Discussion
The actual burden of childhood cancer in lower middle income countries
is unknown due to lack of population-based cancer registries. According
to GLOBOCAN’s 2020 estimates, South-central Asia and Eastern Asia have
the highest incidence of cancers in children (<19 years) with
over 143,000 new cases annually. The exact incidence and prevalence of
pediatric cancer cases in low and middle-income countries like Pakistan
are unknown due to a lack of resources needed to establish and maintain
a centralized national cancer registry; however, it is estimated that
around 8000 new pediatric cancer cases and diagnosed in Pakistan each
year accounting for almost 10% of the total reported cancer cases in
the country.[4] Overall survival of childhood cancer patients has
improved fairly over the last few decades, from less than 30% to about
80% in high-income countries owing to the introduction of aggressive
multimodal treatment protocols which include a combination of
chemotherapy, radiation, and surgery.[5] However, the overall
survival is much lower in Pakistan and other low and middle-income
countries due to a number of intrinsic hurdles negatively affecting
outcomes such as poor nutrition, lack of capital to build and maintain
proper facilities and train personnel as well as a lack of
infrastructure to gain access to healthcare. Radiation therapy is a
critical component of childhood cancer worldwide yet access, in terms of
equipment as well as geographic location, is limited in LMICs like
Pakistan where only few hospitals are treating pediatric cancer patients
in the entire country and only our institute utilizes general anesthesia
for planning and treatment of pediatric patients.[6] The
availability of expert manpower for pediatric radiation therapy remains
limited.
The Surveillance, Epidemiology, and End Results (SEER) registry of the
National Cancer Institute reported a decline in the use of RT for ALL,
NHL, and retinoblastoma from 1973 to 2008 as new prognostic groupings
lead to treatment with surgery alone or intensified chemotherapy for
certain patients instead of RT. However, the use of RT for
neuroblastoma, Wilms tumor, brain and bone cancer has declined slightly
over the years, but remained proportionately stable for AML, Hodgkin’s
lymphoma and soft tissue cancers.[7-9] Trends observed in our data
showed an increase in RT use for bone tumors, soft tissue tumors, and
Wilms tumor and a decrease in ALL patients as shown in Figure 3.
Improving pediatric oncology care can be achieved by determining the
actual burden of childhood cancer so that specific demands will be put
on the management of childhood cancer in an environment with limited
resources. The number of patients receiving RT at our institution has
increased steadily over the years, almost doubling over the 10-year
period, possibly reflecting the collaboration with pediatric oncologist
resulting in patient’s referral to radiotherapy and increase in
incidence of cancer cases as well as improvement in prompt
identification and treatment of such patients.
For safe and effective delivery of radiation, patients’ immobility for
15-20 minutes is required which can be difficult for children especially
in an unfamiliar environment of the radiation suite without parents or
caregivers around. Hence, anesthesia is routinely used for patients
under the age of 3, and sedation requirements decrease with increasing
age. Anesthesia use carries a major risk for complications including
‘failure to rescue’ from cardiopulmonary collapse, respiratory
depression or airway obstruction, or the need for emergent procedures
like intubation. However, we did not have any such adverse event
reported for our patients. Also, the long-term effects of repeated GA on
neurocognition are unknown and is a question for future research in our
region.[10] Equipment and drugs to safely deliver anesthesia are
costly and require a dedicated medical team including anesthesiologists,
pediatric nurses, and respiratory therapists.[11] A recent analysis
reported better tolerability of daily RT without anesthesia with the use
of AVATAR (Audiovisual-Assisted Therapeutic Ambience in Radiation
Therapy) during RT delivery. This unique approach has potential to
minimize the burden of health care staff and health care cost needed in
LMIC.[12]
Advances in multimodal therapy for childhood cancer have led to more
than 80% cure and survival rates for pediatric solid tumors but the
adverse effects of therapy may cause debilitating events and sometimes
poor quality of life beyond the primary disease process. The Childhood
Cancer Survivor Study (CCSS) estimated that 1 in 5 childhood cancer
survivors died after 30 years of survivorship with 1 in 10 deaths due to
treatment-related factors.[13] Radiotherapy-related late effects
include cardiac dysfunction, cognitive deficits, hypopituitarism,
cataracts, ototoxicity, spinal and bone growth abnormalities, pulmonary
fibrosis, bowel fibrosis, etc. A noteworthy point for pediatric cancers
remain the long term radiation induced effects which may adversely
impact the quality of life among childhood cancer survivors. These late
effects might be compromised neurocognitive functions, memory loss,
cataract formations, endocrine problems, bone weakness, and other
primary tumors. Subsequent neoplasms due to radiation exposure are the
major cause of no relapse-related mortality with the CCSS reporting a
20.5% 30-year cumulative incidence. Hence, it is important to screen
and monitor childhood survivors for late toxicity according to standard
guidelines and deliver a lower cumulative dose for fewer
treatment-related side effects. Our study reported different aspects of
radiation practices including age at treatment, body site(s) affected,
and radiation delivery with time has a potential to work on survivorship
issues of children treated with RT. This guides us on planning
survivorship program for these children tailored according to the common
body sites irradiated.
The World Health Organization’s Global Initiative for Childhood Cancer
goal to reach 60% survival rate for pediatric cancer by 2030 can only
be done with a special focus on cancer care in LMICs. This includes
establishing specialized pediatric RT units to alleviate the burden on
existing facilities. For a sustainable system, suitable equipment
including pediatric-specific immobilization devices, anesthesia
machines, etc. should be acquired, and adequate, trained staff including
radiation oncologists, clinical medical physicists, radiation therapy
technologists, and technical machine engineers should be hired.[14]
Staffing ratio and competency can improve over time to build capacity in
terms of patient numbers and RT techniques. Exchange of ideas between
experts at different institutions at combined forums such as tumor board
meetings, etc. could also help develop appropriate treatment protocols
for the maximum benefit of the patients. Clinical research and studies
on RT practices from LMIC are needed for the development of new
treatment strategies in children with cancer specifically applicable to
our region who do not enroll in clinical trials. To overcome the
challenges faced by LMIC, sharing our radiotherapy experience will help
in collaboration, and assistance from international organizations,
societies, and institutions to make an appreciable difference.