Table 4.

Crude incidence rates (per 10,000-person years) and estimated subHazard Ratios by Gray and Fine method (with adjustment for age and calendar year at time of radiotherapy) for IMRT versus the reference group 3DCRT.

Subsite (ICD10 code)	IMRT		3DCRT		Fine & Gray Model
	n with SPC	Incidence rate	n with SPC	Incidence rate	sHRs (95% CI)	p-value
All solid (except skin) C00–C80	99	20.90	126	13.01	1.23 (0.88–1.76)	0.220
Solid SPC non-pelvis	74	15.62	85	12.27	1.56 (1.03–2.36)	0.034
Age at RT
50–69 years	37	18.93	29	8.49	3.27 (1.65–6.46)	0.001
70–79 years	37	13.29	56	15.96	0.96 (0.59–1.59)	0.887
Smoking Status at RT
Never smoker	17	10.79	24	10.47	0.80 (0.32–1.98)	0.631
Past smoker	21	20.66	30	19.60	0.94 (0.43–2.06)	0.875
Active smoker	25	33.33	15	12.94	2.94 (1.28–6.76)	0.011
Not reported	11	7.88	16	8.22	1.20 (0.42–3.40)	0.734
SPC within anatomical regions
Chest	30	6.33	36	5.20	1.21 (0.65–2.26)	0.548
Abdomen	26	5.48	42	6.06	1.13 (0.59–2.16)	0.719
Pelvis	27	5.70	40	5.77	0.79 (0.41–1.47)	0.437
SPC by tumor site
Urinary tract total	23	4.85	37	5.34	0.72 (0.35–1.49)	0.380
Bladder, urethra	17	3.59	29	4.19	0.56 (0.27–1.18)	0.128
Kidney, renal pelvis, ureter	8	1.69	6	0.87	3.90 (0.64–23.80)	0.140
Gastrointestinal total	34	7.18	53	7.65	1.07 (0.62–1.86)	0.802
Rectum, rectosigmoid	10	2.11	9	1.30	2.41 (0.76–7.64)	0.135
Colon	10	2.11	17	2.45	0.82 (0.31–2.15)	0.688
Oesophagus & Stomach	9	1.90	13	1.88	1.30 (0.41–4.19)	0.655
Pancreas, liver, biliary tract	6	1.27	14	2.02	0.57 (0.20–1.61)	0.287
Lung & Bronchus	21	4.43	24	3.46	1.19 (0.57–2.48)	0.636
Soft tissue/sarcoma	2	0.42	2	0.29	1.20 (0.05–31.84)	0.914

Numbers reflect observed number of survivors experiencing the SPC event of interest. For SPC sub-sites, only the first SPC is taken into consideration. Grouping of regions and ICD10 codes is reflected in Supplementary File 2.

Bold numbers represent significantly elevated SIRs (p < 0.05).