Reduction in growth threshold for pulmonary metastases: an opportunity for volumetry and its impact on treatment decisions

Objectives: This study compares tumour response assessment by automated CT volumetry and standard manual measurements regarding the impact on treatment decisions and patient outcome. Methods: 58 consecutive patients with 203 pulmonary metastases undergoing baseline and follow-up multirow detector CT (MDCT) under chemotherapy were assessed for response to chemotherapy. Tumour burden of pulmonary target lesions was quantified in three ways: (1) following response evaluation criteria in solid tumours (RECIST); (2) following the volume equivalents of RECIST (i.e. with a threshold of −65/+73%); and (3) using calculated limits for stable disease (SD). For volumetry, calculated limits had been set at ±38% prior to the study by repeated quantification of nodules scanned twice. Results were compared using non-weighted κ-values and were evaluated for their impact on treatment decisions and patient outcome. Results: In 15 (17%) of the 58 patients, the results of response assessment were inconsistent with 1 of the 3 ...