Definitive radical external beam radiotherapy for rectal cancer: Evaluation of local effectiveness and risk of late small bowel damage

Figures & data

Table I. Characteristics of patients.

	Number of patients (%) unless otherwise stated N = 41
Sex Male Female	25 (61) 16 (39)
Age in years: median (range)	72 (40–87)
WHO Performance status 0 1 2 3	10 (24) 23 (56) 6 (15) 2 (5)
Carcinoembryonic antigen serum level in ng/ml ≤ 5 6–10 11–50 >51 No data	20 (50) 8 (20) 7 (18) 5 (13) 1
Tumour status Primary Local recurrence after anterior resection Local recurrence after abdominoperineal resection R2 resection	13 (32) 14 (34) 11 (27) 3 (7)
Clinical T stage of primary tumours T2N0 T3N0 T4N0	5 6 2
Involved lymph nodes on pelvic CT Yes No	18 (44) 23 (56)
Tumour mobility on digital rectal or vaginal examination Fixed Tethered Mobile Not applicable – high tumour not palpable or abdominoperineal resection in males	20 (59) 7 (21) 7 (21) 7
Maximal tumour dimension measured on pelvic CT 1–4.9 cm ≥ 5–7 cm > 7 cm No data	21 (53) 13 (33) 6 (15) 1
Reasons for decision ruling out surgery # tumour considered to be unresectable even if preoperative radiotherapy would be given unfit for major surgery due to co-morbidity no patient's consent for surgery high CEA serum level reason unknown	26 (65) 8 (20) 5 (13) 1 (3) 1

# involvement of: S1-2 presacral area – 6; illiac blood vessels – 4; ureter – 3; reason unknown – 13.

Figure 1. Local control in relation to the initial tumour response.

Figure 2. Cumulative incidence of local recurrence.

Table II. Local control in relation to the pre-treatment patients’ characteristics.

	Number of patients (%) with local control N = 11	Number of patients (%) with local failure N = 30	p-value
Carcinoembryonic antigen serum level in ng/ml			1
≤5	6 (30)	14 (70)
> 5	5 (25)	15 (75)
No data	0	1
Tumour status			1
Primary	4 (31)	9 (69)
Local recurrence	6 (24)	19 (76)
R2 resection	1	2
Involved lymph nodes on pelvic CT			0.075
Yes	2 (11)	16 (89)
No	9 (39)	14 (61)
Tumour mobility on digital rectal or vaginal examination			1
Fixed	5 (25)	15 (75)
Tethered or mobile	4 (29)	10 (71)
Not applicable – high tumour not palpable or abdominoperineal resection in males	2	5
Maximal tumour dimension measured on pelvic CT			1
<5 cm	6 (29)	15 (71)
≥5 cm	5 (26)	14 (74)
No data	0	1
Reasons for decision ruling out surgery			0.700
unresectable tumour#	6 (22)	21 (78)
co-morbidity or no patient's consent for surgery	4 (31)	9 (69)
Reason unknown	1	0

# including one patient with high CEA.

Figure 3. Panel A. Overall survival. Panel B. Cancer specific survival.

Table III. Late postradiation small bowel damage in relation to dose and volume in 32 patients for whom 3D dose distribution within small bowel was available.

	Dmax + 3/32 (9.4%)	V50ˆ 3/27 (11.1%)#	V55 3/26 (11.5%)	V60 2/18 (11.1%)	V65 1/9 (11.1%)	V70 0/1
Small bowel damage*
Yes	60, 62, 68	9, 10, 134	3, 8, 117	7, 52	5	–
No	58 ± 3	130 ± 26	81 ± 16	54 ± 12	17 ± 5	20
Median follow-up in months (range)	29 (5–92)	25 (5–92)	27 (5–92)	24 (5–92)	24 (7–60)	18

Individual values were given when the numbers of patients were less than 4 or mean values ± standard error for larger numbers of patients.

+ Maximum dose in Gy given to the small bowel.

ˆVolumes of irradiated small bowel in cm³ using doses higher then 50 Gy, 55 Gy, 60 Gy, 65 Gy, and 70 Gy, respectively.

#Number of patients with late damage receiving to the small bowel dose higher than 50 Gy, 55 Gy, 60 Gy, 65 Gy, and 70 Gy / total number of patients receiving to the small bowel dose higher than 50 Gy, 55 Gy, 60 Gy, 65 Gy, and 70 Gy, respectively. Five patients had small bowel dose lower than 50 Gy.

*Bowel obstruction treated conservatively with bowel rest in all patients. In one patients with bowel obstruction, 3D dose distribution within small bowel was not available.