Table 2.

Monitoring Studies: Sensitivities for Detecting Unsuspected Relapse

Study and Relapse	131I-MIBG Group (n = 22)		123I-MIBG Group (n = 91)		All Patients (N = 113)
	No./Total No.	%	No./Total No.	%	No./Total No.	%
131I-MIBG scan	14/22	64*	NA		NA
123I-MIBG scan	NA		75/91	82	NA
Bone marrow histology	13/22	59	25/89	28	38/111	34†
Bone scan	12/22	55	12/44	27	24/66	36†
CT chest/abdomen/pelvis	6/22	27	26/90	29	31/112	28†
CT head/orbits	3/14	21	16/73	22	19/87	22†
Urine catecholamines	9/21	43	14/76	18	23/97	24†
Months to relapse
First CR/VGPR group
Median	19		19		19
Range	10.5–36		8–53		8–53
Second CR/VGPR group
Median	14		15		15
Range	13–44‡		5–45		5–45

Abbreviations: ¹³¹I-MIBG, iodine-131–metaiodobenzylguanidine; ¹²³I-MIBG, iodine-123–metaiodobenzylguanidine; NA, not applicable; CT, computed tomography; CR/VGPR, complete remission/very good partial remission.

^*P = .1 when compared with ¹²³I-MIBG scan.

^†P < .001 when compared with ¹²³I-MIBG scan.

^‡Only three patients.