Approximately 42,170 women will die from breast cancer in 2020, which emphasizes the importance of early detection, according to the American Cancer Society (ACS).1 There are more than 3.5 million breast cancer survivors in the United States, which includes individuals undergoing treatment and those who have completed therapy.1 

Current breast cancer treatment strategies include surgery, radiation, chemotherapy, hormone therapy, and targeted therapy.2 Early detection is critical for the best health outcomes.3 
Pharmacists can play an important role in educating patients about the importance of breast cancer screening, counseling on the condition and medications, and managing drug and radiation toxicities. 

Breast Cancer Screening and Diagnosis 
The ACS recommends that women at average risk (no personal or family history or genetic mutation that can increase the risk of breast cancer) have the option to start screening with a yearly mammogram between ages 40 and 44 years.3 Women aged 45 to 54 years should have a mammogram annually. Additionally, women aged 55 years and older can switch to a mammogram every other year or continue with yearly mammograms.3 Individuals aged 55 years and older should continue receiving yearly mammograms as long as they are in good health and are expected to live at least 10 more years.3 

Evidence demonstrates that women who have yearly mammograms are more likely to have breast cancer detected early, less likely to need aggressive treatment (eg, surgery, chemotherapy), and more likely to be cured.3 One recent study in Sweden that evaluated data among 549,091 women revealed that individuals who received a mammogram screening had a 41% reduction in their risk of dying of breast cancer within 10 years (P <.001) and a 25% reduction in the rate of advanced breast cancers (P <.001).4 

The ACS recommends that women at high risk for breast cancer (FIGURE) should receive a breast MRI and mammogram annually starting at aged 30 years.3 Ultrasounds should be used in women who have dense breast tissue and to evaluate suspicious areas detected by mammograms.5 Ultrasounds can also help guide a biopsy needle that will remove small pieces from a suspicious area to determine whether it is cancerous.5 Breast tomosynthesis (3D mammogram) is a newer test for imaging being used in some facilities, and other innovative tests are currently being studied.6 

Managing Toxicities 
Pharmacists can play an important part of the multidisciplinary team by helping patients manage toxicities associated with chemotherapy and radiation. Common adverse effects associated with chemotherapy include nausea and vomiting, loss of appetite, hair loss, and diarrhea.7 

Medications used to prevent and treat chemotherapy-induced nausea and vomiting include serotonin receptor antagonists (eg, ondansetron, granisetron), neurokinin-1 receptor antagonists (eg, aprepitant, rolapitant), corticosteroids (eg, dexamethasone), benzodiazepines (eg, alprazolam, lorazepam), and dopamine receptor antagonists (eg, metoclopramide).8 

Cardiotoxicity can occur with the anthracycline (eg, doxorubicin, epirubicin) drug class and can lead to cardiomyopathy, with the greatest risk associations with long duration of therapy and high doses.7,9 Patients should receive an echocardiogram prior to initiating therapy with anthracycline drugs, and they should be closely monitored during treatment.9 Dexrazoxane (Zinecard) is FDA-approved as a cytoprotective medication that can be used to decrease the incidence and severity of cardiomyopathy associated with doxorubicin in women with metastatic breast cancer who received a cumulative doxorubicin dose of 300 mg/m2 and will continue doxorubicin therapy.10 

Radiation therapy can cause reddened or irritated skin, and it is important to keep the area dry.11 Patients should wash their skin daily with warm water and a mild soap, and pat dry. Lotions, creams, perfumes, cosmetics, and deodorants should not be used on the skin where radiation is given.11 Radiation therapy to the underarm lymph nodes may cause lymphedema or pain and swelling in the arm or chest.12 It’s important for patients to know the symptoms, which include swelling in the body, skin changes, tingling and numbness, and decreased movement or flexibility. Exercise can help the lymph fluid circulate and drain, and physical therapists can assist with prevention and treatment measures. Compression garments or devices can be used to treat lymphedema.12 

Counseling Pearls 
Pharmacists can educate patients about breast cancer support services, such as the ACS Reach To Recovery program.13 In this program, individuals can speak online with a trained volunteer who is a breast cancer survivor, and one-on-one support is provided. Individuals can also search for local support groups through the ACS website.13 

Most medical organizations currently do not recommend routine breast self-exams, as research has not shown a clear benefit, especially in those individuals who get regular mammograms.14 However, it is important for women to be familiar with how their breasts normally look and report any changes immediately to their health care providers.3,14 

Pharmacists should also discuss the importance of using contraception during treatment since chemotherapy can cause birth defects.7 

Additionally, it is important for pharmacists to stay up-to-date with the latest drug safety communications because the FDA recently issued an alert regarding the use of atezolizumab and paclitaxel in patients with breast cancer, which demonstrated in a clinical trial that the combination was not effective and that potential safety concerns may exist. Atezolizumab in combination with paclitaxel is not approved for breast cancer treatment. However, atezolizumab in combination with protein-bound paclitaxel is FDA-approved for the treatment of metastatic triple-negative breast cancer with certain tumor expressions.  Pharmacists should ensure that protein-bound paclitaxel is not replaced with paclitaxel in practice, and they should educate other health care professionals about this recent drug safety communication.15 

Some clinical studies have shown an increased risk of breast cancer recurrence in patients treated with tamoxifen (treatment for hormone receptor–positive breast cancer) who are also taking selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs) versus those receiving tamoxifen monotherapy.16 The proposed mechanism of action is that SSRI and SNRI antidepressants may inhibit the conversion of tamoxifen to its active metabolite, which can decrease the efficacy of tamoxifen. If an SSRI or SNRI must be used while patients are taking tamoxifen, then a mild CYP2D6 inhibitor (sertraline, citalopram, venlafaxine, escitalopram) should be used over a moderate-to-potent inhibitor (paroxetine, fluoxetine, fluvoxamine, bupropion, duloxetine).16 

REFERENCES
  1. How common is breast cancer? American Cancer Society. Updated January 8, 2020. Accessed September 13, 2020. https://www.cancer.org/cancer/breast-cancer/about/how-common-is-breast-cancer.html
  2. Advances in breast cancer research. National Cancer Institute. Updated June 18, 2020. Accessed September 13, 2020. https://www.cancer.gov/types/breast/research 
  3. American Cancer Society recommendations for the early detection of breast cancer. American Cancer Society. Updated March 5, 2020. Accessed September 26, 2020. https://www.cancer.org/cancer/breast-cancer/screening-tests-and-early-detection/american-cancer-society-recommendations-for-the-early-detection-of-breast-cancer.html
  4. Duffy SW, Tabár L, Yen AMF, et al. Mammography screening reduces rates of advanced and fatal breast cancers: results in 549,091 women. Cancer. 2020;126(13):2971-2979. doi:10.1002/cncr.32859
  5. Breast ultrasound. American Cancer Society. Updated October 3, 2019. Accessed September 26, 2020. https://www.cancer.org/cancer/breast-cancer/screening-tests-and-early-detection/breast-ultrasound.html 
  6. Newer and experimental breast imaging tests. American Cancer Society. Updated October 3, 2019. Accessed September 26, 2019. https://www.cancer.org/cancer/breast-cancer/screening-tests-and-early-detection/experimental-breast-imaging.html 
  7. Chemotherapy for breast cancer. American Cancer Society. Updated September 18, 2019. Accessed September 26, 2019. https://www.cancer.org/cancer/breast-cancer/treatment/chemotherapy-for-breast-cancer.html
  8. Nausea and vomiting related to cancer treatment (PDQ®)-health professional version. National Cancer Institute. Updated July 23, 2020. Accessed September 26, 2020. https://www.cancer.gov/about-cancer/treatment/side-effects/nausea/nausea-hp-pdq 
  9. Bansal N, Adams MJ, Ganatra S, et al. Strategies to prevent anthracycline-induced cardiotoxicity in cancer survivors. Cardiooncology. 2019;5:18. doi:10.1186/s40959-019-0054-5
  10. Zinecard. Prescribing information. Pfizer; 2016. Accessed September 26, 2020. http://labeling.pfizer.com/showlabeling.aspx?id=514 
  11. Skin care during radiation therapy. Johns Hopkins Medicine. Accessed September 26, 2020. https://www.hopkinsmedicine.org/kimmel_cancer_center/patient_and_family_services/patient_information/education/side_effects/skin_care.html 
  12. Radiation for breast cancer. American Cancer Society. Updated September 18, 2019. Accessed September 26, 2020.  
  13. Find support programs and services in your area. American Cancer Society. Accessed September 26, 2020. https://www.cancer.org/treatment/support-programs-and-services.html
  14. Breast self-exam for breast awareness. Mayo Clinic. Updated June 9, 2020. Accessed September 26, 2020. https://www.mayoclinic.org/tests-procedures/breast-exam/about/pac-20393237 
  15. FDA alerts health care professionals and oncology clinical investigators about efficacy and potential safety concerns with atezolizumab in combination with paclitaxel for treatment of breast cancer. FDA. September 8, 2020. Accessed September 26, 2020. https://www.fda.gov/drugs/drug-safety-and-availability/fda-alerts-health-care-professionals-and-oncology-clinical-investigators-about-efficacy-and
  16. National Comprehensive Cancer Network guidelines NCCN. Clinical Practice Guidelines in Oncology. Bladder cancer, version 4.2019. Accessed September 30, 2019.https://www.nccn.org/professionals/physician_gls/pdf/bladder.pdf