Why the Perfect Valentine's Gift Isn't One Scent—It's Two

Respiratory Oncology

Lung
Cancer

A comprehensive clinical overview covering aetiology, histology, presentation, investigations, staging, and management strategies for first-year medical students.

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01 — Aetiology

Causes & Risk Factors

🚨 Red Flag for Students: Any smoker >40 years with new cough, haemoptysis, or unexplained weight loss requires urgent chest X-ray. Do not attribute symptoms to "smoker's cough" without imaging.

Cigarette smoking is by far the most important cause of lung cancer, responsible for ~85% of cases. The incidence is slightly higher in urban than rural dwellers, reflecting atmospheric pollution and occupational exposures [[1]].

A number of industrial materials are associated with lung cancer, including asbestos (synergistic risk with smoking), radon, arsenic, and chromium. Lung cancers arise from the bronchial epithelium or mucous glands. Tumours in a large bronchus produce early symptoms, while peripheral tumours can grow very large before detection — resulting in delayed diagnosis [[2]].

02 — Histology

Common Cell Types

40%

Adenocarcinoma

25%

Squamous Cell

15%

Small-Cell

10%

Large-Cell

💡 Precision Medicine Note: All non-squamous NSCLC should undergo molecular testing for EGFR, ALK, ROS1, BRAF, KRAS, MET, RET, NTRK mutations. Targeted therapies significantly improve survival in mutation-positive patients [[3]].

03 — Presentation

Clinical Features

01

Cough

The most common early symptom. A change in a chronic smoker's cough pattern warrants investigation.

02

Haemoptysis

Common especially with central bronchial tumours. Haemoptysis in a smoker must always be investigated to exclude lung cancer.

03

Bronchial Obstruction

Depends on site and extent of obstruction, secondary infection, and coexisting lung disease. Complete obstruction causes lobar collapse with breathlessness, mediastinal displacement, and dullness to percussion.

04

Breathlessness

May be caused by collapse, pneumonia, large pleural effusion, or phrenic nerve compression leading to diaphragmatic paralysis.

05

Mediastinal Spread

Oesophageal involvement may cause dysphagia. Pericardial invasion may cause arrhythmia or pericardial effusion. Superior vena cava obstruction causes facial swelling and dilated chest veins.

06

Pain & Nerve Entrapment

Pleural pain may indicate malignant invasion. Intercostal nerve involvement causes thoracic dermatome pain. Pancoast tumours cause shoulder/arm pain and Horner's syndrome.

07

Metastatic Spread

May lead to focal neurological defects, epileptic seizures (brain mets), jaundice (liver), bone pain (skeletal), or skin nodules.

08

Paraneoplastic Syndromes

SIADH and ectopic ACTH secretion are associated with small-cell lung cancer. Hypercalcaemia may indicate bone destruction or PTHrP production (squamous cell).

04 — Investigations

Diagnosis & Workup

The main aims are to confirm diagnosis, establish histological cell type, and define extent of disease.

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Imaging

Chest X-ray reveals a range of appearances — from lobar collapse to mass lesions, effusion, or rib destruction. CT chest with contrast should be performed early to detect mediastinal or metastatic spread and guide biopsy planning [[4]].

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Biopsy & Histopathology

Over half of primary lung tumours can be visualised and sampled directly by biopsy and brushing using a flexible bronchoscope. CT-guided percutaneous biopsy is used where bronchoscopy is not feasible. Molecular profiling is essential for NSCLC [[3]].

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TNM Staging Simplified

T = Tumour size/invasion
N = Node involvement
M = Metastasis

Stage I: T1-2 N0 M0 → Surgery curative
Stage III: N2/N3 or T4 → Multimodal therapy
Stage IV: M1 → Systemic therapy ± palliation

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Molecular Testing

Required for all advanced non-squamous NSCLC: EGFR, ALK, ROS1, BRAF V600E, KRAS G12C, MET exon 14, RET, NTRK. Results guide targeted therapy selection [[3]].

05 — Staging

Staging to Guide Treatment

Small-cell lung cancer metastasises early and is usually not suitable for surgical intervention. In NSCLC, treatment and prognosis are determined by disease extent — careful staging is essential.

>80%

Stage I
5-yr survival

>70%

Stage II
5-yr survival

Stage I: N0 tumour confined within visceral pleura. Stage II: includes resection in patients with ipsilateral peribronchial or hilar node involvement. Accurate preoperative staging with physiological testing is required to assess whether respiratory and cardiac function allows aggressive treatment [[5]].

💡 Clinical Pearl: PET-CT is superior to CT alone for detecting occult metastases and should be performed before curative-intent treatment in NSCLC [[4]].

06 — Management

Treatment Options

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Surgical Treatment

Offers the best outcomes for localised NSCLC. With accurate preoperative staging and modern surgical care, 5-year survival exceeds 80% in stage I and 70% in stage II disease [[5]].

☢️

Radiotherapy

Less effective than surgery, but radical radiotherapy can offer long-term survival in patients with localised disease where comorbidity precludes surgical intervention. SBRT is preferred for early-stage inoperable patients.

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Chemotherapy

Combinations of cytotoxic drugs (±radiotherapy) increase median survival in small-cell carcinoma from 3 months to over a year. Less effective in NSCLC but used adjuvantly or with immunotherapy [[6]].

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Targeted Therapy

EGFR inhibitors (osimertinib), ALK inhibitors (alectinib), and others dramatically improve outcomes in mutation-positive NSCLC. Requires molecular testing first [[3]].

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Immunotherapy

PD-1/PD-L1 inhibitors (pembrolizumab, nivolumab) improve survival in advanced NSCLC, especially with high PD-L1 expression. Often combined with chemotherapy [[6]].

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Palliative Care

Early integration improves quality of life and may extend survival. Includes symptom control, psychosocial support, and advance care planning.

07 — FAQ

Frequently Asked Questions

Q: When should I suspect lung cancer in a primary care setting?

A: Suspect lung cancer in any patient >40 years with: persistent cough (>3 weeks), haemoptysis, unexplained weight loss, recurrent chest infections, or new breathlessness. Always obtain a chest X-ray first [[1]].

Q: What is the difference between NSCLC and SCLC management?

A: NSCLC (85% of cases) is often treated with surgery if early-stage. SCLC (15%) is aggressive, metastasises early, and is treated primarily with chemotherapy + radiotherapy; surgery is rarely an option [[6]].

Q: Why is molecular testing so important?

A: Targeted therapies for mutations like EGFR or ALK can improve median survival from ~1 year to 3-5+ years with better quality of life. Testing is standard for all advanced non-squamous NSCLC [[3]].

Q: Can lung cancer be prevented?

A: Smoking cessation is the most effective prevention. Low-dose CT screening is recommended for high-risk individuals (50-80 years, ≥20 pack-year history, current smoker or quit <15 years) [[7]].

📚 Evidence-Based Sources:
1. American Cancer Society: Lung Cancer Risk Factors
2. NICE Guideline NG122: Lung Cancer Diagnosis & Referral (2024)
3. NCCN Guidelines: NSCLC Molecular Testing (2026)
4. American Thoracic Society: Lung Cancer Imaging Guidelines
5. ESMO Guidelines: Early-Stage NSCLC Management
6. NCCN Guidelines: Small Cell Lung Cancer (2026)
7. USPSTF: Lung Cancer Screening Recommendations (2024)

#LungCancer #MedicalEducation #RespiratoryMedicine #Oncology #MedStudents #ClinicalReasoning #IraqHealth #CommunityMedicine #NSCLC #PrecisionMedicine

💬 Join the Discussion!

Dr. Ali Al-Saedi | Family Medicine & Community Health Educator 🎓
University of Baghdad – Teaching First-Year Medical Students

What was the most challenging lung cancer case you've encountered? What diagnostic clue helped you suspect it early? Share your clinical experiences below! 👇

© 2026 Community Medicine Education Hub

Dr. Ali Al-Saedi

Family Medicine | Baghdad, Iraq