Clinical significance of peripheral blood circulating tumor cells detection in osteosarcoma patients

Abstract

Objective To discuss the correlations amongst the count, molecular and clinicopathological characteristics of circulating tumor cells (CTCs), and the feasibility of using CTC as an aid to judge the metastasis of osteosarcoma, evaluate the ther-apeutic effect, and predict the prognosis of patients. Methods Retrospective analysis of 30 patients with newly diagnosed osteo-sarcoma diagnosed from January 2015 to June 2016, there were 17 males and 13 females. The average age was 13.77±4.31 years old (ranged from 7 to 21 years). There were 21 cases of Ennecking stage II, including 2 cases of IIA, 19 cases of IIB, and 9 cases of Ennecking III. Peripheral blood of all patients was obtained and processed using CanPatrolTM System at baseline, pre- and post-op-eration. Multiplex RNA-in situ hybridization (RNA-ISH) assay was used to characterize the molecular markers. Combined with clinical data, the relationship between peripheral blood CTC counts, count changes, molecular characteristics, tumor metastasis, chemotherapy effects, and prognosis of patients with osteosarcoma was analyzed and compared. Results The CTC count in pe-ripheral blood was 10.44±5.70 in Ennecking stage III patients and 4.76±3.56 in stage II patients. The increase or decrease in CTC counts was associated with good or poor neoadjuvant chemotherapy (P=0.002). In patients with good chemotherapy effect, the CTC count in peripheral blood was decreased after chemotherapy. The mean progression-free survival time was 11.85±4.93 months for patients with CTC number ≥7, and the average progression-free survival time was 15.53±4.09 months for patients with CTC num-ber<7 (P=0.012). The proportion of interstitial CTC in Ennecking stage III was 40.42%, which was higher than that of Enneck-ing IIB stage 23.00%. The difference was statistically significant (P=0.010). The positive rate of metastasis-associated gene 1 (MTA1) in interstitial CTC was 85.50%, and the positive rate of other types of CTC was 66.67%. The difference was statistically significant (P=0.000). Conclusion The counting and typing of peripheral blood CTC in osteosarcoma patients can be used as a complement to the commonly used imaging examinations, and they can play an auxiliary role in judging tumor metastasis, curative effect observation and prediction of poor prognosis. Key words: Neoplastic cells, circulating; Osteosarcoma; Neoplasm metastasis; Prognosis