Lung cancer

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'Lung cancer' refers to a cancer originating in the lung, in contrast to a cancer originating elsewhere in the body and spreading to the lung, a process referred to as metastasis. Lung cancer can itself metastasize to other organs. The leading factor that increases a person's risk of developing lung cancer, exposure of the lungs to tobacco smoke, can occur either through purposely inhaling the smoke from burning tobacco (e.g., smoking cigarettes), or through inhaling tobacco smoke emanating from others actively smoking tobacco products — i.e., through so-called active or passive smoking. Risk increases with duration and amount of exposure. Exposure to certain environmental pollutants, radiation and asbestos can also increase the risk of developing lung cancer. Health scientists have identified several different types of lung cancer, not all related specifically to exposure to tobacco smoke.

Screening

Practice guidelines

Clinical practice guidelines issued by the American College of Chest Physicians in 2007 recommended against routine screening for lung cancer because of a lack of evidence that such screening was effective.[1]

In 2004, a clinical practice guideline by the U.S. Preventive Services Task Force (USPSTF) gave a grade I recommendation indicating that "the evidence is insufficient to recommend for or against screening asymptomatic persons for lung cancer".[2][3]

Studies of efficacy

Chest x-ray

Regular chest x-ray and sputum examination programs were not effective in reducing mortality from lung cancer.[4] Previous studies (Mayo Lung Project and Czechoslovakia lung cancer screening study, combining over 17,000 smokers) had shown that early detection of lung cancer was possible with such programs, but mortality was not improved. Simply detecting a tumor at an earlier stage may not necessarily lead to improved survival. For example, plain chest X-ray screening resulted in increased time from diagnosis of cancer until death and those cancers being detected by screening tended to be earlier stages. However, these patients continued to die at the same rate as those who are not screened.

Computed tomography

Annual x-ray computed tomography for three years of patients 55 and 74 years of age and who had smoked at least 30 pack-years, and, "if former smokers, had quit within the previous 15 years" had reduced mortality according to a randomized controlled trial by the National Lung Screening Trial Research Team:[5]

(details of calculation)

Mass screening may improve the stage of lung cancers that are detected.[6][7] The International Early Lung Cancer Action Project cohort study of mass screening with x-ray computed tomography in over 31,000 high-risk patients found that 85% of the 484 detected lung cancers were stage I and thus highly treatable.[7] Mathematically these stage I patients would have an expected 10-year survival of 88%. However, this was an uncontrolled cohort study and the patients were not actually followed out to 10 years post detection (the median followup was 40 months). Additional controversy surrounded the study after a 2008 New York Times report found that it had been funded indirectly by the parent company of the Liggett Group, a tobacco company; the use of tobacco industry funds was not disclosed in the paper.[8]

Mass screening does not clearly reduce mortality. A cohort study found no mortality benefit from mass screening with x-ray computed tomography.[9] 3,200 current or former smokers were screened for 4 years and offered 3 or 4 CT scans. Lung cancer diagnoses were 3 times as high, and surgeries were 10 times as high, as predicted by a model, but there were no significant differences between observed and expected numbers of advanced cancers or deaths.[10] Mass screening with low-dose spiral x-ray computed tomography was not found helpful in the DANTE randomized controlled trial.[11]

Positive results, most of which are false, may occur in a quarter of patients after one round[12][6] and one third of patients after two rounds[12].

Diagnosis

Solitary pulmonary nodule

A clinical prediction rule can help guide assessment.[13] On online version of this calculator is available at http://www.nucmed.com/nucmed/SPN_Risk_Calculator.aspx.

Nodules stable over two years time are likely to be benign (but not always).[14][15] The doubling time for a cancer (a double in volume is a 25% increase in diameter) is usually less than 400 days.[16] The mean doubling time for malignant nodules with a ground glass appearance is 813 days.[14]

Regarding diagnostic imaging, metanalyses of positron-emission computed tomography (PET Scan) with 18-Fluorodeoxyglucose (18F-FDG) report:

For dynamic spiral computed tomography:[18]

A clinical practice guideline[19] by the American College of Chest Physicians, with accompanying systematic review[15], recommends computed tomography, with dynamic images if available.

Prognosis

5-Year Relative Survival Rates By Year Dx By Cancer Site All Ages, All Races, Both Sexes 1975-2000.

Staging

Non-small cell lung cancer staging information from the National Cancer Institute's Physician Data Query


Small cell lung cancer staging information from the National Cancer Institute's Physician Data Query


Treatment

Non-small cell lung cancer treatment information from the National Cancer Institute's Physician Data Query


Small cell lung cancer treatment information from the National Cancer Institute's Physician Data Query


References

  1. ↑ Alberts WM (2007). "Diagnosis and Management of Lung Cancer Executive Summary: ACCP Evidence-Based Clinical Practice Guidelines (2nd Edition)" 132 (3_suppl): 1S–19S. DOI:10.1378/chest.07-1860. PMID 17873156. Research Blogging.
  2. ↑ U.S. Preventive Services Task Force (2004). "Lung cancer screening: recommendation statement". Ann. Intern. Med. 140 (9): 738-9. PMID 15126258. [e]
  3. ↑ Humphrey LL, Teutsch S, Johnson M (2004). "Lung cancer screening with sputum cytologic examination, chest radiography, and computed tomography: an update for the U.S. Preventive Services Task Force". Ann. Intern. Med. 140 (9): 740-53. PMID 15126259. [e]
  4. ↑ Manser RL, Irving LB, Stone C, Byrnes G, Abramson M, Campbell D (2004). "Screening for lung cancer". Cochrane database of systematic reviews (Online) (1): CD001991. DOI:10.1002/14651858.CD001991.pub2. PMID 14973979. Research Blogging.
  5. ↑ (2011-06) "Reduced Lung-Cancer Mortality with Low-Dose Computed Tomographic Screening". New England Journal of Medicine: 110629140038061. DOI:10.1056/NEJMoa1102873. ISSN 0028-4793. Retrieved on 2011-06-30. Research Blogging.
  6. ↑ 6.0 6.1 Gohagan JK, Marcus PM, Fagerstrom RM, et al (2005). "Final results of the Lung Screening Study, a randomized feasibility study of spiral CT versus chest X-ray screening for lung cancer". Lung Cancer 47 (1): 9-15. DOI:10.1016/j.lungcan.2004.06.007. PMID 15603850. Research Blogging.
  7. ↑ 7.0 7.1 Henschke CI, Yankelevitz DF, Libby DM, Pasmantier MW, Smith JP, Miettinen OS (2006). "Survival of patients with stage I lung cancer detected on CT screening". N. Engl. J. Med. 355 (17): 1763-71. DOI:10.1056/NEJMoa060476. PMID 17065637. Research Blogging. Cite error: Invalid <ref> tag; name "pmid17065637" defined multiple times with different content
  8. ↑ Cigarette Company Paid for Lung Cancer Study, by Gardiner Harris. Published in the New York Times on March 26, 2008. Accessed March 26, 2008.
  9. ↑ Bach PB, Jett JR, Pastorino U, Tockman MS, Swensen SJ, Begg CB (2007). "Computed tomography screening and lung cancer outcomes". JAMA 297 (9): 953-61. DOI:10.1001/jama.297.9.953. PMID 17341709. Research Blogging.
  10. ↑ Crestanello JA, Allen MS, Jett J, Cassivi SD, et al. (2004). "Thoracic surgical operations in patients enrolled in a computed tomographic screening trial". Journal of Thoracic and Cardiovascular Surgery 128 (2): 254-259. PMID 15282462.
  11. ↑ Infante M, Cavuto S, Lutman FR, Brambilla G, Chiesa G, Ceresoli G et al. (2009). "A randomized study of lung cancer screening with spiral computed tomography: three-year results from the DANTE trial.". Am J Respir Crit Care Med 180 (5): 445-53. DOI:10.1164/rccm.200901-0076OC. PMID 19520905. Research Blogging. Review in: Ann Intern Med. 2009 Dec 15;151(12):JC6-11
  12. ↑ 12.0 12.1 Croswell JM, Baker SG, Marcus PM, Clapp JD, Kramer BS (2010). "Cumulative incidence of false-positive test results in lung cancer screening: a randomized trial.". Ann Intern Med 152 (8): 505-12, W176-80. DOI:10.1059/0003-4819-152-8-201004200-00007. PMID 20404381. Research Blogging. Cite error: Invalid <ref> tag; name "pmid20404381" defined multiple times with different content
  13. ↑ Swensen SJ, Silverstein MD, Ilstrup DM, Schleck CD, Edell ES (April 1997). "The probability of malignancy in solitary pulmonary nodules. Application to small radiologically indeterminate nodules". Arch. Intern. Med. 157 (8): 849–55. PMID 9129544. [e]
  14. ↑ 14.0 14.1 Hasegawa M, Sone S, Takashima S, et al (December 2000). "Growth rate of small lung cancers detected on mass CT screening". Br J Radiol 73 (876): 1252–9. PMID 11205667. [e]
  15. ↑ 15.0 15.1 Wahidi MM, Govert JA, Goudar RK, Gould MK, McCrory DC (September 2007). "Evidence for the treatment of patients with pulmonary nodules: when is it lung cancer?: ACCP evidence-based clinical practice guidelines (2nd edition)". Chest 132 (3 Suppl): 94S–107S. DOI:10.1378/chest.07-1352. PMID 17873163. Research Blogging.
  16. ↑ van Klaveren RJ, Oudkerk M, Prokop M, Scholten ET, Nackaerts K, Vernhout R et al. (2009). "Management of Lung Nodules Detected by Volume CT Scanning.". N Engl J Med 361 (23): 2221-2229. DOI:10.1056/NEJMoa0906085. PMID 19955524. Research Blogging.
  17. ↑ 17.0 17.1 Gould MK, Maclean CC, Kuschner WG, Rydzak CE, Owens DK (February 2001). "Accuracy of positron emission tomography for diagnosis of pulmonary nodules and mass lesions: a meta-analysis". JAMA 285 (7): 914–24. PMID 11180735. [e] ACPJC Review
  18. ↑ 18.0 18.1 18.2 Cronin P, Dwamena BA, Kelly AM, Carlos RC (March 2008). "Solitary pulmonary nodules: meta-analytic comparison of cross-sectional imaging modalities for diagnosis of malignancy". Radiology 246 (3): 772–82. DOI:10.1148/radiol.2463062148. PMID 18235105. Research Blogging. ACPJC Review
  19. ↑ Gould MK, Fletcher J, Iannettoni MD, et al (September 2007). "Evaluation of patients with pulmonary nodules: when is it lung cancer?: ACCP evidence-based clinical practice guidelines (2nd edition)". Chest 132 (3 Suppl): 108S–130S. DOI:10.1378/chest.07-1353. PMID 17873164. Research Blogging.
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