Comprehensive Clinical Notes on Lung Cancer Treatment Modalities, Pathways, and Management

Overview and Learning Outcomes for Lung Cancer Treatment

• Instructor: David R. Baldwin, Nottingham University Hospitals, Honorary Professor of Medicine, University of Nottingham.
• Primary Goals:
  • Describe treatment modalities including surgery, radiation therapy, chemotherapy (adjuvant, neoadjuvant, palliative), targeted therapy, and immunotherapy.
  • Understand treatment decisions based on stage, tumour characteristics, and receptor status.
  • Address survivorship and the importance of long-term follow-up care.
• Treatment Categories:
  • Curative: Surgery, Radical Radiotherapy (including SABR), and Radical Chemoradiotherapy.
  • Palliative: Radiotherapy, Systemic Anticancer Therapy (SACT), and combination treatments.

Independent Predictors of Survival in Lung Cancer

Survival outcomes are influenced by several variables, as detailed in Khakwani et al. (Br J Cancer, 2013). Adjusted Hazard Ratios (HR) include:

• Sex:
  • Female: $1$
  • Male: $1.13$ ($1.12-1.14$)
• Stage of Disease:
  • IA-IB: $1$
  • IIA-IIB: $1.54$ ($1.48-1.61$)
  • IIIA: $2.33$ ($2.25-2.42$)
  • IIIB: $3.20$ ($3.10-3.30$)
  • IV: $4.58$ ($4.45-4.71$)
• Age Groups:
  • $<54$: $1$
  • $55-59$: $1.12$ ($1.09-1.16$)
  • $60-64$: $1.19$ ($1.16-1.23$)
  • $65-69$: $1.25$ ($1.21-1.29$)
  • $70-74$: $1.35$ ($1.31-1.39$)
  • $75-79$: $1.45$ ($1.40-1.49$)
  • $80-84$: $1.55$ ($1.51-1.60$)
  • $85+$: $1.62$ ($1.57-1.68$)
• Performance Status (PS):
  • $0$: $1$
  • $1$: $1.28$ ($1.25-1.31$)
  • $2$: $1.84$ ($1.80-1.89$)
  • $3$: $2.72$ ($2.65-2.79$)
  • $4$: $4.39$ ($4.24-4.54$)

Surgical Modalities and Outcomes

Surgery is a primary curative option, with a shift toward minimally invasive techniques. A comparison between Open surgery and Video-assisted Thoracic Surgery (VATS) ($n = 2721$ per group) reveals significant differences (Falcoz P-E et al.):

• Complications: Open ($31.7\%$) vs. VATS ($29.1\%$); $P = 0.0357$.
• Major C/P (Cardiopulmonary) Complications: Open ($19.6\%$) vs. VATS ($15.9\%$); $P = 0.0094$.
• Atelectasis: Open ($5.5\%$) vs. VATS ($2.4\%$); $P < 0.0001$.
• Length of Stay (LOS): Open (median $8$ days) vs. VATS (median $6$ days); $P = 0.0003$.
• Mortality (at discharge): Open ($1.9\%$) vs. VATS ($1.0\%$); $P = 0.0201$.

Principles of Radiotherapy (RT)

• Radio-sensitivity:
  • Squamous cell lung cancer is more radiosensitive.
  • Small cell lung cancer (SCLC) is highly radiosensitive and chemotherapy-sensitive.
• Clinical Applications:
  • Radical: Aim for cure or local control.
  • Palliative: Aim for symptom control (pain, bleeding) or emergencies (e.g., spinal cord compression) using single or short-course fractions.
• Key Terminology:
  • Gray (Gy): SI unit of absorbed radiation dose.
  • Fraction (#): The total dose divided into smaller individual doses.
  • Hypofractionation: Dose per fraction $> 2\,Gy$.
  • Hyperfractionation: Dose per fraction $< 2\,Gy$.
• Biological Mechanism: RT causes double-stranded DNA breaks, primarily via free radicals. Cancer cells are less efficient at DNA repair compared to normal tissues.
• Therapeutic Ratio: The balance between the dose required for tumour control and the dose causing toxicity to normal tissues.

Curative-Intent Radiotherapy Techniques

• Stereotactic Ablative Body Radiotherapy (SABR):
  • Doses: Often $55-65\,Gy$ delivered in $3-7$ fractions (e.g., $3 \times 20.0\,Gy$, $3 \times 10.7\,Gy$, or $10.7\,Gy \times 3$).
  • Patient Selection: Small ($< 5\,cm$), node-negative, peripheral NSCLC. Ideal for patients medically inoperable or with poor lung function.
  • The "No Fly Zone": A region of the proximal bronchial tree (defined by the trachea, upper, middle, and lower lobe bronchi) where high-dose radiation is avoided to prevent massive haemoptysis, pneumonia, airway necrosis, or pericardial effusion.
• Conventional Radical RT: $66\,Gy$ over $6-7$ weeks.
• Continuous Hyperfractionated Accelerated RT (CHART): $55\,Gy$ given $3$ times daily over $14$ days.
• Radiotherapy Regimens: Can be SABR, concurrent chemo-radiotherapy, sequential chemo-radiotherapy, or RT alone.

Palliative and Metastatic Management

• General Palliation: Targeted at specific symptoms (cough, pain, SVCO, haemoptysis) with a $60-70\%$ response rate in chest symptoms.
• Brain Metastases in NSCLC:
  • Whole Brain Radiotherapy (WBRT) is now uncommon.
  • Stereotactic Radiosurgery (SRS)/Gamma Knife/Cyberknife: Preferred if prognosis is $> 6$ months, no targetable mutations exist, and based on the volume (rather than just number) of metastases.
• Brain Metastases in SCLC: SRS is not typically used; WBRT is used occasionally despite poor prognosis.
• Alternative Local Control: Radiofrequency or microwave ablation (RFA/MWA).
• Endobronchial Palliation: Used for urgent airway clearance via laser, stenting, electrocautery, brachytherapy, or cryotherapy.

Systemic Anti-Cancer Treatment (SACT)

• Functional Categories:
  • Neoadjuvant: Before surgery to shrink tumours or stop spread (e.g., tumours $\ge 4\,cm$ or node-positive).
  • Adjuvant: After surgery to reduce metastasis risk.
  • Induction: Aimed at down-staging (not typically used in lung cancer currently).
  • Palliative: Used for disease control in the majority of advanced patients.
• Types of SACT:
  • Chemotherapy: Platinum-containing (Cisplatin/Carboplatin). Pemetrexed is used specifically for non-squamous histology.
  • Immunotherapy: Immune checkpoint inhibitors (PD-1 and PD-L1).
  • Targeted Therapy: Specifically for mutations: EGFR, ALK, BRAF, ROS1, RET, NTRK, KRAS G12C, and METex14 skipping alterations.

Molecular Targets and Clinical Evidence

• EGFR Mutations: Targeted by Tyrosine Kinase Inhibitors (TKIs) like Gefitinib, Erlotinib, Afatinib, Dacomitinib, and Osimertinib ($T790M$ mutation-specific). The LACE meta-analysis shows survival benefits for adjuvant chemotherapy, while the ADAURA trial highlights significant Disease-Free Survival (DFS) for Osimertinib in Stage IB-IIIA NSCLC (Hazard Ratio $0.13$ to $0.20$).
• ALK/ROS1/BRAF: Targeted by specialized drugs like Crizotinib, Alectinib (superior to Crizotinib in CNS progression control), Brigatinib, Ceritinib, and Lorlatinib.
• PD-L1 Expression: Decision pathways for non-small-cell lung cancer (NSCLC) depend on whether PD-L1 expression is $< 50\%$ or $\ge 50\%$. High expression often warrants Pembrolizumab or Atezolizumab mono-therapy.
• SCLC Treatment: First-line treatment for extensive-stage SCLC includes Atezolizumab plus chemotherapy (IMpower133 study), which improved 12-month survival from $38.2\%$ to $51.7\%$ ($P = 0.007$).

Clinical Case Scenarios

• Case 2 (NSCLC Stage T1cN2M0): 76-year-old female, never smoker, PS 1. Management requires MDT discussion. Options include neoadjuvant Nivolumab + chemotherapy (Checkmate 816) for 3 cycles followed by surgery.
• Case 3 (Extensive-Stage SCLC): 71-year-old male smoker with 10kg weight loss and a lung mass. Treated with Atezolizumab + Carboplatin + Etoposide.
• Case 4 (Limited-Stage SCLC): 67-year-old female ex-smoker. Primary treatment is concurrent twice-daily chemoradiotherapy (CONVERT trial) followed by Prophylactic Cranial Irradiation (PCI) to reduce brain metastasis risk (increases 3-year survival by $5\%$).
• Case 5 (Metastatic Squamous Cell NSCLC): 77-year-old male, current smoker, PS 1, 70% PD-L1 expression. Management: Pembrolizumab or chemotherapy based on shared decision-making.

Survivorship and Long-Term Care

• Survivorship Issues: Patients face breathlessness, neuropathy, immune-related side effects, cardiac toxicity (from radical RT), and risks of second primary cancers.
• Recurrence: High recurrence rates observed within the first 2 years.
• Prehabilitation Pillars: Fitness, Smoking cessation, Nutrition, and Psychological support.
• Smoking Cessation: Essential intervention that improves survival by enhancing treatment response and reducing the risk of second cancers.
• Regulatory Access: Programs like the Cancer Drugs Fund (CDF) provide access via Commercial Access Agreements, Patient Access Schemes, and Managed Access Agreements to resolve clinical and cost uncertainties.