Table 2.

Risk of leukaemia, lymphoma and brain cancer by follow-up interval

	Observed/expected numbers of cancer and SIRs (95% CI)
	0–<6 months of follow-up		6 months–<5 years		5+ years
Lymphoid leukaemia*	15/2	6.2 (3.5 to 10.3)	27/16	1.7 (1.1 to 2.4)	8/10	0.8 (0.3 to 1.5)
Myeloid leukaemia†	7/<1	14.8 (6.0 to 30.6)	8/3	2.6 (1.1 to 5.2)	2/3	0.8 (0.1 to 2.7)
Hodgkin’s lymphoma‡	8/<1	60.8 (26.2 to 120)	2/1	1.4 (0.2 to 5.0)	6/8	0.7 (0.3 to 1.5)
Non-Hodgkin’s lymphoma§	5/<1	15.9 (5.2 to 37.2)	8/3	2.7 (1.2 to 5.3)	11/6	1.7 (0.9 to 3.0)
Brain¶	8/2	4.4 (1.9 to 8.7)	23/14	1.7 (1.1 to 2.5)	30/20	1.5 (1.0 to 2.2)

Some of the most frequent subtypes of cancer were as follows:

*42 of 50 children had precursor cell lymphoblastic leukaemia, not otherwise specified.

†10 of 17 children had acute myeloid leukaemia, not otherwise specified.

‡10 of 16 children had nodular sclerosis classical Hodgkin’s lymphoma.

§5 of 24 children had diffuse large B cell, not otherwise specified; 5 had mature T-cell lymphoma, not otherwise specified; 4 had Burkitt lymphoma, not otherwise specified and 4 had anaplastic large cell lymphoma.

¶15 of 61 children had glioblastoma; 8 had medulloblastoma, not otherwise specified, and 28 had other or unspecified brain cancer.

SIR, standardised incidence ratio.