Asia’s First Study: Five Sessions of Proton Therapy for Early-Stage Prostate Cancer

HONG KONG, March 20, 2026 /PRNewswire/ — The HKSH Medical Group (HKSH) has announced the results of Asia’s inaugural clinical study focusing on early-stage prostate cancer patients who received a regimen of five sessions of proton therapy. The findings indicate significant efficacy, evidenced by a notable reduction in prostate-specific antigen (PSA) levels alongside only mild side effects.

Traditionally, proton therapy for prostate cancer necessitates approximately 30 treatment sessions over a span of 8 to 9 weeks. However, since the introduction of proton therapy services in 2023, the HKSH Cancer Centre has enhanced treatment precision through the implementation of hypofractionation, effectively reducing the number of sessions by 80%. For patients with early-stage prostate cancer, treatment can now be completed in just 2 to 3 weeks with 5 sessions of proton therapy, facilitating improved disease control.

The inherent properties of proton beams allow for precise tumour targeting, minimising damage to adjacent essential organs such as the bladder and bowel. This advancement is crucial in promoting an enhanced quality of life for patients throughout their cancer treatment journey.

Dr. Ben YU, Head of the Medical Physics Department at HKSH, alongside other key figures including Dr. Joseph CHAN, Chief Medical Officer, and Dr. Darren POON, Associate Director of the HKSH Comprehensive Oncology Centre, presented the data from this groundbreaking study.

Key Achievements in Proton Therapy

Dr. POON remarked on the significance of integrating proton therapy with advanced targeting technologies, highlighting that “the foundation of hypofractionation rests on our ability to deliver precise treatments effectively.” This breakthrough underscores HKSH’s commitment to advancing clinical applications, enabling patients to access more sophisticated treatment options with reduced side effects.

Looking ahead, the HKSH research team is investigating the potential of further shortening the treatment regimen for early-stage prostate cancer from 5 sessions to just 2. Additionally, HKSH has introduced the world’s first Photon-Counting CT Simulation System (PCCT-Sim), which boasts advanced simulation capabilities and can be utilised in the planning of proton therapy for prostate cancer, enhancing disease control efficacy.

Clinical Study Insights

Prostate cancer predominantly affects older adults, with the highest incidence observed among individuals aged 65 to 74. Data from 2023 indicates that new cases in this demographic constitute approximately half of all diagnoses, highlighting the urgent need for improved cancer management strategies.

To evaluate the clinical efficacy of the five-session proton therapy, HKSH commenced a study involving 94 early-stage prostate cancer patients who underwent Stereotactic Body Proton Therapy between June 2024 and January 2026. The report reflects a median follow-up duration of 10.93 months (ranging from 0.9 to 25.5 months). Following the five sessions, patients exhibited a significant decrease in PSA levels, dropping from a baseline of 12.57 ng/mL (±13.59 ng/mL) to 1.13 ng/mL (±2.07 ng/mL) three months post-treatment, maintaining high efficacy despite the reduced number of sessions.

Dr. POON further articulated that the concentrated delivery of proton beams allows for precise targeting of tumours, resulting in minimal adverse reactions among the majority of patients in the study. Patient-Reported Outcome Measures (PROMs) indicated encouraging urinary and bowel function scores three months post-treatment, suggesting that quality of life remained largely unaffected. The most common adverse reactions were related to the urinary system; during the acute phase, 33.0% (31/94) of patients experienced mild Grade 1 dysuria, which subsequently improved.

Advancements in Hypofractionation

In relation to the core technologies underpinning hypofractionation, Dr. POON explained that the proton therapy team employs Intensity Modulated Proton Therapy (IMPT) with pencil-beam scanning for each case. Before treatment, tumour characteristics are meticulously defined, and radiation intensity is precisely calculated at various positions within the tumour. Patients undergo MRI and CT scans prior to treatment, ensuring accurate targeting through real-time X-ray imaging.

To protect surrounding organs, rectal spacers may be employed to enhance the distance between the rectum and prostate. Additionally, bladder volume assessments are conducted to ascertain bladder filling before each treatment session, further aiding in precise tumour targeting and minimising unnecessary radiation exposure.

Overall, this pioneering study not only establishes HKSH’s leading role in proton therapy within the region but also lays a significant foundation for the development of more precise and safer treatment options for cancer patients across Asia in the future.