The role of neoadjuvant therapy in the multimodal treatment of rectal cancer - clinical outcome

Abstract

A retrospective analysis of two pre-surgical treatment modalities in patients with stage II and III rectal neoplasms was performed from January 1998 to January 2008 at the Department of Radiation Oncology, St. Elisabeth Cancer Institute and the Slovak Medical University in Bratislava. 96 patients were treated with short-term pre-surgical radiotherapy using a total dose of 25 Gy in five fractions and subsequently treated with surgery in the five-day interval after radiotherapy. Long-term radiotherapy was applied to 55 patients with the entire doses of 50.4 Gy fractionated 1.8 to 2.0 Gy/day with or without the chemoradiotherapy based on 5-fluorouracil. In this group of patients the surgery was performed four to eight weeks after termination of the radiotherapy. Patients belonging to both investigation groups were irradiated by means of an X-ray linear accelerator 6-18 MV, the 3D conformal radiotherapy, the three convergent field technique, or by the BOX technique. The effect of both treatment modalities on the selection of surgical intervention, down-staging, pathological complete remission (pCR), frequency of local recurrences and distant metastasis, toxicity, the overall survival (OS) and disease-free survival (DFS) related to the disease stage were analysed. From the statistic perspective significantly more patients with progressing rectal cancer were treated with long-term radiotherapy as compared to short-term treatment (p = 0.00002 < 0.05). It is to be noted that all results of the present study should be considered in this context. Down-staging as well as pCR were achieved solely in patients treated with long-term radiotherapy. Concerning the LR frequency, the occurrence of distant metastasis, toxicity, OS and DFS, no statistically significant difference of long-term vs short-term radiotherapy was registered. On the other hand, in contrastto the radiotherapy alone, a statistically significant improvement in the LR, frequency of distant metastases, OS and DFS was observed in patients treated with long-term pre-surgical chemotherapy. Our results are relevant to comparable randomised studies indicating that long-term chemoradiotherapy is more beneficial for the treatment of patients with advanced rectal neoplasms. The ongoing clinical trials indicate a new alternative of pre-surgical short-term radiotherapy with concomitant chemotherapy followed by surgery in a four-week interval after the termination of radiotherapy.