Table 1.

Characteristics of studies included in the meta-analysis

First author of study (ref.), yNO. of patientsSampling timeStageDetection methodDetection rate, %Cutoff of CTC+OutcomeHR estimation
Stathopoulou (25), 2002148BaselineM0RT-PCR30DFS, OSReported in text
Gaforio (26), 200392BaselineM0, M1Other ICC621 CTC/10 mLPFS, OSData extrapolated
Weigelt (27), 200394Mid-therapyM1RT-PCR31PFS, OSData extrapolated
Xenidis (28), 2003161PosttherapyM0RT-PCR27DFSData extrapolated
Giatromanolaki (29), 2004100BaselineM0RT-PCR33DFSReported in text
Pierga (14), 2004114BaselineM0, M1Other ICC251 CTC/3 × 106 MNCDFS, OSData extrapolated
Masuda (30), 200598BaselineM0RT-PCR18DFSReported in text
Benoy (15), 2006148BaselineM0, M1RT-PCR15, 20aOSReported in text
Budd (7), 2006138Mid-therapyM1Cellsearch255 CTC/7.5 mLOSReported in text
Hayes (6), 2006177BaselineM1Cellsearch495 CTC/7.5 mLPFS, OSReported in text
Mid-therapy31
Ntoulia (18), 2006101BaselineM0RT-PCR14DFS, OSReported in text
Wiedswang (31), 2006318PosttherapyM0Other ICC101 CTC/1 × 107 MNCDFS, OSReported in text
Wong (32), 2006123Mid-therapyM0, M1Other ICC344 CTC/sample13 CTC/samplebPFS, OSReported in text Data extrapolatedc
Wulfing (11), 200635BaselineM0Other ICC491 CTC/50 mLDFS, OSData extrapolated
Xenidis (12), 2006167BaselineM0RT-PCR22DFS, OSReported in text
Apostolaki (23), 2007214PosttherapyM0RT-PCR21DFS, OSReported in text
Cristofanilli (33), 2007151BaselineM1Cellsearch445 CTC/7.5 mLOSReported in text
Ignatiadis (34), 2007185BaselineM0RT-PCR34, 52dDFS, OSReported in text
Xenidis (35), 2007119PosttherapyM0RT-PCR18DFS, OSReported in text
Bidard (8), 200837BaselineM1Other ICC411 CTC/3 × 106 MNCOSData extrapolated
Dawood (36), 2008185BaselineM1Cellsearch385 CTC/7.5 mLOSReported in text
Ignatiadis (37), 2008175BaselineM0RT-PCR41, 8, 29eDFS, OSReported in text
Tkaczuk (38), 2008105BaselineM0, M1Other ICC561 CTC/15–20 mLOSData extrapolated
Yagata (9), 200838BaselineM1Cellsearch295 CTC/7.5 mLPFS, OSData extrapolated
Apostolaki (24), 2009216BaselineM0RT-PCR25DFS, OSReported in text
Botteri (10), 200980BaselineM1Cellsearch615 CTC/7.5 mLPFS, OSData extrapolated
Daskalaki (39), 2009165BaselineM0RT-PCR55DFS, OSReported in text
Posttherapy52
De Giorgi (40), 2009102BaselineM1Cellsearch505 CTC/7.5 mLOSReported in text
Mid-therapy21
Liu (41), 200972BaselineM1Cellsearch355 CTC/7.5 mLPFSData extrapolated
Mid-therapy28
Marques (17), 2009321BaselineM0RT-PCR19DFSReported in text
Serrano (16), 200971Mid-therapyM0, M1Other ICC666 CTC/10 mLPFS, OSReported in text
Posttherapy54
Tewes (42), 200932Mid-therapyM1RT-PCR52OSData extrapolated
Xenidis (13), 2009437BaselineM0RT-PCR41DFS, OSReported in text
Posttherapy33
Bidard (43), 2010115BaselineM0Cellsearch231 CTC/7.5 mLDFS, OSReported in text
Bidard (44), 201067BaselineM1CellSearch525 CTC/7.5 mLPFSData extrapolated
Chen (19), 201050BaselineM0RT-PCR54DFSReported in text
De Giorgi (45), 2010195BaselineM1Cellsearch475 CTC/7.5 mLOSReported in text
Hu (46), 201045BaselineM0, M1Other ICC40OSReported in text
Nakamura (47), 2010107BaselineM1CellSearch375 CTC/7.5 mLOSReported in text
Gradilone (20), 201142BaselineM1RT-PCR675 CTC/7.5 mLPFSData extrapolated
Consoli (48), 201193BaselineM1CellSearch475 CTC/7.5 mLPFS, OSReported in text
Mid-therapy44
Giordano (49), 2011517BaselineM1CellSearch315 CTC/7.5 mLPFS, OSReported in text
Hayashi (50), 201152BaselineM1CellSearch605 CTC/7.5 mLPFS, OSReported in text
Mego (21), 2011292BaselineM1CellSearch411 CTC/7.5 mLOSData extrapolated
Molloy (51), 201182BaselineM0RT-PCR20DFSReported in text
Muller (52), 2011245BaselineM1CellSearch505 CTC/7.5 mLOSReported in text
Pierga (53), 2011267BaselineM1CellSearch445 CTC/7.5 mLPFS, OSReported in text
Reinholz (54), 201186BaselineM1RT-PCR56–75; 23–38fPFS, OSReported in text
Serrano (55), 201165PosttherapyM0, M1Other ICC63, 46, 43, 31g5 CTC/10 mLOSData extrapolated

Abbreviations: ref., reference; CTC, circulating tumor cells; MNC, mononuclear cells; RT-PCR, reverse transcriptase polymerase chain reaction; ICC, immunocytochemistry; OS, overall survival; PFS, progression-free survival; DFS, disease-free survival.

  • aDetection rates were for markers CK-19 and mammaglobin, respectively.

  • bThe cutoff value was 4 CTC/sample in early-stage patients, whereas the cutoff value was 13 CTC/sample in metastatic patients.

  • cHR for OS in early breast cancer was extrapolated from survival curves.

  • dDetection rates were for markers CK-19 and HER2, respectively.

  • eDetection rates were for markers CK-19, mammaglobin and HER2, respectively.

  • fDetection rates were for markers CK-19 and mammaglobin at baseline, respectively.

  • gDetection rates were for the study time intervals of 1 to 5 months, more than 5 to 12 months, more than 12 to 24 months, and more than 24 to 50 months, respectively.