22 Chapter 2 Pre- and post-induction treatment tumour diameters were measured on CT/MRI scans. Response evaluation was performed according to the RECIST criteria 31. In the surgical resection specimens, tumour size was measured on gross pathological exam and the tumour diameter was retrieved from the pathology report. Histological slides of all available paraffin blocks together with the pathology reports of the resection specimens were reviewed. In each case the number of blocks related to the tumour area was estimated. Tumour type was based on the most classifiable specimen, either the pre-treatment histology or cytology, or the resection specimen. For example, a case with a pretreatment biopsy diagnosis of non-small cell carcinoma not otherwise specified, and a resection specimen diagnosis of squamous cell carcinoma was classified as squamous cell carcinoma. In cases without viable tumour in the resection specimen, the tumour was classified according to the pre-treatment histology or cytology. In order to evaluate the histopathologic changes within the tumour mass, items such as amount of viable tumour, fibrotic changes, vasculopathy and intra- and peritumoural inflammatory reaction were identified and for applicable items a semi-quantitatively scoring system was used as shown in Table 1. Table 1. Criteria for scoring histology Item/category 0 1 2 3 41 Tumour type2 Squamous cell Adenocarcinoma Large cell Other, specify Viable tumour3 no vital tumour cells <10% vital tumour cells 10-50% vital tumour cells >50%% vital tumour completely vital tumour Tumour location within mass Not relevant (no tumour) Randomly distributed Mainly peripherally Mainly centrally Diameter macroscopical mass4 ≤ 2 cm > 2 and ≤ 3 cm > 3 and ≤ 5 cm > 5 and ≤ 7 cm > 7 cm Dominant tumour growth pattern Not relevant (no tumour) Mainly confluent nests Randomly distributed nests or cells Mainly perivascular Other, specify Cytonuclear atypia tumour5 Not relevant (no tumour) Slight (uniform nuclei, small nucleoli) Moderate (variation nuclear size, prominent nucleoli) Severe (bizarre nuclei, macronucleoli) Extreme (mainly bizarre nuclei) Mitotic activity7 Not applicable (no tumour) Low (less then 1/ HPF) Moderate (1-3/HPF) High (more then 3/ HPF) Atypical mitosis7 Not applicable (no tumour) None Few (1/HPF) Several (more then 1/ HPF) Amount of fibrosis - necrosis Just fibrosis Mainly fibrosis (> 75%) Equal fibrosisnecrosis Mainly necrosis (> 75%) Just necrosis Presence of cholesterol clefts None Just in alveolar spaces Focal Extensive Presence of foamy macrophages None Focal Extensive
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