{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T11:38:21Z","timestamp":1785411501774,"version":"3.56.0"},"reference-count":30,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2026,7,18]],"date-time":"2026-07-18T00:00:00Z","timestamp":1784332800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["RS-2024-00341570"],"award-info":[{"award-number":["RS-2024-00341570"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"award":["RS-2024-00341570"],"award-info":[{"award-number":["RS-2024-00341570"]}],"id":[{"id":"https:\/\/ror.org\/013aysd81","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Ministry of Health & Welfare","award":["RS-2025-02223506"],"award-info":[{"award-number":["RS-2025-02223506"]}]},{"award":["RS-2025-02223506"],"award-info":[{"award-number":["RS-2025-02223506"]}],"id":[{"id":"https:\/\/ror.org\/00vxgjw72","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cancers"],"abstract":"<jats:p>Background\/Objectives: Testicular cancer (TC) is the most common solid malignancy in young males globally, yet population-level longitudinal data characterizing claims-based patient volume trends and co-occurring urological condition burden in South Korea remain limited. This study aimed to describe national trends in TC patient volume from 2020 to 2024, quantify exploratory associations with co-occurring urological and oncological conditions using aggregate annual counts, and generate exploratory 2026\u20132028 forecasts using validated statistical methods. Methods: We conducted a retrospective longitudinal analysis of administrative claims data from the Health Insurance Review and Assessment (HIRA) database of South Korea (2020\u20132024). Ten disease categories were analyzed: testicular cancer, bladder cancer, kidney cancer, prostate cancer, benign prostatic hyperplasia (BPH), chronic kidney disease (CKD), cystitis, neurogenic bladder, pyelonephritis, and carcinoma in situ. Annual patient counts, inpatient\/outpatient utilization, and healthcare costs were extracted. Pearson and Spearman correlations were computed between TC and co-occurring condition volumes. Forecasting for 2026\u20132028 used a three-method ensemble: ARIMA(1,1,0), linear regression with 95% prediction intervals, and Holt\u2013Winters exponential smoothing (weights: 0.35, 0.35, 0.30, respectively). The study was approved by the Institutional Review Board of Chungnam National University (IRB No. 202601-SB-014-01). All data were fully de-identified; informed consent was waived. Results: TC patient volume increased from 2309 in 2020 to 2992 in 2024 (compound annual growth rate [CAGR]: 6.69%). Exploratory ensemble forecasts projected 3287 (95% prediction interval [PI]: 2856\u20133540), 3767 (95% PI: 2962\u20133749), and 4531 (95% PI: 3066\u20133962) patients in 2026, 2027, and 2028, respectively, under a continued linear-trend assumption. TC patient volume showed strong positive exploratory correlations with CKD (r = 0.946, p &lt; 0.05), prostate cancer (r = 0.945), kidney cancer (r = 0.932), BPH (r = 0.932), carcinoma in situ (r = 0.937), and bladder cancer (r = 0.928); given n = 5 annual observations, these reflect parallel secular trends and must not be interpreted causally. Nine of ten analyzed conditions demonstrated increasing trends; pyelonephritis showed a negative CAGR (\u22121.37%). Conclusions: TC patient volume in South Korea increased substantially over 2020\u20132024, with exploratory forecasts projecting continued growth through 2028. Parallel upward trends in co-occurring urological and oncological conditions are consistent with shared secular drivers including population ageing and improved detection, though individual-level causal inference is not possible from aggregate claims data. These findings support claims-based trend monitoring, urological oncology resource planning, and hypothesis generation for future individual-level studies.<\/jats:p>","DOI":"10.3390\/cancers18142325","type":"journal-article","created":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T02:32:08Z","timestamp":1784514728000},"page":"2325","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Longitudinal Analysis of Testicular Cancer Patient Volume and Co-Occurring Urological Conditions Using the Health Insurance Review and Assessment (HIRA) Database in South Korea (2020\u20132024) with Exploratory Forecasts for 2026\u20132028"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-2428-2677","authenticated-orcid":false,"given":"Hyeran","family":"Jung","sequence":"first","affiliation":[{"name":"Department of Pathology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8701-4282","authenticated-orcid":false,"given":"Minsun","family":"Jung","sequence":"additional","affiliation":[{"name":"Department of Pathology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,18]]},"reference":[{"key":"ref_1","first-page":"417","article-title":"Global incidence and outcome of testicular cancer","volume":"5","author":"Shanmugalingam","year":"2013","journal-title":"Clin. 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