Baseline chest radiograph for lung cancer detection in the randomized Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.
BACKGROUND
The Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial was initiated in 1992 to examine cause-specific mortality reduction from screening for these four cancers in men and women. We report lung cancer detection results of the baseline screening round.


METHODS
Of the 154,942 participants enrolled, who were aged 55-74 years with no history of PLCO cancers, 77,465 were randomly assigned to the intervention arm. Current or former smokers and never smokers in this arm received an initial single-view posterior-anterior chest radiograph.


RESULTS
In the initial screen, 5991 (8.9%, 95% confidence interval [CI] = 8.7% to 9.2%) of radiographs were suspicious for lung cancer: 8.2% (95% CI = 7.9% to 8.5%) for women and 9.6% (95% CI = 9.3% to 10.0%) for men. Rates were highest for older age groups and for smokers. Among those 5991 participants with a positive screen, 206 (3.4%, 95% CI = 3.0% to 3.9%) underwent biopsy examination, 126 (61.2%, 95% CI = 54.5% to 67.8%) of whom were diagnosed with lung cancer within 12 months of the screen (59 in women and 67 in men). The positive predictive value was 2.1% (95% CI = 1.7% to 2.5%), and 1.9 lung cancers were detected per 1000 screens. Among these cancers, 44% (95% CI = 35% to 52%) were stage I non-small-cell lung cancer. High rates of lung cancer were found in current smokers (6.3 per 1000 screens) and in former smokers who had smoked within the past 15 years (4.9 per 1000 screens). The lung cancer detection rate among never smokers was 0.4 per 1000 screens; this group accounted for 11% (95% CI = 5.6% to 16.6%) of the cancers identified.


CONCLUSIONS
In the baseline screen, nearly half the cancers were stage I. Whether this experience results in a reduction in lung cancer mortality is yet to be seen.
Oken
Martin M
MM
Hubert H. Humphrey Cancer Center, North Memorial Medical Center, Robbinsdale, MN 55422, USA. martin.oken@northmemorial.com
Marcus
Pamela M
PM
Hu
Ping
P
Beck
Thomas M
TM
Hocking
William
W
Kvale
Paul A
PA
Cordes
Jill
J
Riley
Thomas L
TL
Winslow
Stephen D
SD
Peace
Steven
S
Levin
David L
DL
Prorok
Philip C
PC
Gohagan
John K
JK
D000230:Adenocarcinoma / Q000000981:diagnostic imaging; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging; D015179:Colorectal Neoplasms / Q000175:diagnosis; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008400:Mass Chest X-Ray; D008403:Mass Screening; D008875:Middle Aged; D008913:Minority Groups / Q000706:statistics & numerical data; D009367:Neoplasm Staging; D010051:Ovarian Neoplasms / Q000175:diagnosis; D015995:Prevalence; D011471:Prostatic Neoplasms / Q000175:diagnosis; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D014481:United States / Q000453:epidemiology