CA 15.3-driven F-18-FDG PET-CT for early detection of breast cancer recurrence: Diagnostic accuracy and clinical impact.

An isolated rise in serum tumor marker CA 15.3 during post-treatment surveillance of breast cancer patients represents a notable diagnostic challenge. In many such cases, conventional imaging modalities fail to identify occult sites of early disease recurrence. Consequently, this diagnostic limitation may result in a delay in timely and appropriate clinical management. This study aimed to evaluate the diagnostic accuracy of whole-body F-18-FDG PET-CT imaging in early localization of breast cancer recurrence in patients with elevated CA 15.3 levels. Hence, the study included 50 routine breast cancer patients at Guru Gobind Singh Medical College & Hospital, Faridkot, who showed signs of disease relapse and were monitored for signs of recurrence, based on rising tumor markers. This study found a significant correlation between elevated CA 15.3 levels and PET-CT-detected recurrences in patients. Bone recurrences had the highest combined CA 15.3 levels. PET-CT findings altered clinical management in 80% of cases, with 28/40 receiving targeted radiotherapy, 9/50 initiating new systemic therapy and 3/40 starting with endocrine therapy. PET-CT is essential for the early detection of occult recurrences in breast cancer patients with elevated CA 15.3 levels.