Table 1. Janssen scoring system to estimate survival probability.

Variable	Points
Age, years
≥65	1
<65	0
Additional comorbidities*	1
BMI, kg/m2
<18.5	2
18.5–30	0
>30	1
Primary tumor with poor prognosis*	2
Multiple bone metastases	1
Visceral metastases*	2
Preoperative HGB, g/dL
>10	0
≤10	1

Weighted score for non-continuous factors assigned by rounding its hazard ratio to the nearest integer. Continuous variables (age, preoperative hemoglobin levels) were dichotomized. *, see text for detailed methods. A poor prognosis was defined as a total score of 6–10, an intermediate prognosis as 3–5, and a good prognosis as 0–2. Table is adapted from one published by Janssen et al. and permission for using the above table was granted by Wolters Kluwer Health, Inc. (9). BMI, body mass index; HGB, hemoglobin.