Fig. 6

Survival outcomes in the subgroups of the external data. a Kaplan–Meier survival curves of the optimal subgroup for chemotherapy. The treated patients in the validation set and untreated patients in the SEER data exhibit significant differences in terms of survival rates (p = 0.039). b Kaplan–Meier survival curves of the worst subgroup for chemotherapy. The treated patients in the validation set and untreated patients in the SEER data exhibit no significant differences in terms of survival rates (p = 0.128). However, the treated patients exhibit a similarly poor prognosis compared to the treated patients in the same subgroup in the SEER dataset