A Prospective Long-Term Follow-Up Study: The Application of Circulating Tumor Cells Analysis to Guide Adjuvant Therapy in Stage II Colorectal Cancer.

Abstract

BACKGROUND: The efficacy of circulating tumor cells (CTCs) in the selection of stage II colorectal cancer (CRC) patients for adjuvant chemotherapy remains inconclusive. OBJECTIVE: The aim of this study was to validate the necessity of adjuvant chemotherapy for stage II CRC patients with positive postoperative CTCs. METHODS: The clinicopathological features and overall survival (OS) of a cohort of 70 patients with confirmed CRC were collected and analyzed. RESULTS: The total rate of positive CTCs was 55.7%, while the average OS was 70.8 months and the OS rate was 75.7% (53/70). These 70 patients were divided into four subgroups, including a CTC-negative group with non-adjuvant chemotherapy (CHEMO-/CTC-) versus a CTC-positive group with non-adjuvant chemotherapy (CHEMO-/CTC+), CHEMO+/CTC- versus CHEMO+/CTC+, CHEMO-/CTC- versus CHEMO+/CTC-, and CHEMO+/CTC+ versus CHEMO-/CTC+; the total numbers in each subgroup were 25 versus 32, 6 versus 7, 25 versus 6, and 7 versus 32, respectively. The average OS of the CHEMO-/CTC- and CHEMO-/CTC+ groups was 82.0 and 68.1 months, respectively (p = 0.020); the average OS of the CHEMO+/CTC- and CHEMO+/CTC+ groups was 83.6 months and 76.4 months, respectively (p = 0.963); the average OS of the CHEMO-/CTC- and CHEMO+/CTC- groups was 82.0 months and 83.6 months, respectively (p = 0.999); and the average OS of the CHEMO+/CTC+ and CHEMO-/CTC+ groups was 76.4 months and 68.1 months, respectively (p = 0.247). CONCLUSIONS: Positive CTCs are a potential prognostic marker for stage II CRC.