Author of

• 16637

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  P1.03 - Poster Session with Presenters Present (ID 455)

  • Event: WCLC 2016
  • Type: Poster Presenters Present
  • Track: Radiology/Staging/Screening
  • Presentations: 1
  • Moderators:
  • Coordinates: 12/05/2016, 14:30 - 15:45, Hall B (Poster Area)

  • 16645

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    P1.03-008 - Clinical Importance of Indolent Lung Cancers (ID 4076)

    14:30 - 14:30  |  Author(s): G. Hillerdal
    • Abstract

    Background:
    The occurrence and importance of “indolent” lung cancers is intensely discussed. In the National Lung Cancer Study Trial (NLST) (1) it was estimated that 18% of all cancers were indolent (2). This was based on comparison with the controls being “the golden standard”, i.e. assuming that there were no indolent cancers among those. However, studies in the 20th century with X-ray screening for lung cancers showed the incidence of indolent tumors to be around 25% in such materials.
    
    Methods:
    We have made some calculations of the NLST material based on the difference in numbers of lung cancers found at the first screening and the subsequent yearly ones.
    
    Results:
    Simple estimation: the 5-year “normal” survival of all lung cancers is 16%; in the NLST X-ray arm only (the controls) it was 53%. If 25% is due to indolence , 12% (53 minus 16 minus 25) must be due to selection. In the screened arm (low CT) , 66% cent were alive, and thus, 38% (66 minus 16 minus 12) must be due to indolent cancers. A sophisticated calculation: The difference in numbers of discovered cancers at first and following screenings in the screened arm only (thus disregarding the controls) can be used to give an indication of the proportion of indolent cancers. This will also result in a percentage of indolent cancers of around 40.
    
    Conclusion:
    Screening for lung cancer with low-dose CT has been proven to save lives. However, this comes with the risk of doing more harm than good to those who actually have an indolent cancer. Of all confirmed and staged patients in the CT arm of the NLST, 70 per cent were stage I and II, and almost all of them had surgery. The indolent cancers would be included among these, and if 30% of all cases they will amount to two thirds of the operated patients. Hopefully, new studies might make it possible to discriminate between indolent and life-threatening tumors. In the meantime, we should choose therapies with as little side effects as possible, even if these methods do not maximize the possibility of cure. 1. National Lung Cancer Screening Trial Research Team. Reduced lung cancer mortality with low-dose computed tomography screening. New Engl J Med 2011; 365:395-409. 2. Patz EF, Pinsky P, Gatsonis et al. Over-diagnosis in low-dose computed tomography screening for lung cancer. JAMA Int Med 2014; 174:269-274.