How long is too long between a colorectal cancer diagnosis and the first treatment? A study from the Indiana University School of Medicine, published in JAMA Network Open in July 2026, puts numbers on it. The answer depends heavily on which treatment route a patient is on.
The team, led by Chi M. Nguyen of the school’s Department of Biostatistics & Health Data Science, followed 11,927 insured adults aged 40 or older. All had nonmetastatic colorectal cancer diagnosed between 2017 and 2021 and had curative-intent surgery. The data came from Optum’s Clinformatics Data Mart, a commercial insurance claims database, and follow-up ran through 2024. Over three years, 1,438 of them, or 12.1%, developed metastatic disease.
The clock depends on the route
The researchers measured how long it took from diagnosis to the first cancer-directed treatment, then sorted patients into four pathways: surgery alone, surgery followed by adjuvant therapy, neoadjuvant therapy followed by surgery, and all three. The shift is that no single deadline fits them all.
Across the whole group, starting treatment 4 to 20 days after diagnosis carried a 19% higher risk of metastasis than starting within 0 to 3 days. In the surgery-plus-adjuvant group the gap widened. Patients who began treatment 4 to 46 days after diagnosis faced a cumulative risk 27% higher than those treated within three days, and those who waited 47 days or more had a 55% higher risk.
For patients who got neoadjuvant therapy before surgery, the threshold sat much later, at 68 days or more. For surgery alone, risk rose only after waits of 223 days or more, and that result was not statistically significant. The trimodality group showed no significant link at all. Oncology Nursing News relayed the authors’ idea that intensive systemic treatment before and after surgery might offset the cost of a slow start.
Where the days go
Most patients, 78%, were in the surgery-alone pathway, and the average gap from diagnosis to treatment across the cohort was 11.6 days. Patients on surgery plus adjuvant therapy averaged 7.3 days. Those on neoadjuvant therapy before surgery averaged 31.
The authors noted that some delay is clinical, such as preoperative evaluation. Other delay is not. They pointed to bottlenecks such as scheduling, insurance appeals and prior authorization. That is the part health systems can change.
There are caveats. The study is observational, so it cannot prove that waiting causes spread. It lacked detailed tumor information, relied on claims data, and had limited representation of underserved populations. The authors called for studies that add clinical and genomic data. What’s changing is the argument itself: not a single countdown, but pathway-specific benchmarks. Watch this space for whether hospitals adopt them.
Anyone worried about symptoms or a diagnosis should consult a doctor.
Sources
- Delay in Colorectal Cancer Treatment Increases Risk of Metastasis: JAMA (Medical Dialogues)
- Longer Time to Treatment Is Associated With Higher Metastasis Risk With Certain CRC Treatments (Oncology Nursing Society)
- CRC Treatment Delays Linked to Increased Metastasis Risk (Oncology Nursing News)
