Is the 8th edition of the Union for International Cancer Control staging of oral cancer good enough?

Depth of invasion is an important predictor of survival. A study by the International Consortium (ICOR) for Outcome Research proposed incorporation of it (together with the greatest surface dimension, or the anatomical criteria, or both) into the T stage. This has been adopted in part by the 8th edition of the Union for International Cancer Control (UICC) TNM 8 classification of malignant tumours for oral squamous cell carcinoma (SCC). Our aim was to verify depth of invasion as an independent prognostic factor, and to validate the staging by comparing it with that specified in the 7th edition (TNM 7) and the T-staging model proposed by the International Consortium. We retrospectively studied 449 patients who had had operations for a previously untreated primary oral cancer between 2006 and 2014 at a single centre, and analysed the independent predictive value of depth of invasion for both disease-specific and overall survival. It was an independent predictor of disease-specific survival as were sex, perineural invasion, and N stage. It was also an independent predictor of overall survival together with sex and N status. Staging in TNM 8 gave a better balance of distribution than that in TNM 7, but did not discriminate between prognosis in patients with T3 and T4 disease. The proposed International Consortium rules for T-staging gave an improved balance in distribution and hazard discrimination. The incorporation of depth of invasion into the T-staging rules for oral SCC improved prognostic accuracy and is likely to influence the selection of patients for adjuvant treatment. Our findings suggest that the TNM 8 staging lacks hazard discrimination in patients with locally-advanced disease because its T4 staging is restricted to anatomical criteria.

Electrically controllable multiple, active, computer-generated hologram.

The multiple, active, computer-generated hologram (MACH) is a novel device combining the attributes of electrically controllable diffraction gratings and computer-generated holograms. The version discussed here consists of a surface relief transmitting structure immersed in a nematic liquid crystal and sandwiched between two, planar indium tin oxide electrodes. Under control of a single applied voltage, the device can selectively generate any one of a number of desired, uncorrelated optical wave fronts. The device principles are discussed and experimental results presented. There is a brief discussion of the relative merits of the MACH and electrically addressed spatial light modulators.

Photodoped chalcogenides as potential infrared holographic media.

The extension of holographic techniques from the visible to the infrared is important. Potentially, holographic diffractive elements have a large range of uses in this wave band. Examples include mirrors, lenses, filters, and beam combiners. All these elements would have similar advantages to those enjoyed by their visible band diffractive analogs. The metal photodissolution effect in chalcogenides shows promise as one of the few techniques for producing low-loss holographic materials for use at any given wavelength from 0.6 to beyond 16 microm. To date, the work has concentrated on the photodissolution of silver into arsenic sulfide glasses. Both bulk and surface relief gratings can be fabricated simply by holographic or mask exposure. In principle, kinoforms (e.g., blazed zone plates) and Fresnel lenses can also be made. The results of material studies show that phase gratings with high modulation and low absorption can be produced. A coupled-wave analysis is used to calculate the likely grating performance, and some initial grating characterization results are presented. The limitations of the medium are discussed and possible solutions are considered.