Assessing the global demand and supply of brachytherapy resources: a population-based observational study.

[BACKGROUND] Brachytherapy is a key component of cancer treatment, yet global access remains poorly characterised. We aimed to quantify worldwide demand and supply of brachytherapy resources and to identify inequities in access.

[METHODS] In this population-based observational study, cancer incidence for six cancers (prostate, vaginal, cervical, endometrial, and vulval cancers, and melanoma) in 185 countries was obtained from GLOBOCAN 2022. Data on brachytherapy centres was extracted from the Directory of Radiotherapy Centres (accessed May 7, 2024) and supplemented by a literature review when brachytherapy caseloads exceeded 500 patients per centre. Annual centre capacity was defined as 218 patients, based on HIC capacity. Countries were classified by World Bank income groups. Brachytherapy utilisation rates from the Collaboration for Cancer Outcomes Research and Evaluation model were applied to estimate demand in high-income countries (HICs). An adjusted model accounted for later-stage presentation in low-income countries (LICs) and middle-income countries (excluding prostate cancer since alternative treatments are available). Brachytherapy utilisation for vulval cancer was separately estimated. Euclidean analysis was used to calculate the average population-weighted travel distance to centres in areas with more than 608 people per km·.

[FINDINGS] 18 528 336 new cancer cases (excluding non-melanoma skin cancer) occurred in 185 countries in 2022, of which 708 948 were estimated to require brachytherapy, corresponding to a global brachytherapy utilisation rate of 3·8%. Cervical cancer accounted for the majority of brachytherapy indications (59·3%, n=420 090), followed by uterine (25·2%, n=178 584) and prostate cancer (11·5%, n=81 849), with smaller numbers for vaginal (2·0%, n=13 996), vulval (1·1%, n=7611), and ocular melanoma (1·0%, n=6817). Brachytherapy demand was met in most HICs (81·5%), some upper-middle-income countries (UMIC; 44·4%), few lower-middle-income countries (LMIC; 11·8%), and in no LICs. The regions with the biggest deficit were sub-Saharan Africa, eastern Asia, and south-eastern Asia. Utilisation rates were higher in LICs (10·4%) compared with LMICs (5·7%), UMIC (3·5%), and HICs (2·9%). Average population-weighted distance to the nearest centre was 68 km in HICs, 167 km in UMICs, 341 km in LMICs, and 551 km in LICs (p<0·0001).

[INTERPRETATION] Global access to brachytherapy remains profoundly unequal, with adequate coverage largely limited to HICs. Resource gaps are greatest in lower-income settings, where patients also travel farthest. Investment in new centres is urgently needed to reduce geographical and economic barriers to access.

[FUNDING] None.