Fig. 3

a Total proportion of re-biopsy feasibility at RECIST-PD and clinical-PD Re-biopsy feasibility may increase with disease progression. At RECIST-PD, 55, 13, and 32% of lesions were category A, B, and C, respectively. At clinical-PD, 74, 10, and 16% were category A, B, and C, respectively. b Comparison of re-biopsy feasibility at primary and metastatic lesions Re-biopsy for primary lesions was evaluated as category A in all cases, both at RECIST-PD and clinical-PD. However, the feasibility of re-biopsy of relapsed lesions in metastatic disease varies among patients and re-biopsy becomes less complex as progressive or relapsed lesions develop in the clinical course. Re-biopsy may be highly invasive or complex (category C) in some patients with metastatic relapse, even at clinical-PD