Table 1

Clinicopathological characteristics and recurrence, according to ctDNA status

VariablePretreatment ctDNA (n=159)Postchemoradiotherapy ctDNA (n=144)Postoperative ctDNA (n=159)
Positive
(n=122)
Negative
(n=37)
PPositive
(n=12)
Negative
(n=132)
PPositive
(n=19)
Negative
(n=140)
P
Age, years
 Median63590.6961620.9759630.97
 Range28–8531–8641–8628–8641–8628–86
Sex, n (%)
 Female40 (33) 12 (32)1.004 (33)43 (33)1.006 (32)46 (33)1.00
 Male82 (67) 25 (68)8 (67)89 (67)13 (68)94 (67)
Distance from anal verge (cm), n (%)
 0–544 (36) 13 (35)0.774 (33)48 (36)0.796 (32)51 (37)0.01
 > 5–1055 (45) 19 (51)5 (42)62 (47)5 (26)69 (49)
 > 1023 (19) 5 (14)3 (25)22 (17)8 (42)20 (14)
Clinical disease stage, n (%)
 Stage II23 (19) 12 (32)0.112 (17)29 (22)1.002 (11)33 (24)0.25
 Stage III99 (81) 25 (68)10 (83)103 (78)17 (89)107 (76)
Pathological T stage, n (%)
 ypT0-265 (53) 23 (62)0.365 (42)73 (55)0.385 (26)83 (59)0.01
 ypT3-457 (47) 14 (38)7 (58)59 (45)14 (74)57 (41)
Pathological N stage, n (%)
 ypN091 (75) 25 (68)0.406 (50)97 (73)0.1010 (53)106 (76)0.05
 ypN1-231 (25) 12 (32)6 (50)35 (27)9 (47)34 (24)
Pathological complete response, n (%)
 Yes24 (20) 10 (27)0.361 (9)28 (21)0.462 (11)32 (23)0.37
 No98 (80) 27 (73)11 (89)104 (79)17 (89)108 (77)
Adjuvant chemotherapy, n (%)
 Yes40 (33) 17 (46)0.174 (33)43 (33)1.0011 (58)91 (65)0.61
 No82 (67) 20 (54)8 (67)89 (67)8 (42)49 (35)
Recurrence at any site, n (%)
 Yes18 (15) 5 (14)1.006 (50)15 (11)0.00311 (58)12 (9)< 0.001
 No104 (85) 32 (86)6 (50)117 (89)8 (42)128 (91)
Site of recurrence, n (%)
 Locoregional only3/18 (17) 0/5 (0)1.000/6 (0)3/15 (20)0.531/11 (9)2/12 (17)1.00
 Distant±locoregional15/18 (83) 5/5 (100)6/6 (100)12/15 (80)10/11 (91)10/12 (83)
  • ctDNA, circulating tumour DNA.