There have been substantial advancements in optical spectroscopybased imaging techniques in recent years. These developments can potentially herald a transformational change in the diagnostic pathway for diseases such as cancer. In this paper, we review the clinical and engineering aspects of novel optical spectroscopy-based imaging tools. We provide a comprehensive analysis of optical and non-optical spectroscopy-based breast cancer diagnosis techniques vis-a-vis the current standard techniques such as X-Ray mammography, ultrasonography, and tissue biopsy. The recent advancements in optical spectroscopy-based imaging systems such as Transillumination Imaging (TI) and the various types of Diffuse Optical Imaging (DOI) systems (parallel-plate, bed-based, and handheld) are examined. The engineering aspects, including mechanical, electronics, optics, automatic interpretation using artificial intelligence (AI), and ergonomics are discussed. The abilities of these technologies for measuring several cancer biomarkers such as hemoglobin, water, lipid, collagen, oxygen saturation (SO2), and tissue oxygenation index (TOI) are investigated. This article critically assesses the diagnostic ability and practical deployment of these new technologies to differentiate between the normal and cancerous tissue.