Repeated adjuvant anti-CEA radioimmunotherapy after resection of colorectal liver metastases: Safety, feasibility, and long-term efficacy results of a prospective phase 2 study.

BACKGROUND: In previous work, a single administration of anticarcinoembryonic antigen (anti-CEA) 131 I-labetuzumab radioimmunotherapy (RIT) after complete resection of colorectal liver metastases was well tolerated and significantly improved survival compared with controls. In the current phase 2 trial, the authors studied repeated RIT in the same setting, examining safety, feasibility, and efficacy. METHODS: Sixty-three patients (median age, 64.5 years) received RIT at 40 to 50 millicuries/m2 per dose. Before the receipt of RIT, restaging was performed with computed tomography/magnetic resonance imaging and 18 F-fluorodeoxyglucose-positron emission to confirm that patients were "truly adjuvant." Patients who had elevated serum CEA levels or radiographically inconclusive new lesions were classified as "possibly nonadjuvant," but they also received RIT. Time to progression (TTP), overall survival (OS), and cause-specific survival (CSS) were calculated. The median follow-up was 54 months. RESULTS: After the first course of RIT, 14 of 63 patients experienced National Cancer Institute Common Toxicity Criteria grade 4 hematotoxicity; 19 patients did not receive the second course of RIT because of impaired performance status (N = 5) or relapse (N = 14). After the second course of RIT, 9 of 44 patients experienced National Cancer Institute Common Toxicity Criteria grade 4 hematotoxicity. Five patients developed myelodysplastic syndrome (MDS) from 22 to 55 months after their last RIT. The median TTP, OS, and CSS for all patients were 16, 55, and 60 months, respectively. The "truly adjuvant" patients (N = 39) had an improved median TTP (not reached vs 6.1 months; hazard ratio, 0.12; P < .001), OS (75.6 vs 33.4 months; hazard ratio, 0.44; P = .014), and CSS (not reached vs 41.4 months; hazard ratio,0.42; P = .014) compared with "possibly nonadjuvant" patients (N = 24). CONCLUSIONS: Repeated RIT with 131 I-labetuzumab is feasible but is associated with hematotoxicity. Survival is very encouraging, especially for "truly adjuvant" patients. However, the maximum safe dose of 131 I-labetuzumab is a single administration of 50 millicuries/m2 . Cancer 2017;123:638-649. © 2016 American Cancer Society.

Multimodal treatment options for bilobar colorectal liver metastases.

PURPOSE: We evaluated individualized multimodal oncological strategies in patients with bilobular colorectal liver metastases (biCRC-LM) as well as their effect on R0 resection rates, disease-free survival (DFS), and overall survival (OS). METHODS: Between January 2001 and December 2008, 64 patients were assigned to straightforward or two-stage liver resection +/- preoperative 5-fluorouracil (5FU)-based chemotherapy (CTx). Postoperative strategy after R0-resection was either "wait and see" or "adjuvant" therapy (3 cycles of CTx or anti-carcinoembryonic antigen (CEA)-radioimmunotherapy with (131)I-labetuzumab in a dose of 40-50 mCi/m(2)). RESULTS: Forty-three initially unresectable patients received preoperative CTx for downsizing of their biCRC-LM. Straightforward or two-stage liver resection was intended in 40 and 24 patients, respectively. Histopathologically confirmed R0-liver resection could be achieved in 47 patients. Surgical morbidity and mortality rates were 33% and 1.5%, respectively. Postoperatively, 26 patients received anti-cancer therapy (5 x CTx, 21 x anti-CEA-radioimmunotherapy). After R0-liver resection, median OS was significantly better compared to R1/R2 resections followed by palliative 5FU-CTx (38 versus 19 months, p = 0.035). There was no significant difference in DFS (p = 0.650) and OS (p = 0.435) between straightforward and two-stage liver resection. Compared to "wait and see" strategy, the application of postoperative therapy in adjuvant intent was associated with a better OS (p = 0.048). CONCLUSION: Extensive liver resection within multimodal treatment concepts is justified in patients with biCRC-LM when complete resection of all metastases seems to be achievable.