Discussion 
Assessment of accurate incidence and prevalence of pediatric cancer is limited by the absence of a central registry since low and middle income countries like Pakistan lack the resources and organization needed to establish effective population based cancer registries; these can also serve as public health surveillance tools to plan, monitor and measure cancer related services, research and education5. However, hospital based cancer registries can provide information about common cancers, localization, age groups, and treatment options available for patients as well as their response rates and survival outcomes to establish the exact need for cancer care services and health policy planning in that particular region6. For a reliable hospital based registry, coordination between the local oncologists and trained cancer registrars is required to find, abstract and register cases in an organized database. Collaborations with other centers catering to pediatric cancer patients in Pakistan to combine validated databases can facilitate improvements in survival outcomes and cancer care in that region and eventually lead to the formation of a proper population based registry.
Aga Khan University Hospital is one of the largest tertiary care hospitals in the country and has been maintaining a pediatric cancer registry since 2009. It is one of the primary referral centers for quality pediatric cancer care, making the registry data capable of commenting on commonly seen cancers in the population. For the time period 2010 to 2019, there was an increasing trend in the cases of pediatric cancers presenting each year with numbers almost doubling over the ten year period- this implies an increase in pediatric cancer incidence and could also be attributed to increased awareness and accessibility to healthcare services leading to prompt diagnosis and treatment initiation. A higher proportion of male patients (62%) was observed in our hospital and this is commonly seen globally such as in the 18 registries included in SEER (Surveillance, Epidemiology and End Results) as well as 162 out of 183 national registries evaluated Globocan 2018- this could be attributed to hormonal variations particularly for bone tumors although a combination of immune related, genetic and social factors could play a role7; 8. In the time period studied, leukemias(33%) were most commonly seen, followed by CNS tumors (17.8%) and lymphomas(11%); this proportion corresponds to Globocan’s estimates for the most common childhood cancers- leukemia and CNS tumors accounted for 45% of cases and 57% deaths according to the 2018 report7. Patterns of site-wise case distribution are also somewhat similar within Pakistan- data from a study reporting pediatric cancer cases from 3 centers within Pakistan between 2016 and 2018 also showed a male predominance and leukemia, lymphomas and retinoblastomas as the top three cancers9. The Punjab Cancer Registry, which collects cancer incidence from 27 collaborating centers within Punjab province reported acute lymphoblastic leukemia, glioma and Hodgkins lymphoma as the most commonly occurring childhood cancers in 202010. Globocan also reported most of the cases(42%) in the under-5 age group followed by the 5-9 age group- however, we had more patients (27%) between the ages of 15 and 19, followed by the under 5 age patients (23% cases).
Pediatric cancers mostly present with non specific signs and symptoms that can be easily attributed to more common, benign conditions, thus diagnosis and workup is often delayed, especially in resource limited settings like Pakistan where the sophisticated technology required to make accurate diagnoses is not available at most healthcare facilities coupled with a general lack of health awareness, cultural factors and financial constraints11. This is particularly concerning since Globocan ranked South-central Asia and Eastern Asia the highest for incidence of cancers in children (<19 years), with an incidence of over 143000 according to the 2020 estimates. Over the past few decades, overall survival of childhood cancer patients has improved from less than 30% to about 80% in high income countries12. However this number is much lower in Pakistan and other low and middle income countries. This burden is complex due to the number of intrinsic hurdles negatively affecting outcomes such as malnutrition, social access, lack of infrastructure to gain access to healthcare as well as lack of capital to build and maintain proper facilities.
The Global Initiative for Childhood Cancer, announced by the World Health Organization (WHO) aims to reach a 60% survival rate for pediatric cancer by 2030 and this can only be done with a special focus on cancer care in LMICs. To improve cancer care delivery systems especially in low resource countries, a continuous quality improvement system could help streamline existing resources for better utilization while simultaneously improving infrastructure and caregiver knowledge. Collaboration between institutions to identify gaps and implement local research with careful monitoring of outcomes could also increase long term survival.