Korea University study identifies age 70 as cutoff for chemotherapy benefit in colorectal cancer

Colorectal cancer remains a leading cause of cancer death, with incidence rising among older adults. One of the most pressing clinical questions has been whether elderly patients should receive oxaliplatin, a standard component of adjuvant chemotherapy that is known to cause serious side effects.

To address this, Dr. Jun Woo Bong from Korea University Guro Hospital, with Dr. Hwamin Lee, and Dr. Seogsong Jeong from Korea University College of Medicine, conducted a large-scale population study, which was made available online on August 6, 2025, in JAMA Network Open.

The team examined health records from more than 8,500 patients with stage II or III colorectal cancer who underwent surgery followed by chemotherapy between 2014 and 2016. Patients were divided into two groups: those treated with oxaliplatin-based combinations, and those given standard chemotherapy alone. Using advanced statistical methods, the researchers systematically tested whether an age threshold existed at which oxaliplatin stopped providing survival benefits.

The results were decisive. In stage III patients aged 70 or younger, oxaliplatin reduced the risk of death by 41%, boosting five-year survival from 78% to nearly 85%. But in those older than 70, oxaliplatin did not improve survival and was linked to higher rates of treatment discontinuation. In fact, almost 40% of older patients receiving oxaliplatin stopped chemotherapy early, often due to toxicity. For stage II patients of any age, oxaliplatin showed no added survival benefit.

“The most important point is that oxaliplatin improves survival only in patients with stage III colorectal cancer who are aged 70 years or younger. Beyond 70, the benefit disappears, and oxaliplatin is associated with higher discontinuation rates due to toxicity,” said Dr. Bong.

These findings have immediate real-world applications.

“Oncologists can use this age threshold to make more precise, evidence-based choices about whether to add oxaliplatin, avoiding unnecessary toxicity in patients unlikely to benefit,” said Dr. Jeong.

The broader significance extends to healthcare policy. Avoiding ineffective chemotherapy in older patients may help reduce costs, complications, and hospitalizations. Health systems could redirect resources to therapies and supportive care that make a greater difference in survival and quality of life. The research also sets the stage for longer-term changes in global cancer care.

 “Clinical practice guidelines may adopt age 70 as a critical factor in recommending oxaliplatin, laying the foundation for precision oncology and future research focused on safer, more effective treatments for older patients,” said Dr. Lee.

The authors note some limitations, including the retrospective design and lack of molecular marker data. Even so, the sheer size of the national dataset lends strong weight to the findings, which are likely to influence both clinical guidelines and everyday oncology practice. As cancer treatment increasingly moves toward personalization, this study underscores the importance of tailoring care not only to tumor stage but also to patient age and resilience. For younger stage III patients, oxaliplatin remains an important tool. For those beyond 70, it may be time to reconsider and focus on therapies that preserve both survival and quality of life.

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Reference                                    

DOI: http://doi.org/10.1001/jamanetworkopen.2025.25660

About Korea University College of Medicine

Korea University College of Medicine is the medical school of Korea University. It is located in Seoul, South Korea. As one of the oldest medical schools in South Korea, it has been historically regarded as one of the country's top medical schools. The school was founded as Chosun Women's Medical Training Institute in 1928 by Rosetta Sherwood Hall. The institute was subsequently renamed several times and ultimately merged with Korea University to become Korea University College of Medicine. So far, the school has produced over 7,000 graduates, most of whom are working as prominent physicians and public health advocates worldwide.

Website: https://medicine.korea.ac.kr/en/index.do

About the author

Prof. Jun Woo Bong is a colorectal surgeon and Associate Professor at Korea University Guro Hospital and Korea University College of Medicine. His work focuses on surgical outcomes, chemotherapy optimization, and population-based analyses of colorectal cancer. He has led multiple national database studies exploring treatment effectiveness, patient safety, and age-specific strategies in cancer care. Prof. Bong is also committed to advancing precision oncology by integrating clinical evidence and genetic mechanisms to overcome resistance to chemotherapy to improve outcomes and quality of life for patients with colorectal disease.