Usefulness of two independent histopathological classifications of tumor regression in patients with rectal cancer submitted to hyperfractionated pre-operative radiotherapy

Abstract

INTRODUCTIONColorectal cancer is the third most common malignancy diagnosed in the USA [1] . The estimated colorectal cancer mortality in the USA in 2006 is 55 170 [2] . The primary treatment method for rectal cancer is surgery, namely anterior rectal resection, abdomino-perineal resection or local excision [3][4][5][6] . Preoperative radiotherapy and radiochemotherapy play an increasing role in the treatment of rectal cancer [7][8][9][10][11][12][13] . The effectiveness of neo-adjuvant therapy may be assessed and monitored by means of longterm survival follow up, incidence of local recurrence, estimation of the percentage of patients with primary high stage tumor suitable for radical surgery, estimation of the percentage of patients suitable for sphincter-saving surgery or by monitoring the tumor stage using visualizing diagnostic methods [14,15] . Transrectal ultrasound (TRUS) is a useful method for the assessment of the local tumor stage and the regional lymph node status prior to neo-adjuvant therapy [3,4,6,16] . Basing on TRUS and histopathological examination one can define the tumor reg ression parameter "T-downstaging". Lower ypT parameter value (local tumor stage assessed by the pathologist in surgical specimen following neo-adjuvant therapy) than uT (local Abstract AIM: To assess the usefulness of two independent histopathological classifications of rectal cancer regression following neo-adjuvant therapy. METHODS:Forty patients at the initial stage cT3NxM0 submitted to preoperative radiotherapy (42 Gy during 18 d) and then to radical surgical treatment. The relationship between "T-downstaging" versus regressive changes expressed by tumor regression grade (TRG 1-5) and Nasierowska-Guttmejer classification (NG 1-3) was studied as well as the relationship between TRG and NG versus local tumor stage ypT and lymph nodes status, ypN. RESULTS:Complete regression (ypT0, TRG 1) was found in one patient. "T-downstaging" was observed in 11 (27.5%) patients. There was a weak statistical significance of the relationship between "T-downstaging" and TRG staging and NG stage. Patients with ypT1 were diagnosed as TRG 2-3 while those with ypT3 as TRG5.No lymph node metastases were found in patients with TRG 1-2. None of the patients without lymph node metastases were diagnosed as TRG 5. Patients in the ypT1 stage were NG 1-2. No lymph node metastases were found in NG 1. There was a significant correlation between TRG and NG. CONCLUSION:Histopathological classifications may be useful in the monitoring of the effects of hyperfractionated preoperative radiotherapy in patients