RADIOGRAPHIC SCREENING FOR CANCER PROPOSED PARADIGM FOR REQUISITE RESEARCH

Computed tomography (CT) imaging as an excellent approach to the detec tion and characterization of small solitary pulmonary nodules (SSPN) r aises three questions: (1) How often does CT imaging lead to detection of SSPN? (2) How often is such an SSPN malignant? (3) If malignant, h ow curable is it? The first question pertains to decisions about scree ning use of CT (clinical or mass screening), the second to decisions a bout screening for SSPN and diagnosis of malignancy given SSPN, and th e third - in the context of known curability at ordinary clinical diag nosis - to decisions about screening for SSPN, diagnosis given SSPN an d intervention given malignant SSPN. We present a three component stud y design that addresses these questions. The first is directed primari ly to the first question. Some 1000 persons at high risk for lung canc er will be screened for SSPN using screening-type CT. The primary aim is to determine the prevalence of CT-detectable SSPN as a joint functi on of risk-relevant aspects of the person. The second component addres ses the prevalence of malignancy among the detected cases of SSPN, To develop the prevalence function, a larger series of CT-detected SSPN w ill be obtained by developing a multi-center SSPN ''registry'' A subse quent, third component will focus on the registered cases of malignant SSPN screening incidentally detected and address their curability on the basis of long-term follow-up. This design, in lieu of a randomized trial, may represent a new paradigm for applied research on radiologi c technologies in cancer screening, given its advantages in terms of r esearch efficiency and implications to decisions about diagnostic work up and therapeutic intervention.