[Postsurgical follow-up and long-term monitoring of colorectal cancer : Radiology as a key component].

Clinical/methodological issue: Colorectal cancer is one of the most common malignant tumors worldwide. Postsurgical follow-up and long-term monitoring are essential to detect local recurrence, metastases, or secondary tumors at an early stage.

Standard radiological methods: According to the current guideline on colorectal cancer, radiologic follow-up is primarily performed using a single computed tomography (CT) scan 3 months after completion of therapy. Annual chest X‑ray examinations within the first 5 years after completion of treatment can be employed, and, due to cost-effective availability, regular abdominal ultrasound is recommended.

Methodological innovations: The German guideline on colorectal cancer is currently being revised. As the sensitivity of ultrasound is inferior to CT and magnetic resonance imaging (MRI), thoracoabdominal CT will probably become crucial in follow-up care with the revised guideline, which would align with international recommendations.

Performance: CT is well suited for detecting local recurrence, as well as lung or liver metastases. MRI is used in assessing local cancer grades for treatment planning and monitoring. Structured reporting, stage- and guideline-based recommendations including follow-up intervals as well as interdisciplinary tumor conferences ensure high-quality follow-up care.

Achievements: Radiology is essential to interdisciplinary follow-up care for colorectal cancer.

Practical recommendations: Structured reporting and clear recommendations on follow-up intervals should be standard in radiological reports. The importance of radiological follow-up for patients with colorectal cancer is likely to increase further with the guideline that is currently being revised.