NTCP model validation method for DAHANCA patient selection of protons versus photons in head and neck cancer radiotherapy

Figures & data

Table 1. Organs at risk in the DAHANCA validation cohort.

Organ at risk [Gy]	Patients	Median	1 Quartile	3 Quartile
Sublingual gland	588	53.6	40.5	64.2
Submandibular ipsilateral	583	64.9	60.6	67.6
Submandibular contralateral	580	53.2	46.9	60.3
Parotid ipsilateral	588	35.2	26.3	44.4
Parotid contralateral	588	24.6	18.1	29.0
Superior PCM	588	51.1	39.0	61.3
Middle PCM	587	60.5	53.6	65.6
Inferior PCM	587	49.6	43.8	59.8
Supraglottic larynx	584	57.1	46.7	65.2
Glottic larynx	585	49.4	41.5	62.8
Esophagus inlet	588	43.1	30.6	50.2
Cervical esophagus	588	14.7	4.6	24.3
Esophagus	588	18.6	9.5	28.1
Cricopharyngeus	587	48.2	42.1	55.9
Spinal cord	588	29.6	25.0	34.0
Brain stem	569	5.5	2.9	11.7
Brain	583	1.9	1.0	3.2
Mandible	588	35.2	28.4	42.2
Extended oral cavity	573	43.9	33.7	54.0
Mucosa ipsilateral	585	39.5	22.8	53.2
Mucosa contralateral	585	29.6	15.4	39.6
Lips	578	15.2	9.1	20.8
Thyroid	582	40.7	25.4	51.6
Ear inner ipsilateral	537	2.8	2.0	6.9
Ear inner contralateral	537	2.4	1.7	4.3
External	456	9.8	7.9	13.1

Figure 1. Calibration plot for the original and intercept refit models. The patients were grouped in to 10 equally sized groups (filled black circles) and the binominal uncertainty equal to one standard deviation is displayed in the error bars. The raw data are displayed as open gray circles with added noise, to illustrate the patient density.

Figure 2. Linear predictor plot for the original and intercept refit models. Linear predictor original model (–6.09 + 0.057 × PCM superior D_mean+0.037 × supraglottic larynx D_mean) and intercept refit model (–5.66 + 0.057 × PCM superior D_mean+0.037 × supraglottic larynx D_mean). The patients were grouped in to 10 equally sized groups (filled black circles) and the binominal uncertainty equal to one standard deviation is displayed in the error bars. The raw data are displayed as open gray circles with added noise, to illustrate the patient density.