Figure 2.

Patients at high risk of distant metastasis were identified through a decision-tree learning process. The first classification tree distinguished the presence versus absence of chromosome 8p loss. When this alteration was lacking, the risk of distant spread was trained according to chromosome 1p. When 1p was also lacking, the classification tree in patients harboring T3 to T4 tumors and monosomy 3 as consecutive decision node to classify the risk of distant metastasis. The high-risk group comprised (1) patients with chromosome 8p loss (regardless of tumor size); (2) patients harboring chromosome 1p loss; and (3) patients harboring T3 to T4 tumors and monosomy 3.