احسن اونكولوجيست
Non Small Cell Lung Cancer (NSCLC)
Lung cancer is the second most prevalent cancer both in men and women, after prostate and breast cancers respectively. The number of death from lung cancer is higher than any other cancer.
Smoking: Cigarette smoke contains numerous carcinogens that were proved to induce cancer. Lung cancer incidence increases markedly in smoking people relative to non-smoker. Passive smoking is also correlated with lung cancer.
Asbestos exposure: exposure to asbestos is correlated with increased incidence of lung cancer as well as with mesothelioma. Usually lung cancer appears starting 20 years after exposure.
Ionizing radiation
Air pollution
Lung cancer is defined according to the cells shape revealed my microscopic examination. The two main variants of lung cancer are:
Small cell lung cancer (about 10-20% of lung cancer)
Non-small cell lung cancer (NSCLC)
Non-small cell lung cancer has several subtypes:
Adenocarcinoma
Squamous cell carcinoma
Large cell carcinoma
Combined squamous cell carcinoma and adenocarcinoma
Non-Small Cell Lung cancer infiltrates regional lymph nodes and adjacent organs. Distant metastasis occurs usually to the liver, bone, adrenals, and brain. Small cell lung cancer frequently send metastasis to the liver, brain, bone, adrenals, and mediastinal lymph nodes.
Several steps should be performed for diagnosis of lung cancer:
Careful history taking from the patient by an experienced physician: the main presenting symptoms include cough, dyspnea (difficulty breathing), weakness, weight loss, hemoptysis (coughing up blood), chest pain and hoarseness (due to involvement of specific nerves adjacent to the tumor).
Careful physical examination should be performed. Findings on examination may include cachexia (severe body weight loss), pallor (anemia), tachypnea (increased breath rate), hoarseness, enlarged lymph nodes, wheezes (due to bronchial obstruction), pneumonia (due to airways obstruction), and clubbing of fingers. On auscultation wheezes, or decreased breath sounds (due to pleural effusion) may be noted.
Laboratory tests may reveal anemia of malignant disease; leukocyte count can be normal or elevated (especially if pneumonia is also detected); hyponatremia (low blood sodium level) is not uncommon, and is mainly due to inappropriate secretion of anti diuretic hormone (ADH) by tumor cells; hypercalcemia (elevated blood calcium level); elevated LDH levels.
Radiological evaluation should include initially chest x-ray and computerized tomography of the chest. PET-FDG scan can be helpful in detecting metastatic disease.
Pathological evaluation makes the final diagnosis. Tissue biopsy should be obtained. Several methods are available to get material for pathologic examination:
A. Sputum cytology: the sputum is examined under microscope for the presence of malignant cells.
B. Bronchoscopy: in this method direct inspection of the bronchial tree is performed, and biopsy is taken directly from the tumor. Alternatively, the bronchi are washed with saline, which is recollected and tested for malignant cells (cytology).
C. Fine needle aspiration (FNA): the lesion is approached via a fine needle under the guidance of a radiological facility (ultrasound or CT). The aspirated material is tested for malignancy under microscope.
D. Open biopsy: this is performed in operation setting. This approach is usually good for lesions that can’t be approached by FNA, and for localized tumors that may be totally removed by surgery (tumors localized to single lobe, with no metastasis).
Non Small Cell Lung Cancer (NSCLC)
NSCLC is classified according to the TNM system suggested by the American Joint Committee on Cancer (AJCC). The staging system takes into account the primary tumor characteristics (T1-T4, see table below), lymph nodes involvement (N0-N3, see table below), and the presence (M1) or absence (M0) of distant metastasis.
The combination of the different characteristics of the tumor (the specific T, N, and M) gives the stage of the disease in each patient. Presence of distant metastasis denotes stage IV disease. The TNM combinations indicating Stages I-III diseases are described in the table below.
Small cell lung cancer staging defines “limited” (limited to one hemi-thorax) versus “extensive” disease. Most patients present with extensive disease (60-70%), and about 30-40% with limited disease.
Surgery
Surgery is the best treatment for limited lung cancer. Resection usually includes the entire lung, a lung’s lobes (most used), or a lobe segment. Patients with advanced cancer or metastatic disease rarely gain from surgery. In very specific and rare cases, resection of limited primary lung tumor and single distant metastasis may be considered.
Radiotherapy
Radiotherapy is a pivotal modality for the treatment of lung cancer. It is used both for curative and palliative treatments. Radiotherapy is also used preoperatively in some patients (with or without chemotherapy) to shrink the tumor size so that surgery become feasible.
Side effects of radiotherapy include toxicity to: the normal lung tissue (radiation pneumonitis), heart, esophagus (esophagitis) and spinal cord. These toxicities are more prominent with increased radiation dose and/or intensity, and in patients undergoing concomitant chemotherapy and radiation.
Chemotherapy
Chemotherapy for NSCLC usually includes combination of drugs containing cisplatin (or carboplatin). Other drugs used together with platinum include etoposide, paclitaxel, vinorelbine or gemcitabine. Chemotherapy improve survival in metastatic disease, as well as in locally advanced disease. Recently, clinical trails showed that the use of chemotherapy after resection of lung cancer, improve the survival of patients. Overall, chemotherapy (platinum based) have a role in treatment of lung cancer, but the prognosis for the long term, remains disappointing.
Surgery
SCLC usually develops in the central airways. Most patients present with metastatic disease. Surgery usually is not applicable to most patients, except for patients with “very limited’ and operable disease.
Radiation
Radiotherapy is integral part of the treatment of SCLC (limited disease). Prophylactic radiation to the brain is used in some patients, especially in near or complete responders to induction chemotherapy. Radiation also plays a pivotal role in palliation (e.g. radiotherapy to painful bone lesion).
Chemotherapy
Several drugs have a role in treatment of SCLC. Cisplatin or carboplatin are usually combined with etoposide (VP-16), and were proved to give favorable results in limited stage disease. Other regimens of chemotherapy for SCLC include the ICE protocol (Ifosfamide, Carboplatin, Etoposide), VIP (VP16=Etoposide, Ifosfamide, Platinol), and cisplatin& Irinotecan.
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