---
title: Korea diagnoses thyroid cancer too early and prostate cancer too late. Half of prostate cases are already high-risk when found
publication: Medical Insights Korea
section: news
category: Prostate
canonical_url: https://medicalinsightskorea.com/news/korea-prostate-cancer-high-risk-at-diagnosis
author: Andrew Cho
published: 2026-09-02T11:10:00+09:00
modified: 2026-09-02T11:10:00+09:00
content_type: reporting
license: Quotation permitted with attribution to Medical Insights Korea and a link to the canonical URL.
---

# Korea diagnoses thyroid cancer too early and prostate cancer too late. Half of prostate cases are already high-risk when found

In 27,075 biopsy-confirmed cases from 51 hospitals, 53.9 percent were high-risk at diagnosis and the low-risk share fell from 11.4 to 7.6 percent over a decade. Rural men fared worse than urban ones.

## Answer

Among 27,075 men with biopsy-confirmed prostate cancer diagnosed at 51 Korean general hospitals in 2010, 2012, 2014, 2016, 2018 and 2020, 14,609 (53.9 percent) had high-risk disease at diagnosis and 2,558 (9.5 percent) had low-risk or potentially low-risk disease, with the low-risk share falling from 11.4 percent in 2010 to 7.6 percent in 2020.

## Key takeaways

- In 27,075 biopsy-confirmed Korean prostate cancer cases from 51 general hospitals, 14,609 (53.9 percent) were high-risk at diagnosis, against 1,476 (5.45 percent) low-risk and 1,082 (4.00 percent) potentially low-risk.
- The proportion of low-risk disease at diagnosis fell from 11.4 percent in 2010 to 7.6 percent in 2020.
- High-risk disease accounted for 55.4 percent of cases among rural residents against 47.7 percent among urban residents, which the authors read as a disparity in access to early detection.
- About a quarter of newly diagnosed Korean men — 6,586 of 27,075, or 24.3 percent — were eligible for active surveillance under a deliberately maximised definition that includes favourable intermediate-risk disease.
- That active surveillance eligibility fell over the decade, from 27.6 percent of diagnoses in 2010 to 22.0 percent in 2020.

## Full article

South Korea is the world's reference case for finding cancer too early. Its thyroid cancer incidence rose tenfold on the back of ultrasound scans that people were not sent for, while the number of deaths did not move.

Prostate cancer in the same country, in the same decade, looks like the opposite problem.

### What the national picture looks like

Korea's insurance claims database records that a cancer was diagnosed but not how advanced it was, so risk distribution has not been available nationally. A team at Ewha Womans University assembled it directly, collecting the clinicopathological variables — PSA, clinical stage, Gleason grade, biopsy core involvement — for every biopsy-confirmed case at 51 general hospitals in six sample years between 2010 and 2020. The 27,075 cases represent 37.9 percent of the 71,403 registered nationally in those years.

**Risk at diagnosis, 27,075 Korean prostate cancer cases, 2010–2020**

| Risk category | Patients | Share |
| --- | --- | --- |
| Low risk | 1,476 | 5.45% |
| Potentially low risk | 1,082 | 4.00% |
| Favourable intermediate | 4,028 | 14.88% |
| Unfavourable intermediate | 5,880 | 21.72% |
| High risk | 14,609 | 53.94% |

**53.9%** — of Korean prostate cancers were high-risk at the moment of diagnosis, against 9.5 percent that were low or potentially low risk  
_Source: Ko YH et al., Prostate International, 2026_

The direction of travel is the same. Low-risk disease, including potentially low-risk cases, fell from 11.4 percent of diagnoses in 2010 to 7.6 percent in 2020. Korea is finding proportionally fewer of the prostate cancers that are easiest to treat, not more.

> **The same country, the opposite failure**  
> In thyroid cancer, Korea's problem is a flood of tumours that would never have harmed anyone. In prostate cancer, more than half of the disease is already high-risk when it is first identified. These are not contradictory findings about Korean medicine. They are what happens when detection is driven by opportunistic scanning rather than by a considered policy about which cancers are worth looking for.

### Where a man lives changes what he is diagnosed with

High-risk disease was the most prevalent category in nine of Korea's seventeen administrative regions. It accounted for 55.4 percent of cases among rural residents and 47.7 percent among urban residents, with low-risk disease correspondingly more common in the capital metropolitan area.

The authors read that gap as a disparity in access to early detection and diagnosis rather than as a difference in the disease. It is the same shape this publication found in thyroid cancer, where higher income predicted more screening, more diagnoses and — for a cancer that mostly did not need finding — more harm. Here the gradient runs the other way: the people with less access are the ones presenting with the disease that needed finding early.

### How many men could safely be watched

The same cohort was used to estimate an upper bound on active surveillance — monitoring a confirmed cancer rather than treating it immediately. Defining eligibility as generously as the evidence allows, by including favourable intermediate-risk disease alongside low and potentially low risk, 6,586 of the 27,075 men were eligible: 24.3 percent.

That share fell over the decade, from 27.6 percent in 2010 to 22.0 percent in 2020, which follows arithmetically from the shrinking proportion of low-risk diagnoses. Eligibility also varied significantly by administrative district and by whether a man lived in a city.

The number is an upper bound and the authors describe it as one. It says how many men could be offered surveillance, not how many should be, and nothing in the study records how many actually were.

### What this dataset cannot tell us

1. These are the 37.9 percent of national cases treated at 51 general hospitals with 200 or more beds. Men diagnosed elsewhere, or not diagnosed at all, are not represented, and the direction of that bias is not established.
2. Six sample years between 2010 and 2020 describe a decade in snapshots. A change that occurred between sampled years is invisible here.
3. A rising share of high-risk disease is a proportion, not a count. It is consistent with more high-risk cancer, with less low-risk cancer being found, or with both, and this data cannot separate them.
4. Two papers from the same team on the same 27,075 cases report the high-risk share as 53.94 percent and as approximately 50 percent, under classifications that differ in their details. Both are cited here and neither figure should be quoted as the single national number.
5. Risk category at diagnosis is not an outcome. Nothing here follows these men to find out what happened to them.

> **The question this opens**  
> Korea has spent a decade correcting an epidemic of thyroid cancers that did not need finding. The prostate data suggests a parallel question that has had far less attention: whether the same health system is finding the cancers that do, and whether the men it is missing are the ones furthest from a hospital.

## Sources

- Ko YH, Kim SW, Son NH. Active surveillance could apply to one-quarter of Korean prostate cancer cases: Insights from a 27,075-patient cohort. Prostate International 2026;14(2):127-131. doi:10.1016/j.prnil.2025.12.004. PMID:42382553. https://doi.org/10.1016/j.prnil.2025.12.004
- Ko YH, Kim SW, Son NH. Incidence of High-Risk Prostate Cancer in Korea: Insights From Real-World Data Between 2010 and 2020. Journal of Korean Medical Science 2026;41(14):e10. doi:10.3346/jkms.2026.41.e10. PMID:41978922. https://doi.org/10.3346/jkms.2026.41.e10
- Kang HY, Kim I, Kim YY, Bahk J, Khang YH. Income differences in screening, incidence, postoperative complications, and mortality of thyroid cancer in South Korea: a national population-based time trend study. BMC Cancer 2020;20(1):1096. doi:10.1186/s12885-020-07597-4. PMID:33176753. https://doi.org/10.1186/s12885-020-07597-4

## Citation

Andrew Cho (2026). "Korea diagnoses thyroid cancer too early and prostate cancer too late. Half of prostate cases are already high-risk when found". Medical Insights Korea. https://medicalinsightskorea.com/news/korea-prostate-cancer-high-risk-at-diagnosis

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