Limited-stage small cell lung carcinoma

Small cell lung cancer is often treated as a systematic disease due to its tendency for early dissemination,[4] thus, instead of the traditional TNM staging system, the Veterans' Administration Lung Study Group (VALSG) introduced a simplified 2-stage system in 1950s to divide small cell lung cancer into limited stage and extensive stage.[7] As a result of the change in policy from targeting all nodal stations by radiotherapy ports to target only obviously involved nodal stations, the definition of the limited disease varies.[4]

According to a broad medical consensus, limited-stage small cell lung carcinoma is generally considered to be encompassed within a radiation portal.[4][5] Variability in categorising small-cell lung cancer as limited or extensive occurs with reference to the extent of pleural effusion and nodal stations involvement.[4][8] In addition, patients with an ipsilateral pleural effusion are frequently excluded from the limited-disease category.[4][9] In rare cases, patients with minimal pleural effusions are included in the limited-disease protocols; this includes those with demonstrated effusions only on chest CT, as well as those with blunting of the costophrenic angle on chest radiographs.[4][10] In most cases, all patients demonstrated any positive sign of pleural effusion on any type of imaging tests are excluded.[11]

Likewise, ambiguities in the definition of limited disease also occurs in classification of the limited disease with reference to the extent of lymphadenopathy. For instance, patients with bilateral supraclavicular adenopathy are included in the limited-disease category in some cases,[12] others include only those with ipsilateral adenopathy.[10] Similarly, the presence of contralateral hilar adenopathy frequently, though not uniformly, includes patients in the limited-disease category.[13][14]

The traditional TNM classification system is preferred over the 2-stage system when surgery is the recommended treatment option.[4]

Similar to other lung cancers, according to the American Cancer Society, the most common symptoms of limited-stage of lung cancer are:[6]

• Progressive and persistent cough
• Coughing up blood or rust-coloured sputum
• Shortness of breath
• Chest pain that is often worse with deep breathing, coughing, or laughing
• Weight loss and loss of appetite
• Fatigue
• New onset of wheezing
• Recurrent respiratory tract infections such as pneumonia and bronchitis

In addition, patients diagnosed with small cell lung carcinoma has an increased vulnerability to nervous system problems (i.e. Lambert-Eaton syndrome, paraneoplastic cerebellar degeneration), Cushing syndrome and Syndrome of Inappropriate Anti-diuretic Hormone (SIADH) and can demonstrate relevant symptoms .[6]

Microscopic photograph of small cell lung carcinoma under high power.

Imaging tests are often the first diagnostic step if a patient reports symptom that may be suggestive of lung cancer.[15] A chest x-ray is the most standard imaging test to look for any abnormality within the lung. If abnormality is present, a computed tomography (CT) scan is frequently ordered to reveal the size, shape, and position of any lung tumour and can help locate enlarged lymph nodes that might contain cancer metastasised from the lung origin.[15] Most patients with limited-stage small cell lung cancer will receive a CT scan of the chest and abdomen to search for abnormality within the lungs and lymph nodes, as well as abnormal areas in more distal organs such as adrenal glands and liver that might arise from the metastasis of lung cancer.[15]

For patient with limited-stage small cell lung cancer, a positron emission tomography (PET) scan is a useful diagnostic tool to investigate the extent of lymph node involvements, which can help determine treatment options.[15]

Though results of imaging test might be suggestive of lung cancer, the actual diagnosis is made by investigating the lung cells under the microscope via lab tests. The cells can be obtained from lung secretions (sputum cytology), fluid removed from pleural effusion (thoracentesis), or from a suspicious area (needle biopsy).[15]

The standard treatments of limited-stage small cell lung cancer are surgery, platinum-based combination chemotherapy, thoracic irradiation, and prophylactic cranial irradiation.[4][5]

Unlike extensive-stage small cell lung cancer, limited-stage small cell lung cancer is potentially curable.[4] In limited small cell lung cancer, the median overall survival time is approximately 12–16 months, with five year survival rate of approximately 26% and long-term survival rate of approximately 4 - 5%.[19]

According to multiple studies, common prognostic factors of limited stage small cell lung cancer lies in performance status, age, life expectancy, comorbidities, extent of disease and smoking. Continued cigarette smoking negatively impacts limited-stage small cell lung cancer survival. All clinicians and care providers should strongly encourage smoking cessation at the diagnosis of limited stage small cell lung cancer. Comparing to continued smokers, patients who quit at or after diagnosis lower the risk of death by 45%.[29]