Long‐term clinical outcomes after 12‐fractionated carbon‐ion radiotherapy for localized prostate cancer

Abstract

There are no clinical reports of long‐term follow‐up after carbon‐ion radiotherapy (CIRT) using a dose of 51.6 Gy (relative biological effectiveness [RBE]) in 12 fractions for localized prostate cancer, or of a comparison of clinical outcomes between passive and scanning beam irradiation. A total of 256 patients with localized prostate cancer who received CIRT at a dose of 51.6 Gy (RBE) in 12 fractions using two different beam delivery techniques (passive [n = 45] and scanning [n = 211]), and who were followed for more than 1 year, were analyzed. The biochemical relapse‐free (bRF) rate was defined by the Phoenix definition, and the actuarial toxicity rates were evaluated using the Kaplan‐Meier method. Of the 256 patients, 41 (16.0%), 111 (43.4%), and 104 (40.6%) were classified as low, intermediate, and high risk, respectively, after a median follow‐up of 7.0 (range 1.1‐10.4) years. Androgen deprivation therapy was performed in 212 patients (82.8%). The 5‐year bRF rates of the low‐, intermediate‐, and high‐risk patients were 95.1%, 90.9%, and 91.1%, respectively. The 5‐year rates of grade 2 late gastrointestinal and genitourinary toxicities in all patients were 0.4% and 6.3%, respectively. No grade ≥3 toxicities were observed. There were no significant differences in the rates of bRF or grade 2 toxicities in patients who received passive irradiation versus scanning irradiation. Our long‐term follow‐up results showed that a CIRT regimen of 51.6 Gy (RBE) in 12 fractions for localized prostate cancer yielded a good therapeutic outcome and low toxicity rates irrespective of the beam delivery technique.

64Cu-ATSM Predicts Efficacy of Carbon Ion Radiotherapy Associated with Cellular Antioxidant Capacity

“…To investigate the association between the RBE of carbon ions and cellular 64 Cu-ATSM uptake in cancer cells in vitro, we first assessed the X-ray- or carbon ion-sensitivity of ten human cancer cell lines originated from the cancer types targeted by CIRT in the clinic ( Supplementary Table S1 ) [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. The cell lines showed various sensitivities to the radiation; however, the cell killing effect was greater for carbon ions than for X-rays in all cell lines examined ( Figure 1 A).…”

“…Carbon ion radiotherapy (CIRT) is an emerging cancer treatment modality that has a greater therapeutic window than conventional photon radiotherapy [ 1 ]. Clinical evidence suggests that CIRT shows promising antitumor effects against a wide spectrum of cancers, including head and neck cancer [ 2 ], lung cancer [ 3 , 4 ], colorectal cancer [ 5 ], prostate cancer [ 6 , 7 ], and sarcoma [ 8 ]. Preclinical evidence suggests that carbon ions exert strong cell killing effects even against photon-resistant cells and that the relative biological effectiveness (RBE) of carbon ions over photons varies widely among different cell lines [ 9 , 10 , 11 ].…”

Landscape of Carbon Ion Radiotherapy in Prostate Cancer: Clinical Application and Translational Research

“…Therefore, a dose of 51.2 GyE/ 12Fx was prescribed for subsequent NIRS. The clinical outcome of 51.2 GyE/12Fx regimen indicated that 5-year bRFS in low-, intermediate-, and high-risk patients was 95.1%, 90.9%, 91.1%, respectively; and the late grade 2 GU and GI toxicity was 6.3% and 0.4% (45). Studies on carbon ion radiotherapy for prostate cancer at other institutions in Japan are shown in Table 3.…”

Carbon Ion Radiotherapy Induce Metabolic Inhibition After Functional Imaging-Guided Simultaneous Integrated Boost for Prostate Cancer

“…Carbon ion radiotherapy (CIRT) is an emerging cancer treatment strategy (2)(3)(4)(5)(6) for PCa patients which has a stronger effect on tumor cells per physical dose (higher relative biological effect) and better dose distribution compared with photon-based radiotherapies (7). Numerous studies (8)(9)(10)(11) from Japan reported that CIRT may improve 5-and 10-year progressionfree survival rates with favorable late genitourinary and gastrointestinal toxicities compared with photon radiotherapy.…”