A predictive model for survival in metastatic cancer patients attending an outpatient palliative radiotherapy clinic
IJROBP:Volume 53, Issue 5, Pages 1291-1302 (1 August 2002)

Purpose: To develop a predictive model for survival from the time of presentation in an outpatient palliative radiotherapy clinic.

Methods and Materials: Sixteen factors were analyzed prospectively in 395 patients seen in a dedicated palliative radiotherapy clinic in a large tertiary cancer center using Cox’s proportional hazards regression model.

The severity of the nine symptoms (covariates 8–16) assessed by the modified ESAS was classified as none (0), mild (1–3), moderate (4–7), and severe (8–10).

Number of risk factors method

The patients were also grouped according to the total number of risk factors that they possessed.  The six risk factors are as follows: (1) non-breast cancer patients, (2) sites of metastases other than bone only, (3) KPS <60, (4) fatigue score moderate to severe, (5) appetite score severe, and (6) shortness of breath score any.

Ninety-eight of 395 (25%) patients with 3 or less risk factors were classified in Group 1, 117 (30%) patients with 4 risk factors were assigned to Group 2, and 180 (46%) patients with 5 to 6 risk factors were assigned to Group 3. This grouping led to reasonable separation of survival curves, with a fairly good fit between the model and the actual Kaplan-Meier survival curves.

Values of median survival and 95% confidence intervals for each group were as follows: Group 1 = 62 weeks (41–70 weeks), Group 2 = 24 weeks (18–29 weeks), and Group 3 = 11 weeks (9–14 weeks) (p < 0.0001).

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