood Work
Before starting immunotherapy, doctors evaluate your general health with routine blood tests:
CBC (Complete Blood Count): Checks overall health, including the presence of infection or anemia.
Liver & Kidney Function Tests: Drugs like PD-1/PD-L1 inhibitors can affect these organs, so baseline monitoring is important.
Thyroid Profile (TSH, T3, T4): Immunotherapy may affect thyroid function, leading to hyper- or hypothyroidism.
2. Biopsy & Histopathology
A biopsy is essential to confirm the type of lung cancer:
Cancer Type: Determines whether you have Non-Small Cell Lung Cancer (NSCLC) or Small Cell Lung Cancer (SCLC).
Eligibility for Immunotherapy: Most immunotherapy treatments are approved for NSCLC. The biopsy helps doctors decide if you are a suitable candidate.
3. Molecular / Biomarker Testing
This is one of the most critical steps before immunotherapy:
PD-L1 Expression Test (Immunohistochemistry): High PD-L1 levels increase the likelihood of responding to immunotherapy.
Gene Mutation Tests (EGFR, ALK, ROS1, KRAS, MET, BRAF, RET): If certain mutations are present, targeted therapy may be more effective than immunotherapy.
NGS (Next-Generation Sequencing): Provides comprehensive profiling for multiple genetic changes at once.
4. Infection Screening
Since immunotherapy stimulates the immune system, it can worsen existing infections. Screening usually includes:
Hepatitis B & C, HIV tests
Tuberculosis (TB) screening: Especially important in countries like India with high TB prevalence.
5. Imaging Tests
Imaging helps assess cancer spread and provides a baseline before starting treatment:
CT scan / PET-CT scan: Confirms staging, detects metastasis, and provides a reference for future treatment response.
MRI Brain: Recommended in advanced cases to check for brain metastasis.
6. Other Special Tests (As Needed)
Depending on your health and history, additional tests may include:
Autoimmune disease screening: Patients with severe autoimmune conditions may not be suitable for immunotherapy.
Pulmonary function tests: Assess baseline lung capacity to ensure safe treatment.
Patient-Friendly Summary
Before starting immunotherapy for lung cancer, your oncologist will evaluate:
General health: Blood counts, liver, kidney, and thyroid function.
Tumor markers: PD-L1, EGFR, ALK, KRAS, and other mutations.
Infection status: Hepatitis B/C, HIV, and TB.
Cancer spread: CT, PET-CT, and possibly MRI.
These tests help your doctor decide whether immunotherapy is the right choice, or if you may benefit more from targeted therapy, chemotherapy, or a combination approach.
Frequently Asked Questions (FAQs)
1. Why is PD-L1 testing important before immunotherapy?
PD-L1 levels help predict the likelihood of responding to immune checkpoint inhibitors.
2. Do all lung cancer patients need EGFR and ALK tests?
Most NSCLC patients undergo these tests, as targeted therapies may be more effective than immunotherapy for certain mutations.
3. Can I get immunotherapy if I have hepatitis or TB?
Special precautions are taken; some patients may need treatment of infections before starting immunotherapy.
4. Is PET-CT necessary before immunotherapy?
It helps confirm staging and detect metastasis, which guides treatment planning.
5. How long do biomarker results take in India?
Results can take from 1 to 3 weeks, depending on the test and laboratory.
