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Extra radiation to lymph nodes reduces breast cancer recurrence, studies show

BMJ 2015; 351 doi: https://doi.org/10.1136/bmj.h4012 (Published 23 July 2015) Cite this as: BMJ 2015;351:h4012
  1. Susan Mayor
  1. 1London

Giving radiotherapy to the lymph nodes in addition to standard treatment with whole breast irradiation after breast conserving surgery significantly reduces breast cancer recurrence but has no effect on overall survival, two studies in the New England Journal of Medicine have shown.1 2

The first study1 randomised 1832 women with early stage breast cancer to treatment with whole breast irradiation plus irradiation of regional lymph nodes, including the internal mammary, supraclavicular, and axillary lymph nodes, or to whole breast irradiation alone.

All of the women had axillary node positive breast cancer or high risk node negative disease, with no cancer in the axillary nodes but breast tumours with adverse prognostic features. They had breast conserving surgery and adjuvant systemic therapy in addition to radiotherapy at centres in Canada, North America, and Australia.

Results showed no significant difference in overall survival at 10 years: the survival rate was 82.8% in women who had nodal irradiation, compared with 81.8% in the control group (hazard ratio 0.91 (95% confidence interval 0.72 to 1.13); P=0.38).

But the rate of breast cancer recurrence was significantly lower—a disease-free survival rate of 82.0% in women treated with nodal irradiation, compared with 77.0% in controls (0.76 (0.61 to 0.94); P=0.01). Side effects were increased: the results showed that 1.2% of patients given nodal irradiation had acute pneumonitis, compared with 0.2% of the control group, and a near doubling of lymphoedema (8.4% v 4.5%).

The second study2 randomised 4004 women who had a centrally or medially located primary breast tumour, irrespective of axillary involvement, or who had an externally located tumour with axillary node involvement, to undergo whole breast or thoracic wall irradiation either with or without regional nodal irradiation.

Results showed a marginal improvement in overall survival at 10 years in women treated with nodal irradiation when compared with controls (82.3% v 80.7%) (hazard ratio for death 0.87 (0.76 to 1.00); P=0.06). But, as in the first study, the risk of recurrence was reduced: a disease-free survival rate of 72.1% with nodal irradiation, compared with 69.1% without it (0.89 (0.80 to 1.00); P=0.04). The rates of distant disease-free survival and breast cancer mortality were also found to be reduced.

In an accompanying editorial3 Harold Burstein, of the Dana-Farber Cancer Institute in Boston, and Monica Morrow, of Memorial Sloan Kettering Cancer Center in New York City, said that the two trials “indicate that some patients benefit from comprehensive nodal irradiation after axillary dissection.”

But they warned, “Treatment selection for the individual patient is the key issue.” This is simple at the extremes, they said, with a strong rationale for nodal irradiation in women with metastases in several lymph nodes but no reason to use it in those with negative axillary nodes; but it is more difficult in women with one to three nodal metastases. Burstein and Morrow said that genomic profiling may be a reliable predictor of local recurrence and that it “holds the promise for more refined approaches to regional radiotherapy.”

Notes

Cite this as: BMJ 2015;351:h4012

References

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