Medical Discussions

For the actual article, click here

Background

• In 1993, the International Early Lung Cancer Action Project (I-ELCAP) studied the use of CT cancer as a screening tool in the early detection of lung cancer .
  • The study found that eighty percent of lung cancers detected by annual screening were stage 1 cancer.
• But does this actually save lives?
• Using ELCAP protocal, this study investigates whether early detection leads to a mortality benefit.
• This study was supported with grants from National Institute of Health

Methods

• For a flowchart of the actual protocol, click here
• Pt’s initially underwent baseline screening.  If the patient had a negative CT scan, then they underwent annual screening at 12 month intervals
• This is a prospective, observational trial with no control group.
• For baseline screening, a positive result on the initial low-dose CT scan was defined as
  • At least one solid (completely obscuring lung paranchyma) or partly solid (obscuring part of paranchyma) non calcified pulmonary nodule 5 mm or more in diameter
  • At least one non solid, non calcified pulmonary nodule 8mm or more in diameter, or
  • a solid endobronchial nodule
• For positive results at the baseline screen:
  • Patients with nodules 5 mm to 14 mm were either re-imaged with CT scan or underwent a PET scan.  If the PET scan was positive or after 3 months the CT scan showed nodules that were growing, then a biopsy was performed
  • For lesions greater or equal to 15 mm, biopsy was immediately performed.
  • Lesions that were suspected to be infections underwent a 2wk period of antibiotics
• For annual screening, a positive results was any newly identified noncalcified nodule, regardless of size.
  • Repeat CT scan performed for nodules less than 5 cm at 3 months or 6 months depending on the size of the nodule.  If there was no growth in the nodules, then the workup was stopped and pt was re-screened at 12 month interval from the previous CT
  • For pts with nodules greater than 5 cm, a 2wk course of antibiotics was prescribed followed by a CT scan one month later.  If the nodules did not resolve, then a biopsy was performed
• Patients were enrolled from 1993 to 2995
• Inclusion criteria- 40 yo or older, at risk for lung cancer b/c of cigarette smoking, occupational exposure, or exposure to second hand smoking, pts were “considered fit” to undergo thoracic surgery
• 31,567 pts underwent baseline screening and of these, 27,456 underwent annual screening
• The average age 61 yo and median pack year history was 30

Results

• Among the 31,567 asymptomatic patients that underwent baseline screening, 405 patients were diagnosed with lung cancer.
• Among the 27,456 patients who underwent annual screening 74 patients were diagnosed with lung cancer.
• Of the total of 484 patients that developed lung cancer, 411 (85 percent) underwent resection, 57 (12 percent) underwent radiation and/or chemotherapy, and 16 recieved no treatment.
  • Of the 484 patients diagnosed 85% had stage I lung ca 
• The estimated 10 year survival for all participants was 80% (95%CI, 74 to 85), but in patients with stage I disease the survival rate was 88% (95% CI, 84 to 91).  Moreover, in patients with stage 1 disease who underwent resection within 0ne month of diagnosis the survival rate was 92 % (95% CI, 88 to 95).
• The operative mortality rate was 0.5%.

Discussion

• The authors contend that using CT scans to screen for lung cancer could prevent 80% of death from lung cancer.  Currently the death rate of lung cancer in US is 95%.
• The rate of detection in this study was 1.3% on baseline screen and 0.3% on annual screen, which is comparable to breast cancer screening with mammograms.

THE BOTTOM LINE:  In high risk patients patients, using the I-ELCAP protocol which includes a baseline CT scan and subsequent annual CT scans, 85 percent of the cancers identified in this study were stage I disease.  Moreover, the ten year survival was 80 percent in all patients diagnosed with lung cancer, 88 percent in patients with stage I disease, and 92% in patients with stage I disease and resection within one month of diagnosis.