What tests are required to start immunotherapy and how successful is it?

Required Tests for Starting Immunotherapy and Their Success Rate

Before starting immunotherapy, patients should undergo specific screening tests including interferon gamma release assay (IGRA) or tuberculin skin test (TST), HIV testing, hepatitis serologies, and a comprehensive baseline assessment including thyroid function tests and other laboratory markers. These tests are essential to identify potential contraindications and establish baseline values for monitoring during treatment 1.

Pre-Immunotherapy Testing Requirements

Infectious Disease Screening

• Tuberculosis screening:

  • IGRA is preferred over TST in cancer patients due to higher sensitivity in immunosuppressed individuals 1
  • All positive patients must be evaluated to rule out active TB through clinical history, physical examination, chest imaging, and respiratory sampling 1

• HIV screening:

  • Mandatory for patients with AIDS-defining cancers or those in high-risk groups 1
  • For HIV-positive patients, immunotherapy should only be administered when plasma viral load is undetectable 1
  • CD4+ T cell counts should preferably be above 200 cells/mm³ 1

• Viral hepatitis screening:

  • HBV and HCV serologies 1

Baseline Laboratory Assessment

• Complete blood count
• Serum electrolytes, renal function (creatinine with eGFR)
• Liver function tests (bilirubin, AST, ALT, GGT, alkaline phosphatase)
• Thyroid function (TSH, T4)
• Morning cortisol and ACTH
• Reproductive hormones (LH, FSH, estradiol, testosterone)
• Proteinuria assessment
• Inflammatory markers (CRP, albumin)
• Autoantibodies (ANA, TPO Ab, Tg Ab) 1

Baseline Imaging

• Chest X-ray
• Thoracic CT scan with thin sections (with and without contrast) as reference for potential pulmonary toxicity 1

Success Rate of Immunotherapy

Immunotherapy represents a paradigm shift in cancer treatment with significant benefits for many patients, though response rates vary considerably by cancer type, biomarker status, and individual patient factors 2, 3, 4.

Effectiveness by Approach:

• Immune checkpoint inhibitors (anti-PD-1/PD-L1, anti-CTLA-4):

  • Response rates range from 15-40% in most solid tumors
  • Some patients experience durable responses lasting years
  • Higher response rates in tumors with high PD-L1 expression or high tumor mutational burden 3, 4

• Adoptive cell therapies (CAR-T cells):

  • Complete response rates of 60-90% in certain hematological cancers
  • More limited success in solid tumors to date 4

Important Considerations:

1. Unique response patterns:

   • Pseudoprogression may occur (initial increase in tumor size followed by response)
   • Hyperprogression (accelerated tumor growth) occurs in a small percentage of patients 2

2. Response assessment:

   • Traditional RECIST 1.1 criteria may not fully capture immunotherapy response patterns
   • iRECIST guidelines have been developed specifically for immunotherapy response assessment 1

3. Potential adverse effects:

   • Immune-related adverse events affecting various organ systems
   • Require vigilant monitoring and prompt management 1

Is Immunotherapy Worth It?

For many cancer patients, particularly those with advanced disease who have failed standard therapies, immunotherapy is worth pursuing due to the potential for durable responses and improved survival with manageable toxicity profiles. The decision should consider:

1. Cancer type and biomarker status: Some cancers (melanoma, certain lung cancers) show higher response rates

2. Patient factors:

   • Performance status
   • Comorbidities (autoimmune diseases may increase risk of adverse events)
   • Infection status (HIV, TB, hepatitis)

3. Monitoring requirements:

   • Regular clinical and laboratory monitoring during and after treatment
   • Every 3-6 months during the first year, then every 6 months 1

4. Management of toxicities:

   • Early recognition and treatment of immune-related adverse events is critical
   • Some toxicities may require immunosuppressive therapy

Pitfalls to Avoid

1. Failing to screen for latent TB: Patients with positive IGRA/TST should be evaluated for TB prophylaxis before starting immunotherapy 1

2. Overlooking HIV status: HIV-positive patients can receive immunotherapy but require viral suppression and adequate CD4+ counts 1

3. Misinterpreting response: Pseudoprogression may be mistaken for treatment failure; follow iRECIST guidelines for proper assessment 1

4. Inadequate baseline testing: Comprehensive baseline assessment is essential for monitoring treatment-related changes 1

5. Delayed recognition of immune-related adverse events: These can affect any organ system and require prompt management 1

Immunotherapy has transformed cancer treatment, offering hope to patients with previously limited options. While not effective for all patients, the potential for durable responses and improved survival makes it a valuable treatment modality in modern oncology.