Securin identifies a subgroup of patients with poor outcome in rectal cancer treated with long-course (chemo)radiotherapy

Figures & data

Table I. The clinical characteristics of the patients in the three groups.

	Short-course RT, n (%)	Long-course RT, n (%)	Control, n (%)	p-value*
Study population (n = 211)
Male	53 (61%)	34 (63%)	32 (46%)	0.09
Female	34 (39%)	20 (37%)	38 (54%)
Mean age (years)	65.2	64.9	74.1	<0.001
Preoperative T^a
T1-2	28 (32%)	0	21 (30%)
T3	51 (59%)	2 (4%)	11 (16%)	<0.001
T4	1 (1%)	51 (94%)	3 (4%)
Tx	7 (8%)	1 (2%)	35 (50%)
Postoperative T^a
T1	3 (3%)	2 (4%)	5 (7%)
T2	33 (38%)	7 (13%)	27 (39%)
T3	49 (56%)	28 (52%)	35 (50%)	<0.001
T4	2 (2%)	13 (24%)	3 (4%)
T0	0	4 (7%)	0
Postoperative N^b
N0	51 (59%)	35 (65%)	41 (59%)
N1	24 (28%)	14 (26%)	15 (21%)	0.78
N2	12 (14%)	5 (9%)	11 (16%)
Nx	0	0	3 (4%)
Postoperative G^c
G1	9 (10%)	10 (19%)	13 (19%)
G2	56 (64%)	34 (63%)	47 (67%)	0.07
G3	20 (23%)	3 (6%)	10 (14%)
Gx	2 (2%)	7 (13%)	0
Crm (mm)^d
0	2 (2%)	11 (20%)	4 (6%)
< 1	6 (7%)	5 (9%)	3 (4%)	0.007
1 ≤ crm ≤ 2	3 (3%)	3 (6%)	4 (6%)
> 2	62 (71%)	26 (48%)	30 (43%)
unknown	14 (16%)	9 (17%)	29 (41%)
Disease specific outcome
Alive without recurrence	66 (76%)	29 (54%)	42 (60%)
Alive with recurrence	5 (6%)	6 (11%)	6 (9%)	0.16
Died of disease	9 (10%)	13 (24%)	14 (20%)
Died of other causes	7 (8%)	6 (11%)	8 (11%)

*Fisher's exact test.

^aThe extent of tumour invasion according to TNM classification of malignant tumours (6^th edition, 2002).

^bPostoperative nodal status according to TNM classification of malignant tumours (6^th edition, 2002).

^cTumour differentiation grade.

^dCircumferential margin.

Figure 1. Immunohistochemical staining of securin (a) and Ki-67 (b) in rectal cancer. Staining pattern of Ki-67 was almost exclusively nuclear, while securin had a combination of nuclear and cytoplasmic staining with a clear prominence of nuclear one.

Table II. The expression of securin and Ki-67 in the operative specimens related to key clinicopathological variables.

		SECURIN		Ki-67
Variable	n = 207	Mean expression	p-value*	Mean expression	p-value**
Patient group
Short-course RT	87	33%	<0.001	50%	<0.001
Long-course RT	50	23%		50%
Control	70	34%		68%
Patient age
< 70 years	107	29%	0.04	53%	0.02
> 70 years	100	33%		59%
Postoperative T^a
T1-2	77	34%		56%
T3	112	29%	0.01	56%	0.96
T4	18	24%		54%
Postoperative N^a
N0	124	31%		56%
N1	53	30%	0.80	57%	0.86
N2	27	29%		54%
Nx	3	25%		50%
Postoperative G^a
G1	32	27%		51%
G2	137	31%	0.19	58%	0.12
G3	33	34%		56%
Gx	5	17%		36%
TRG^b
Poor	27	26%		62%
Moderate	15	19%	0.21	42%	0.02
Excellent	8	18%		29%

*ANOVA

**Mann Whitney U-test for two and Kruskal-Wallis test for multiple independent samples.

^aFor abbreviations, see Table I.

^bTumour regression grade (TRG) after long-course RT related to studied markers; n = 50.

Table III. The pairwise-comparison of biopsy and operative specimens according to securin and Ki-67 expression.

		Operative specimens
	Biopsy n	Decrease n (%)	Increase n (%)	Unchanged n (%)	Significance
Securin
All pairs	65	51 (78%)	13 (20%)	1 (2%)	**
Short-course RT	46	36 (78%)	10 (22%)	0	**
Long-course RT	19	15 (79%)	3 (16%)	1 (5%)	*
Ki-67
All pairs	57	55 (96%)	2 (4%)	0	**
Short-course RT	39	39 (100%)	0	0	**
Long-course RT	18	16 (89%)	2 (11%)	0	**

*Wilcoxon signed-ranks test; p = 0.001.

**Wilcoxon signed-ranks test; p < 0.001.

Figure 2. Securin expression in operative specimens of the long-course (chemo)RT patients related to DFS and DSS (a–b). Tumour regression grade (TRG) after long-course (chemo)RT related to DFS and DSS (c–d).