Early cancer non-invasive diagnosis is a leading medical topic worldwide due to the threat to human life and the high death rate of this disease. Light-absorption-based thermophotonic diagnostic imaging is well positioned for this challenge thanks to its speed, safety, and high molecular contrast advantages. In this Letter, an enhanced truncated-correlation photothermal coherence tomography (TC-PCT) imaging modality is presented for early in vivo tumor detection and tested using a nude mouse thigh. Compared with conventional TC-PCT, the enhanced imaging modality was found to exhibit higher contrast that contributed to the precise measurement of the size and shape of the detected tumor. The experimental results were validated following histological analysis from hematoxylin and eosin staining. This increased contrast advantage gives rise to possible clinical applications in early tumor detection and treatment and in monitoring the effects of anti-tumor drugs.