Fig. 5.

53-year-old woman with stage IV adenocarcinoma of lung treated with paclitaxel, carboplatin, and concurrent vascular epidermal growth factor receptor inhibitor, bevacizumab.

A, Baseline CT scan of chest before bevacizumab therapy shows spiculated mass (double-ended arrow) in left upper lobe, which measured 3.6 cm in longest diameter.

B, Follow-up CT after 6 weeks of therapy reveals development of tumor cavitation. Measurement of lesion by Response Evaluation Criteria in Solid Tumors would be 3.6 cm (black double-ended arrow), which is not different compared with baseline, even though decrease of tumor volume is evident after bevacizumab therapy. Using alternate method incorporating cavitation, measurement of lesion would be 1.8 cm (white double-ended arrow) because diameter of cavity (1.8 cm) should be extracted from longest diameter of entire lesion (3.6 cm). Measurement by alternate method shows 50% decrease compared with baseline, meeting criteria for partial response.