Los Angeles, Calif. - More than thirty leading Southern California pulmonologists and allied health professionals met at UCLA on February 20, 2014 as part of the Trudeau Society’s Daniel Simmons Visiting Professor lecture and dinner. Trudeau Society, in coordination with BREATHE LA, is Los Angeles leading regional lung health network, annually hosting professional symposia and grand rounds for experts in respiratory care.

This year’s Visiting Professor was Dr. Michael K. Gould, Senior Research Scientist, Director of Health Services Research & Implementation Science, Kaiser Permanente Southern California.  Dr. Gould discussed potential harms and benefits of low radiation-dose chest computed tomography (LDCT) but emphasized screening with LDCT is not a substitute for smoking cessation.

Depicted (L-R): Dr. Thomas Maher, Kaiser; Dr. Michael K Gould, Kaiser Permanente; Dr. Barbers, USC; Dr. Guy Soo Hoo, Veteran’s Administration Greater Los Angeles Healthcare System & BREATHE LA Board; Dr. Cooper, UCLA; and Dr. Yossef Aelony, BREATHE LA Board.  PHOTO CREDIT: Jennifer Clark

Lecture Summary

“Who should be Screened for Lung Cancer” by Michael K. Gould, MD

Lung cancer screening has become an acceptable option in the management of patients at high risk for lung cancer, but is not a substitute for SMOKING CESSATION.

Previous lung cancer screening trials have not demonstrated reduction in mortality until the National Lung Screening Trial (NLST) comparing low dose chest CT scan with chest roentgenograms (CXR) in patients at high risk for lung cancer in > 50,000 subjects.

  • High risk smokers are defined at those between 55-74 years of age, with > 30 pack year smoking history or ex-smokers within 15 years of their quit date.
  • Comparison was made between annual low dose chest CT scans and annual CXRs for three years. The trial used a standardized approach to management of abnormalities defined as lesions > 0.4 cm in size.
  • Study arm found 73 more lung cancers/100,000 person years with a relative reduction of 20% in mortality. Number needed to screen to prevent one lung cancer death was 320. Over 60% of lung cancers detected were early stage with adenocarcinoma histology.  However, definition of abnormal resulted in >95% false positive lesions.
  • False positive findings led to invasive procedures to confirm malignancy with death within 60 days of the procedure in 1.5% (ten patients) of those with confirmed lung cancer and 0.04% (eleven patients) of those without confirmed lung cancer. Other potential harms as a result of screening involve radiation harm and over-diagnosis (~20% of those detected in NLST).

Comparisons of the risk/benefit of low dose CT screening with other established practices such as smoking cessation have not been done or are not yet amenable to this type of comparison.

Models are under investigation to determine the optimal group and time frame that would benefit from low dose chest CT scans for lung cancer screening.

These models also need to address those who do not meet the NLST criteria for screening and those with other risk factors such as asbestos exposure and a strong family history of lung cancer.

Multiple models were reviewed including models increasing the at-risk patient pool so that the benefits of screening outweigh the risks. This effectively increases the prevalence of lung cancer in the screened population.  Biomarkers to select at risk patients are also under investigation.

One strategy that may increase the prevalence of lung cancer in the screening pool is to follow an initial abnormal scan with a second scan since the group with an abnormal scan already has a higher prevalence of lung cancer than the unscreened population.

Lung cancer screening with low dose chest CT scans has been endorsed by several healthcare organizations with strength of endorsement ranging from recommended to a suggestion that it be offered with an informed dialogue weighing its risks and benefit.