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Multicenter Study
. 2025 Nov 1;117(11):2229-2239.
doi: 10.1093/jnci/djaf177.

Breastfeeding after breast cancer in young BRCA carriers

Eva Blondeaux  1 , Virginia Delucchi  1 , Elene Mariamidze  2 , Rinat Bernstein-Molho  3 , Sophie Frank  4 , Alberta Ferrari  5   6 , Sabine Linn  7 , Hee Jeong Kim  8 , Elisa Agostinetto  9 , Shani Paluch-Shimon  10   11 , Laura Cortesi  12 , Antonio Di Meglio  13 , Judith Balmana  14   15 , Rinat Yerushalmi  16 , Kenny A Rodriguez-Wallberg  17 , Tiphaine Renaud  18 , Wanda Cui  19   20 , Halle C F Moore  21 , Stephanie M Wong  22 , Katarzyna Pogoda  23 , Maryam Lustberg  24 , Kelly-Anne Phillips  19   20   25 , Sileny Han  26 , Fabio Puglisi  27   28 , Claudio Vernieri  29   30 , Jyoti Bajpai  31 , Amir Sonnenblick  32 , Christine Rousset-Jablonski  33   34 , Laura De Marchis  35   36 , Ugo De Giorgi  37 , Giampaolo Bianchini  38   39 , Luis Texeira  40 , Francois P Duhoux  41 , Cynthia Villarreal-Garza  42 , Valentina Sini  43 , Robert Fruscio  44   45 , Lucia Del Mastro  46   47 , Isabelle Demeestere  48   49 , Hatem A Azim Jr  50 , Fedro A Peccatori  51 , Ann H Partridge  52 , Matteo Lambertini  46   47
Affiliations
Multicenter Study

Breastfeeding after breast cancer in young BRCA carriers

Eva Blondeaux et al. J Natl Cancer Inst. .

Abstract

Background: We investigated safety of breastfeeding after breast cancer in patients carrying germline BRCA pathogenic or likely pathogenic variants.

Methods: This was an international, multicenter, hospital-based, retrospective cohort study including BRCA carriers diagnosed with stage I-III invasive breast cancer at age 40 years or younger between January 2000 and December 2020 (NCT03673306). Locoregional recurrences and/or contralateral breast cancers, disease-free survival (DFS), and overall survival (OS) were compared between patients who breastfed after delivery and those who did not.

Results: Among 4732 patients included from 78 centers worldwide, 659 had a pregnancy after breast cancer diagnosis, of whom 474 delivered a child. After excluding patients with uptake of bilateral risk-reducing mastectomy prior to delivery (n = 225) or unknown breastfeeding status (n = 71), 110 (61.8%) breastfed (median duration 5 months) and 68 (38.2%) did not breastfeed. Compared to patients in the no breastfeeding group, those who breastfed were more frequently nulliparous at breast cancer diagnosis (61.8% vs 45.6%) and did not report prior smoking habit (71.8% vs 57.4%). After a median follow-up of 7.0 years following delivery, 7-year cumulative incidence of locoregional recurrences and/or contralateral breast cancers was 29% in the breastfeeding group and 36% in the no breastfeeding group (adjusted subdistribution hazard ratio [HR] = 1.08, 95% CI = 0.57 to 2.06). No difference in DFS (adjusted hazard ratio [aHR] = 0.83, 95% CI = 0.49 to 1.41) nor in OS (aHR = 1.32, 95% CI = 0.31 to 5.66) was observed.

Conclusions: Breastfeeding did not appear to be associated with a higher risk of developing locoregional recurrences or contralateral breast cancers, emphasizing the possibility of achieving a balance between maternal and infant needs without compromising oncological safety.

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Conflict of interest statement

E.B. reports speaker’s fee from Eli Lilly, research funding (to the institution) from Gilead, all outside the submitted work. R.B.-M. reports honoraria for lectures from AstraZeneca, Roche, Pfizer; support for attending meetings from Pfizer (to the institution), AstraZeneca (to the institution), Gilead (to the institution), all outside the submitted work. E.A. reports speaker honoraria from Eli Lilly, AstraZeneca, Abscint, Bayer; advisory role for AstraZeneca; research grant to institution from Gilead; meeting/travel grants from Eli Lilly, AstraZeneca, Daiichi Sankyo, Abscint, Menarini, all outside the submitted work. A.D.M. reports speaker honoraria from Kephren and Techspert, all outside the submitted work. J.B. reports speaker honoraria and research at institution, AstraZeneca, all outside the submitted work. S.M.W. reports advisory role for Merck, AstraZeneca, all outside the submitted work. K.P. reports consultations/lectures/training/clinical trials and payment of conference fees from AstraZeneca, Gilead, Roche, Novartis, Eli Lilly, Pfizer, MSD, Swixx, all outside the submitted work. K.A.P. reports research funding to institution from AstraZeneca, all outside the submitted work. F.P. reports honoraria for advisory boards, activities as a speaker, travel grants from AstraZeneca, Daiichi Sankyo, Eisai, Eli Lilly, Exact Sciences, Gilead, Italfarmaco, Menarini, MSD, Novartis, Pfizer, Roche, and Seagen; research funding from AstraZeneca, Eisai, and Roche, all outside the submitted work. C.V. reports advisory role for Eli Lilly, Novartis, Pfizer, Menarini Stemline, Daiichi Sankyo; speaker honoraria from Eli Lilly, Menarini Stemline, MSD, Novartis, Pfizer, Istituto Gentili, Accademia Nazionale di Medicina; research funding (to the institution) from Roche, all outside the submitted work. A.S. reports consulting or advisory role from Eli Lilly, Pfizer, Novartis, Roche, Gilead, MSD, AstraZeneca, Progenetics, Rhenium, Stemline; travel, accommodation, expenses from Neopharm, Celgene, Medison, Roche, MSD, Gilead, Pfizer; speakers’ bureau from Teva, Roche, Pfizer, Novartis, Eli Lilly and grant support from Novartis, Roche, all outside the submitted work. U.D.G. reports advisory role/speaker’s fee for AstraZeneca, MSD, Bristol Myers Squibb, Janssen, Astellas, Sanofi, Bayer, Pfizer, Ipsen, Novartis, and Merck; research funding (to the institution) from AstraZeneca, Sanofi, and Roche, all outside the submitted work. F.P.D. reports a postdoctoral research grant from Fondation Belge contre le Cancer; consulting fees from Amgen, AstraZeneca, Daiichi Sankyo, Eli Lilly, Gilead Sciences, MSD, Novartis, Pfizer, Pierre Fabre, Roche, and Seagen; and travel support from Amgen, AstraZeneca, Daiichi Sankyo, Gilead Sciences, Pfizer, Roche, and Teva, all outside the submitted work. V.S. reports speaker honoraria from Novartis, Daiichi Sankyo, Istituto Gentili, Accord; travel grants from Pfizer, Novartis, all outside the submitted work. I.D. reports research grants from Roche, speaker honoraria from Ferring, Novartis and travel grant from Theramex, Ferring, Gedeon Richter, all outside the submitted work. H.A.A. reports honoraria from AstraZeneca, consultant for LinKinVax and PEP Therapy, all outside the submitted work. M.L. reports advisory role for Roche, Lilly, Novartis, AstraZeneca, Pfizer, Seagen, Gilead, MSD, Exact Sciences, Pierre Fabre, Menarini, Nordic Pharma; speaker honoraria from Roche, Lilly, Novartis, Pfizer, Sandoz, Libbs, Daiichi Sankyo, Takeda, Menarini, AstraZeneca; travel grants from Gilead, Daiichi Sankyo, Roche, all outside the submitted work. Research funding (to the institution) from Gilead. M.L., who is a JNCI Associate Editor and co-author on this paper, was not involved in the editorial review or decision to publish the manuscript. All the other authors declare no conflict of interest.

Figures

Figure 1.
Figure 1.
Study flow chart. Abbreviation: VUS = variant of unknown significance.
Figure 2.
Figure 2.
Cumulative incidence of locoregional recurrences and/or contralateral breast cancers between patients who breastfed after delivery and those who did not. CIF = cumulative incidence function.
Figure 3.
Figure 3.
Survival outcomes between patients who breastfed after delivery and those who did not: (A) disease-free survival and (B) overall survival.
See this image and copyright information in PMC

Comment in

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