Inflammatory infiltration, fibrosis, necrosis and mucinous content in relation to clinicopathological and molecular factors in rectal cancers with or without preoperative radiotherapy.

The association between inflammatory infiltration, fibrosis, necrosis and mucinous content in rectal cancers, and their relationship to preoperative radiotherapy (RT) clinicopathological and biological factors (p53, apoptosis and Cox-2) is not fully characterised. We analysed these histopathological parameters and their relationships in rectal cancer patients who participated in a clinical trial of preoperative RT. One hundred and forty-eight preoperative biopsies and 153 surgically resected tumours were examined. Of the surgical specimens, 81 had surgery alone and 72 received RT before surgery. A higher grade of inflammatory infiltration was related to favourable survival in the whole group of patients (p=0.004, for multivariate analysis p=0.01) as well as in the subgroups of patients with (p=0.04) or without RT (p=0.01). After RT, tumours showed a decreased infiltration (p=0.0003) and increased necrosis (p=0.006), strong necrosis was related to favourable survival (p=0.046). Necrosis (p=0.054) and fibrosis (p=0.06) tended to be increased in p53-negative tumours after RT. Inflammatory infiltration was a strong prognostic factor in rectal cancer patients, regardless of RT. RT tended to induce necrosis and fibrosis in p53-negative tumours.