MKI67 and neuroendocrine neoplasm: Conversely, there was no association of the upfront PRRT approach with improved PFS in the grade 3 neuroendocrine tumor subgroup (aHR, 0.31; 95% CI, 0.12-1.37; P = .13) or in the group with tumors with a Ki-67 proliferation index greater than 10% (aHR, 0.73; 95% CI, 0.29-1.43; P = .31).