Lung Cancer

Notes
  • This is the leading killer cancer globally
  • It arises more commonly from bronchial epithelium.
  • The risk factors include: smoking (both firsthand and secondhand), family history of lung cancer, chronic lung diseases, prior history of lung cancer, radiation therapy, toxic substances such as asbestos, diesel exhaust, arsenic and silica among others.
  • There are two types of cancers of the lungs;

♦Small cell lung cancer (SCLC) that;

_Are further divided into oat cells and combined small cells.

_Constitutes 15% of all cases of lung cancers

_is almost exclusively found among smokers

_Is very aggressive

_Metastasizes in 80% of cases by the time of diagnosis.

_Tends to have nonmetastatic endocrine effects

♦Non-small cell lung cancer (NSCLC) that;

_Are further subdivided into squamous cell types (which tend to be central) and adenocarcinoma (which are usually peripheral).

_Constitutes 85% of all lung cancers.

_Metastasizes in 40% of cases by the time of diagnosis

_Constitutes practically all the Pancoast tumours (also known as pulmonary sulcus tumor or superior sulcus tumor). These tumours are found at the apex of the lungs. 

♦Staging of lung cancers:

 

Cancer stage

Description

Occult stage

♦Cancer cells are found in the sputum

♦Mostly, there are no symptoms but there can be persistent cough.

Stage: 0

♦Cancer cells can be detected in airway lining  and they have not grown through it (are in situ)

Stage: 1A

♦Cancer cells have grown through the airway lining.

♦The size  of  the tumour ≤ 3cm 

Stage: 1B

♦Cancer cells have spread into main bronchus.

♦The size of  the tumour ≥ 3cm 

Stage 11A

♦Cancer cells have spread to the  lymph nodes on the same side of the chest.

♦The size  of  the tumour ≤ 3cm 

Stage 11B

♦The size  of  the tumour ≤ 3cm 

♦Cancer cells may not have spread to the  lymph nodes but instead they have spread to diaphragm, chest wall, pleural cavity, main bronchus and pericardium

♦Cancer cells may have spread to the  lymph nodes on the other side of the chest as well as the adjoining structures to the the lungs.

Stage 111A

♦The size  of  the tumour -any size

♦Cancer cells may not have spread to the  lymph nodes but instead they have spread to diaphragm, chest wall, pleural cavity, main bronchus and pericardium

Stage 111B

♦Cancer cells may have spread to the  lymph nodes on the other side of the chest as well as the adjoining structures to the the lungs.

Stage 1V

♦The size  of  the tumour can be any size

♦Cancer cells have metastasize to other parts of the body.

♦ Alternative and simpler staging of lung cancer;

 

Cancer stage

Description

Limited- stage

♦Only one lung and nearby lymph nodes are affected

Extensive-stage

♦The cancer spreads to other lung, lymph nodes of other lung and the rest of the body.

  • Statistics: Number of deaths from lung cancer globally - 1.59M; proportion of lung cancer caused by smoking - 85%; global annual mortality rate due to tobacco - related cancers alone - 20%; contribution of mortality rate from lung cancer to overall mortality rate from all cancers -13%.
Symptoms
  • About 25% of lung cancers are asymptomatic
  • Persistent cough
  • Hemoptysis
  • Chronic fatigue
  • Dyspnea
  • Chest pain
  • Wheezing
  • Hoarseness of voice
  • Weight loss
  • Superior vena cava syndrome that is characterized by headache, plethora, facial swelling, upper extremity swelling, dilated veins in the neck as well as in the face and trunck.
  • Drooping or falling of the upper eyelid (ptosis)
  • Frequent lung infections e.g. pneumonia
  • Dysphagia – due to esophageal compression
  • Symptoms of paraneoplastic syndrome or PNS (which are phenomena that are mediated by hormones, cytokines or other humoral factors that are secreted by tumor cells or by an immune response against the tumor cell) that include:

♦ Myasthenia-like symptoms

♦ Hypercalcemia, which is caused by parathyroid hormone–related proteins that are produced by tumors, especially the squamous cell carcinoma.

♦ Symptoms of Cushing syndrome

♦ Finger clubbing

♦Neurological disorders

  • Symptoms of metastasis in the;

♦ Liver e.g. early satiety, nausea and other signs of hepatic disorders.

♦Bones e.g. pain and bone fractures

♦Brain e.g. seizure, confusion, paralysis, coma and death,

♦Adrenal  glands e.g. adrenal insufficiency.

Diagnosis
  • Chest X-ray:

_This is the most common investigation to in the low resource setting

_Expected findings: tumour mass, enlarged lymph nodes, single or multiple pulmonary nodules.

  • CT;

_It facilitates staging of tumour as it more accurate.

  • PET (Positron Emission Tomography);

_Useful in assessment of the extent of systemic disease

  • MRI;

_Useful in assessment of the extent of Pancoast’s tumour or brain metastasis

  • Cytopathology examination of pleural fluid or sputum
  • Biopsy using either of the following methods:

_Bronchoscopy

_Ultrasound guided biopsy

_Fine needle aspiration (FNA) cytology

_Mediastinoscopy

_Core needle biopsy

_Open biopsy

_Biopsy of metastasis of secondary deposit

  • Sampling and testing of sputum and thoracocentesis specimens for tumor.
  • Specific tests such as calcium and alkaline phosphatase levels that are suggestive of metastasis.
  • Routine tests such as CBC, ALT, AST and Creatinine Clearance Test among others.
Differential
  • Bacterial Pneumonia
  • Bronchitis
  • Carcinoid Lung Tumors
  • Granuloma
  • Hamartoma
  • Metastatic cancer
  • Mycoplasmal
  • Pleural Effusion
  • Pneumonia
  • Pneumothorax
  • Tuberculosis
  • Vena Cava Syndrome in Emergency Medicine
  • Viral Pneumonia
Prevention
  • Avoid smoking
  • Weight management
  • Avoid carcinogenic chemicals
Management
  • Surgery;

♦Segmentectomy (wedge resection) - the surgical removal of a segment of a lung lobe – that is indicated in management of early of stage of cancer that is confined to the tissue lining the airways without involving the nearby lung tissue. It is indicated in management of tumour located at the sides of the lungs.

♦Lobectomy – a lobe of a lung is removed.

♦Pneumonectomy – one side of lung is removed

♦Sleeve resection – a diseased section of the large airway is removed and healthy sections are rejoined.

  • Adjuvant chemotherapy

♦For NSCLC:

_Cisplatin (or carboplatin for those who cannot tolerate cisplatin) regime is the most effective regime when it is used together vinorelbine, docetaxel, paclitaxel.

♦For SCLC:

_Etoposide and cisplatin (or carboplatin) and other drugs that include: irinotecan, topotecan, vinblastine, vincristine, vinorelbine, cyclophosphamide, ifosfamide, doxorubicin, docetaxel, paclitaxel and gemcitabine.

  • Radiotherapy: given to operable patients who are not medically fit for surgery
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