Leukaemia diagnosed in the first month of life: a different presentation and a different prognosis
also called congenital ALL · neonatal leukaemia · first month of life leukaemia · congenital leukaemia outcome
ALL diagnosed in the first month of life is rarer, comes with higher white counts, and relapses far more often than in older babies - 60% within two years against 34%. But it is not automatically fatal: about one child in five was alive at two years on a standard infant protocol, and the toxicity was no worse, which is why these newborns are treated with the intention of curing them.
The same thing, for a scientist
Congenital ALL - diagnosed in the first month of life - was assumed fatal until 30 uniformly treated patients were reported from Interfant-99 [E1]. That analysis establishes four things. Presentation differs: higher white cell count, and a strong trend towards a higher incidence of MLL/KMT2A rearrangement and CD10-negative B-lineage disease compared with older infants. Induction failure did **not** differ (13% vs 7%, p = 0.14). Relapse did: 2-year cumulative incidence 60.0% (SE 9.3) against 34.2% (SE 2.3), p < 0.001. Two-year event-free survival and survival were both 20% (SE 9.1), with 17% alive at last follow-up. Early death in complete remission and treatment delays from toxicity were **not** different from older infants, which is the finding that justifies curative-intent treatment [E1]. Separately, neonatal leukaemia as a whole is more often myeloid than lymphoid, has high mortality, and presents with hepatosplenomegaly, leukaemia cutis and/or hyperleucocytosis, with congenital infection to be excluded first [E2]. Within infancy generally, age under 6 months is an independent adverse factor in Interfant-99 [E3], and in CCCG-ALL-2015 age under 3 months was associated with inferior event-free survival among KMT2A-rearranged patients [E4].
The Interfant-99 congenital series, the only uniformly treated cohort
| Endpoint | Congenital ALL (n = 30) | Older infants |
|---|---|---|
| Induction failure | 13% | 7% (p = 0.14) |
| 2-year cumulative incidence of relapse | 60.0% (SE 9.3) | 34.2% (SE 2.3), p < 0.001 |
| 2-year EFS | 20% (SE 9.1) | - |
| 2-year survival | 20% (SE 9.1) | - |
| Early death in complete remission | not different | - |
| Treatment delay from toxicity | not different | - |
The shape of this table is the point. The congenital disadvantage is entirely in relapse, not in getting into remission and not in tolerating the treatment 1. An infant in the first month of life can be got into remission about as often as a six-month-old and can take the chemotherapy about as well; the disease then comes back roughly twice as often. That locates the problem in disease biology and in post-remission therapy, not in supportive care - which is the opposite of where the problem sits for the rest of the infant age range (see concept-induction-mortality-and-infection-infant-all).
The age gradient does not have one cut-point
Three different protocols use three different ages to define the youngest high-risk group:
- Interfant-99 and Interfant-06: 6 months 3
- CCCG-ALL-2015 multivariable analysis within KMT2A-rearranged patients: 3 months was the factor associated with inferior EFS 4
- COG AALL0631 eligibility: under 366 days; the historical COG high-risk line is 90 days 5
These are administrative choices. Age at diagnosis is continuous, and in a disease whose cell of origin is a fetal progenitor, the biologically meaningful variable is probably time since the initiating event in utero, which nobody can measure. Any statement of the form 'infants under X months do worse' carries the size of its effect from where X was put.
The diagnostic trap at the front door
A neonate with hepatosplenomegaly and skin lesions is a congenital-infection presentation until the blood count says otherwise 2. Leukaemoid reactions, transient abnormal myelopoiesis in Down syndrome, and congenital infection all mimic it. The discriminating investigations are the full blood count and film, then flow cytometry and KMT2A testing - and a 2026 neonatal case with the complete clinical triad had no KMT2A rearrangement on molecular testing 6, so the clinical picture does not identify the genotype.
| metric | outcome by age stratum within infancy |
|---|---|
| population | infants <1 year with ALL |
congenital interfant99
{
"n": 30,
"induction_failure_pct": 13,
"comparator_induction_failure_pct": 7,
"p": 0.14,
"relapse_2y_cip_pct": 60,
"relapse_2y_cip_se": 9.3,
"comparator_relapse_2y_cip_pct": 34.2,
"comparator_se": 2.3,
"p_relapse": "<0.001",
"efs_2y_pct": 20,
"efs_2y_se": 9.1,
"survival_2y_pct": 20,
"alive_last_followup_pct": 17,
"pmid": "19657114",
"nct": "NCT00015873",
"title": "Outcome of congenital acute lymphoblastic leukemia treated on the Interfant-99 protocol.",
"authors": "van der Linden MH, Valsecchi MG, De Lorenzo P, et al.",
"venue": "Blood",
"year": 2009,
"title_provenance": "Title/authors/venue backfilled from PubMed esummary on 2026-09-20 because this citation stored a bare PMID with no title, which made it unscoreable by verify-citations.py. BACKFILLING IS NOT VERIFICATION: it confirms the PMID resolves to a real paper, not that this is the right paper for the claim. That still requires reading."
}age cutpoints in use
[
{
"protocol": "Interfant-99/06",
"months": 6
},
{
"protocol": "CCCG-ALL-2015 KMT2A-r analysis",
"months": 3
},
{
"protocol": "COG AALL0631 eligibility",
"days": 366
}
]- A congenital cohort whose relapse rate is 60% at two years will make any new agent look effective on early endpoints and then fail at two years, so single-arm pilots in this group are especially prone to over-promise.
- Because toxicity and induction death are no worse in congenital ALL, there is a standing temptation to intensify for this group; the Interfant-21 experience of reverting dosing after excess infectious deaths shows how that temptation resolves in practice.
- Neonatal organ immaturity changes the pharmacokinetics of almost every agent in the backbone, so a dose that is safe at six months is not automatically safe at six days, and no infant trial has pharmacokinetic data at that age.
- Why is congenital ALL's disadvantage confined to relapse when induction failure and toxicity are comparable? The answer would say whether the target is the disease or the consolidation.
- Is age at diagnosis in infant ALL a proxy for time since the in-utero initiating event, and could breakpoint or clonal-diversity measures estimate that directly?
- Would a continuous model of age outperform the 6-month and 3-month dichotomies now used to stratify infants, and how much of the reported age effect is created by the cut-point?
- E1strong confidence 4 of 5: Replicated in peer-reviewed work by more than one group.paper
In 30 patients with congenital ALL treated on Interfant-99, presentation featured a higher white cell count and a strong trend to more MLL rearrangement and CD10-negative B-lineage disease; induction failure was 13% vs 7% in older infants (p = 0.14), 2-year cumulative incidence of relapse was 60.0% (SE 9.3) vs 34.2% (SE 2.3) (p < 0.001), and 2-year EFS and survival were both 20% (SE 9.1), with toxicity and early death in remission no different from older infants.
Outcome of congenital acute lymphoblastic leukemia treated on the Interfant-99 protocol. · van der Linden MH, Valsecchi MG, De Lorenzo P, Moricke A, Janka G, Leblanc TM, et al. · Blood 2009What this evidence cannot show
n = 30 across an international trial, so all congenital estimates have wide intervals (SE 9.3 on the relapse incidence, SE 9.1 on EFS). The comparison with older infants is within-trial but not randomised and congenital patients differ in every measured baseline factor. The non-significant induction-failure difference (p = 0.14) at n = 30 is an underpowered comparison, not evidence of equivalence. Abstract read; full text not retrieved.
Evidence that argues against this (1)
- The finding that toxicity was 'not different' rests on 30 patients and is exactly the kind of null that an underpowered comparison produces; a real toxicity excess of clinically important size would not have been detectable here. Salzer WL et al. 2015
- E2strong confidence 4 of 5: Replicated in peer-reviewed work by more than one group.review
Neonatal leukaemia is rare, is more often myeloid than lymphoid, carries high mortality, typically presents with hepatosplenomegaly, leukaemia cutis and/or hyperleucocytosis, and requires congenital infection to be excluded before diagnosis; MLL rearrangement is the commonest genetic aberration.
Diagnosis and management of neonatal leukaemia. · van der Linden MH, Creemers S, Pieters R · Semin Fetal Neonatal Med 2012What this evidence cannot show
Narrative review with no denominator for any of the frequencies described as typical. Covers AML and ALL together, and the two have different presentations and prognoses, with AML the better of the two in this age group.
Evidence that argues against this (1)
- The Interfant-99 congenital ALL series, which is the actual cohort evidence, characterises congenital disease primarily by white cell count and immunophenotype and not by the skin sign that the review leads with. van der Linden MH et al. 2009
- E3established confidence 5 of 5: Multiple independent lines of evidence; treated as settled in the field.paper
In Interfant-99 (n = 482) age younger than 6 months was independently associated with inferior outcome, alongside MLL rearrangement, very high white cell count and poor prednisone response.
A treatment protocol for infants younger than 1 year with acute lymphoblastic leukaemia (Interfant-99): an observational study and a multicentre randomised trial. · Pieters R, Schrappe M, De Lorenzo P, Hann I, De Rossi G, Felice M, et al. · Lancet 2007What this evidence cannot show
The 6-month line is a protocol-defined dichotomy of a continuous variable; the abstract reports no continuous or spline analysis of age. Full text paywalled.
Evidence that argues against this (1)
- CCCG-ALL-2015 found age under 3 months, not under 6 months, to be the factor associated with inferior EFS among KMT2A-rearranged infants, which shows the apparent age effect moves with where the line is drawn. Leung AWK et al. 2024
- E4moderate confidence 3 of 5: One strong study, or several smaller consistent ones.paper
Among KMT2A-rearranged infants in CCCG-ALL-2015, age under 3 months and MRD positivity at day 19 and day 49 were associated with inferior event-free survival; only day-19 MRD above 0.01% remained significant in multivariable analysis.
Outcome of infants with acute lymphoblastic leukemia treated with the Chinese Children's Cancer Group Acute Lymphoblastic Leukemia 2015 study protocol. · Leung AWK, Cai J, Wan Z, Qin J, Fang Y, Sun L, et al. · Haematologica 2024What this evidence cannot show
71 KMT2A-rearranged patients, of whom the under-3-month group is a small subset whose size is not given in the letter. The cohort under-enrolled infants under six months (18.4% against 50-68% elsewhere), so the youngest stratum is especially thin. Read in the open-access full text at PMC11290514.
Evidence that argues against this (1)
- In the same analysis the age effect did not survive multivariable adjustment while MRD did, so age under 3 months may be a proxy for early MRD response rather than an independent factor. Tomizawa D et al. 2020
- E5established confidence 5 of 5: Multiple independent lines of evidence; treated as settled in the field.paper
COG AALL0631 enrolled infants under 366 days of age with newly diagnosed ALL.
Decreased induction morbidity and mortality following modification to induction therapy in infants with acute lymphoblastic leukemia enrolled on AALL0631: a report from the Children's Oncology Group. · Salzer WL, Jones TL, Devidas M, Dreyer ZE, Gore L, Winick NJ, et al. · Pediatr Blood Cancer 2015What this evidence cannot show
An eligibility boundary, not a biological one; 366 days is the operational definition of 'infant' and differs from the under-1-year and under-12-month wording used by other groups in ways that matter at the margin.
Evidence that argues against this (1)
- That three cooperative groups use three different age boundaries for the same disease concept is itself evidence that none of them is biological. Pieters R et al. 2019
- E6weak confidence 2 of 5: Preliminary, small, indirect, or not yet peer reviewed.paper
A 7-day-old neonate presenting with the full clinical triad of extreme hyperleukocytosis, purpuric skin lesions and severe cytopenias had negative molecular testing for KMT2A rearrangements and other recurrent fusion genes.
Extreme hyperleukocytosis and blueberry muffin skin lesions as the initial presentation of neonatal leukemia: a case report. · Bustamante-Ordonez MA, Macavilca-Toribio MA, Arenas-Vasquez JR, Roman-Lazarte V, Zavaleta-Corvera C, Samanez-Obeso A · BMC Pediatr 2026What this evidence cannot show
A single case. Negative fusion testing by a targeted panel returns negative for every partner the panel was not designed around, so 'no KMT2A rearrangement' here means 'not detected by the assay used', and the assay is not described in the abstract.
Evidence that argues against this (1)
- A targeted RT-PCR or FISH panel can miss a cryptic or unusual-partner KMT2A rearrangement, so this case is weak evidence that the clinical triad can occur without KMT2A involvement rather than proof of it. van der Linden MH et al. 2012
the first-month-of-life stratum of infant ALL
30 congenital ALL patients treated uniformly on Interfant-99
the skin sign peaks in the neonatal window
congenital disease presents with higher white cell counts
three protocols use three different age lines within infancy
- ← supportsWhen infant leukaemia comes back, it comes back early and while treatment is still running
congenital ALL's 60% two-year relapse incidence is the extreme of the gradient