Clinical Trials of Carbon Ion Radiotherapy for Early-Stage Breast Cancer

PURPOSE/OBJECTIVE(S)

Our institute conducted a clinical trial of curative partial breast irradiation using carbon ion radiotherapy (CIRT) to patients with stage 0 and I breast cancer since 2013. The purpose of this report is to evaluate treatment outcomes up to now.

MATERIALS/METHODS

To date, we have conducted three clinical trials and one advanced medical treatment (NIRS 9404 Comprehensive Research). The first study (UMIN000010848: commonly known as Breast I trial) was 4-split irradiation for stage I low-risk patients aged 60 years or older, and the next clinical study (UMIN000029478: commonly known as Breast II trial) was for Tis-1N0M0 cases of 2 cm or less. On the other hand, 4-split irradiation using standard adjuvant drug therapy according to risk combined with whole breast irradiation by X-ray, the latest clinical trial (UMIN000046859: commonly known as Breast III trial) is a single irradiation for Tis-1N0M0 patients aged 50 years or older. be. In each phase I, the dose increase test was performed, and in phase II, treatment was performed with the recommended dose determined in phase I. Advanced medical care was provided in parallel with breast I for stage I breast cancer that was difficult or rejected to participate in breast I trial.

RESULTS

By January 2023, 60 cases were enrolled. A total of 19 were enrolled In Breast I, 7 in Phase I, 12 in Phase II of the recommended dose of 60.0 Gy (RBE). A total of 14 were enrolled in the 9404 Comprehensive Research. A total of 17 were enrolled In Breast II, 5 cases in Phase I, 12 cases in Phase II of recommended dose 60.0 Gy (RBE). A total of 10 were enrolled in Breast III, 6 cases in Phase I, and 4 in Phase II of recommended dose 50.0 Gy (RBE). As acute adverse events, grade 2 of acute radiation dermatitis were observed in 1 case, grade 1 of acute radiation dermatitis was observed in 31 cases, and grade 1 of mastitis was observed in 6 cases. As a late adverse event, grade 3 of pneumonia of unknown causality were observed in one case, but there were no other problematic adverse events, and breast cosmetic outcome was excellent in all cases. Tumor disappearance after CIRT took 3 to 24 months. Local recurrence and axillary lymph node metastasis were observed in one high-risk case of advanced medical treatment who refused any other therapy. Two cases had ipsilateral intramammary metachronous breast cancer with different subtypes. To date, no other recurrences or metastases have been observed.

CONCLUSION

CIRT for early-stage breast cancer is expected to be effective with mild adverse events, and it is considered meaningful to continue research.

Clinical Outcomes of Carbon-Ion Radiotherapy for Large-Sized (≥4cm) Hepatocellular Carcinoma

PURPOSE/OBJECTIVE(S)

Radical treatment options for bulky unresectable locally advanced hepatocellular carcinoma (HCC) are limited. The purpose of this study is to evaluate the safety and efficacy of carbon-ion radiotherapy (C-ion RT) for bulky (≥4cm) locally advanced HCC.

MATERIALS/METHODS

We performed a retrospective cohort study of patients with bulky (≥4cm) locally advanced HCC treated by C-ion RT between April 2000 and March 2020 in our institution. The eligibility criteria for this study were: (1) the treatment protocols of 45.0-48.0 Gy/2 fractions or 52.8-60.0 Gy/4 fractions, which proven the safety and efficacy in the past clinical trials; (2) Tumors within 3 intrahepatic lesions and with a maximum tumor diameter of 4 cm or greater; (3) N0M0 status; (4) an Eastern Cooperative Oncology Group performance status of 0 to 2; (5) controllable ascites; (6) Child-Pugh grade was A or B. Overall survival (OS), progression-free survival (PFS), and local control rate (LC) were calculated by the Kaplan-Meier method, and Cox regression analysis was used for multivariate analysis. Adverse events were evaluated by CTCAE ver. 5.0. JMP® 12 (SAS Institute Inc., Cary, NC, USA) was used for all analyses. We defined p < 0.05 as statistically significant.

RESULTS

A total of 187 patients met the criteria and were evaluated. The median patient age was 73 years (range, 37-90), and 139 of 187 patients were male. Child-Pugh grade was A in 163 patients and B in 24. Modified albumin-bilirubin (mALBI) grade was 1 in 96 patients, 2a in 50, and 2b in 41. The number of HCV-related HCC cases was in 80, HBV in 32 and non-B and non-C in 75. In 51 patients, identification of vascular invasion to the first-order branch of the portal vein and/or major hepatic vein was confirmed. The median maximum tumor diameter was 5.1 cm (4.0-13.5 cm). In 76 patients, C-ion RT were treated for recurrence. With a median follow-up period of 25.9 months (range, 1.1-215.1), 2-year overall survival, progression-free survival and local control rates were 68.3% (95% confidence interval [CI], 64.7-72.0%), 39.0% (95% CI, 35.2 - 42.8%) and 86.7% (95% CI, 84.7 - 89.7%), respectively. Late adverse events were observed in 3 patients (1.6%) with Grade 3 liver dysfunction and in 3 patients (1.6%) with Grade 3 skin disorders, but there were no cases of Grade 4 or higher. Multivariate analysis of prognostic factors for overall survival revealed that mALBI grade in 2b(HR:3.13, 1.97-4.78, p<0.0001), tumor status in recurrent treatment (HR:1.50, 1.02-2.21, p = 0.039), the number of tumors in 2 or more (HR:2.16, 1.01-2.17, p = 0.045), and maximum tumor diameter in larger than 6 cm (HR:2.34, 1.50-3.61, p = 0.0001) were the predominant prognostic factors, while age, presence of vascular invasion, AFP and DCP were not.

CONCLUSION

The safety and efficacy of C-ion RT for bulky (≥4cm) locally advanced HCC was demonstrated. These results suggested that C-ion RT may be a new treatment option for locally advanced bulky HCC with no curative treatment options.

Long-Term Clinical Outcome of Carbon Ion Radio Therapy for Hepatocellular Carcinoma in the Caudate Lobe

PURPOSE/OBJECTIVE(S)

Surgical resection is the first-line treatment for hepatocellular carcinoma in the caudate lobe (caudate HCC), but it is often difficult due to the tumor's location. In addition, radiofrequency ablation and transcatheter arterial chemoembolization are also difficult for the same reason. This study aimed to evaluate the safety and efficacy of carbon-ion radiation therapy (C-ion RT) for caudate HCC.

MATERIALS/METHODS

We performed a retrospective cohort study of patients with hepatocellular carcinoma treated by C-ion RT between April 2000 and March 2020 in our institution. The eligibility criteria for this study were: (1) located mainly in the caudate lobe (2) the treatment protocols of 45.0-48.0 Gy/2 fractions or 52.8-60.0 Gy/4 fractions, which proved the safety and efficacy in the past clinical trials; (3) N0M0 status; (4) an Eastern Cooperative Oncology Group performance status (PS) of 0 to 2; (5) controllable ascites. The prescribed dose (Gy) used in this study is relative biological effectiveness (RBE) weighted dose. Overall survival (OS), progression-free survival (PFS), and local control rate (LC) were calculated by the Kaplan-Meier method. Adverse events were evaluated by NCI-CTCAE ver. 5.0. SPSS software version 27.0 (IBM Inc.) was used for all analyses. We defined p-value < 0.05 as statistically significant.

RESULTS

A total of 25 patients met the criteria and were evaluated. The median patient age was 73 years (range 58-89), and 21 of 25 patients were male. The number of patients with PS 0 was 22, PS 1 was 1, and PS 2 was 2. The number of HBV-related HCC cases was in 8, HCV-related HCC cases was in 11, and non-B and non-C cases was in 6. The median maximum tumor diameter was 3.0 cm (1.1-4.8 cm). In 6 patients, identification of vascular invasion to the main trunk of the portal vein and/or major hepatic vein was confirmed. The Child-Pugh (CP) grade was A in 21 patients and B in 4. The modified albumin-bilirubin (mALBI) grade 1 is in 17 patients, 2a in 4, 2b in 4. Prescribed doses were 45 Gy / 2 fr in 3 cases, 48 Gy / 2 fr in 12 cases, 52.8 Gy / 4 fr in 7 cases, and 60 Gy / 4 fr in 3 cases. With a median follow-up period of 43.6 months (range 0.3-85.0), 3-year OS, PFS, and LC were 74% (95% confidence interval [CI], 54.8-93.8%), 32% (95% CI, 11.8-51.4%), and 93% (95% CI, 79.4-106%), respectively. All patients had no Grade 2 or higher adverse events during the observation period.

CONCLUSION

The safety and efficacy of C-ion RT for caudate HCC were demonstrated. These results suggested that C-ion RT may be a promising treatment option for patients with caudate HCC.

Significance of Hypofractionated Radiotherapy in Postoperative Irradiation for Breast Cancer: An Asian Multi-institutional Prospective Study

AIMS

There is a need for the adequate distribution of healthcare resources in Southeast Asia. Many countries in the region have more patients with advanced breast cancer who are eligible for postmastectomy radiotherapy (PMRT). Therefore, it is critical that hypofractionated PMRT is effective in most of these patients. This study investigated the significance of postoperative hypofractionated radiotherapy in patients with breast cancer, including advanced breast cancer, in these countries.

MATERIALS AND METHODS

Eighteen facilities in 10 Asian countries participated in this prospective, interventional, single-arm study. The study included two independent regimens: hypofractionated whole-breast irradiation (WBI) for patients who had undergone breast-conserving surgery and hypofractionated PMRT for patients who had undergone total mastectomy at a dose of 43.2 Gy in 16 fractions. In the hypofractionated WBI group, patients with high-grade factors received additional 8.1 Gy boost irradiation sessions for the tumour bed in three fractions.

RESULTS

Between February 2013 and October 2019, 227 and 222 patients were enrolled in the hypofractionated WBI and hypofractionated PMRT groups, respectively. The median follow-up periods in the hypofractionated WBI and hypofractionated PMRT groups were 61 and 60 months, respectively. The 5-year locoregional control rates were 98.9% (95% confidence interval 97.4-100.0) and 96.3% (95% confidence interval 93.2-99.4) in the hypofractionated WBI and hypofractionated PMRT groups, respectively. Regarding adverse events, grade 3 acute dermatitis was observed in 2.2% and 4.9% of patients in the hypofractionated WBI and hypofractionated PMRT groups, respectively. However, no other adverse events were observed.

CONCLUSION

Although further follow-up is required, hypofractionated radiotherapy regimens for postoperative patients with breast cancer in East and Southeast Asian countries are effective and safe. In particular, the proven efficacy of hypofractionated PMRT indicates that more patients with advanced breast cancer can receive appropriate care in these countries. Hypofractionated WBI and hypofractionated PMRT are reasonable approaches that can contain cancer care costs in these countries. Long-term observation is required to validate our findings.

Individual response of humans to ionising radiation: governing factors and importance for radiological protection

Tissue reactions and stochastic effects after exposure to ionising radiation are variable between individuals but the factors and mechanisms governing individual responses are not well understood. Individual responses can be measured at different levels of biological organization and using different endpoints following varying doses of radiation, including: cancers, non-cancer diseases and mortality in the whole organism; normal tissue reactions after exposures; and, cellular endpoints such as chromosomal damage and molecular alterations. There is no doubt that many factors influence the responses of people to radiation to different degrees. In addition to the obvious general factors of radiation quality, dose, dose rate and the tissue (sub)volume irradiated, recognized and potential determining factors include age, sex, life style (e.g., smoking, diet, possibly body mass index), environmental factors, genetics and epigenetics, stochastic distribution of cellular events, and systemic comorbidities such as diabetes or viral infections. Genetic factors are commonly thought to be a substantial contributor to individual response to radiation. Apart from a small number of rare monogenic diseases such as ataxia telangiectasia, the inheritance of an abnormally responsive phenotype among a population of healthy individuals does not follow a classical Mendelian inheritance pattern. Rather it is considered to be a multi-factorial, complex trait.