Cancer was a journey Kang Min-ji never thought she would take during her early 30s. She was physically active, a non-smoker and didn't drink that often.

But her world shattered in July 2022 after she was found to have thyroid cancer and a brain tumor when she underwent a health checkup.

"Little did I know that I would have cancer because I was young and had a relatively healthy lifestyle, although I did have an exhausting work pattern where I stayed up until late at night and early morning for work," the YouTuber confided in her recently-uploaded video titled "Who would have thought I would have cancer?"

"Almost nobody in the hospital was from my age group. Those who made their visits were the elderly people," she said, adding that she felt out of place.

"I realized that an illness like cancer can come (to young people) without any reason. Just because I maintained a healthy diet by avoiding ham or bacon does not guarantee immunity from getting cancer," Kang added.

Kang's diagnosis highlights a troubling trend: The odds of a cancer diagnosis are gradually increasing among young South Koreans adults.

For example, actor Kim Woo-bin was diagnosed with Nasopharyngeal cancer -- a rare form of cancer that occurs in the upper part of the pharynx, located behind the nose and above the back of the throat -- at the age of 28 in 2017. Before he was declared cancer-free two years later, his doctor diagnosed that he only had six months to live.

Actor Jang Keun-suk, 37, also shocked fans when he opened up in August that he has been battling against thyroid cancer for a year, suggesting that the idea of cancer as a disease of old age might no longer ring true.

Rise in young patients

According to the Health Insurance Review and Assessment Service's data on the number of patients by year released in October 2022, cancer diagnoses in their 20s and 30s were on the rise in the country, with rectal cancer being the most common.

The number of cancer patients in their 20s gradually rose by nearly 26 percent between 2016 and 2021, jumping from 20,131 to 25,384. The increase among 30-something patients was 7 percent, rising from 78,483 to 83,944 during the same period. The increase rate for the 40s and 50s was 9 and 8 percent, respectively.

The cases of rectal cancer, for example, were especially striking. The numbers for the diagnosis in men in their 20s rose from 100 to 207, or a 107 percent increase, between 2016 and 2021. For 20-something women, the cases rose from 59 to 143, or by 142 percent, in the corresponding period.

A study released by the University of Colorado Anschutz Medical Center in September 2022 showed that Korea had the highest colon cancer rate among individuals aged 20 to 49, with 12.9 cases per 100,000 people. The figure was the highest among the 42 countries in the study.

Also, the number of adults in their 20s being treated for breast, cervical, colorectal, liver and stomach cancer from 2014 to 2018 has increased by 45 percent in Korea, with cases of breast cancer up to 40 percent, according to a report titled "Rising Rate of Cancer in the Young" published in December 2020.

Behind early-onset cancer

Health care experts tie the climbing cancer rates and the likelihood of developing cancer among young people to excessive stress and the rise in one-person households, which could impact their healthy lifestyle, calling out for more personalized care and maintaining healthy habits.

Shin Hyun-Young, a family medicine professor at Seoul St. Mary's Hospital, said the eating habits of young adults living alone have shifted toward more convenient diet options like meal kit products, processed foods and ready-to-eat meals at convenience stores.

"It's frustrating to see how people in their 20s and 30s favor ready-to-eat items because consuming meals rich in a variety of colorful vegetables, such as red and green, is the key to reducing the risk for cancer. It's realistically hard to cook and work out to maintain a healthy body when you live alone," Shin told The Korea Herald.

Single-person households in Korea hit an all-time high of over 10 million as of March this year, accounting for 41.8 percent of some 24 million households in total, according to the resident registration data from the Interior Ministry.

Instead, Shin advises eating a well-balanced diet with a proper mix of carbohydrates, fats and proteins instead of over-relying on nutritional supplements.

"For example, taking fish, eggs, tofu and cheese and refraining from carcinogenic substances such as sausages, foods with trans fat, processed foods and burnt meat. Apart from maintaining a healthy diet, people should cut smoking and drinking," the professor explained.

Similarly, a report published by the World Health Organization International Agency for Research on Cancer in 2015 linked processed meats such as bacon, salami, hot dogs and deli meat with cancer. The report also estimated that each 50-gram portion of processed meat eaten daily increases the risk of colorectal cancer by 18 percent.

The professor also singled out Korea's corporate culture, which often lacks work-life balance, as another factor.

"Night-shift work and gatherings after work that often cover alcoholic beverages are extremely harmful and could even add more stress. However, stress can contribute to changes in the body at the cellular level that may cause healthy cells to become cancerous. Also, environmental factors like radiation, for example, elevates the risks of developing thyroid cancer," Shin warned.

Cho Jung-jin, a family medicine professor at Hallym University Dongtan Sacred Heart Hospital, concurred that stress could wake up cancer cells, citing animal testing conducted by the Cold Spring Harbor Laboratory. The research found that the stressed mice developed at a fourfold higher rate than mice that weren't stressed but who also previously had cancer.

"NK cells, also known as natural killer cells, which are first-line defenders in cancer, become fewer in number when you gain stress. This means that having fewer NK cells weakens the ability to fight off cancerous growth," the professor said during her appearance on a health care program named "Dr. Jekyll and the Guide" in late October.

Shim Kyung-won, a family medicine professor at Ewha Womans University Medical Center, noted that young adults' stress stems from heated competition from trying to get good grades at school to trying to land a job and succeed at work.

"Due to the cycle of constant stress and poor sleeping patterns, people may turn to eating food, often unhealthy ones, to reward themselves. This, however, leads to unhealthy eating habits," the professor noted.

Park Kui-seon, the director of the Health Promotion Center at Cha Ilsan Medical Center, recommended that younger adults get screening tests to detect if they have cancers before they spread.

"Those feeling fatigued or with greater sensitivity to temperature changes may want to get a thyroid function test, which is done through a blood sample since a growing number of young adults are being diagnosed with thyroid problems," Park underscored.

In cases where cancer runs in the family, the professor advises to undergo extra medical tests such as breast ultrasound gastroscopy to catch any early signs of cancer.

In light of rising rates of cancer among the young, the Korean Cancer Association launched a program last month to help cancer patients in their 20s and 30s by covering some of their medical expenses so that they can focus on their treatment. The program provides financial support of up to 1 million won ($716) per person.

Other experts, however, noted that although cancer screenings increase the chances of finding certain cancers before they show symptoms, young adults are often unnecessarily screened for cancer, leading to overdiagnosis.

"Chest CT scans, for example, should be conducted on those considered to be at high risk. However, several medical institutions perform these scans on individuals that don't need this," Myung Seung-kwon, a professor and dean of the National Cancer Center Graduate School of Cancer Science and Policy, said during the National Academy of Medicine of Korea forum held in November 2022.

Also, Korea reported high proportions of overdiagnosis of thyroid cancer between 1998 and 2012, where 90.3 percent and 94.9 percent of the diagnosed cases in men and women, respectively, are considered overdiagnosed, according to a study published by the National Library of Medicine in July 2023. The research was based on data from 13 cancer registries in Korea, Japan, and China, and it analyzed time trends in the overdiagnosis of thyroid cancer between 1998 and 2012.

"Overdiagnosis of thyroid cancer can lead to overtreatment and unnecessary harm. Comprehensive measures are needed to minimize overdiagnosis and curb the ongoing increase in thyroid cancer incidence," the report underscored.

This article is part of a series that delves into the health and well-being of people in South Korea, highlighting the latest developments in healthcare needs and the services available to meet them. -- Ed.