After an introduction to the mid-infrared (IR) spectral region, the tremendous significance of mid-IR spectroscopic sensing is highlighted. The remarkable progress made towards mid-IR spectral in vitro mapping of tissue and cancer detection is reviewed, with emphasis on diagnosis of skin cancer. The status quo of chalcogenide glass mid-IR fibre optics and photonics for meeting opportunities for remote mid-IR sensing in general, and in in vivo cancer detection in particular, is assessed. Raman spectroscopy is a sister technique to mid-IR spectroscopy. The current success of Raman spectroscopy in medical diagnosis is appraised, with particular emphasis on Raman spectral imaging of tissue towards skin cancer diagnosis in vivo, based on a silica-glass fibreoptic sensor-head. The challenges to be met in chalcogenide glass science and technology towards facilitating analogous fibreoptic diagnostics based on mid-IR spectroscopy are addressed.