Editorial orientation provided by MedAPI — not part of the coding instruction.
Common Histologies
- Non-small cell lung cancer (NSCLC)
- Adenocarcinoma – most common NSCLC histology; also occurs frequently in people who have never smoked
- Squamous cell carcinoma – major NSCLC subtype, strongly associated with tobacco exposure
- Large cell carcinoma – less common, poorly differentiated NSCLC subtype
- Other / unclassified NSCLC – used when a more specific histological subtype cannot be established
- Small cell lung carcinoma (SCLC)
- Small cell carcinoma – aggressive neuroendocrine carcinoma characterized by rapid growth and early dissemination
- Combined small cell carcinoma – SCLC with an additional non-small-cell carcinoma component
Common Symptoms
- Persistent or worsening cough (R05.3)
- Shortness of breath (dyspnea) (R06.02)
- Chest pain (R07.9)
- Coughing up blood (hemoptysis) (R04.2)
- Hoarseness (R49.0)
- Unexplained weight loss (R63.4)
- Fatigue (R53.83) or malaise (R53.81)
Early lung cancer may also be asymptomatic and discovered incidentally on imaging.
Diagnosis
Diagnosis typically combines:
- Chest imaging – chest X-ray and especially CT
- Bronchoscopy – particularly for centrally located bronchial lesions and tissue sampling
- Tissue biopsy and histopathology – establishes the malignant diagnosis and histological subtype
- PET/CT – primarily used to assess disease extent and staging
- Mediastinal lymph-node evaluation – when relevant for staging
- Molecular and biomarker testing – particularly relevant in NSCLC for treatment selection
Staging
- TNM classification
- Tumor extent (
T) - Regional lymph-node involvement (
N) - Distant metastasis status (
M)
- Stage groups I–IV
- For SCLC, the additional clinical distinction between limited-stage and extensive-stage disease is commonly used
Molecular Markers
Particularly relevant in NSCLC:
- EGFR
- ALK
- ROS1
- KRAS
- BRAF
- MET
- RET
- NTRK
- PD-L1 expression – predictive biomarker for immunotherapy rather than a molecular tumor subtype
Common Treatments
Treatment depends on histology, stage, molecular findings and patient fitness.
NSCLC
- Surgical resection – particularly for resectable early-stage disease
- Radiation therapy
- Chemotherapy
- Immunotherapy
- Targeted therapy – for tumors with actionable molecular alterations
- Combined multimodal treatment – depending on stage and resectability
SCLC
- Platinum-based combination chemotherapy
- Thoracic radiation therapy, particularly in limited-stage disease
- Immunotherapy in appropriate treatment settings
- Surgery only in selected very early-stage disease
Scope Note
C34 describes primary malignant neoplasms of the bronchus and lung by anatomical site. Histology, TNM stage and molecular characteristics provide additional clinical characterization but are not represented by the C34 site code itself.
Secondary malignant neoplasms involving the lung are outside the scope of C34 and belong to separate ICD code families.