Predictive factors for histological response to neo-adjuvant treatment in rectal cancers

The complete histological response represents the goal of neo-adjuvant treatment of locally advanced rectal cancer. This objective is a real challenge requiring the research of predictive factors for this response, from the perspective of targeted therapeutic strategies. The results of the various studies focused on these predictive factors are discordant.

To seek a correlation between 7 prognostic factors tested in pre-therapy and the histological response to neo-adjuvant treatment.

A retrospective study involving 44 patients with locally advanced rectal adenocarcinoma who received neo-adjuvant radiotherapy or radiochemotherapy. The 7 prognostic factors studied were clinical (age and sex), radiological (tumor size and parietal invasion) and histological (histological grade, vascular and nerve invasion) features. The complete histological response was defined by Bateman's tumor grade m-RCRG 1 and the absence of lymph node metastases.

A complete histological response was observed in 25% of cases (n = 11). In multivariate analysis, age> 60 years (OR: 1.14 and p = 0.028), male sex (OR: 21 and p = 0.045) and radiological wall invasion exceeding the subserosa (OR: 11 , 5 and p = 0.008) were significantly associated with the histological response. In contrast, none of the 3 histological factors tested were correlated with this response's intensity.

Age, gender, and pre-therapeutic parietal invasion could be used to select "good" and "poor" responders to neo-adjuvant treatment in locally advanced rectal cancers.