Figure 7d:

Limitations of response assessment using RECIST in a 58-year-old woman with stage IV adenocarcinoma of the lung. (a, b) Contrast-enhanced axial and coronal CT images of the chest during pemetrexed and cisplatin therapy demonstrate a spiculated mass in the left upper lobe. The measurement of the dominant mass according to RECIST was 2.9 cm, measured in the longest diameter on an axial plane. Note a small nodular component of the mass at its inferior portion (arrow, b). (c, d) At follow-up CT during therapy, (c) the axial plane at the level of the longest diameter of the mass demonstrated a similar appearance and size of mass, 3.0 cm in the longest diameter. However, on (d) a coronal reformatted image at the level of the mass, the inferior component of the mass (arrow, d) has increased compared with the prior study (b), indicating increase of tumor burden, which is not captured by either RECIST or World Health Organization (WHO) measurements.