Cancer Immunotherapy — How It Works, Benefits & Recovery — Procedure Guide, Recovery & Risks | MyMedicPlus

Cancer immunotherapy is a class of systemic cancer treatments that work by mobilising and enhancing the patient's own immune system — particularly T-lymphocytes — to recognise and destroy cancer cells, rather than directly killing tumour cells as chemotherapy does. The field has been transformed by the development of immune checkpoint inhibitors (ICIs): monoclonal antibodies that block inhibitory receptor-ligand interactions (PD-1/PD-L1, CTLA-4) that cancer cells exploit to evade immune surveillance. Major checkpoint inhibitors in clinical practice include pembrolizumab (Keytruda) and nivolumab (Opdivo) — both anti-PD-1 antibodies — and atezolizumab (Tecentriq), durvalumab (Imfinzi), and avelumab — anti-PD-L1 antibodies — and ipilimumab (Yervoy), which targets CTLA-4. Beyond checkpoint inhibitors, cancer immunotherapy encompasses CAR-T cell therapy (chimeric antigen receptor T-cell therapy), in which the patient's T-cells are genetically engineered to express tumour-specific receptors and reinfused as living drug; cancer vaccines; cytokine therapy (interleukin-2, interferon-alpha); and bispecific T-cell engager (BiTE) antibodies. Immunotherapy has fundamentally transformed the outlook for multiple cancer types and is now integrated into first-line, adjuvant, and maintenance therapy regimens across many tumour types.

This treatment represents an important component of modern medical management, supported by clinical evidence from multiple randomised controlled trials and systematic reviews. Treatment protocols are continually refined based on emerging evidence to optimise patient outcomes while minimising treatment burden.

Patient suitability is assessed through a structured multidisciplinary evaluation incorporating clinical history, physical examination findings, and results of relevant investigations. Treatment planning considers the full clinical context including disease characteristics, patient comorbidities, functional status, and individual treatment goals to ensure the most appropriate therapeutic approach is selected for each patient.

Immunotherapy is now indicated across an expanding range of cancer types and clinical settings. Major approved indications include: non-small cell lung cancer (NSCLC) — pembrolizumab as first-line monotherapy for PD-L1 ≥50% tumours, and pembrolizumab-plus-chemotherapy combinations for all PD-L1 levels; melanoma — combination ipilimumab plus nivolumab for advanced/metastatic disease, achieving 5-year survival above 50%; urothelial (bladder) cancer — atezolizumab and pembrolizumab in first and second line; head and neck SCC — pembrolizumab in first line for PD-L1+ tumours; colorectal cancer with MSI-H/dMMR status — pembrolizumab as first-line therapy; hepatocellular carcinoma — atezolizumab plus bevacizumab as first-line standard; cervical cancer, gastric/gastro-oesophageal junction cancer, endometrial cancer, triple-negative breast cancer, Merkel cell carcinoma, and Hodgkin lymphoma. Patient selection biomarkers guiding treatment decision include PD-L1 expression (by immunohistochemistry), tumour mutational burden (TMB — high TMB tumours respond better to checkpoint inhibitors), and microsatellite instability status (MSI-H/dMMR — pembrolizumab is approved pan-tumour for MSI-H). Autoimmune diseases, organ transplant recipients, and patients on chronic high-dose corticosteroids are relative contraindications to checkpoint inhibitor therapy.

Checkpoint inhibitors are administered as intravenous infusions in an outpatient oncology day unit. Each infusion takes 30–90 minutes, depending on the agent. Pre-medications (antihistamines, corticosteroids) may be given before infusion to reduce infusion reactions, though serious acute reactions are rare. Treatment cycles vary by agent: pembrolizumab and nivolumab are given every 3 or 6 weeks (flat dosing); ipilimumab every 3 weeks for 4 doses in the induction phase; combination ipilimumab-nivolumab (for melanoma, RCC) follows an induction schedule then maintenance nivolumab. Treatment continues for a defined period — typically up to 2 years for adjuvant pembrolizumab or pembrolizumab monotherapy in NSCLC, or until disease progression or unacceptable toxicity in palliative settings. CAR-T therapy involves leukapheresis (collection of the patient's T-cells via a peripheral blood apheresis procedure), ex-vivo genetic engineering to insert the CAR transgene using viral vector transduction (a process taking 2–4 weeks in a specialist manufacturing facility), lymphodepleting conditioning chemotherapy, and re-infusion of the engineered T-cells. CAR-T is currently approved for B-cell lymphoma (axicabtagene ciloleucel — Yescarta; tisagenlecleucel — Kymriah), multiple myeloma, and B-cell ALL. Patients are monitored closely for 7–14 days in a specialist centre after CAR-T infusion for cytokine release syndrome.

The procedure is performed in an appropriately equipped facility by experienced specialist clinicians. Prior to commencement, the patient undergoes pre-procedural assessment including vital signs measurement, review of relevant investigations, and confirmation of informed consent. Intravenous access is established and monitoring equipment including ECG, pulse oximetry, and blood pressure monitoring is applied.

The procedural site is prepared according to aseptic technique standards. Anaesthesia or analgesia is administered as appropriate for the specific procedure and patient needs, ranging from local anaesthesia for minor procedures to regional or general anaesthesia for more complex interventions.

The procedure is performed under direct visualisation or image guidance as appropriate. Key technical steps are executed with attention to anatomical landmarks and patient safety parameters. Haemostasis is achieved and confirmed before completion. Post-procedural assessment includes clinical evaluation of the immediate result, complication surveillance, and documentation of the procedure.

Recovery room monitoring continues until the patient meets defined discharge criteria. Written post-procedural instructions covering activity restrictions, wound care, medication management, and symptoms requiring urgent review are provided before discharge.

Immunotherapy has produced some of the most dramatic improvements in cancer survival in oncology history. In advanced melanoma, combination ipilimumab plus nivolumab has increased 5-year overall survival from approximately 15% (historical chemotherapy era) to over 50%, with a unique 'plateau' in the survival curve suggesting prolonged durable responses — potentially curative — in 15–30% of patients. In advanced NSCLC with PD-L1 ≥50%, pembrolizumab monotherapy achieves a 5-year OS of approximately 31% compared to historical rates of 5% with chemotherapy. Adjuvant pembrolizumab in resected stage III melanoma reduces 5-year recurrence risk by approximately 40% compared to placebo (KEYNOTE-054 trial). MSI-H colorectal cancer, historically resistant to chemotherapy, responds dramatically to pembrolizumab with response rates of 40–45%. Durable complete responses — potentially representing cure in a proportion of metastatic patients — are a unique characteristic of immunotherapy unlike any cytotoxic regimen. Toxicity profile differs from chemotherapy: hair loss and severe nausea are uncommon; immune-related adverse events affect specific organ systems but are often reversible with immunosuppressive therapy, improving quality of life during treatment compared to traditional chemotherapy.

The primary mechanism of immunotherapy toxicity is immune dysregulation — the same activated immune system attacking normal tissues. Immune-related adverse events (irAEs) affect approximately 30–40% of patients on checkpoint inhibitors overall; Grade 3–4 severe irAEs requiring treatment interruption affect 5–15%. Common irAEs and their management include: dermatitis (skin rash, pruritus) in 30–40% — managed with topical steroids; colitis (diarrhoea, abdominal pain, bloody stool) in 10–20% — managed with oral or IV corticosteroids (prednisolone 1–2 mg/kg); hepatitis (elevated AST/ALT) in 5–10% — managed with corticosteroids; pneumonitis (cough, dyspnoea, new infiltrates on CT) in 3–5% — potentially life-threatening; requires urgent steroids; endocrinopathy (hypothyroidism 10–20%, hypophysitis, adrenal insufficiency, type 1 diabetes) — often permanent, requiring hormone replacement; nephritis in 1–3%. Fatal irAEs (fulminant myocarditis, severe pneumonitis, toxic epidermal necrolysis) occur in under 1%. Anti-CTLA-4 agents (ipilimumab) carry higher rates of severe irAEs than anti-PD-1 agents; combination checkpoint blockade carries the highest irAE rates. Patients receive an irAE alert card and education about warning symptoms requiring urgent review. Infusion reactions (fever, rigors, hypotension) occur in under 5% and are managed with temporary infusion rate reduction and pre-medications.

Unlike chemotherapy, immunotherapy infusions do not typically cause immediate nausea, significant fatigue, or hair loss, allowing most patients to maintain normal activities on treatment days. The day-unit infusion takes 30–90 minutes, after which the patient is observed briefly before discharge. Regular monitoring throughout treatment is essential and includes: blood tests before each cycle (complete blood count, liver function tests, thyroid function, urea and creatinine, blood glucose) to detect early organ irAEs; clinical review at each treatment visit to assess for irAE symptoms; and periodic CT or PET-CT imaging every 8–12 weeks to assess tumour response. Patients are provided a dedicated irAE contact number and instructed to seek urgent review for new diarrhoea (more than 3 loose stools per day above baseline), new breathlessness, yellowing of eyes, significant skin rash, severe headache, or unexplained fatigue — all potential signs of serious irAEs. Most irAEs are managed with oral corticosteroids with good outcomes; severe irAEs require hospitalisation and IV methylprednisolone. Endocrine irAEs (hypothyroidism, adrenal insufficiency) may be permanent and require lifelong hormone replacement. Treatment is typically continued for 2 years in adjuvant and monotherapy settings, or until disease progression or intolerable toxicity. Surveillance continues after treatment completion.