Tumor measurements on computed tomographic images of non-small cell lung cancer were similar among cancer professionals from different specialties.

Objective: In this study, we addressed the influence of the observer's background and experience on the accuracy of imaging-based tumor measurements. The consistency of measures with Response Evaluation Criteria in Solid Tumors (RECIST) vs. WHO criteria is also reported.

Study Design And Setting: Twenty-five observers (five radiologists, five thoracic surgeons, five radiotherapists, five pulmonologists, and five medical oncologists) were asked to measure three lesions on selected serial chest computed tomographic images from three non-small cell lung cancer patients treated with chemotherapy. The observers were asked to measure the longest diameter (RECIST), along with its perpendicular diameter (WHO criteria). Measurements by radiologists were used as reference values.

Results: There was no significant difference in the accuracy of measurements among the different groups. The highest intraobserver consistency was achieved by radiologists. Neither familiarity with measuring tumor lesions nor years since the MD degree correlated with measurement accuracy. A comparison of RECIST and WHO criteria showed consistent response ratings (kappa=.74, CI 95%=.57-.91).

Conclusion: Measurements of selected lesions were consistent among specialists, suggesting that assessment of tumor response is reliable even when it is not done by radiologists.