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This retrospective study was conducted on 255 consecutive patients with locally advanced squamous-cell carcinoma of the oral cavity, oropharynx, larynx or hypopharynx, treated at the Radiotherapy Department of Pordenone General Hospital between January 1975 and December 1985. All patients underwent radical surgery followed, after an interval ranging from 10 days to 2.9 months, by radiotherapy given either through a 6 MeV linear accelerator or a cobalt-60 unit. Field extension and dose delivered were comparable in relation to stage and involvement of the surgical resection margins. The aims of the study were to evaluate the survival rate and to analyze the clinical parameters which can influence the disease-free survival. The adjusted overall 5-year survival rate was 71%; stage, performance status at diagnosis, and site of the primary tumor were significant factors in determining patient prognosis, whereas Infiltration of resection margins was not significant in determining locoregional control of disease. Seventy-five patients relapsed and 67 died of cancer-related diseases whereas death in 52 patients was not related to the head and neck cancer. The combined modality treatment consisting of surgery followed by radiotherapy was well tolerated and proved to be effective in the treatment of locally advanced head and neck tumors.

Recent theoretical investigations treat quantum computations as functions, quantum processes which operate on other quantum processes, rather than circuits. Much attention has been given to the N-switch function which takes N black-box quantum operators as input, coherently permutes their ordering, and applies the result to a target quantum state. This is something which cannot be equivalently done using a quantum circuit. Here, we propose an all-optical system design which implements coherent operator permutation for an arbitrary number of input operators. [ABSTRACT FROM AUTHOR]