This work has been presented in part at the 2012 ESMO Annual Meeting, Vienna.
Early tumor shrinkage in metastatic colorectal cancer: Retrospective analysis from an irinotecan-based randomized first-line trial
Version of Record online: 14 APR 2013
© 2013 Japanese Cancer Association
Volume 104, Issue 6, pages 718–724, June 2013
How to Cite
(Cancer Sci, doi: 10.1111/cas.12148, 2013)
- Issue online: 23 MAY 2013
- Version of Record online: 14 APR 2013
- Accepted manuscript online: 10 MAR 2013 04:08AM EST
- Manuscript Accepted: 5 MAR 2013
- Manuscript Revised: 1 MAR 2013
- Manuscript Received: 11 JAN 2013
Early tumor shrinkage (ETS) has been highlighted as a favorable prognostic factor related to progression-free survival (PFS) and overall survival (OS) in cytotoxic treatment of metastatic colorectal cancer. Data from a randomized phase III study comparing infusional 5-fluorouracil plus irinotecan (FUFIRI) versus irinotecan plus oxaliplatin (mIROX) were evaluated. Patient groups were analyzed according to the relative change in maximum tumor diameter between baseline and after 7 weeks of treatment. The ETS cohort was defined as a decrease of ≥20%. Additionally, the non-ETS cohort was subdivided into “minor shrinkage” (0–19%), “tumor progression” (any increase) and development of “new metastatic lesions”. Progression-free survival and OS were estimated in all patient subgroups. Assessment of ETS was possible in 201 patients. Early tumor shrinkage was observed in 47% (94/201) and non-ETS in 53% (107/201) of patients. Patients with ETS had a more favorable outcome with regard to PFS (9.9 months vs 6.1 months, P = 0.029) and OS (27.5 months vs 17.8 months, P = 0.002). In the non-ETS subgroups, patients with “minor shrinkage” (PFS 8.4 months, OS 21.6 months) showed a markedly better outcome than patients with “early tumor progression” (PFS 4.0 months, OS 15.3 months) or with “new metastatic lesions (PFS 2.2 months, OS 7.6 months). In conclusion, ETS assessment offers accelerated response evaluation when compared to RECIST. In patients treated with chemotherapy alone, ETS ≥20% is associated with excellent outcome. Non-ETS is a heterogeneous subgroup where patients with minor shrinkage clearly benefit from treatment, and patients with early progression or development of new lesions have an unfavorable prognosis.