Outcomes among survivors of childhood cancer in low- and middle-income countries: A systematic review.

Abstract

10057 Background: Low- and middle-income countries (LMICs) account for most of the global childhood cancer burden. Though cure rates lag behind those in high-income countries (HICs), a substantial proportion of LMIC children do survive. Long-term side effects of cancer or cancer therapy (late effects) are well-documented among childhood cancer survivors (CCS) in HICs, but whether prevalence and risk factors of late effects are comparable in LMICs is unclear. We thus conducted a systematic review to assess LMIC CCS outcomes. Methods: Five major health sciences databases were searched from inception to November 2022 in all languages. We included observational studies conducted in LMICs (World Bank 2021 classification) that evaluated outcomes in CCSs diagnosed with any malignancy. Mean or median length of follow-up must have been ≥ 5 years from original cancer diagnosis. Meta-analyses were precluded by cohort and outcome heterogeneity. Results: Of 1,994 studies identified, 113 underwent full-text review and 21 met inclusion criteria (16 full articles and 5 conference abstracts). Studies were conducted in lower-middle income (N = 12, 57%) or upper-middle income (N = 9, 43%) countries; no low-income country data were found. Study regions were mainly South and East Asia (N = 10, 48%) and the Americas (N = 8, 38%). Almost half (N = 9, 43%) of studies were conducted in India and only one African study from Cameroon was identified. Over half (N = 12, 57%) of studies were cross-sectional in design. Only five (24%) cohorts were comprised entirely of 5-year survivors. CCS of all childhood cancer types were evaluated in 12 (57%) cohorts, and 9 (43%) were specific to one cancer type. Ten (48%) studies were conducted in a survivorship clinic. Second cancers, followed by endocrine, reproductive, and cardiovascular late effects were most frequently assessed. Second cancers were reported in 1%–11% of CCS cohorts (N = 10 studies). The prevalence of hypothyroidism and metabolic syndrome ranged from 2%-49% (N = 6 studies) and 4%-17% (N = 5 studies), respectively. Gonadal dysfunction ranged from 2%-82% (N = 6 studies). Cardiac dysfunction and hypertension ranged from 1%-16% (N = 3 studies) and 5-19% (N = 3 studies), respectively. Late effects of the musculoskeletal (N = 4 studies) and urinary (N = 4 studies) systems were least investigated. Conclusions: Substantial knowledge gaps exist in LMIC childhood cancer survivorship. Few LMIC-based studies were identified, with no low-income country data available. In middle-income countries, variability existed in how late effects were defined and assessed; data was also limited by selection bias and small sample sizes. Additional systematically collected data on LMIC CCS cohorts are urgently needed.