Measuring tumor response and shape change on CT: esophageal cancer as a paradigm.
BACKGROUND
Accurate response assessment is essential for evaluating new cancer treatments. We evaluated the impact of Response Evaluation Criteria in Solid Tumors (RECIST), World Health Organization (WHO) criteria and tumor shape on response assessment in patients with metastatic esophageal cancer.


METHODS
In 19 patients with metastatic esophageal cancer in a phase II trial of bryostatin-1 and paclitaxel, response was retrospectively assessed for 89 lesions with RECIST and WHO criteria on baseline and serial follow-up CT scans. The eccentricity factor (EF) was introduced for measuring the degree to which tumor shape diverges from a perfect sphere [EF = radical1-(LPD/MD)(2), where LPD is the largest perpendicular diameter and MD is the maximal diameter].


RESULTS
The disagreement rate in best overall response categorization between RECIST (unidimensional) and WHO (bidimensional) criteria was 26.3%. Change in eccentricity was significantly greater (P < 0.01) for patients with disagreement (mean 0.31, range 0-0.91). When the short axis was used for unidimensional lymph node measurement, disagreement between WHO and RECIST lessened.


CONCLUSIONS
Response assessment by WHO and RECIST differs substantially. Greater change in eccentricity is associated with greater discordance between WHO and RECIST. The discordance between WHO and RECIST may impact on how effective a therapy is judged to be.
Schwartz
L H
LH
Department of Radiology, Biostatistics and Epidemiology and Medicine, Memorial Sloan-Kettering Cancer Center, New York, 10021,USA. schwartg@mskcc.org
Colville
J A C
JA
Ginsberg
M S
MS
Wang
L
L
Mazumdar
M
M
Kalaigian
J
J
Hricak
H
H
Ilson
D
D
Schwartz
G K
GK
D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use* / Q000633:toxicity; D054713:Bryostatins; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D018942:Macrolides / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009369:Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D017239:Paclitaxel / Q000008:administration & dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
D054713:Bryostatins; D018942:Macrolides; C046785:bryostatin 1; D017239:Paclitaxel