Stereotactic body radiotherapy (SBRT) provides comparable 5-year biochemical progression-free survival (PFS) and is associated with slightly lower rates of gastrointestinal (GI) and genitourinary (GU) toxicities compared with conventional radiotherapy (RT) in Chinese patients with low- to intermediate-risk prostate cancer, according to a real-world study in Hong Kong.
While conventional RT has long been a standard of care in prostate cancer, its high fraction burden (76 Gy in 37–39 fractions) places considerable demands on healthcare resources and is inconvenient for patients. SBRT delivers a higher dose per fraction in just five fractions, thereby reducing the treatment burden. Although the international PACE-P study has reported 5-year efficacy and toxicity outcomes of SBRT, long-term data in Asian patients remain limited, and toxicity risks may vary across ethnicities. [Hong Kong Med J 2026;32:234-242]
Therefore, researchers from the Chinese University of Hong Kong and Prince of Wales Hospital conducted a retrospective study in 130 Chinese men with low- to intermediate-risk prostate cancer who received conventional RT at 76 Gy in 38 fractions (n=99; median prostate-specific antigen [PSA], 9.1 ng/mL) or SBRT at 36.25 Gy in 5 fractions (n=31; median PSA, 10.2 ng/mL) between 2015 and 2019 at a hospital in Hong Kong. The median age was 70 years in both groups.
Comparable disease control at 5 years
Over a median follow-up of >5 years (65.7 months for conventional RT and 78.0 months for SBRT), both groups exhibited declines in PSA levels over time. At 60 months, the median PSA level was 0.3 ng/mL in both groups.
The 5-year biochemical PFS rate was 90.3 percent for conventional RT and 88.2 percent for SBRT. Conventional RT was not associated with a significantly longer biochemical PFS vs SBRT (median, 65.7 vs 78.0 months; hazard ratio, 0.91; 95 percent confidence interval, 0.29–2.87; p=0.9).
Slightly lower GI and GU toxicities with SBRT
Of note, SBRT appeared to be associated with a slightly — but not significantly — lower incidence of grade ≥2 GI (29.3 vs 16.1 percent; p=0.146) and GU toxicities (22.2 vs 12.9 percent; p=0.2581). The incidence of these toxicities peaked between 2 and 3 years after treatment.
Despite similar median clinical target volume in the conventional RT and SBRT groups (39.3 vs 33.7 mL), the SBRT group showed a substantially smaller median planning target volume than the conventional RT group (68.3 vs 127.1 mL), which could explain the slightly lower incidence of GU and GI toxicities with SBRT.
“These findings are consistent with those of the PACE-B trial, in which most participants [>85 percent] were from Western countries and only 1 percent were East Asians,” wrote the researchers.
Clinical implications
“These local data support SBRT as a standard-of-care option for low- to intermediate-risk prostate cancer, offering comparable efficacy with slightly lower GI and GU toxicities,” noted the researchers.
“Given the similar efficacy and toxicity profiles of conventional RT and SBRT, reducing treatment to five fractions may also decrease workload in radiotherapy centres and reduce the number of hospital visits for patients,” added the researchers.