Degree of tumor regression after preoperative chemo-radiotherapy in locally advanced rectal cancer-Preliminary results.

Aim: The aim of this investigation is to determine the degree of tumor regression by histopathological evaluation of surgical specimen after neoadjuvant chemo-radiotherapy for patients with stage IIIB rectal cancer.

Background: The standard therapy for rectal carcinoma is surgical, however, preoperative radiochemotherapy will play an increasing role especially in locally advanced disease. To estimate the prognosis and the effect of radiochemotherapy the postradiochemotherapeutical pathological features are important to assess.

Materials And Methods: Ten patients with cT3-4, cN1 stage rectal cancer received preoperative chemo-radiotherapy. A total tumor dose of 50 Gy was applied to all patients, with a daily fraction of 2 Gy, 5 times a week, with concomitant Capecitabine 1650 mg/m(2). A pathomorphologic assessment of the therapeutic response of the residual tumor volumes and estimation of tumor control were performed using Dworak's system of tumor regression grading (TRD) from no regression (0) to a complete tumor control (4).

Results: Dworak's TRD for the examined patients is as follows: in 20% of the patients no tumor regression was observed - Grade 0, in 30% - Grade 1, in 20% - Grade 2 and in 30% a complete tumor regression was achieved - Grade 4. Four of the patients (40%) presented with borderline resectable tumors before the neoadjuvant chemo-radiotherapy. Nine of the patients (90%) underwent radical surgery. In one case (10%) a radical surgery was not possible. One patient (10%) developed severe radiation enteritis in both the early and late postoperative period, with her tumor regression evaluated as Grade 4.

Conclusion: Accurate evaluation of local tumor control using Dworak's tumor regression grading scale after preoperative chemo-radiotherapy gives the basis for a larger investigation and search for a correlation with the prognosis of the disease and individual choice of adjuvant treatment.