Development and validation of a prognostic nomogram for recurrence-free survival after complete surgical resection of localised primary gastrointestinal stromal tumour: a retrospective analysis.
BACKGROUND
Adjuvant imatinib mesylate prolongs recurrence-free survival (RFS) after resection of localised primary gastrointestinal stromal tumours (GIST). We aimed to develop a nomogram to predict RFS after surgery in the absence of adjuvant therapy to help guide patient selection for adjuvant imatinib therapy.


METHODS
A nomogram to predict RFS based on tumour size (cm), location (stomach, small intestine, colon/rectum, or other), and mitotic index (<5 or > or =5 mitoses per 50 high-power fields) was developed from 127 patients treated at Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY, USA. The nomogram was tested in patients from the Spanish Group for Research on Sarcomas (GEIS; n=212) and the Mayo Clinic, Rochester, MN, USA (Mayo; n=148). The nomogram was assessed by calculating concordance probabilities and testing calibration of predicted RFS with observed RFS. Concordance probabilities were also compared with those of three commonly used staging systems.


RESULTS
The nomogram had a concordance probability of 0.78 (SE 0.02) in the MSKCC dataset, and 0.76 (0.03) and 0.80 (0.02) in the validation cohorts. Nomogram predictions were well calibrated. Inclusion of tyrosine kinase mutation status in the nomogram did not improve its discriminatory ability. Concordance probabilities of the nomogram were better than those of the two NIH staging systems (0.76 [0.03] vs 0.70 [0.04, p=0.04] and 0.66 [0.04, p=0.01] in the GEIS validation cohort; 0.80 [0.02] vs 0.74 [0.02, p=0.04] and 0.78 [0.02, p=0.05] in the Mayo cohort) and similar to those of the AFIP-Miettinen staging system (0.76 [0.03] vs 0.73 [0.004, p=0.28] in the GEIS cohort; 0.80 [0.02] vs 0.76 [0.003, p=0.09] in the Mayo cohort). Nomogram predictions of RFS seemed better calibrated than predictions made with the AFIP-Miettinen system.


CONCLUSIONS
The nomogram accurately predicts RFS after resection of localised primary GIST and could be used to select patients for adjuvant imatinib therapy.
Department of Surgery VA Boston Healthcare System/Brigham and Women's Hospital West Roxbury, MA, USA.
Jason S
JS
Gold
Mithat
M
Gönen
Antonio
A
Gutiérrez
Javier Martín
JM
Broto
Xavier
X
García-del-Muro
Thomas C
TC
Smyrk
Robert G
RG
Maki
Samuel
S
Singer
Murray F
MF
Brennan
Cristina R
CR
Antonescu
John H
JH
Donohue
Ronald P
RP
DeMatteo
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D017024:Chemotherapy, Adjuvant; D002648:Child; D013505:Digestive System Surgical Procedures; D018572:Disease-Free Survival; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy / Q000401:mortality / Q000556:secondary / Q000601:surgery*; D006801:Humans; D000068877:Imatinib Mesylate; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D008940:Mitotic Index; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D049451:Nomograms; D018579:Patient Selection; D010879:Piperazines / Q000627:therapeutic use*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use*; D011743:Pyrimidines / Q000627:therapeutic use*; D012042:Registries; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D013030:Spain / Q000453:epidemiology; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D055815:Young Adult
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D000068877:Imatinib Mesylate