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Effect of radiotherapy after mastectomy and axillary surgery on 10-year recurrence and 20-year breast cancer mortality : meta-analysis of individual patient data for 8135 women in 22 randomised trials

(2014) In The Lancet 383(9935). p.35-2127
Abstract

BACKGROUND: Postmastectomy radiotherapy was shown in previous meta-analyses to reduce the risks of both recurrence and breast cancer mortality in all women with node-positive disease considered together. However, the benefit in women with only one to three positive lymph nodes is uncertain. We aimed to assess the effect of radiotherapy in these women after mastectomy and axillary dissection.

METHODS: We did a meta-analysis of individual data for 8135 women randomly assigned to treatment groups during 1964-86 in 22 trials of radiotherapy to the chest wall and regional lymph nodes after mastectomy and axillary surgery versus the same surgery but no radiotherapy. Follow-up lasted 10 years for recurrence and to Jan 1, 2009, for... (More)

BACKGROUND: Postmastectomy radiotherapy was shown in previous meta-analyses to reduce the risks of both recurrence and breast cancer mortality in all women with node-positive disease considered together. However, the benefit in women with only one to three positive lymph nodes is uncertain. We aimed to assess the effect of radiotherapy in these women after mastectomy and axillary dissection.

METHODS: We did a meta-analysis of individual data for 8135 women randomly assigned to treatment groups during 1964-86 in 22 trials of radiotherapy to the chest wall and regional lymph nodes after mastectomy and axillary surgery versus the same surgery but no radiotherapy. Follow-up lasted 10 years for recurrence and to Jan 1, 2009, for mortality. Analyses were stratified by trial, individual follow-up year, age at entry, and pathological nodal status.

FINDINGS: 3786 women had axillary dissection to at least level II and had zero, one to three, or four or more positive nodes. All were in trials in which radiotherapy included the chest wall, supraclavicular or axillary fossa (or both), and internal mammary chain. For 700 women with axillary dissection and no positive nodes, radiotherapy had no significant effect on locoregional recurrence (two-sided significance level [2p]>0·1), overall recurrence (rate ratio [RR], irradiated vs not, 1·06, 95% CI 0·76-1·48, 2p>0·1), or breast cancer mortality (RR 1·18, 95% CI 0·89-1·55, 2p>0·1). For 1314 women with axillary dissection and one to three positive nodes, radiotherapy reduced locoregional recurrence (2p<0·00001), overall recurrence (RR 0·68, 95% CI 0·57-0·82, 2p=0·00006), and breast cancer mortality (RR 0·80, 95% CI 0·67-0·95, 2p=0·01). 1133 of these 1314 women were in trials in which systemic therapy (cyclophosphamide, methotrexate, and fluorouracil, or tamoxifen) was given in both trial groups and, for them, radiotherapy again reduced locoregional recurrence (2p<0·00001), overall recurrence (RR 0·67, 95% CI 0·55-0·82, 2p=0·00009), and breast cancer mortality (RR 0·78, 95% CI 0·64-0·94, 2p=0·01). For 1772 women with axillary dissection and four or more positive nodes, radiotherapy reduced locoregional recurrence (2p<0·00001), overall recurrence (RR 0·79, 95% CI 0·69-0·90, 2p=0·0003), and breast cancer mortality (RR 0·87, 95% CI 0·77-0·99, 2p=0·04).

INTERPRETATION: After mastectomy and axillary dissection, radiotherapy reduced both recurrence and breast cancer mortality in the women with one to three positive lymph nodes in these trials even when systemic therapy was given. For today's women, who in many countries are at lower risk of recurrence, absolute gains might be smaller but proportional gains might be larger because of more effective radiotherapy.

FUNDING: Cancer Research UK, British Heart Foundation, UK Medical Research Council.

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Contribution to journal
publication status
published
subject
keywords
Axilla, Breast Neoplasms/mortality, Female, Humans, Lymph Node Excision, Lymphatic Metastasis, Mastectomy, Neoplasm Recurrence, Local, Randomized Controlled Trials as Topic
in
The Lancet
volume
383
issue
9935
pages
35 - 2127
publisher
Elsevier
external identifiers
  • pmid:24656685
  • scopus:84902807345
ISSN
0140-6736
DOI
10.1016/S0140-6736(14)60488-8
language
English
LU publication?
yes
additional info
Copyright © 2014 EBCTCG. Open Access article distributed under the terms of CC BY. Published by Elsevier Ltd. All rights reserved.
id
1105eb48-b031-461d-b340-50b85ecbfa58
date added to LUP
2024-02-06 09:48:51
date last changed
2024-11-21 08:53:34
@article{1105eb48-b031-461d-b340-50b85ecbfa58,
  abstract     = {{<p>BACKGROUND: Postmastectomy radiotherapy was shown in previous meta-analyses to reduce the risks of both recurrence and breast cancer mortality in all women with node-positive disease considered together. However, the benefit in women with only one to three positive lymph nodes is uncertain. We aimed to assess the effect of radiotherapy in these women after mastectomy and axillary dissection.</p><p>METHODS: We did a meta-analysis of individual data for 8135 women randomly assigned to treatment groups during 1964-86 in 22 trials of radiotherapy to the chest wall and regional lymph nodes after mastectomy and axillary surgery versus the same surgery but no radiotherapy. Follow-up lasted 10 years for recurrence and to Jan 1, 2009, for mortality. Analyses were stratified by trial, individual follow-up year, age at entry, and pathological nodal status.</p><p>FINDINGS: 3786 women had axillary dissection to at least level II and had zero, one to three, or four or more positive nodes. All were in trials in which radiotherapy included the chest wall, supraclavicular or axillary fossa (or both), and internal mammary chain. For 700 women with axillary dissection and no positive nodes, radiotherapy had no significant effect on locoregional recurrence (two-sided significance level [2p]&gt;0·1), overall recurrence (rate ratio [RR], irradiated vs not, 1·06, 95% CI 0·76-1·48, 2p&gt;0·1), or breast cancer mortality (RR 1·18, 95% CI 0·89-1·55, 2p&gt;0·1). For 1314 women with axillary dissection and one to three positive nodes, radiotherapy reduced locoregional recurrence (2p&lt;0·00001), overall recurrence (RR 0·68, 95% CI 0·57-0·82, 2p=0·00006), and breast cancer mortality (RR 0·80, 95% CI 0·67-0·95, 2p=0·01). 1133 of these 1314 women were in trials in which systemic therapy (cyclophosphamide, methotrexate, and fluorouracil, or tamoxifen) was given in both trial groups and, for them, radiotherapy again reduced locoregional recurrence (2p&lt;0·00001), overall recurrence (RR 0·67, 95% CI 0·55-0·82, 2p=0·00009), and breast cancer mortality (RR 0·78, 95% CI 0·64-0·94, 2p=0·01). For 1772 women with axillary dissection and four or more positive nodes, radiotherapy reduced locoregional recurrence (2p&lt;0·00001), overall recurrence (RR 0·79, 95% CI 0·69-0·90, 2p=0·0003), and breast cancer mortality (RR 0·87, 95% CI 0·77-0·99, 2p=0·04).</p><p>INTERPRETATION: After mastectomy and axillary dissection, radiotherapy reduced both recurrence and breast cancer mortality in the women with one to three positive lymph nodes in these trials even when systemic therapy was given. For today's women, who in many countries are at lower risk of recurrence, absolute gains might be smaller but proportional gains might be larger because of more effective radiotherapy.</p><p>FUNDING: Cancer Research UK, British Heart Foundation, UK Medical Research Council.</p>}},
  issn         = {{0140-6736}},
  keywords     = {{Axilla; Breast Neoplasms/mortality; Female; Humans; Lymph Node Excision; Lymphatic Metastasis; Mastectomy; Neoplasm Recurrence, Local; Randomized Controlled Trials as Topic}},
  language     = {{eng}},
  number       = {{9935}},
  pages        = {{35--2127}},
  publisher    = {{Elsevier}},
  series       = {{The Lancet}},
  title        = {{Effect of radiotherapy after mastectomy and axillary surgery on 10-year recurrence and 20-year breast cancer mortality : meta-analysis of individual patient data for 8135 women in 22 randomised trials}},
  url          = {{http://dx.doi.org/10.1016/S0140-6736(14)60488-8}},
  doi          = {{10.1016/S0140-6736(14)60488-8}},
  volume       = {{383}},
  year         = {{2014}},
}