Concurrent chemoradiation of metastases with capecitabine and oxaliplatin and 3D-CRT in patients with oligometastatic colorectal cancer: results of a phase I study

BACKGROUND Local control appears to be an important treatment aim in patients with limited metastases (oligometastases) of colorectal cancer (CRC). Those patients show a favourable prognosis, if--in addition to the local effective treatment--an occurrence of new metastases may also be postponed by effective systemic therapy. The purpose of this dose escalation phase I study was to establish the efficacy of local radiotherapy (RT) of oligometastatic CRC with a concurrent standard chemotherapy regimen. METHODS Patients with first-, second- or third-line therapy of oligometastatic CRC (1-3 metastases or local recurrence plus max. 2 metastases) received capecitabine (825 mg/m²/d BID d 1-14; 22-35) and oxaliplatin (50 mg/m² d 1, 8, 22, 29). 3D-conformal RT of all metastatic lesions was delivered in 2.0 Gy up to 36 Gy to 50 Gy (3 dose levels). Primary endpoint was the maximal tolerable dose (MTD) of RT defined as the level at which two or more of six patients experienced dose-limiting toxicity (DLT). RESULTS Between 09/2004 and 08/2007, 9 patients (7 male, 2 female, 50-74 years) were enrolled, 6 patients treated at dose level 1 (36 Gy), 3 patients at dose level 2 (44 Gy). 1 patient from the first cohort experienced DLT (oxaliplatin-related hypersensitivity reaction). No radiation-induced DLT occurred. 6/9 patients achieved objective response (partial remission). One year after initiation, all patients were alive, 6 patients survived (16 to 54 months) patients died of tumor progression (14 to 23 months). The phase II part of the trial had to be closed due to recruitment failure. CONCLUSIONS Local 3D-CRT to metastatic lesions in addition to standard chemotherapy was feasible, DLT was not documented. 3/9 patients survived for a period of 3.5 to 4.4 years (time at the last evaluation). Radiotherapy of metastatic lesions should be incorporated into subsequent trials.