Background: The effectiveness of proton beam therapy (PBT) as initial treatment for patients with unresectable intrahepatic cholangiocarcinoma (ICC) is unclear, particularly as related to ICC histological subtypes. We performed this study to address this gap in knowledge. Methods: Thirty-seven patients with unresectable ICC who underwent PBT as their initial treatment were evaluated. Twenty-seven patients had Child-Pugh class A liver function, 11 exhibited jaundice, and 10 had multiple tumors. Nineteen, 7, and 11 tumors were classified as mass forming (MF), periductal infiltrating (PI), and intraductal growth (IG) types, respectively, based on gross appearance in imaging studies. Patients were classified into the curative group (n = 25) and palliative group (n = 12) depending on whether the planning target volume covered all the macroscopic tumors. Results: The 1- and 2-year overall survival rates were 60.3, and 41.4%, respectively; the median survival time (MST) was 15 months for all patients. The MSTs for curative and palliative groups were 25 and 7 months, respectively. Curative treatment and adjuvant chemotherapy significantly improved overall survival, while the presence of periductal infiltrating type tumors was a negative prognostic factor. In the curative group, the 1- and 2-year local control rates were 100 and 71.5%, respectively, while the 1-, and 2-year progression-free survival rates were 58.5, and 37.6%, respectively. No severe acute toxicities were observed. Three patients experienced grade 3 biliary tract infection, although it was unclear whether this was radiotherapy-related. Conclusion: PBT may yield to improve survival and local tumor control among patients with unresectable ICC.

Glioblastoma (GBM) is difficult to cure with conventional multimodal treatment and has an extremely poor prognosis. Boron neutron capture therapy (BNCT) is a new particle therapy for malignant tumors in the brain and head and neck region. This radiotherapy utilizes a nuclear reaction between neutrons and a nonradioactive isotope, boron-10. In this method, a boron compound is administered transvenously into the body. The boron compound has the property of being selectively taken up only by the cells of malignant tumors, and the subsequent irradiation with neutrons can destroy malignant tumor cells without damaging normal cells. Since the irradiation dose to normal tissues is reduced in BNCT, it may be possible to re-irradiate malignant tumors that recur after radiotherapy. Clinical trials have reported prolonged survival and safety of BNCT in a small number of patients with refractory malignancies, including GBM, but these reports do not address quality of life or activities of daily living (ADL) after treatment, and there is no information on the assessment of local control by imaging. Here, we report a case of GBM that recurred after surgery, 60 Gy of conventional radiotherapy and standard treatment with temozolomide. The patient achieved long-term local control and survival over five years after BNCT and was able to maintain ADL at home without any specialist care. We describe the case with evaluation using longitudinal magnetic resonance imaging (MRI).

This report details the experience of a patient who developed a second primary glioblastoma (GB), offering insights into the treatment process and reviewing relevant literature. A male patient, who was diagnosed with medulloblastoma at age 9, received treatment with cobalt-60 craniospinal irradiation (CSI) (36 Gy/20 fractions) and a tumor bed boost (total of 56 Gy). After 32 years, at age 41, an MRI revealed a space-occupying mass in the left cerebellar hemisphere. Surgical resection was performed, and postoperative pathology confirmed a diagnosis of radiation-induced glioblastoma (RIGB). Given the history of irradiation and the current tolerability of brainstem doses, proton beam therapy (PBT) combined with Temozolomide (75 mg/m2) was chosen. The treatment plan included 60 Gy on the gross tumor bed and 54 Gy on the clinical target volume, delivered in 30 fractions. The patient underwent regular follow-up and achieved a complete response. For childhood cancer survivors, the development of a second primary tumor significantly impacts prognosis. RIGB is a rare form of secondary tumor with distinct molecular characteristics compared to primary GB and recurrent secondary GB. Molecular markers such as IDH and MGMT status can help differentiate between primary GB, recurrent secondary GB, and radiation-induced secondary GB in patients with a history of prior radiation therapy. Surgical resection remains a primary treatment option, while PBT is preferred for postoperative treatment due to its superior protection of normal tissues and the ability to deliver high-dose irradiation. RIGB is a rare second primary tumor that requires strategic molecular profiling and individualized management. Proton beam therapy provides effective high-dose irradiation in the postoperative phase and is the preferred treatment option for such cases.

This case report and literature review presents a 4-month-old infant with a synchronous malignant rhabdoid tumor of the kidney and adrenal neuroblastoma, an exceptionally rare combination without established treatment guidelines. Following surgical resection, proton beam therapy (14 Gy in 10 fractions) was administered to the abdominal–pelvic tumor bed with stringent organ-sparing objectives. Contemporary literature supports proton beam therapy’s (PBT’s) dosimetric advantages for organ preservation in pediatric abdominal malignancies. At 1-year follow-up, the patient remained disease-free, with preserved renal function and normal skeletal development, supporting PBT’s role in minimizing late effects while achieving local control in infant malignancies when conventional photon radiotherapy would pose substantial developmental risks.

Paragangliomas (PGLs) are rare neuroendocrine tumors with malignant potential that may prove challenging to manage. Those arising at the jugular foramen are particularly problematic, especially if recurring after primary surgical treatment. Long‑term follow‑up is required, and effective treatment options for such recurrences are needed. The present study chronicles a recurring PGL of the jugular foramen that emerged after two surgeries. Alternative therapeutic strategies were accordingly pursued. This account of the related clinical course includes a discussion of the associated literature, focusing on the role of proton beam therapy (PBT) in PGL management and its benefits. The patient under treatment received hypofractionated PBT, utilizing intensity‑modulated proton therapy/pencil‑beam scanning techniques. The prescribed dose was 40 Gy in 15 fractions [equivalent dose in 2‑gy fractions (EQD2), 42.09 Gy, assuming α/β=10) delivered to the gross tumor volume (GTV). Simultaneous integrated boosts to two inner subvolumes [GTV reduced by 2‑mm margin, 50 Gy/15 fractions (EQD2, 55.49 Gy); and GTV reduced by 3‑mm margin, 60 Gy/15 fractions (EQD2, 70.00 Gy)] took place as well. This process ensured precise radiation dosing, while adhering to strict dose constraints for adjacent critical structures. Hence, a quicker therapeutic response (aligned with that of stereotactic radiotherapy principles) was tenable, aiming for both tumor control and clinical improvement. Long‑term follow‑up is imperative to assess outcome durability. The aforementioned events illustrate the potential utility of advanced PBT techniques (namely pencil‑beam scanning, hypofractionated regimens) in managing PGL recurrences of this type, especially if surgical options are limited or carry substantial risks. PBT offers a precise therapeutic alternative, with tumor control capabilities that promise to preserve critical tissues near key locations at the base of the skull.