Hypofractionated postmastectomy radiotherapy held locoregional control at ten years

Design

Phase 3, randomised, open-label, non-inferiority trial; ten-year analysis

Population

810 women with high-risk breast cancer after mastectomy and axillary dissection, 94% stage III, in China

Primary outcome

Locoregional recurrence (five-year primary; ten-year prespecified long-term)

Effect

Ten-year 12.0% vs 10.3%; HR 1.19 (95% CI 0.79–1.82)

CHN HYPOPMRT randomised 820 women aged 18–75 with high-risk breast cancer after modified radical mastectomy and axillary dissection at a national cancer centre in China. Most (94%) had stage III disease. Radiotherapy to the chest wall and supraclavicular region was 43.5 Gy in 15 fractions over three weeks or 50 Gy in 25 fractions over five weeks. The trial was open-label, with five-year locoregional recurrence as its primary end point.

At a median follow-up of 11.5 years, ten-year locoregional recurrence was 12.0% with hypofractionation and 10.3% with conventional fractionation (HR 1.19, 95% CI 0.79–1.82). Severe late effects were rare and similar: grade 3 ischaemic heart disease in 1% of each group, lymphoedema and shoulder dysfunction in about 1% or fewer. There were no grade 4–5 events and no brachial plexopathy.

Two fewer weeks of daily treatment matters for patients who travel far, for working women and for radiotherapy departments with long waiting lists — all of which apply in India. The ten-year analysis was not a formal non-inferiority test, and all patients had modified radical mastectomy with axillary dissection, so the results apply most directly to that setting.

• Consider 43.5 Gy in 15 fractions for postmastectomy chest wall and supraclavicular radiotherapy in high-risk breast cancer.
• Ten-year recurrence and late toxicity were similar to five-week schedules.
• No brachial plexopathy was seen with this schedule, a common concern with nodal hypofractionation.
• All patients had modified radical mastectomy and axillary dissection; apply the result to similar patients.
• A three-week course can shorten waiting lists and reduce travel for patients far from a centre.

Why it matters

It extends long-term evidence for hypofractionation to the mastectomy and nodal setting, where it had been thinnest.

Don't overread it

The ten-year comparison was descriptive, not a confirmatory non-inferiority test.

The statistics, in plain English

A hazard ratio of 1.19 with an interval from 0.79 to 1.82 crosses 1.0, so the trial cannot exclude a modest increase or decrease in recurrence. The absolute difference at ten years was 1.7 percentage points.

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