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. Author manuscript; available in PMC: 2021 Jan 1.
Published in final edited form as: Ann Surg. 2021 Jan 1;273(1):128–138. doi: 10.1097/SLA.0000000000003277

Table 3:

Univariate and multivariate analysis of RFS in the pre-imatinib era (top) and imatinib era (bottom).

PRE-IMATINIB ERAa Univariate Analysis   Multivariate Analysis
Class value Reference HR (95% CI) p-value HR (95% CI) p-value
Age at first surgery (yrs) N/A N/A 1.01 (0.998–1.029) 0.088   1.02 (1.002–1.037) 0.030
Sex M F 1.52 (0.99–2.33) 0.053 - -
Primary tumor site Small Bowel Stomach 1.35 (0.81–2.25) 0.250 2.13 (1.67–3.90) 0.014
Rectum 2.63 (1.41–4.91) 0.002 2.25 (1.08–4.68) 0.030
Other 1.47 (0.73–2.95) 0.280 1.36 (0.65–2.83) 0.409
Primary tumor size (cm) 5–10 <5 1.21 (0.73–2.00) 0.466 1.72 (0.96–3.09) 0.071
>10 1.82 (1.10–3.01) 0.020 2.63 (1.44–4.8) 0.002
Primary tumor mitotic rate per 50 HPF >5 ≤5 2.56 (1.65–3.99) <0.001 2.80 (1.71–4.61) <0.001
Marginsb R1 R0 1.10 (0.58–2.07) 0.769 - -
Second Malignancyc Yes No 0.79 (0.47–1.32) 0.370 - -
IMATINIB ERA Univariate Analysis   Multivariate Analysisd
Class value Reference HR (95% CI) p-value HR (95% CI) p-value
Age at first surgery (yrs) N/A N/A 1.02 (1.00–1.04) 0.014   - -
Sex M F 1.24 (0.85–1.81) 0.274 - -
Primary tumor site Small Bowel Stomach 1.29 (0.78–2.11) 0.318 - -
Rectum 0.93 (0.38–2.30) 0.873 - -
Other 2.06 (0.95–4.47) 0.068 - -
Primary tumor size (cm) 5–10 <5 1.43 (0.90–2.25) 0.138 1.66 (0.96–2.87) 0.070
>10 2.72 (1.71–4.32) <0.001 3.85 (2.00–7.40) <0.001
Primary tumor mitotic rate per 50 HPF >5 ≤5 1.91 (1.21–3.00) 0.005 - -
Histologic variant Epithelioid Spindle 1.25 (0.63–2.47) 0.526 1.09 (0.55–2.16) 0.811
Mixed 2.64 (1.50–4.66) <.001 2.1 (1.19–3.79) 0.011
Marginsb R1 R0 1.29 (0.63–2.65) 0.492 - -
Imatinib treatment Any None 1.78 (1.21–2.63) 0.004 1.11 (0.65–1.91) 0.693
Second Malignancyc Yes No 1.90 (1.30–2.77) <0.001 2.37 (1.49–3.76) 0.0003
a

Histologic variant was not routinely recorded in the pre-imatinib era.

b

R2 margins were excluded from this analysis of recurrence-free survival.

c

Any preceding or synchronous second malignancy

d

All statistically significant values from the univariate analysis were included in the initial multivariate model. The least significant values (p>0.05) were removed stepwise to provide the final strongest model which is shown. Although age and mitotic rate were significant univariately in the imatinib era, they were never significant on multivariate analysis. Imatinib treatment was left in the final model to adjust for any undetected treatment bias.