Leukemia remains one of the most common and clinically significant hematological malignancies, with striking differences in its epidemiology across age groups. Worldwide, pediatric leukemia is the leading cancer of childhood, accounting for nearly one-third of childhood cancers, with acute lymphoblastic leukemia (ALL) being the most frequent subtype. In contrast, adult leukemias display a broader spectrum, with acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) being more frequent, while chronic lymphocytic leukemia (CLL) dominates in Western adult cohorts. These distinctions are not merely academic—they influence diagnosis, therapy, and prognosis, since age-specific patterns often dictate therapeutic choices and long-term outcomes.

In India, the epidemiological profile of leukemia diverges from Western populations. CML, for instance, is encountered more often in Indian adults compared with their Western counterparts, where CLL predominates. Similarly, Indian patients tend to present at younger ages, and hospital-based data often show higher proportions of acute leukemias, particularly in children. Regional variations within India add further complexity, as socioeconomic conditions, healthcare accessibility, and environmental exposures influence the distribution of subtypes and the stage at which patients present. Despite these differences, there is a scarcity of comparative studies that directly evaluate pediatric versus adult leukemias within the same population.

Understanding such age-based differences is crucial for multiple reasons. First, the clinical presentations often overlap with benign conditions like nutritional anemia or infections, which are common in resource-limited regions and can delay diagnosis. Second, the hematological parameters and subtype-specific distribution provide valuable insight into prognosis and guide therapeutic decisions. Third, comparing pediatric and adult leukemia within the same healthcare system provides a clearer understanding of diagnostic challenges and helps design regionally relevant protocols for timely diagnosis and treatment.

Against this backdrop, the present study analyzes 283 leukemia cases diagnosed over three years in Eastern Uttar Pradesh, dividing them into pediatric (≤18 years) and adult (>18 years) groups. By systematically comparing clinical and hematological profiles, this work aims to delineate key differences between the two cohorts, situate these findings in the context of Indian and international data, and highlight the diagnostic and therapeutic implications for clinicians working in similar resource-limited settings.

Study design and setting: This was a retrospective observational study conducted at a teaching hospital in Eastern Uttar Pradesh over a three-year period.

 Study population: A total of 283 patients diagnosed with leukemia were included. Patients were divided into two groups:

• Pediatric group (≤18 years): 142 patients.
• Adult group (>18 years): 141 patients.

Data collection: Demographic details, clinical features, hematological parameters (hemoglobin, total leukocyte count [TLC], platelet count), and leukemia subtype were extracted from hospital records. Subtype diagnosis was based on peripheral smear, bone marrow examination, and where available, cytochemistry and flow cytometry.

Statistical analysis: Data were summarized as frequencies, percentages, and mean ± SD. Pediatric and adult cohorts were compared descriptively, with emphasis on subtype distribution, hematological features, and sex ratio

Demographic Profile

Of 283 patients, 142 (50.2%) were pediatric and 141 (49.8%) adult. The overall male-to-female ratio was 2.1:1, consistent across both groups. Pediatric patients were mostly in the 6–15 years range, while adults spanned from the third to fifth decades, with some elderly cases.

Subtype Distribution

• Pediatric group: ALL was the predominant subtype (48.6%), followed by AML (20.4%), acute unclassified leukemia (25.3%), and rare cases of CML (5.7%).
• Adult group: CML was most common (36.9%), followed by AML (25.5%), acute unclassified leukemia (19.1%), ALL (12.1%), and CLL (6.4%).
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Table 1. Subtype Distribution of Leukemia in Pediatric vs. Adult Groups

Hematological Findings

Anemia was nearly universal, with mean hemoglobin lower in pediatric patients (7.4 g/dL) compared with adults (8.9 g/dL). TLC showed hyperleukocytosis in pediatric ALL and AML, while CML in adults presented with the highest leukocyte counts. Platelet counts were markedly reduced in pediatric ALL/AML, whereas adult CML patients often showed preserved or even elevated platelet counts.

Sex Distribution

Both groups showed a male predominance. In pediatric patients, males accounted for 62% of cases, while in adults, 68% were male.

Figure 1: Pie chart showing proportion of pediatric vs adult leukemia cases.

Figure 2: Bar chart comparing mean Hb, TLC, and platelet counts in pediatric vs adult groups.

Figure 3: Stacked bar chart showing subtype distribution by age group.

Leukemia continues to represent a diverse group of hematological malignancies with variable epidemiology and clinical manifestations across different age groups. The present study, analyzing 283 cases over a three-year period in Eastern Uttar Pradesh, provides valuable insight into the comparative patterns of pediatric and adult leukemia within a single institutional cohort. The results confirm several established trends while also highlighting region-specific variations that carry implications for both clinical practice and health policy. The age-stratified distribution revealed that nearly half of the cohort were children, emphasizing that leukemia remains a major burden in the pediatric population. ALL accounted for almost half of all childhood cases, while CML emerged as the most common subtype in adults, followed by AML. Such findings are broadly consistent with published data but also raise important points regarding delayed diagnosis, incomplete immunophenotyping, and access disparities in resource-limited settings.

The predominance of ALL in the pediatric population is in line with global observations. In Western populations, particularly data from the SEER program in the United States, ALL constitutes approximately 75% of childhood leukemias. Our proportion (48.6%) is lower, but similar to reports from Indian tertiary centers in Delhi, Chennai, and Vellore, which have reported pediatric ALL ranging between 45% and 55% of childhood leukemia. The discrepancy compared to Western data is partly due to the significant proportion of unclassified acute leukemias in our cohort (25.3%), many of which may have been ALL if diagnostic facilities such as immunophenotyping had been universally available. Earlier studies from North India have highlighted similar diagnostic challenges, underscoring the need to expand access to flow cytometry and molecular diagnostics in regional hospitals. The persistence of a large “acute unclassified” category hampers treatment decisions, as precise classification directly influences therapeutic regimens and outcomes.

AML accounted for 20.4% of pediatric cases in our series, a figure that is slightly higher than Western cohorts where AML represents 15% to 20% of childhood leukemias. This relative increase has also been observed in other Indian studies, where AML proportions among children reach 25% to 30%. Possible explanations include environmental risk factors such as pesticide exposure, higher prevalence of consanguinity, or referral bias toward tertiary hospitals. Clinically, pediatric AML patients presented with more profound cytopenias compared to adults, reflecting the aggressive biology and delayed presentation often seen in this setting. Our findings resonate with reports from South Indian centers where hyperleukocytosis and severe thrombocytopenia were frequent at diagnosis. The clinical implication is significant: pediatric AML requires rapid initiation of intensive chemotherapy, yet survival outcomes remain suboptimal in India due to resource limitations, delayed diagnosis, and treatment abandonment.

In adults, CML was the most frequent subtype, comprising 36.9% of cases. This observation is highly consistent with previous Indian studies but markedly contrasts with Western data, where CLL dominates the adult leukemia spectrum. For instance, registry data from Europe and the United States report CLL as the most common adult leukemia, with CML comprising less than 15%. In contrast, Indian studies from Delhi, Lucknow, and Mumbai consistently report CML as the leading adult subtype, with median age at diagnosis nearly a decade earlier than in Western patients. Our cohort reinforces this younger age of presentation, with most CML patients in their third and fourth decades. The introduction of TKIs has transformed CML outcomes globally, yet in low-resource regions, adherence, monitoring, and affordability remain major hurdles. Thus, while the epidemiological profile aligns with prior Indian data, the therapeutic challenges unique to this setting continue to influence long-term survival.

AML constituted 25.5% of adult cases, underscoring its importance as a significant contributor to morbidity and mortality across age groups. This is comparable to global data, where AML accounts for 25%–30% of adult leukemias. However, adult AML patients in our cohort often presented with markedly elevated leukocyte counts, suggestive of delayed diagnosis. Similar findings have been reported in tertiary centers across India, where lack of awareness and overlapping clinical features with infections or nutritional anemia often delay referral. Clinically, AML remains an aggressive disease with poor outcomes, and while targeted therapies are evolving in high-income countries, most Indian patients still rely on conventional chemotherapy regimens with variable success. This highlights the need for regional capacity building in diagnostics and supportive care to improve outcomes.

The relative scarcity of CLL in our adult cohort (6.4%) is another notable finding. This is consistent with Indian epidemiology, where CLL is far less common than in Western countries. While genetic predisposition may partly explain this discrepancy, underdiagnosis also contributes, as CLL often presents indolently and may go undetected without routine health screening. In contrast, CML and AML, with their more dramatic presentations, are more likely to be diagnosed in symptomatic patients. The clinical implication is that Indian oncologists must prepare for a larger burden of aggressive leukemias in adults, necessitating robust infrastructure for both acute management and long-term therapy.

Another recurring observation in our study was the significant male predominance across both pediatric and adult groups, with an overall male-to-female ratio of 2.1:1. While biological factors may contribute marginally, gender disparities in healthcare access are a more plausible explanation, especially in rural regions. Several Indian studies have documented underrepresentation of female patients in hospital data, reflecting societal biases that delay or prevent care-seeking for women. Addressing this imbalance requires community-level interventions, awareness campaigns, and efforts to reduce barriers to care for female patients. Beyond epidemiology, such disparities highlight broader inequities in health systems that must be addressed to achieve equitable cancer outcomes.

Hematological parameters further highlight age-specific differences. Pediatric ALL and AML patients demonstrated profound anemia and thrombocytopenia at diagnosis, while adult CML patients often had preserved platelet counts and extreme leukocytosis. These trends align with biological differences in disease presentation, but also serve as practical diagnostic clues for clinicians in resource-limited settings where advanced diagnostics may be unavailable. For instance, severe thrombocytopenia in a child with hyperleukocytosis strongly suggests acute leukemia, whereas extreme leukocytosis with splenomegaly in an adult is highly indicative of CML. Utilizing such patterns for early suspicion can expedite referrals and improve outcomes, particularly in peripheral centers with limited resources.

From a public health perspective, this study underscores the urgent need for improved diagnostic infrastructure in Eastern Uttar Pradesh and similar regions. A substantial fraction of cases remained unclassified due to lack of immunophenotyping, highlighting systemic gaps in diagnostic capabilities. Expanding access to flow cytometry and cytogenetic testing is critical not only for accurate diagnosis but also for tailoring therapy, as treatment protocols differ significantly between ALL and AML. Furthermore, strengthening supportive care, reducing treatment abandonment, and ensuring access to newer therapies like TKIs are essential steps to improving survival outcomes. Collaborative efforts between government agencies, tertiary hospitals, and international partners can help bridge these gaps.

In conclusion, the present study reinforces known global patterns—ALL dominating pediatric leukemia and CML/AML dominating adult cases—while also highlighting region-specific differences such as the lower proportion of CLL and higher proportion of unclassified acute leukemias. The clinical and epidemiological insights derived from this analysis emphasize the importance of age-stratified strategies, timely diagnosis, and expansion of diagnostic facilities. Future efforts must focus not only on improving treatment access but also on addressing gender disparities and public health barriers to ensure equitable care for leukemia patients in resource-limited settings.

Leukemia in Eastern Uttar Pradesh demonstrates distinct age-specific patterns. ALL predominates in children, while CML and AML are more frequent in adults. Anemia and thrombocytopenia were more severe in pediatric acute leukemias, while adults with CML presented with extreme leukocytosis. These findings emphasize the importance of age-based diagnostic and therapeutic approaches, as well as the urgent need to strengthen diagnostic capacity to ensure accurate classification and optimal management.

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