The natural history of radiographically occult bronchogenic squamous cell carcinoma: a retrospective study of overdiagnosis bias.
OBJECTIVE
An overdiagnosis bias occurs with the diagnosis of a disease that does not produce signs or symptoms before the patient dies from other causes. We sought to determine whether overdiagnosis bias is a factor when screening for squamous cell carcinoma of the lung.


METHODS
Retrospective study of the Miyagi Population-Based Lung Cancer Screening Registry for high-risk patients who were seen between January 1, 1982 (when sputum cytology tests were added for men with long smoking histories), and December 31, 1996.


METHODS
Miyagi Prefecture, Japan.


METHODS
A total of 251 patients (all men) who had sputum cytology test results that were positive for squamous cell carcinoma but had normal radiograph findings, 44 of whom declined cancer treatment (mean age, 70 years) and 207 of whom were treated with resection within 12 weeks of diagnosis (mean age, 65.5 year).


METHODS
Five-year and 10-year survival rates from primary lung cancer in both groups as of August 15, 2001.


RESULTS
Among the 44 untreated patients, 15 (34%) remained asymptomatic. The survival rate due to primary lung cancer death in the untreated group was 53.2% at 5 years and 33.5% at 10 years. The survival rate among treated patients was 96.7% at 5 years and 94.9% at 10 years. Of the 125 treated patients who died, 14 (11.2%) died from primary lung cancer.


CONCLUSIONS
Given that the two thirds of the untreated patients with squamous cell carcinoma of the bronchus died from lung cancer within 10 years, overdiagnosis bias does not appear to be a factor in screening for this disease. Thus, we recommend that patients with radiographically occult squamous cell carcinoma of the bronchus undergo tumor treatment after localization.
Sato
Masami
M
Department of Thoracic Surgery, Institute of Development, Aging, and Cancer, Tohoku University, Sendai 980-8575, Japan. m-sato@idac.tohoku.ac.jp
Saito
Yasuki
Y
Endo
Chiaki
C
Sakurada
Akira
A
Feller-Kopman
David
D
Ernst
Armin
A
Kondo
Takashi
T
D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000401:mortality; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000401:mortality; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011859:Radiography; D012042:Registries; D012189:Retrospective Studies; D013183:Sputum / Q000166:cytology*; D015996:Survival Rate