Cancer statistics usually mean “how many people were diagnosed this year.” But there is a much larger number sitting next to it: how many people alive today have ever been diagnosed with cancer.
⭐⭐ In 2023 Korea counted 2,732,906 prevalent cancer cases.
That is “1 in every 19 citizens (5.3% of the total population).”
— National Cancer Information Center, cancer prevalence (2023)
In the same year, 288,613 people were newly diagnosed. ⭐ Prevalence is 9.47 times incidence (our own calculation) — and that single ratio is more or less what this article is about.
⭐ First, who counts as a "prevalent case"
Read that figure as “people currently ill with cancer” and you have it wrong. The source definition is explicit.
“A figure that includes both patients receiving cancer treatment and people surviving after being cured”
Basis — people diagnosed between 1 January 1999 and 31 December 2023 who were alive on 1 January 2024
— National Cancer Information Center, cancer prevalence
⭐⭐ It is 25 years of accumulation, and cured people are in it. So 2.73 million is not a patient count — it is the number of people who have been through cancer and are alive now. ⚠️ Miss that distinction and the number reads much heavier than it is.
⭐⭐ And 62% of them are more than five years out
| Time since diagnosis | People | Share |
|---|---|---|
| 2 years or less | 482,734 | 17.7% |
| Over 2 to 5 years | 552,373 | 20.2% |
| ⭐ Over 5 years | ⭐ 1,697,799 | ⭐ 62.1% |
| Total | 2,732,906 | 100% |
⭐⭐⭐ Close to two in three were diagnosed more than five years ago. Conversely, only about one in six was diagnosed within the last two years.
That is what “cancer has become a chronic condition” actually refers to. Not a turn of phrase — a composition. Most of that 2.73 million are people diagnosed long ago who are still living.
⭐⭐ Split incidence from prevalence and the cancers separate
Here an interesting calculation appears. Divide prevalence by that year's incidence for each site, and the same word — “cancer” — covers very different shapes.
| Site | Prevalent | New in 2023 | ⭐ Ratio (our calculation) | 5-year relative survival |
|---|---|---|---|---|
| ⭐ Thyroid | 587,292 | 35,440 | ⭐ 16.6× | 100.2% |
| Stomach | 366,717 | 28,943 | 12.7× | 78.6% |
| Breast | 354,699 | 29,871 | 11.9× | 94.7% |
| Colorectal | 340,064 | 32,610 | 10.4× | 75.6% |
| Prostate | 161,768 | 22,640 | 7.2× | 96.9% |
| Liver | 85,687 | 14,707 | 5.8× | 40.4% |
| ⚠️ Lung | 141,143 | 32,953 | ⚠️ 4.3× | ⚠️ 42.5% |
⭐⭐⭐ Put thyroid and lung side by side and the table speaks.
Roughly the same number of people are diagnosed each year — thyroid 35,440, lung 32,953 (a 7.5% gap).
Yet the number alive differs by 4.16 times: 587,292 against 141,143.
⚠️ If the same number enters and a different number accumulates, the difference is how long people stay.
⭐ And indeed, 5-year relative survival is 100.2% for thyroid and 42.5% for lung. Across the table, a larger ratio tends to come with higher survival.
⚠️ But the relationship is not clean. Prostate cancer has 96.9% survival yet only a 7.2× ratio. The ratio must also depend on when a given cancer started rising — ⚠️ and we could not obtain the incidence trend by year. So we write it as a tendency, no further.
⚠️ Survival of 100.2% — a number above 100
One value in the table catches the eye: thyroid cancer, 5-year relative survival 100.2%.
⭐ The word “relative” in the name is the answer. This is not a plain proportion of survivors but a comparison.
“Five-year relative survival (the probability that a cancer patient survives five years, compared with the general population)”
“A relative survival of 100% means survival equal to the general population; thyroid cancer exceeding 100% means that, going by the number alone, patients outlive the general population.”
— Korean news report (20 January 2026) on the national cancer registry statistics released by the Ministry of Health and Welfare and the Korea Central Cancer Registry (National Cancer Center). ⚠️ A news source, not agency source text.
⭐⭐ So 100.2% does not mean “100 out of 100 survive.” It is closer to “the same as comparable people without the diagnosis.” Because the baseline is the general population rather than “everyone alive,” and the general population also dies of other causes over five years, the measure has room to pass 100.
⚠️⚠️ Note the hedge in the report itself — “going by the number alone.” Why it comes out above the general population is not explained there, and we could not verify it either. So do not read this as “having the cancer makes you live longer.” ⚠️ And the National Cancer Information Center's own survival page still carries no definition or formula — the wording above is a journalist's paraphrase.
The same page gives 73.7% five-year relative survival for all cancers (2019–2023 diagnoses), 68.2% for men and 79.4% for women. ⭐ It also lists the sites that rose most since 2001–2005 — lung +25.9%p, stomach +20.6%p, liver +19.8%p.
⭐⭐ All three of the biggest risers were cancers with low survival to begin with — and they are the ones with small ratios in the table above.
⭐ More than half are 65 or older
| Age | Prevalent cases | Note |
|---|---|---|
| ⭐ 65 and over | ⭐ 1,408,234 | ⭐ 51.5% of all prevalent cases |
| 60s | 774,510 | largest single age band |
| 70s | 616,281 | |
| 50s | 528,312 |
⭐⭐ Over half are 65 or older, and as we saw, 62% are more than five years past diagnosis. Overlay the two and a picture forms: people who finished cancer treatment and are now ageing alongside other chronic conditions.
Which means this population needs more than cancer care. Managing several medicines at once is covered in the medication guide; bone health and holding on to muscle each have their own article.
By sex, women are the larger group
| Group | Prevalent cases |
|---|---|
| Men | 1,193,944 |
| ⭐ Women | ⭐ 1,538,962 |
| Total | 2,732,906 |
⭐ 345,018 more women (our calculation — 1.29 times the male figure). ⭐⭐ And that gap is almost entirely explained by a single site. That story is in why thyroid cancer tops the list for women.
How to use these numbers
| Don't read it as | Read it as |
|---|---|
| ⚠️ “2.73 million cancer patients” | 25 years of survivors, cured people included — that is the definition |
| ⚠️ “cancer means dying soon” | ⭐ 62.1% are past five years; overall 5-year survival 73.7% |
| ⚠️ “100.2% survival, so it's a safe cancer” | ⭐ a comparison with the general population — not “everyone lives,” but “about the same as everyone else” |
| ⚠️ “common cancer = deadly cancer” | ⭐ near-identical incidence, 4× difference in prevalence |
| ⚠️ “screening matters only after diagnosis” | National cancer screening exists to shrink the left column of that table |
Questions that remain
If it's 1 in 19, does that mean someone I know?
⭐ The source phrasing is “1 in every 19 citizens (5.3% of the total population).” ⚠️ But 51.5% of prevalent cases are 65 or older, so the density varies enormously by age — far rarer among younger people, far more common among older ones. Don't apply "1 in 19" evenly across ages.
Does passing five years mean cured?
⚠️ The source never says so. The statistic simply bands time since diagnosis at 2 and 5 years; nothing states that five years is a clinical cure threshold. ⭐ The prevalence definition itself covers both people in treatment and people cured. Individual judgments belong with your doctor.
Why count from 1999?
The stated basis is “people diagnosed from 1 January 1999 to 31 December 2023.” ⚠️ The page does not explain why 1999 is the starting point, so the figure should always be read with the "25-year accumulation" condition attached.
Incidence or prevalence — which should I look at?
⭐ They answer different questions. Incidence asks “how fast is this arising now,” prevalence asks “how many people in society have been through it.” Use incidence for prevention and screening; use prevalence for care, return to work and long-term management.
What if I have symptoms?
This article is about reading statistics, not symptoms. For a symptom decision see ER or clinic; for prevention, national cancer screening. If something worries you, settle it with a doctor, not a statistic.
62% of that 2.73 million were diagnosed more than five years ago. The fastest-growing cell in Korea's cancer statistics is "diagnosed long ago, still living" — and "cancer has become a chronic condition" is not rhetoric but a description of that composition.
Sources
- ⭐ National Cancer Information Center (Korea) — Cancer prevalence (2023). ⭐⭐ Source for 2,732,906 prevalent cases, “1 in every 19 citizens (5.3% of the total population),” ⭐⭐ the time-since-diagnosis bands (482,734 / 17.7%; 552,373 / 20.2%; 1,697,799 / 62.1%), the sex split (1,193,944 men, 1,538,962 women), the age figures (1,408,234 aged 65+, 51.5%; 774,510 in their 60s; 616,281 in their 70s; 528,312 in their 50s), and ⭐ the definition “includes both patients receiving cancer treatment and people surviving after being cured” with its basis (diagnosed 1999-01-01 to 2023-12-31, alive on 2024-01-01).
- National Cancer Information Center — Prevalence by cancer site (2023). Source for the prevalent counts by site (thyroid 587,292 / 21.5%; stomach 366,717; breast 354,699; colorectal 340,064; prostate 161,768; lung 141,143; liver 85,687).
- National Cancer Information Center — Incidence by cancer site (2023). Source for 288,613 new cases and the site-level incidence (thyroid 35,440 / 12.3%; lung 32,953; colorectal 32,610; breast 29,871; stomach 28,943; prostate 22,640; liver 14,707).
- National Cancer Information Center — Cancer survival (2019–2023 diagnoses). Source for 73.7% all-cancer 5-year relative survival, 68.2% men / 79.4% women, the site-level rates (thyroid 100.2%, prostate 96.9%, breast 94.7%, stomach 78.6%, colorectal 75.6%, lung 42.5%, liver 40.4%, pancreas 17.0%), and the gains since 2001–2005 (lung +25.9%p, stomach +20.6%p, liver +19.8%p).
- ⭐ Our own calculation. The prevalence-to-incidence ratios (9.47× overall, 16.6× thyroid and so on), the 345,018 / 1.29× sex gap, and the 7.5% incidence gap versus 4.16× prevalence gap between thyroid and lung are computed by us from the tables above, not printed in the source. ⭐ Check: the three time bands and the two sex figures each sum to exactly 2,732,906.
- ⚠️ News report (not agency source text) — Korean coverage of the national cancer registry statistics released by the Ministry of Health and Welfare and the Korea Central Cancer Registry (National Cancer Center), 20 January 2026. ⭐ Source for “five-year relative survival (the probability that a cancer patient survives five years, compared with the general population)”, “100% means survival equal to the general population,” and “exceeding 100% means that, going by the number alone, patients outlive the general population.” ⚠️ A journalist's paraphrase, not an agency definition.
What we could not verify
- ⚠️ The agency's own definition and formula for relative survival. The meaning was confirmed from a news report, but the National Cancer Information Center page still has no definition, and how the expected survival of the general population is derived was not obtained.
- ⚠️⚠️ Why it exceeds 100. The report itself only says “going by the number alone” and gives no reason. The body therefore describes only the structure (the baseline is the general population) and offers no cause.
- ⚠️ How to read the prevalence-to-incidence ratio. Beyond survival time it must depend on when each cancer began rising, and we could not obtain incidence trends by year. We cannot explain why prostate cancer sits at 96.9% survival but a 7.2× ratio, so we wrote only “a tendency.”
- ⚠️ Why the count starts in 1999. The page gives no reason for the start date.
- ⚠️ Age by sex. We verified 51.5% aged 65+, but no age-by-sex cross table was available.
- Mortality. This article uses prevalence, incidence and survival only; death counts were not checked.
- Lifetime probability of developing cancer — a commonly cited figure, but not on the pages we opened.
- Employment, income and return-to-work statistics for cancer survivors, which would support the "chronic condition" framing, were not obtained.
- ⚠️ Effectively a single institution. All four pages are the National Cancer Information Center; no cross-check against another body was possible.
As of July 2026. All figures come from the National Cancer Information Center's 2023 statistics (survival on 2019–2023 diagnoses), and ratios and gaps are our own calculations, marked as such in the body. For prevention and screening see national cancer screening; for the thyroid side, why thyroid cancer tops the list for women. This is general information about reading statistics and does not replace medical diagnosis or treatment. If a symptom worries you, have it checked.
