Efficacy and feasibility of re-irradiation using carbon ions for pancreatic cancer that recurs after carbon-ion radiotherapy

Abstract

Background and purpose: Patients who receive carbon-ion radiotherapy (C-ion RT) for primary pancreatic cancer may experience locoregional recurrence; however, the treatment options for such patients are limited. We aimed to investigate the feasibility and efficacy of carbon-ion re-irradiation for patients with pancreatic cancer who experienced recurrence after initial C-ion RT. Materials and methods: Twenty-one patients with recurrent pancreatic cancer who underwent repeat Cion RT between December 2010 and November 2016 at our institute were retrospectively evaluated. The sites of post-initial C-ion RT failure were in-field central in 16 patients (76.2%) and marginal in 5 (23.8%). The median doses of initial and repeat C-ion RT were both 52.8 Gy (relative biological effectiveness [RBE]). Thirteen patients (61.9%) received concurrent chemotherapy with re-irradiation, while 11 (52.4%) received adjuvant chemotherapy. Results: The median follow-up period after re-irradiation was 11 months. The 1-year local control, progression-free survival, and overall survival rates were 53.5%, 24.5%, and 48.7%, respectively. Toxicity data was obtained from the patients' charts. Only 1 patient (4.8%) developed grade 3 acute toxicities and none developed grade 3 late toxicities. Univariate analysis indicated that patients who received adjuvant chemotherapy had significantly improved local control rates compared with those who did not; the 1-year local control rates were 80.0% and 0.0%, respectively (P = 0.0469). Conclusion: Repeating C-ion RT may be a reasonable option with tolerable toxicity for patients with recurrent pancreatic cancers. Adjuvant chemotherapy appears to improve the local control rate. This is the first study to examine re-irradiation using C-ion for recurrent pancreatic cancer after initial C-ion RT.

Feasibility and Safety of Repeated Carbon Ion Radiotherapy for Locally Advanced Unresectable Pancreatic Cancer

“…Recently, several reports described re-irradiation for pancreatic cancer using C-ion radiotherapy [ 11 ], stereotactic body radiotherapy (SBRT) [ 12 , 13 , 14 , 15 ], and proton therapy [ 16 ]. Re-irradiation with C-ion radiation in 21 patients at a single center resulted in an LC rate of 53.5% and a 1-year survival rate of 48.7% [ 11 ]. Only one patient developed grade 3 acute toxicity and no grade 3 or higher late toxicities were observed.…”

Carbon Ions for Hypoxic Tumors: Are We Making the Most of Them?

“…Another NIRS trial combined CIRT with concurrent gemcitabine, leading to 2-year overall survival rates of 35% in all patients and 48% in the high-dose group with stage III LAPC [ 74 ]. Encouraging results have also been reported from Gunma and Chiba with respect to C-ion reirradiation for the treatment of local recurrences [ 75 , 76 ]. A model of chemoradiotherapy for LAPC showed that Japanese results are superior to those reported in all trials conducted with X-rays in Europe and the USA in terms of TCP [ 77 ].…”

Evaluation of the availability of single‐position treatment with a rotating gantry and the validity of deformable image registration dose assessment for pancreatic cancer carbon‐ion radiotherapy

“… 1 Among the treatment options, carbon‐ion radiotherapy (CIRT) reportedly has shown some efficacy in unresectable and recurrent cases. 2 , 3 , 4 , 5 , 6 In CIRT for pancreatic cancer, the dose to the gastrointestinal (GI) tract surrounding the pancreas should be considered. In some cases, reducing the tumor dose is necessary to reduce the GI dose.…”

“…Pancreatic cancer is one of the most intractable cancers 1 . Among the treatment options, carbon‐ion radiotherapy (CIRT) reportedly has shown some efficacy in unresectable and recurrent cases 2–6 . In CIRT for pancreatic cancer, the dose to the gastrointestinal (GI) tract surrounding the pancreas should be considered.…”