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Lung cancer: Difference between revisions
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<section begin="oncology" />'''Lung cancer''' is the second most frequent cancer, but it causes the most cancer-related deaths worldwide. [[Smoking]] is famously the biggest risk factor, and also the reason that lung cancer incidence increased dramatically during the 1900s. 85 – 90% of cases of lung cancer are attributable to smoking. | <section begin="surgery" /><section begin="oncology" />'''Lung cancer''' is the second most frequent cancer, but it causes the most cancer-related deaths worldwide. [[Smoking]] is famously the biggest risk factor, and also the reason that lung cancer incidence increased dramatically during the 1900s. 85 – 90% of cases of lung cancer are attributable to smoking. | ||
Around 95% of all primary lung tumors are carcinomas (epithelial origin), and these four types are most important: | Around 95% of all primary lung tumors are carcinomas (epithelial origin), and these four types are most important: | ||
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** [[Polycyclic hydrocarbon|Polycyclic hydrocarbons]] | ** [[Polycyclic hydrocarbon|Polycyclic hydrocarbons]] | ||
* Family history (Genetic susceptibility) | * Family history (Genetic susceptibility) | ||
<section end="surgery" /> | |||
Smoking is by far the important cause of lung cancer, and it's estimated that 90% of lung cancer cases would be avoided if not for smoking and 80% of lung cancer deaths are due to tobacco use. Lung adenocarcinoma is not as strongly associated with smoking and is actually more common in nonsmokers than in smokers. The other types of lung cancer are very strongly associated with smoking. | Smoking is by far the important cause of lung cancer, and it's estimated that 90% of lung cancer cases would be avoided if not for smoking and 80% of lung cancer deaths are due to tobacco use. Lung adenocarcinoma is not as strongly associated with smoking and is actually more common in nonsmokers than in smokers. The other types of lung cancer are very strongly associated with smoking. | ||
We can compare smoking habits with a measure called “pack-year”. If you have smoked 1 pack of cigarettes (20 pcs) every day for one year you have accumulated 1 pack-year. If you smoke one half pack every day for four years you have accumulated 2 pack-years. This allows us to quantify smoking habits, and it has prognostic significance. Higher pack years means higher risk of smoking-induced cancer, as well as a poorer prognosis in the case of lung cancer. | We can compare smoking habits with a measure called “pack-year”. If you have smoked 1 pack of cigarettes (20 pcs) every day for one year you have accumulated 1 pack-year. If you smoke one half pack every day for four years you have accumulated 2 pack-years. This allows us to quantify smoking habits, and it has prognostic significance. Higher pack years means higher risk of smoking-induced cancer, as well as a poorer prognosis in the case of lung cancer. | ||
<section begin="surgery" /> | |||
== Pathology == | == Pathology == | ||
<section end="surgery" /> | |||
=== Localisation === | === Localisation === | ||
The different types of lung tumors have a tendency to where they prefer to originate in the lung, either centrally or peripherally. | The different types of lung tumors have a tendency to where they prefer to originate in the lung, either centrally or peripherally. | ||
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=== Metastasis === | === Metastasis === | ||
Lung cancer usually spreads to: | <section begin="surgery" />Lung cancer usually spreads to: | ||
* Hilar lymph nodes | * Hilar lymph nodes | ||
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** Oedema of the face | ** Oedema of the face | ||
* Hoarse voice – due to compression of the recurrent laryngeal nerve | * Hoarse voice – due to compression of the recurrent laryngeal nerve | ||
<section end="surgery" /> | |||
=== Paraneoplastic syndrome === | === Paraneoplastic syndrome === | ||
[[Paraneoplastic syndrome|Paraneoplastic syndromes]] are more frequent in lung cancer compared to other cancers, espacially in SCLC. Common occurrences include: | [[Paraneoplastic syndrome|Paraneoplastic syndromes]] are more frequent in lung cancer compared to other cancers, espacially in SCLC. Common occurrences include: | ||
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[[Lymphangitis carcinomatosa]] may occur in the lung. It’s caused by the lymph vessels being filled up with invading malignant tumor cells. This causes the lymph vessels to dilate and become visible. | [[Lymphangitis carcinomatosa]] may occur in the lung. It’s caused by the lymph vessels being filled up with invading malignant tumor cells. This causes the lymph vessels to dilate and become visible. | ||
<section begin="surgery" /> | |||
== Clinical features == | == Clinical features == | ||
Lung cancer can produce many different signs and symptoms. They may be due to the intrathoracic effects, distant metastases, or paraneoplastic syndromes. Central carcinomas, like SCC and SCLC, tend to produce symptoms more often. | Lung cancer can produce many different signs and symptoms. They may be due to the intrathoracic effects, distant metastases, or paraneoplastic syndromes. Central carcinomas, like SCC and SCLC, tend to produce symptoms more often. | ||
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The initial investigation is usually [[chest x-ray]], which may show a solitary nodule. In this case, the patient proceeds to a contrast chest [[CT]]. | The initial investigation is usually [[chest x-ray]], which may show a solitary nodule. In this case, the patient proceeds to a contrast chest [[CT]]. | ||
For a definite diagnosis, histopathology is required. Ideally, a large enough biopsy should be taken to allow for immunohistochemical and genetic analysis, as this has implications for treatment and prognosis. There exist multiple modalities for obtaining biopsy, including [[endobronchial ultrasound]]-guided biopsy (EBUS), transthoracic needle biopsy, transoesophageal endoscopic ultrasound, mediastinoscopy, etc. | For a definite diagnosis, histopathology is required. Ideally, a large enough biopsy should be taken to allow for immunohistochemical and genetic analysis, as this has implications for treatment and prognosis. There exist multiple modalities for obtaining biopsy, including [[endobronchial ultrasound]]-guided biopsy (EBUS), transthoracic needle biopsy, transoesophageal endoscopic ultrasound, mediastinoscopy, etc.<section end="surgery" /> | ||
Acquiring tissue specimens is better than acquiring cytologic specimens, as only tissue specimens yield enough material for immunohistochemistry and genetic testing. This is important for prognosis and treatment. However, cytologic specimen is usually sufficient to determine the histological subtype and to confirm the cancer diagnosis. Cytology is most commonly acquired from a malignant pleural effusion, but can also be acquired from sputum analysis and [[bronchoalveolar lavage]]. | Acquiring tissue specimens is better than acquiring cytologic specimens, as only tissue specimens yield enough material for immunohistochemistry and genetic testing. This is important for prognosis and treatment. However, cytologic specimen is usually sufficient to determine the histological subtype and to confirm the cancer diagnosis. Cytology is most commonly acquired from a malignant pleural effusion, but can also be acquired from sputum analysis and [[bronchoalveolar lavage]]. | ||
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* Abdominal [[ultrasound]] | * Abdominal [[ultrasound]] | ||
* If CT finds metastases (advanced disease), then perform brain MRI for brain metastases and x-ray/bone scintigraphy for skeletal metastases | * If CT finds metastases (advanced disease), then perform brain MRI for brain metastases and x-ray/bone scintigraphy for skeletal metastases | ||
<section begin="surgery" /> | |||
== Treatment == | == Treatment == | ||
The treatment for NSCLC and SCLC is different. | The treatment for NSCLC and SCLC is different. | ||
<section end="surgery" /> | |||
=== Non-small cell lung cancer (NSCLC) === | === Non-small cell lung cancer (NSCLC) === | ||
For NSCLC, tumours up to and including stage IIIb are potentially curable: | For NSCLC, tumours up to and including stage IIIb are potentially curable: | ||
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=== Surgical treatment === | === Surgical treatment === | ||
Surgery is the main treatment of NSCLC stages I – IIIa. It is not used for SCLC. | <section begin="surgery" />Surgery is the main treatment of NSCLC stages I – IIIa. It is not used for SCLC. | ||
Surgical options include wedge resection, segmentectomy, lobectomy, and pneumonectomy. The less invasive options are preferred if they allow for margin negative (R0) resection. Lobectomy is usually preferred over wedge resection or segmentectomy, as the risk for R1 resection is smaller, but the latter may be chosen if the patient is deemed to have insufficient pulmonary function to tolerate a lobectomy. | Surgical options include wedge resection, segmentectomy, lobectomy, and pneumonectomy. The less invasive options are preferred if they allow for margin negative (R0) resection. Lobectomy is usually preferred over wedge resection or segmentectomy, as the risk for R1 resection is smaller, but the latter may be chosen if the patient is deemed to have insufficient pulmonary function to tolerate a lobectomy. | ||
Surgery is preferably performed with video-assisted thoracoscopy (VATS) rather than open surgery.<section end="oncology" /><noinclude>[[Category:Thoracic surgery]] | Surgery is preferably performed with video-assisted thoracoscopy (VATS) rather than open surgery.<section end="surgery" /><section end="oncology" /><noinclude>[[Category:Thoracic surgery]] | ||
[[Category:Oncology]] | [[Category:Oncology]] | ||
</noinclude> | </noinclude> | ||