Trial Information

Determination of the False Negative Rate of Percutaneous Needle Biopsies That Include Core Tissue Samples

We will review medical records to identify patients who underwent percutaneous needle biopsy
of a lung mass between 5/1/01 and 10/30/04. If the pathology report indicates that the
biopsy showed no evidence of malignancy, we will examine the medical record for a "gold
standard" diagnosis of the lesion in question, including the pathology result from a
surgical resection or a repeat biopsy, imaging follow-up demonstrating regression of the
lesion or size stability for at least 2 years, or clinical follow-up for at least 2 years
with no clinical evidence of malignant disease. If this information is not available in the
University Hospital medical record, we will contact the patient to obtain consent for
follow-up using external sources (physician records, imaging studies, pathology reports).

We will derive descriptive statistics (prevalence of malignancy, sensitivity, specificity,
and false negative rates). The overall sample size will be ~500 patients who had PTNB of a
lung mass within the study period. Approximately 80 are expected to have a biopsy result
showing no evidence of malignancy, based on a retrospective review performed under an IRB
exemption (87-04, letter dated 9/28/04). The expected proportion of cases with no evidence
of malignancy is approximately 0.15. For a 95% confidence interval of 0.15+/-0.075 we will
need follow-up information from 61 patients, considering that this is a descriptive study
with a dichotomous variable. This gives us a margin for patients who will be lost to
follow-up