Prognosis

In the US, the estimated 5-year relative survival rate for ALL is 72.6% (2015-2021 data).[10]

​Outcome in adult patients is age-dependent. The estimated 5-year relative survival rate (2015-2021 data) is:[11]

  • 81.9% for patients aged <50 years

  • 45.3% for patients aged 50-64 years

  • 25.6% for patients aged 65 years and above

Prognostic factors

Negative prognostic features include older age, elevated white blood cell (WBC) count at presentation, failure to achieve a complete remission (CR), and adverse cytogenetic and molecular abnormalities.

Younger patients with WBC less than 30 × 10⁹/L (30,000/microlitre) and who respond to treatment within 4 weeks have the best prognosis.[1][98][174][175][176][177]

Individual risk depends on a variety of clinical and biological factors, including:

  • Age: among children, those aged <1 year are considered very high risk, those aged ≥10 years are considered high risk, and those aged 1-9 years are considered standard risk.[84][178]​​ Adults aged >35 years are considered high risk, although the impact of age is a continuous variable.[85][86]

  • WBC count at presentation: a continuous variable, >30 × 10⁹/L (>30,000/microlitre) for B-ALL and >100 × 10⁹/L (>100,000/microlitre) for T-ALL are considered high risk for adults, and >50 × 10⁹/L (>50,000/microlitre) for B-ALL is considered high risk for children.[84]

  • Cytogenetic and molecular abnormalities. See  Diagnostic criteria.

  • Immunophenotypic subtype: CD20 expression and early T-cell precursor (ETP)-ALL subtype (negative for CD5, CD8, and CD1a and positive for one or more myeloid/stem cell markers) is associated with a poor prognosis.[87][89]

  • Response to induction therapy: patients receiving induction therapy who do not achieve a CR, or who respond poorly, are considered high risk.

  • Presence of measurable residual disease (MRD; e.g., ≥0.01%) following induction therapy: persistent MRD after induction is associated with poor outcomes.[88]

Central nervous system (CNS) involvement

CNS involvement is a major complication of ALL occurring in 5% to 7% of patients at diagnosis; incidence is higher in patients with T-ALL (8%) and mature B-ALL (Burkitt's lymphoma/leukaemia, 13%).[9][55][56]​​[57][58]​ CNS involvement can lead to severe neurological morbidity (i.e., cranial nerve palsies), and is a major obstacle to cure, accounting for up to 40% of initial relapses in clinical trials.[90][91][92]​ Studies have shown that use of intensive regimens in patients with CNS involvement at diagnosis results in similar outcomes (i.e., CR, disease-free survival, and overall survival) to patients without CNS involvement at diagnosis, particularly among adults.[55][56][93][94][95][96]​ However, outcomes are often poor in patients with CNS relapse (median overall survival <1 year).[97] Patients with CNS involvement (particularly CNS relapse) usually warrant consideration for post-remission allogeneic SCT.[74][82]​​

Relapse/refractory disease

The prognosis in relapsed or refractory disease is generally poor. Median survival is less than 1 year, and less than 25% of patients survive in the long term.[145]

Long-term survival is dependent upon attaining a complete remission (CR) with subsequent allogeneic stem cell transplantation (SCT).

An individual's risk depends on a variety of clinical and biological factors including:[179][180][181]

  • Age: younger patients are more likely to attain a CR and have better survival.

  • Long duration of first CR: survival is better for those whose duration of first remission is more than 2 years.

  • Site of relapse: if there is involvement of additional sites.

  • Status of disease at SCT: patients who underwent SCT in CR after salvage did better than those who were not in CR at the time of SCT. Patients who achieve MRD-negative remission with salvage therapy prior to SCT may also have better outcomes, but this has not been definitively established in a prospective trial.

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