Editing Breast cancer (section)

== Management ==
{{Main|Breast cancer management}}

The management of breast cancer depends on the affected person's health, the cancer case's molecular characteristics, and how far the tumor has spread at the time of diagnosis.

=== Local tumors ===
[[File:Mastectomie 02.jpg|thumb|Chest after right breast [[mastectomy]]]]

Those whose tumors have not spread beyond the breast often undergo surgery to remove the tumor and some surrounding breast tissue.{{sfn|Hayes|Lippman|2022|loc="Local (Primary) Treatments"}} The surgery method is typically chosen to spare as much healthy breast tissue as possible, removing just the tumor ([[lumpectomy]]) or a larger part of the breast (partial [[mastectomy]]). Those with large or multiple tumors, high genetic risk of subsequent cancers, or who are unable to receive [[radiotherapy|radiation therapy]] may instead opt for full removal of the affected breast(s) (full mastectomy).{{sfn|Hayes|Lippman|2022|loc="Local (Primary) Treatments"}} To reduce the risk of cancer spreading, women will often have the nearest lymph node removed in a procedure called [[sentinel lymph node]] biopsy. Dye is injected near the tumor site, and several hours later the lymph node the dye accumulates in is removed.{{sfn|Hayes|Lippman|2022|loc="Evaluation and Treatment of the Axillary Lymph Nodes"}} 

After surgery, many undergo radiotherapy to decrease the chance of [[cancer recurrence]].{{sfn|Hayes|Lippman|2022|loc="Local (Primary) Treatments"}} Those who had lumpectomies receive radiation to the whole breast.<ref name=ACS-Radio>{{cite web|url=https://www.cancer.org/cancer/types/breast-cancer/treatment/radiation-for-breast-cancer.html |accessdate=12 April 2024 |title=Radiation for Breast Cancer |publisher=American Cancer Society |date=27 October 2021}}</ref> Those who had a mastectomy and are at elevated risk of tumor spread – tumor greater than five centimeters wide, or cancerous cells in nearby lymph nodes – receive radiation to the mastectomy scar and chest wall.<ref name=ACS-Radio/>{{sfn|Hayes|Lippman|2022|loc="Local (Primary) Treatments"}} If cancerous cells have spread to nearby lymph nodes, those lymph nodes will be irradiated as well.<ref name=ACS-Radio/> Radiation is typically given five days per week, for up to seven weeks.<ref name=ACS-Radio/> Radiotherapy for breast cancer is typically delivered via [[external beam radiotherapy]], where a device focuses radiation beams onto the targeted parts of the body. Instead, some undergo [[brachytherapy]], where radioactive material is placed into a device inserted at the surgical site the tumor was removed from. Fresh radioactive material is added twice a day for five days, then the device is removed.<ref name=ACS-Radio/> Surgery plus radiation typically eliminates a person's breast tumor. Less than 5% of those treated have their breast tumor grow back.{{sfn|Hayes|Lippman|2022|loc="Local (Primary) Treatments"}} After surgery and radiation, the breast can be [[breast reconstruction|surgically reconstructed]], either by adding a [[breast implant]] or transferring excess tissue from another part of the body.{{sfn|Hayes|Lippman|2022|loc="Local (Primary) Treatments"}} 

Chemotherapy reduces the chance of cancer recurring in the next ten years by around a third. However, 1-2% of those on chemotherapy experience life-threatening or permanent side effects. To balance these benefits and risks, chemotherapy is typically offered to those with a higher risk of cancer recurrence. There is no established risk cutoff for offering chemotherapy; determining who should receive chemotherapy is controversial.{{sfn|Hayes|Lippman|2022|loc="Prognostic and Predictive Variables"}} Chemotherapy drugs are typically given in two- to three-week cycles, with periods of drug treatment interspersed with rest periods to recover from the therapies' side effects.<ref>{{cite web|url=https://www.cancer.org/cancer/types/breast-cancer/treatment/chemotherapy-for-breast-cancer.html |accessdate=15 April 2024 |title=Chemotherapy for Breast Cancer |publisher=American Cancer Society |date=27 October 2021}}</ref> Four to six cycles are given in total.{{sfn|Hayes|Lippman|2022|loc="Chemotherapy"}} Many classes of chemotherapeutic agents are effective for breast cancer treatment, including the [[Alkylating antineoplastic agent|DNA alkylating]] drugs ([[cyclophosphamide]]), [[anthracycline]]s ([[doxorubicin]] and [[epirubicin]]), [[antimetabolite]]s ([[fluorouracil]], [[capecitabine]], and [[methotrexate]]), [[taxane]]s ([[docetaxel]] and [[paclitaxel]]), and [[platinum-based chemotherapy|platinum-based chemotherapies]] ([[cisplatin]] and [[carboplatin]]).
{{sfn|Hayes|Lippman|2022|loc="Chemotherapy"}} Chemotherapies from different classes are typically given in combination, with particular chemotherapy drugs selected based on the affected person's health and the different chemotherapeutics' side effects.{{sfn|Hayes|Lippman|2022|loc="Chemotherapy"}} Anthrocyclines and cyclophosphamide cause [[leukemia]] in up to 1% of those treated. Anthrocyclines also cause [[congestive heart failure]] in around 1% of people treated. [[Taxane]]s cause [[peripheral neuropathy]], which is permanent in up to 5% of those treated.{{sfn|Hayes|Lippman|2022|loc="Chemotherapy Toxicities"}} The same chemotherapy agents can be given before surgery – called [[neoadjuvant therapy]] – to shrink tumors, making them easier to safely remove.{{sfn|Hayes|Lippman|2022|loc="Neoadjuvant Chemotherapy"}}

For those whose tumors are HER2-positive, adding the [[HER2]]-targeted antibody [[trastuzumab]] to chemotherapy reduces the chance of cancer recurrence and death by at least a third.{{sfn|Hayes|Lippman|2022|loc="Predictive Factors"}}{{sfn|Hayes|Lippman|2022|loc="Anti-HER2 Therapy"}} Trastuzumab is given weekly or every three weeks for twelve months.{{sfn|Hayes|Lippman|2022|loc="Anti-HER2 Therapy"}} Adding a second HER2-targeted antibody, [[pertuzumab]] slightly enhances treatment efficacy.{{sfn|Hayes|Lippman|2022|loc="Anti-HER2 Therapy"}} In rare cases, trastuzumab can disrupt heart function, and so it is typically not given in conjunction with anthracyclines, which can also damage the heart.{{sfn|Hayes|Lippman|2022|loc="Anti-HER2 Therapy"}}

After their chemotherapy course, those whose tumors are ER-positive or PR-positive benefit from [[endocrine therapy]], which reduces the levels of [[estrogen]]s and [[progesterone]]s that hormone receptor-positive breast cancers require to survive.<ref name=ACS-Hormone>{{cite web|url=https://www.cancer.org/cancer/types/breast-cancer/treatment/hormone-therapy-for-breast-cancer.html |accessdate=16 April 2024 |title=Hormone Therapy for Breast Cancer |publisher=American Cancer Society |date=31 January 2024}}</ref> [[Tamoxifen]] treatment blocks the ER in the breast and some other tissues, and reduces the risk of breast cancer death by around 40% over the next ten years.{{sfn|Harbeck|Penault-Llorca|Cortes|Gnant|2019|loc="Systemic Therapy"}}{{sfn|Hayes|Lippman|2022|loc="Endocrine Therapy"}} Chemically blocking estrogen production with [[GnRH]]-targeted drugs ([[goserelin]], [[leuprolide]], or [[triptorelin]]) and [[aromatase inhibitors]] ([[anastrozole]], [[letrozole]], or [[exemestane]]) slightly improves survival, but has more severe side effects.{{sfn|Harbeck|Penault-Llorca|Cortes|Gnant|2019|loc="Systemic Therapy"}}{{sfn|Hayes|Lippman|2022|loc="Endocrine Therapy"}} Side effects of estrogen depletion include [[hot flash]]es, vaginal discomfort, and muscle and joint pain.{{sfn|Hayes|Lippman|2022|loc="Endocrine Therapy"}} Endocrine therapy is typically recommended for at least five years after surgery and chemotherapy, and is sometimes continued for 10 years or longer.{{sfn|Hayes|Lippman|2022|loc="Endocrine Therapy"}}{{sfn|Harbeck|Penault-Llorca|Cortes|Gnant|2019|loc="Systemic Therapy"}}

Women with breast cancer who had a [[lumpectomy]] or a [[mastectomy]] and kept their other breast have similar survival rates to those who had a double mastectomy.<ref>{{cite journal | vauthors = Giannakeas V, Lim DW, Narod SA | title = Bilateral Mastectomy and Breast Cancer Mortality | journal = JAMA Oncology | volume = 10 | issue = 9 | pages = 1228–1236 | date = September 2024 | pmid = 39052262 | pmc = 11273285 | doi = 10.1001/jamaoncol.2024.2212 | pmc-embargo-date = July 25, 2025 }}</ref> There seems to be no survival advantage to removing the other breast, with only a 7% chance of cancer occurring in the other breast over 20 years.<ref>{{Cite news | vauthors = Kolata G |date=2024-07-25 |title=Breast Cancer Survival Not Boosted by Double Mastectomy, Study Says |url=https://www.nytimes.com/2024/07/25/health/breast-cancer-double-mastectomy-study.html |access-date=2024-07-27 |work=The New York Times }}</ref>

=== Metastatic disease ===

For around 1 in 5 people treated for localized breast cancer, their tumors eventually spread to distant body sites – most commonly the nearby bones (67% of cases), liver (41%), lungs (37%), brain (13%), and [[peritoneum]] (10%).{{sfn|Hayes|Lippman|2022|loc="Diagnostic Considerations"}}{{sfn|Harbeck|Penault-Llorca|Cortes|Gnant|2019|loc="Fig. 9: Common Metastatic Sites in Breast Cancer"}} Those with metastatic disease can receive further chemotherapy, typically starting with capecitabine, an anthracycline, or a taxane. As one chemotherapy drug fails to control the cancer, another is started. In addition to the chemotherapeutic drugs used for localized cancer, [[gemcitabine]], [[vinorelbine]], [[etoposide]], and [[epothilone]]s are sometimes effective.{{sfn|Hayes|Lippman|2022|loc="Systemic Treatments for Metastatic Breast Cancer"}} Those with bone metastases benefit from regular infusion of the bone-strengthening agents [[denosumab]] and the [[bisphosphonate]]s; infusion every three months reduces the chance of bone pain, fractures, and bone [[hypercalcemia]].{{sfn|Hayes|Lippman|2022|loc="Bone-Modifying Agents"}}

Up to 70% of those with ER-positive metastatic breast cancer benefit from additional endocrine therapy. Therapy options include those used in localized cancer, plus [[toremifene]] and [[fulvestrant]], often used in combination with [[CDK inhibitor|CDK4/6 inhibitor]]s ([[palbociclib]], [[ribociclib]], or [[abemaciclib]]). When one endocrine therapy fails, most will benefit from transitioning to a second one. Some respond to a third sequential therapy as well.{{sfn|Hayes|Lippman|2022|loc="Systemic Treatments for Metastatic Breast Cancer"}} Adding an [[mTOR inhibitor]], [[everolimus]], can further slow the tumors' progression.{{sfn|Hayes|Lippman|2022|loc="Systemic Treatments for Metastatic Breast Cancer"}}

Those with HER2-positive metastatic disease can benefit from continued use of trastuzumab, alone, in combination with pertuzumab, or in combination with chemotherapy. Those whose tumors continue to progress on trastuzumab benefit from HER2-targeted [[antibody drug conjugate]]s (HER2 antibodies linked to chemotherapy drugs) [[trastuzumab emtansine]] or [[trastuzumab deruxtecan]]. The HER2-targeted antibody [[margetuximab]] can also prolong survival, as can HER2 inhibitors [[lapatinib]], [[neratinib]], or [[tucatinib]].{{sfn|Hayes|Lippman|2022|loc="Systemic Treatments for Metastatic Breast Cancer"}}

Certain therapies are targeted at those whose tumors have particular gene mutations: [[Alpelisib]] or [[capivasertib]] for those with mutations activating the protein [[PIK3CA]].{{sfn|Hayes|Lippman|2022|loc="Systemic Treatments for Metastatic Breast Cancer"}}<ref name=ACS-Meta/> [[PARP inhibitor]]s ([[olaparib]] and [[talazoparib]]) for those with mutations that inactivate [[BRCA1]] or [[BRCA2]].{{sfn|Hayes|Lippman|2022|loc="Systemic Treatments for Metastatic Breast Cancer"}} The [[immune checkpoint inhibitor]] antibody [[atezolizumab]] for those whose tumors express [[PD-L1]].{{sfn|Hayes|Lippman|2022|loc="Systemic Treatments for Metastatic Breast Cancer"}}<ref name=ACS-Meta>{{cite web|url=https://www.cancer.org/cancer/types/breast-cancer/treatment/treatment-of-breast-cancer-by-stage/treatment-of-stage-iv-advanced-breast-cancer.html |accessdate=18 April 2024 |title=Treatment of Stage IV (Metastatic) Breast Cancer |publisher=American Cancer Society |date=28 November 2023}}</ref> And the similar immunotherapy [[pembrolizumab]] for those whose tumors have mutations in various [[DNA repair]] pathways.<ref name=ACS-Meta/>

=== Supportive care ===
[[File:Breast reconstruction 15.jpg|thumb|Breasts after double mastectomy followed by nipple-sparing reconstruction with implants]]

Many breast cancer therapies have side effects that can be alleviated with appropriate supportive care. Chemotherapy causes [[alopecia|hair loss]], [[nausea]], and [[vomiting]] in nearly everyone who receives it. [[Antiemetic]] drugs can alleviate nausea and vomiting; cooling the scalp with a [[Hypothermia cap|cold cap]] during chemotherapy treatments may reduce hair loss.{{sfn|Hayes|Lippman|2022|loc="Chemotherapy Toxicities"}} Many complain of [[Post-chemotherapy cognitive impairment|cognitive issues during chemotherapy treatment]]. These usually resolve within a few months of the end of chemotherapy treatment.{{sfn|Hayes|Lippman|2022|loc="Chemotherapy Toxicities"}} Those on endocrine therapy often experience [[hot flash]]es, muscle and joint pain, and vaginal dryness/discomfort that can lead to issues having sex. Around half of women have their hot flashes alleviated by taking [[antidepressant]]s; pain can be treated with [[physical therapy]] and [[nonsteroidal anti-inflammatory drug]]s; counseling and use of [[personal lubricant]]s can improve sexual issues.{{sfn|Hayes|Lippman|2022|loc="Endocrine Therapy"}}{{sfn|Hayes|Lippman|2022|loc="Breast Cancer Survivorship Issues"}} 

In women with non-metastatic breast cancer, psychological interventions such as [[cognitive behavioral therapy]] can have positive effects on outcomes such as cognitive impairment, anxiety, depression and mood disturbance, and can also improve the quality of life.<ref>{{cite journal | vauthors = Jassim GA, Doherty S, Whitford DL, Khashan AS | title = Psychological interventions for women with non-metastatic breast cancer | journal = The Cochrane Database of Systematic Reviews | volume = 1 | issue = 1 | pages = CD008729 | date = January 2023 | pmid = 36628983 | pmc = 9832339 | doi = 10.1002/14651858.CD008729.pub3 }}</ref><ref name=":4">{{cite journal | vauthors = Lange M, Joly F, Vardy J, Ahles T, Dubois M, Tron L, Winocur G, De Ruiter MB, Castel H | title = Cancer-related cognitive impairment: an update on state of the art, detection, and management strategies in cancer survivors | journal = Annals of Oncology | volume = 30 | issue = 12 | pages = 1925–1940 | date = December 2019 | pmid = 31617564 | pmc = 8109411 | doi = 10.1093/annonc/mdz410 }}</ref><ref name=":5">{{cite journal | vauthors = Janelsins MC, Kesler SR, Ahles TA, Morrow GR | title = Prevalence, mechanisms, and management of cancer-related cognitive impairment | journal = International Review of Psychiatry | volume = 26 | issue = 1 | pages = 102–113 | date = February 2014 | pmid = 24716504 | pmc = 4084673 | doi = 10.3109/09540261.2013.864260 }}</ref> Physical activity interventions, yoga and meditation may also have beneficial effects on health related quality of life, cognitive impairment, anxiety, fitness and physical activity in women with breast cancer following adjuvant therapy.<ref>{{cite journal | vauthors = Lahart IM, Metsios GS, Nevill AM, Carmichael AR | title = Physical activity for women with breast cancer after adjuvant therapy | journal = The Cochrane Database of Systematic Reviews | volume = 1 | issue = 1 | pages = CD011292 | date = January 2018 | pmid = 29376559 | pmc = 6491330 | doi = 10.1002/14651858.cd011292.pub2 }}</ref><ref name=":4" /><ref name=":5" /><ref>{{cite journal | vauthors = Biegler KA, Chaoul MA, Cohen L | title = Cancer, cognitive impairment, and meditation | journal = Acta Oncologica | volume = 48 | issue = 1 | pages = 18–26 | date = 2009 | pmid = 19031161 | doi = 10.1080/02841860802415535 }}</ref>

In-person and virtual peer support groups for patients and survivors of breast cancer can promote quality of life and companionship based on similar lived experiences.<ref name=":42">{{cite journal |last1=Hu |first1=Jieman |last2=Wang |first2=Xue |last3=Guo |first3=Shaoning |last4=Chen |first4=Fangfang |last5=Wu |first5=Yuan-yu |last6=Ji |first6=Fu-jian |last7=Fang |first7=Xuedong |title=Peer support interventions for breast cancer patients: a systematic review |journal=Breast Cancer Research and Treatment |date=April 2019 |volume=174 |issue=2 |pages=325–341 |doi=10.1007/s10549-018-5033-2 |pmid=30600413 }}</ref><ref>{{cite journal |last1=Zhang |first1=Shufang |last2=Li |first2=Juejin |last3=Hu |first3=Xiaolin |title=Peer support interventions on quality of life, depression, anxiety, and self-efficacy among patients with cancer: A systematic review and meta-analysis |journal=Patient Education and Counseling |date=November 2022 |volume=105 |issue=11 |pages=3213–3224 |doi=10.1016/j.pec.2022.07.008 |pmid=35858869 }}</ref> The potential benefits of peer support are particularly impactful for women with breast cancer facing additional unique challenges related to ethnicity and socioeconomic status.<ref name=":42" /> Peer support groups tailored to adolescents and young adult women can improve coping strategies against age-specific types of distress associated with breast cancer, including post-traumatic stress disorder and body image issues.<ref>{{cite journal |last1=Saxena |first1=Vartika |last2=Jain |first2=Vama |last3=Das |first3=Amity |last4=Huda |first4=Farhanul |title=Breaking the Silence: Understanding and Addressing Psychological Trauma in Adolescents and Young Adults with Breast Cancer |journal=Journal of Young Women's Breast Cancer and Health |date=January 2024 |volume=1 |issue=1&2 |pages=20–26 |doi=10.4103/YWBC.YWBC_6_24 |doi-access=free }}</ref>