Research table: Radiation therapy after mastectomy for invasive breast cancer

This summary table contains detailed information about research studies. Summary tables are a useful way to look at the science behind many breast cancer guidelines and recommendations. However, to get the most out of the tables, it’s important to understand some key concepts. Learn how to read a research table.

Introduction: Radiation therapy isn’t often used after mastectomy for women with early stage breast cancer. However, it’s recommended for women with 4 or more positive lymph nodes to improve overall survival [1].

Radiation therapy after mastectomy is also strongly considered for women with 1-3 positive lymph nodes and for those who have positive tumor margins (when surgery to get negative tumor margins can’t be done) [1].

A meta-analysis that combined the results of 22 randomized clinical trials found radiation therapy after mastectomy lowered the risk of breast cancer recurrence and the risk of dying from breast cancer [2].

Radiation therapy after mastectomy is also considered for women with negative lymph nodes who have [1]:

• A tumor larger than 5 centimeters
• A tumor 5 centimeters or smaller, but the tumor margins are close

Learn more about radiation therapy.

Learn about the short-term side effects and the long-term health risks of radiation therapy.

Learn about the strengths and weaknesses of different types of studies.

Study selection criteria: Randomized clinical trials with at least 1,000 participants and 10 or more years of follow-up and meta-analyses.

Study	Study Population (number of participants)	Stage of Breast Cancer*	Follow-up (years)	Number of Positive Nodes	Overall Survival (for length of follow-up)
					Radiation Therapy after Mastectomy	No Radiation Therapy after Mastectomy
Randomized clinical trials
DBCG 82b Trial [3]	1,708 premenopausal women	Stage II-III	10	1-3	62%	54%SIG
				4 or more	32%	20%SIG
DBCG 82c Trial [4]	1,375 postmenopausal women	Stage II-III	10	1-3	55%	44%SIG
				4 or more	24%	17%SIG
Meta-analyses
EBCTC [2]	3,131	Stage II-III	20	1 or more	35%	30%SIG
	1,314	Stage II-III	20	1-3	46%	43%NS
	1,772	Stage II-III	20	4 or more	25%	17%SIG
Gebski et al. [5]	6,946†	Stages I-III	10	1 or more	53%	47%SIG,‡

SIG = Statistically significant difference between groups

NS = No statistically significant difference between groups

* Breast cancer stage as classified before 2018

† Only included studies that used optimal radiation dose and coverage

‡ Calculated from data in study  

References

1. National Comprehensive Cancer Network. NCCN Clinical practice guidelines in oncology: Breast cancer, Version 1.2022. http://www.nccn.org, 2021.
2. Early Breast Cancer Trialists’ Collaborative Group. Favourable and unfavourable effects on long-term survival of radiotherapy for early breast cancer: an overview of the randomised trials. Lancet. 355:1757-70, 2000.
3. Overgaard M, Hansen PS, Overgaard J, et al. Postoperative radiotherapy in high-risk premenopausal women with breast cancer who receive adjuvant chemotherapy. Danish Breast Cancer Cooperative Group 82b Trial. N Engl J Med. 337:949-55, 1997.
4. Overgaard M, Jensen MB, Overgaard J, et al. Postoperative radiotherapy in high-risk postmenopausal breast cancer patients given adjuvant tamoxifen: Danish Breast Cancer Cooperative Group DBCG 82c randomised trial. Lancet. 353:1641-8, 1999.
5. Gebski V, Lagleva M, Keech A, et al. Survival effects of postmastectomy adjuvant radiation therapy using biologically equivalent doses: a clinical perspective. J Natl Cancer Inst. 98(1):26-38, 2006.

Updated 12/03/21