Immunotherapy for Breast Cancer: — PD-L1 Testing, TNBC & Pembrolizumab

No. Immunotherapy is mainly used for triple-negative breast cancer (TNBC), which lacks oestrogen, progesterone and HER2 receptors. TNBC tends to have more immune cells and higher PD-L1 levels, so it responds better to checkpoint inhibitors. For most hormone-positive (ER/PR+) and HER2-positive breast cancers, hormone therapy, CDK4/6 inhibitors and HER2-targeted drugs are more effective, so immunotherapy is generally not used there. At CION, your tumor board confirms your subtype and PD-L1 status before recommending immunotherapy, so it is only offered when the evidence supports a real benefit for you.

PD-L1 is a protein on tumour cells that helps cancer hide from the immune system. Testing a biopsy sample for PD-L1 tells us how likely your cancer is to respond to a checkpoint inhibitor. The test must match the drug: pembrolizumab uses the 22C3 assay with a Combined Positive Score (CPS) of 10 or more, while atezolizumab uses the SP142 assay measuring immune-cell staining. In advanced TNBC, PD-L1 status strongly guides treatment. In high-risk early TNBC, pembrolizumab is given regardless of PD-L1 status, so testing matters most when the disease is advanced.

Immunotherapy is given as an intravenous drip in a day-care setting, usually every 3 weeks, combined with chemotherapy. You do not stay overnight for a routine cycle. For high-risk early TNBC, pembrolizumab is given with chemotherapy before surgery and then continued for several cycles after surgery, often over several months. For advanced TNBC, it is combined with chemotherapy and continued as long as it keeps working and is well tolerated. Each infusion takes around 30 minutes plus monitoring time, and you are reviewed before every cycle so the plan can be adjusted to how you are responding.

Because immunotherapy switches on the immune system, it can sometimes cause it to attack healthy organs — these are called immune-related adverse events. The most common are thyroid changes (an underactive thyroid in roughly 4–18% of patients), skin rash and itching, and fatigue. Less commonly, the lungs (pneumonitis, about 1–4%), liver (about 1–6%) or gut can become inflamed. Most side effects are mild and reversible, and many are managed with steroids without stopping treatment. The key is early detection, which is why CION checks blood tests before every cycle and gives you a direct line to the team for any new symptoms.

Immunotherapy costs more than chemotherapy alone because the drugs themselves are expensive. As a broad guide in India, checkpoint-inhibitor immunotherapy commonly costs in the region of ₹1.5–6 lakh per cycle, with breast cancer regimens usually given every 3 weeks over several months. The total depends on the drug chosen, your body weight (the dose is weight-based) and how many cycles you need. Many private insurance policies cover immunotherapy for approved breast cancer indications. At CION we give you a written cost estimate at your first consultation, verify your insurance and cashless eligibility up front, and offer an EMI facility where needed — with no unnecessary cycles.

Yes, in the right patients. In high-risk early TNBC, adding pembrolizumab to chemotherapy before surgery raised the rate of patients with no remaining cancer at surgery to about 64.8% (versus 51.2% with chemotherapy alone), and improved 3-year event-free survival to 84.5% versus 76.8%. In advanced PD-L1-positive TNBC (CPS ≥ 10), pembrolizumab plus chemotherapy improved median overall survival to about 23 months versus 16 months. These are meaningful gains, but immunotherapy is not a guaranteed cure and works best when matched to the right subtype and PD-L1 status — which is exactly what the CION tumor board confirms before starting.

Yes — in fact, for breast cancer it is almost always combined rather than used alone. Chemotherapy exposes more tumour signals to the immune system, which makes the checkpoint inhibitor work better, so the two are planned together. In high-risk early TNBC, immunotherapy plus chemotherapy is given before surgery to shrink the tumour, surgery is then performed, and immunotherapy is continued afterwards to reduce the chance of recurrence. This integrated plan — systemic therapy, surgery and ongoing immunotherapy — is decided by CION's tumor board so that medical, surgical and radiation oncologists agree on the sequence together.

CION brings 150+ years of combined oncology experience, 17 super-specialist oncologists and 35+ centres across Telangana and AP, having treated 15,000+ patients with a 4.8/5 Google rating. Every immunotherapy decision is made by a multi-disciplinary tumor board — not one doctor's opinion — so a second opinion is built into your first plan. We confirm PD-L1 status before recommending immunotherapy, monitor side effects closely with blood tests before every cycle, and put all costs in writing. Our 1-year breast cancer survival rate is 96.9% versus the 85.4% national average.* Your first 45-minute consultation is free, confidential and carries no obligation to start treatment.