[Histologic response after neoadjuvant therapy in rectal adenocarcinoma: own experience and review of the literature].

BACKGROUND: Neoadjuvant therapy has improved outcomes for patients with locally advanced rectal cancer. AIM AUTHORS: We studied the degree of histopathological regression after radiotherapy regimens commonly used in their clinical practice, and its effect on the pathology of by clinically founded T3-T4 rectal cancer. PATIENT AND METHODS: A total of 57 patients were investigated who underwent neoadjuvant radiotherapy or chemoradiotherapy--commonly used at our institute--for biopsy proven primary mid or lower third rectum adenocarcinoma between January and December 2004. The standard surgical treatment was anterior resection sec Dixon, Lloyd-Davies--and Hartmann's procedure, all with total mesorectal excision. RESULTS: The surgical specimens were examined by selected pathologists and a modified pathologic staging system the Rectal Cancer Regression Grade (RCRG) was used. (I) "good" response (n=12, 21%), (II) "median" response (n=25, 44%), (III) "poor" response (n=20, 35%). Significant tumor regression (RCRG I-II.) was seen in 37 patients (65%). Six patients (10.5%) have had complete pathological regression and 6 patients (10.5%) have had only microscopic foci of adenocarcinoma. CONCLUSION: Comparing of pretreatment and pathologic staging revealed that the depth of invasion was significantly downstaged. The authors also reviewed the literature of neoadjuvant therapy, total mesorectal excision, prognostic and predictive factors of rectal cancer.