[Locally restricted dose escalation in radiotherapy of primary advanced and recurrent rectal cancers]

Prognosis in patients with resected rectal carcinomas is correlated to local tumor control. Percutaneous (EBRT) and intraoperative boost irradiation (IORT) can improve local control. The aim of this study was to analyse the role of locally restricted dose escalation and the possibility to integrate IORT in a multi-modality adjuvant treatment approach.

A total of 128 and 71 patients with primary and recurrent disease were eligible for analysis. More than 60% of patients suffered from a stage III carcinoma. Between 26.3 and 38.8% of patients revealed lymphangiosis carcinomatosa in pathohistological examination. A dose of 40.2 Gy was applied using multiple field techniques. Either a percutaneous boost dose of 18.3 Gy or an intraoperative boost dose of 12.1 Gy was given in 97 and 62 patients. 40 patients with non-resectable recurrent carcinomas were treated with radiotherapy alone. In respectively 67.4% and 52.6% of IORT patients (primary and recurrent) a simultaneous chemotherapy was given, whereas only 16.5% and 8.3% of patients with EBRT alone had additional chemotherapy.

Five-year overall survival was 64% and 41% in stage II and III (T2-3) carcinomas. All patients with stage III (T4) carcinomas died within 3 years. Overall the local failure rate was correlated to tumor stage (12.7 to 19.7%) and lymphangiosis carcinomatosa (12.5 vs. 22.9%). In patients with radiotherapy alone, local failure rate decreased with increasing irradiation dose (32%/40 to 48 Gy, 25%/49 to 56 Gy, 20.5%/57 to 66 Gy 0%/40.2 Gy + IORT). The overall 2-year survival was significantly improved after IORT and IORT plus simultaneous chemotherapy in both primary and recurrent disease. Perioperative morbidity was not increased. The toxicity of the multi-modality approach with IORT was low and acceptable.

The local tumor control in rectal carcinoma after radiotherapy was dose dependent, IORT could be integrated in an adjuvant multi-modality treatment concept, without increasing morbidity. Local failure rate could be markedly reduced.