Predicting the survival of patients with painful tumours treated with palliative radiotherapy: a secondary analysis using the 3-variable number-of-risk-factors model

Table 4 Accuracy of predicting death within 2, 4, and 12 months using three-variable number-of-risk-factors model cutoff values of 1–3

		Bone metastases (n = 485)			Miscellaneous painful tumours (n = 302)
		NRF model cutoff values			NRF model cutoff values
		1	2	3	1	2	3
Sensitivity (%)	2-month	96	74	0	87	34	0
	4-month	97	68	0	86	32	0
	12-month	92	92	0	76	23	0
Specificity (%)	2-month	23	70	100	35	85	100
	4-month	28	78	100	39	89	100
	12-month	41	88	100	45	94	100
PPV (%)	2-month	19	32	NA	14	22	NA
	4-month	36	56	NA	30	47	NA
	12-month	70	86	NA	62	83	NA
NPV (%)	2-month	97	94*	84	96	91*	89
	4-month	96	85	70	90	82	77
	12-month	78	56	41	62	51	46

NRF = three-variable number-of-risk-factors, PPV = positive predictive value, NPV = negative predictive value, NA = not applicable
Cutoff value of 2 means that the patients who belong to the group I and II are predicted to survive > 2, 4, and 12 months. Cutoff value of 3 means that all patients are predicted to survive > 2, 4, and 12 months
*Probability of not dying within 2 months for patients in group I or II (therefore, predicted not to die within 2 months)

ISSN: 1748-717X