- Design
- Randomised, open-label, phase 3 non-inferiority trial; prespecified 10-year analysis
- Population
- 810 women with high-risk breast cancer after modified radical mastectomy, 94% stage III
- Primary outcome
- Locoregional recurrence (5-year primary; 10-year descriptive)
- Effect
- 10-year locoregional recurrence 12.0% vs 10.3%; HR 1.19 (95% CI 0.79–1.82)
CHN HYPOPMRT, a phase 3 non-inferiority trial at a national cancer centre in China, randomised 820 women with high-risk breast cancer after modified radical mastectomy and axillary dissection. They received either 50 Gy in 25 fractions over five weeks or 43.5 Gy in 15 fractions over three weeks to the chest wall and supraclavicular region. Median age was 49, and 94% had stage III disease. Median follow-up was 11.5 years.
At 10 years, locoregional recurrence was 10.3% with conventional and 12.0% with hypofractionated treatment (HR 1.19, 95% CI 0.79–1.82). Grade 3 late effects were rare and similar: ischaemic heart disease in 1% in each arm, lymphoedema in about 1%. There was no brachial plexopathy, no grade 4 or 5 toxicity and no treatment-related death.
Hypofractionation is standard after breast-conserving surgery, but evidence with nodal irradiation after mastectomy has been thinner, particularly over the long term. These results, in younger women with advanced disease, support three-week regimens for this group. That matters in India, where radiotherapy capacity and travel limit access and fewer visits mean more patients complete treatment. The 10-year comparison was descriptive rather than a formal non-inferiority test, and treatment covered only the chest wall and supraclavicular region.
- Consider a 15-fraction regimen for post-mastectomy chest wall and supraclavicular radiotherapy in high-risk breast cancer.
- Locoregional recurrence at 10 years was about 12% with 15 fractions and 10% with 25, a difference that was not significant.
- Late grade 3 toxicity, including cardiac events and lymphoedema, was rare and similar between regimens.
- Check applicability where internal mammary nodes or a reconstructed breast are in the field; the trial treated only the chest wall and supraclavicular region.
- Fewer fractions can improve completion where travel and machine time are limiting.
Why it matters
It extends long-term evidence for shorter radiotherapy to the women with the most advanced disease after mastectomy.
Don't overread it
The 10-year analysis was descriptive, and the fields covered only the chest wall and supraclavicular region.
The statistics, in plain English
A hazard ratio of 1.19 with a 95% interval of 0.79 to 1.82 crosses 1.0, so no difference in recurrence was detected. The interval still allows recurrence to be modestly higher with 15 fractions, which is why the 5-year non-inferiority result, not this 10-year update, is the formal test.
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