Table 1 Baseline patient and tumour characteristics of 228 patients with analysable pre-treatment MR scans, Christie series 2006 to 2015, stratified by T size < and ≥ 4 cm

From: Pre-treatment magnetic resonance imaging in anal cancer: large-scale evaluation of mrT, mrN and novel staging parameters

 

Totals

Stratification by PLATO trial T size strata

P value

<4 cm (102)

≥4 cm (126)

Demographics

 Men (%)

86 (37.7)

41 (40.2)

45 (35.7)

0.49a

 Age (years, median, IQR)

61 (52–69)

60 (51–68)

62 (52–70)

0.45c

 MSM (%)

18 (7.9)

3 (2.9)

15 (11.9)

0.007a

 HIV positive (%)

9 (4.0)

2 (2.0)

7 (5.6)

0.19b

Tumour Characteristics

Anatomical Position (%)

 Canal

173 (75.9)

73 (71.6)

100 (79.4)

 

 Margin

20 (8.8)

16 (15.7)

4 (3.2)

 

 Canal and Margin

35 (15.4)

13 (12.8)

22 (17.5)

0.003a

T-Size (cm, median, IQR)

4.2 (3.2–5.6)

3.0 (2.5–3.5)

5.5 (4.6–6.3)

<0.0001c

T-Stage (%)

 T1

7 (3.1)

7 (6.7)

0

 

 T2

124 (54.4)

88 (86.3)

36 (28.6)

 

 T3

52 (22.8)

0

52 (41.3)

 

 T4

45 (19.7)

7 (6.7)

38 (30.2)

<0.001b

Nodal Characteristics

 Any nodal detection (%)

92 (40.2)

26 (25.5)

66 (52.4)

<0.001a

 Perirectal Nodes (%)

62 (27.2)

14 (27.7)

48 (38.1)

<0.001a

 Pre-Sacral Nodes (%)

24 (10.5)

5 (4.9)

19 (15.1)

0.013a

 Inguinal Nodes (%)

33 (14.5)

9 (8.8)

24 (19.1)

0.029a

 Internal Iliac Nodes (%)

18 (7.9)

3 (2.9)

15 (11.9)

0.013a

 External Iliac Nodes (%)

5 (2.2)

1 (1.0)

4 (3.2)

0.38b

Total Nodes (median, IQR)

0 (0–1)

0 (0–1)

1 (0–3)

<0.0001c

N Stage (AJCC V7)

 N0 (%)

136 (59.7)

76 (74.5)

60 (47.6)

 

 N1 (%)

44 (19.3)

13 (12.8)

31 (24.6)

 

 N2 (%)

20 (8.8)

8 (7.8)

12 (9.5)

 

 N3 (%)

28 (12.3)

5 (4.9)

23 (18.3)

<0.001a

Additional Characteristics

Dentate Position (%)

 Above

36 (15.8)

22 (21.6)

14 (11.1)

 

 Below

52 (22.8)

38 (37.3)

14 (11.1)

 

 Straddling

140 (61.4)

42 (41.2)

98 (77.8)

<0.001a

Rectal Extension (%)

140 (61.4)

43 (42.2)

97 (77.0)

<0.001a

mrEMVI (%)

13 (5.7)

2 (2.0)

11 (8.7)

0.028a

mrTSH (%)

117 (51.3)

49 (48.0)

68 (54.0)

0.37a

Sphincter Infiltrationd (%)

 Confined to Internal Sphincter

62 (27.4)

44 (44.0)

18 (14.3)

 

 Confined to External Sphincter

113 (50.0)

47 (47.0)

66 (52.4)

 

 Breached into ischio-rectal fossa

51 (22.6)

9 (9.0)

42 (33.3)

<0.001a

Perianl abscess (%)

19 (8.3)

9 (8.8)

10 (7.9)

0.81a

Organ Extension (%)

45 (19.7)

7 (6.7)

38 (30.2)

<0.001a

  1. N number of patients, IQR interquartile range, MSM men who have sex with men, EMVI extramural vascular invasion, TSH tumour signal heterogeneity
  2. aChi-squared test;
  3. bFisher’s exact test;
  4. cWilcoxan Rank Sum test;
  5. dReaders were unable to assign the degree of sphincter infiltration in two cases and of the 226 further assessable patients, half had tumours that had breached beyond the internal sphincter but remained confined within the external sphincter and the other quarter had tumours that had breached the external sphincter and infiltrated into the ischio-anal fossa.
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