Lung cancer is the leading cause of cancer death in the United States and worldwide, accounting for nearly 160,000 deaths per year in the United States [50 (link), 51 ]. Recent investigations of the molecular basis of lung cancer have enabled clinical applications of targeted therapeutic agents, including the EGFR tyrosine kinase inhibitors and antiangiogenic agents, such as vascular EGFR inhibitors [3 (link)–5 (link), 52 (link)]. Tumor cavitation of pulmonary lesions is commonly observed in NSCLC treated with vascular EGFR inhibitors [53 (link), 54 (link)]. Because the cavitary portion of the tumor filled with air does not contribute to the tumor volume, the assessment of tumor burden may be improved by incorporating the cavitation into the measurement. On the basis of these observations, Crabb et al. [54 (link)] proposed an alternate method incorporating cavitation in response assessment for NSCLC treated with vascular EGFR inhibitors. In this method, the central cavity diameter is subtracted from the overall longest diameter of the lesion (Fig. 5 ). All other details for response assessment are identical to RECIST [54 (link)]. In a retrospective review of 33 patients treated with vascular EGFR inhibitor combined with platinum-based chemotherapy, tumor cavitation was observed in 24% of the patients. However, the alternate method for response assessment resulted in an alteration of response assessment, time to best response, duration of response, and time of disease progression in only a minority of patients compared with RECIST [54 (link)].
More recently, Lee et al. [55 (link)] proposed another set of criteria for NSCLC treated with EGFR tyrosine kinase inhibitors, which include tumor constituents such as solid and ground-glass opacity components, tumor cavitation, and CT attenuation changes. In their analysis of 75 patients with NSCLC treated with EGFR tyrosine kinase inhibitors, the criteria had a statistically significant association with overall survival [55 (link)]. Both criteria remain to be prospectively tested in a larger patient population.
More recently, Lee et al. [55 (link)] proposed another set of criteria for NSCLC treated with EGFR tyrosine kinase inhibitors, which include tumor constituents such as solid and ground-glass opacity components, tumor cavitation, and CT attenuation changes. In their analysis of 75 patients with NSCLC treated with EGFR tyrosine kinase inhibitors, the criteria had a statistically significant association with overall survival [55 (link)]. Both criteria remain to be prospectively tested in a larger patient population.
