Table 4.

Prognostic factors for progression-free survival (PFS) and overall survival (OS) using Cox models

	PFS			OS
	HR	95% CI	P value	HR	95% CI	P value
Age, ≥70 years	1.02	0.43 to 2.41	0.97	1.70	0.50 to 5.81	0.40
ECOG-PS, 1–2	2.21	0.77 to 6.38	0.14	1.32	0.34 to 5.05	0.68
Number of previous regimens, ≥2	1.11	0.43 to 2.88	0.83	1.34	0.34 to 5.17	0.68
Stage, IV or recurrence	1.49	0.60 to 3.69	0.39	1.59	0.47 to 5.45	0.46
Histology, squamous cell carcinoma	1.67	0.70 to 3.98	0.25	1.44	0.42 to 5.00	0.56
TPS, <50%	1.52	0.63 to 3.65	0.35	0.79	0.23 to 2.74	0.71
ΔTLP0−2, ≥60%	3.41	1.34 to 8.65	0.010	2.05	0.59 to 7.11	0.26
ΔTLP0−6, ≥50%*	31.4	3.55 to 276.7	0.0019	2.14	0.48 to 9.63	0.32

*N=22. Three patients did not undergo ¹⁸F-FLT PET at 6 weeks after treatment initiation because of early disease progression.

ECOG-PS, Eastern Cooperative Oncology Group performance status; TLP, total lesion proliferation; TPS, tumor proportion score.