How Long Does Immunotherapy Typically Last in 2026?

When immunotherapy works and side effects remain tolerable, treatment generally continues for several months up to two years, with the exact stopping point determined by the medical team based on cancer type, response, and side effects.

Key Summary

• Immune checkpoint inhibitors are given intravenously at intervals of 2, 3, or 6 weeks depending on the drug, with each infusion taking roughly 30 minutes to an hour.
• Response is typically assessed every 2–3 months by CT scan. If the treatment is working and side effects remain tolerable, treatment generally continues for several months up to two years.
• When to stop treatment varies by cancer type, response, and side effects, and differs from person to person.
• Immunotherapy-specific side effects (affecting the thyroid, lungs, intestines, liver, skin, adrenal glands, etc.) can appear both during treatment and even after treatment ends, which is why blood tests and thyroid function checks are repeated before every cycle.
• A stay in Korea often spans 2–3 weeks to cover testing and the first cycle; subsequent cycles can be continued through periodic return visits or by handing off the treatment plan to a local medical team.

How Often Is Immunotherapy Given, and How?

• Tissue testing is first done to check markers such as PD-L1 and MSI/MMR status. Once a drug is selected, it is administered intravenously. The interval is 2, 3, or 6 weeks depending on the drug, and each infusion takes roughly 30 minutes to an hour.
• Because the first dose requires observation for reactions, it is recommended to undergo it in Korea as an inpatient stay or a day of monitoring. Subsequent doses are then given on an outpatient basis according to the cycle schedule.
• Immune checkpoint inhibitors work by blocking signals (PD-1/PD-L1) that act as a 'brake' on T cells, helping immune cells attack cancer cells. Because the drug does not kill cancer directly but instead mobilizes the immune system, the speed at which effects appear differs from conventional chemotherapy.

What Determines Treatment Duration? (Process)

• Step 1: A biopsy confirms markers such as PD-L1 expression, MSI-High status, or MMR deficiency.
• Step 2: The drug is selected and administration begins at intervals of 2, 3, or 6 weeks.
• Step 3: Response is typically assessed by CT every 2–3 months. Since a tumor can appear larger on an early scan before later shrinking, conclusions are not drawn from a single scan alone.
• Step 4: If the treatment is working and side effects remain tolerable, administration continues; continuing for several months up to two years is the general pattern.
• Step 5: The stopping point is determined by the medical team based on cancer type, response, and side effects.

FAQ — Can side effects occur even after treatment ends?

Yes. Immune-related side effects can appear a few weeks after starting treatment, or even show up after treatment has ended. Common examples include hypothyroidism or hyperthyroidism, diarrhea from colitis, elevated liver enzymes, pneumonitis (interstitial lung disease), and skin reactions. Warning signs that should be reported immediately include diarrhea occurring several times a day, new coughing or shortness of breath, or yellowing of the eyes or skin. Most cases recover if caught early, by temporarily pausing the drug and managing with steroids.

FAQ — Can treatment be continued at a local hospital?

This depends on whether the drug is approved and available locally. It's best to first confirm during the remote review (pre-arrival review) whether continuation is possible, and if so, the dosing schedule and side-effect management guidelines can be provided to hand off to the local medical team. A stay in Korea often spans 2–3 weeks to cover testing and the first cycle.

Sources and Notes

• This article was prepared based on immunotherapy notes (National Cancer Center Korea, NCCN patient guidelines) and notes on immunotherapy/targeted therapy side effects (U.S. National Cancer Institute (NCI), NCCN patient guidelines, National Cancer Center Korea).
• This content is intended for general medical information purposes only. Diagnosis, treatment methods, and outcomes may vary depending on individual condition. Please be sure to consult with a medical professional to determine an accurate diagnosis and treatment plan.