[18F] Positron emission tomography response after rituximab-containing induction therapy in follicular lymphoma is an independent predictor of survival after adjustment for FLIPI in academic and community-based practice

Figures & data

Table 1. Demographics and characteristics of evaluable and propensity score-matched patients.

		Evaluable patients			Propensity score-matched patients
Variable	Statistics or category	PET ± CT(n = 447)	CT alone(n = 537)	p Value*	PET ± CT(n = 361)	CT alone(n = 361)	p Value*
Age (years)	≤60	247 (50%)	250 (50%)	0.0478	186 (50%)	184 (50%)	0.8973
	61–70	108 (43%)	146 (57%)		92 (51%)	90 (49%)
	71–80	70 (40%)	105 (60%)		63 (50%)	62 (50%)
	>80	22 (38%)	36 (62%)		20 (44%)	25 (56%)
Gender	Female	241 (46%)	286 (54%)	0.8372	197 (51%)	186 (49%)	0.4121
	Male	206 (45%)	251 (55%)		164 (48%)	175 (52%)
Race	White	404 (45%)	485 (55%)	0.7914	322 (50%)	322 (50%)	0.9048
	African American	19 (50%)	19 (50%)		18 (55%)	15 (45%)
	Hispanic	17 (40%)	26 (60%)		14 (45%)	17 (55%)
	Other	7 (50%)	7 (50%)		7 (50%)	7 (50%)
Histology by grade	Follicular Grade 1 or 2	277 (41%)	396 (59%)	< 0.0001	238 (50%)	241 (50%)	0.8911
	Follicular Grade 3	122 (59%)	85 (41%)		81 (50%)	80 (50%)
	Missing	48	56		42	40
FLIPI risk group	Good (0–1)	81 (42%)	113 (58%)	0.3111	66 (49%)	68 (51%)	0.8911
	Intermediate (2)	138 (49%)	145 (51%)		110 (53%)	96 (47%)
	Poor (3–5)	161 (45%)	196 (55%)		130 (49%)	137 (51%)
	Missing	67	83		55	60
Stage	Stage II	69 (43%)	92 (57%)	0.4740	55 (51%)	52 (49%)	0.7533
	Stage III or IV	378 (46%)	445 (54%)		306 (50%)	309 (50%)
LDH	Normal	258 (44%)	329 (56%)	0.0951	214 (51%)	206 (49%)	0.4906
	>ULN	102 (51%)	99 (49%)		72 (48%)	79 (52%)
	Missing	87	109		75	76
Hemoglobin	<12 g/dL	110 (47%)	125 (53%)	0.6453	87 (48%)	94 (52%)	0.5152
	≥12 g/dL	321 (45%)	391 (55%)		260 (51%)	251 (49%)
	Missing	16	21		14	16
Nodal sites	<5	224 (42%)	305 (58%)	0.0338	189 (50%)	190 (50%)	0.9399
	≥5	213 (49%)	220 (51%)		165 (50%)	164 (50%)
	Missing	16	21		7	7
Extra-nodal sites	None	169 (46%)	195 (54%)	0.2694	131 (49%)	136 (51%)	0.8645
	1	114 (42%)	201 (58%)		130 (51%)	123 (49%)
	≥2	123 (48%)	134 (53%)		95 (50%)	96 (50%)
	Missing	11	7		5	6
ECOG	0: 100–90	214 (50%)	216 (50%)	0.2946	159 (50%)	158 (50%)	0.7092
	1: 80–70	106 (46%)	126 (54%)		84 (47%)	93 (53%)
	≥2: 60–10	15 (38%)	24 (62%)		14 (44%)	18 (56%)
	Missing	112	171		104	92
B symptoms	Yes	145 (47%)	166 (53%)	0.6082	115 (49%)	120 (51%)	0.6913
	No	302 (45%)	371 (55%)		246 (51%)	241 (49%)
Bone marrow involvement	Yes	166 (46%)	197 (54%)	0.3773	135 (51%)	132 (49%)	0.7451
	No	201 (49%)	210 (51%)		156 (49%)	161 (51%)
	Missing	80	130		70	68
Geographic region	Midwest	112 (36%)	202 (64%)	< 0.0001	103 (50%)	101 (50%)	0.9924
	Northeast	60 (49%)	63 (51%)		49 (50%)	49 (50%)
	Southeast	166 (46%)	193 (54%)		141 (49%)	145 (51%)
	Southwest	53 (67%)	26 (33%)		28 (53%)	25 (47%)
	West	56 (51%)	53 (49%)		40 (49%)	41 (51%)
Center type	Academic	72 (39%)	113 (61%)	0.0485	68 (49%)	70 (51%)	0.8499
	Community	375 (47%)	424 (53%)		293 (50%)	291 (50%)
Induction treatment	R-monotherapy	49 (31%)	111 (69%)	< 0.0001	46 (49%)	48 (51%)	0.8249
	R-chemotherapy	398 (48%)	426 (52%)		315 (50%)	313 (50%)
	R-CHOP	232 (54%)	201 (46%)	0.0071	175 (51%)	166 (49%)	0.8713
	R-CVP	91 (45%)	109 (55%)		76 (49%)	80 (51%)
	R-Flu	53 (41%)	77 (59%)		45 (47%)	50 (53%)
	R-Other	22 (36%)	39 (64%)		19 (53%)	17 (47%)
Duration of induction treatment	≤84 days	67 (34%)	133 (67%)	0.0006	58 (48%)	63 (52%)	0.6188
	85–126 days	226 (48%)	248 (52%)		181 (49%)	188 (51%)
	>126 days	154 (50%)	156 (50%)		122 (53%)	110 (47%)

* Pearson chi-squared test.

CT: computed tomography; ECOG: Eastern Cooperative Oncology Group; FLIPI: Follicular Lymphoma International Prognostic Index; LDH: lactate dehydrogenase; PET: positron emission tomography; R-CHOP: rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone; R-CVP: rituximab plus cyclophosphamide: vincristine, and prednisone; R-Flu: rituximab plus fludarabine; R-Other: rituximab plus other chemotherapy; ULN: upper limit of normal.

Table 2. Five-year survival for the whole cohort and propensity score-matched cohort.

	Evaluable patients		Propensity score-matched patients
Imaging response	OS (%)	PFS (%)	OS (%)	PFS (%)
PET-negative	88	65	88	65
PET-positive	78	51	77	53
CT-negative	87	64	87	65
CT-positive	78	54	77	57

CT: computed tomography; OS: overall survival; PET: positron emission tomography; PFS: progression-free survival.

Table 3. Hazard ratios for survival via PET and CT response.

	Evaluable patients, unadjusted		Evaluable patients, FLIPI-adjusted		Propensity score-matched patients
	Comparison	OS HR (95% CI)	PFS HR (95% CI)	OS HR (95% CI)	PFS HR (95% CI)	OS HR (95% CI)	PFS HR (95% CI)
CT-negative	Ref	Ref	Ref	Ref	Ref	Ref
CT-positive	1.61 (1.13, 2.29)	1.45 (1.12, 1.89)	1.38 (0.96, 1.97)	1.34 (1.03, 1.75)	1.76 (1.15, 2.69)	1.32 (0.96, 1.82)
PET-negative	Ref	Ref	Ref	Ref	Ref	Ref
PET-positive	1.78 (1.16, 2.72)	1.63 (1.21, 2.20)	1.54 (1.01, 2.36)	1.54 (1.14, 2.07)	1.94 (1.22, 3.08)	1.48 (1.06, 2.07)
CT-negative					Ref	Ref
PET-negative	–	–	–	–	0.80 (0.49, 1.31)	0.99 (0.71, 1.38)
CT-positive	–	–	–	–	Ref	Ref
PET-positive					0.88 (0.58, 1.35)	1.10 (0.78, 1.55)

CI: confidence interval; CT: computed tomography; FLIPI: Follicular Lymphoma International Prognostic Index; HR: hazard ratio; OS: overall survival; PET: positron emission tomography; PFS: progression-free survival; Ref: reference.