Practical consensus recommendations on duration of adjuvant hormonal therapy in breast cancer

Systemic Adjuvant Therapy in Women With Resected Node-Negative Breast Cancer

Background monarchE is a phase 3, open-label study evaluating abemaciclib combined with endocrine therapy (ET) compared to ET alone in patients with node positive, HR+, HER2-, high risk early breast cancer (EBC) that resulted in a statistically significant improvement in invasive disease-free survival (IDFS) at a pre-planned interim analysis. Following the positive interim analysis, patients continued to be followed for IDFS, distant recurrence, and overall survival. Methods After surgery and, as indicated, radiotherapy and/or chemotherapy, 5,637 patients with HR+, HER2-, high risk EBC were randomized (1:1) to standard of care adjuvant ET with or without abemaciclib (150 mg BD for 2 years). Patients with ≥4 positive nodes, or 1-3 nodes and either grade 3 disease, tumor size ≥5 cm, or central Ki-67 ≥20% were eligible. Here we present results of the primary outcome IDFS analysis which was planned after approximately 390 IDFS events. Results At the primary outcome analysis, median follow-up was approximately 19 months in both arms (an increase of 3.5 months from the interim analysis). A total of 1437 (25.5%) patients had completed the 2-year treatment period; 3281 (58.2%) were still in the 2-year treatment period. With 395 IDFS events observed in the intent-to-treat population, abemaciclib plus ET continued to demonstrate superior IDFS versus ET alone, with a 28.7% reduction in the risk of developing invasive disease (p=.0009; HR = 0.713; 95% CI = 0.583, 0.871). Two-year IDFS rates were 92.3% in the abemaciclib plus ET arm and 89.3% in the ET alone arm. There was a consistent benefit of abemaciclib in all prespecified subgroups. The addition of abemaciclib to ET also resulted in an improvement in distant relapse-free survival (DRFS). Overall survival was immature at the time of analysis. A key secondary endpoint was efficacy in patients with centrally assessed high Ki-67 (≥20%) (Ki-67H) (n=2498). Disease characteristics were well balanced between the arms of this population. Abemaciclib plus ET demonstrated superior IDFS vs ET alone, with a 30.9% reduction in risk of developing invasive disease (p=.0111; HR = 0.691; 95% CI = 0.519, 0.920) and 2-year IDFS rates of 91.6% and 87.1%, respectively. An improvement in DRFS treatment effect was also observed in the Ki-67H population. At the time of data cutoff, the median treatment duration of abemaciclib was 17.3 months and the median duration of ET was balanced between the arms (18.3 months in the abemaciclib arm and 18.7 months in the ET alone arm). Safety was consistent with the results at the interim IDFS analysis and with the known safety profile of abemaciclib. Conclusions At the primary outcome analysis, with a median follow-up of approximately 19 months, abemaciclib combined with ET continued to demonstrate a clinically meaningful improvement in IDFS in patients with HR+, HER2-, node-positive, high risk, EBC with a statistically significant improvement in IDFS in patients with central Ki-67 ≥20%. ClinicalTrials.gov: NCT03155997 Table 1: PrimaryOutcome EfficacyIntent-to-Treat PopulationIntent-to-Treat PopulationKi-67 ≥20% (Ki-67H) PopulationKi-67 ≥20% (Ki-67H) PopulationEndpointAbemaciclib + ET N=2808ET alone N=2829Abemaciclib + ET N=1262ET alone N=1236IDFS# events, n (%)163 (5.8)232 (8.2)82 (6.5)115 (9.3)log rank P value, HR (95% CI)p=.0009 0.713 (0.583, 0.871)p=.0111 0.691 (0.519, 0.920)Rate (%) at 2 years (95% CI)92.3 (90.9, 93.5)89.3 (87.7, 90.7)91.6 (89.4, 93.4)87.1 (84.3, 89.5)Difference (%) in 2-year rates (95% CI)3 (1.1, 5.0)4.5 (1.2, 7.7)DRFS# events, n (%)131 (4.7)193 (6.8)65 (5.2)102 (8.3)log rank P value, HR (95% CI)p=.0009 0.687 (0.551, 0.858)0.609 (0.445, 0.833)Rate (%) at 2 years (95% CI)93.8 (92.6, 94.9)90.8 (89.3, 92.1)93.6 (91.6, 95.1)88.5 (85.7, 90.7)Difference (%) in 2-year rates (95%CI)3 (1.2, 4.8)5.1 (2.1, 8.1) Citation Format: Joyce A. O'Shaughnessy, Stephen Johnston, Nadia Harbeck, Masakazu Toi, Young-Hyuck Im, Mattea Reinisch, Zhimin Shao, Pirkko Liisa Kellokumpu Lehtinen, Chiun-Sheng Huang, Alexey Tryakin, Matthew Goetz, Hope S Rugo, Elzbieta Senkus, Laura Testa, Michael Andersson, Kenji Tamura, Guenther G. Steger, Lucia Del Mastro, Joanne Cox, Tammy Forrester, Sarah Sherwood, Xuelin Li, Ran Wei, Miguel Martin, Priya Rastogi. Primary outcome analysis of invasive disease-free survival for monarchE: abemaciclib combined with adjuvant endocrine therapy for high risk early breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS1-01.

Background: Sexual dysfunction is a common health problem in women, and it can occur during breast cancer treatment and survivorship. This study aims to determine the frequency of sexual disfunction among Brazilian women with early breast cancer on adjuvant endocrine therapy and to explore its relationships with patients’ clinical and social characteristics, adherence to ET, quality of life, return to work and healthcare insurance. Methodology: Women with history of early-stage ER+ invasive carcinoma of the breast on adjuvant endocrine therapy for at least 6 months were invited to participate of this study. Sexual dysfunction was evaluated using the Female Sexual Function Index questionnaire (FSFI). A score of < 26.55 in FSFI indicates sexual dysfunction. We evaluated sexually active patients (women should have at least one sexual intercourse in the previous four weeks). Demographic and medical information, site of treatment (private versus public), degree of education (completed high school vs not) were reviewed from medical records. Quality of life was assessed using EORTC QLQ C30 and BR-23 forms and adherence to ET was assessed by the Morisky Medication Adherence Scale (MMAS-8). Additionally, patients were interviewed about return to work. Data collection was performed using RedCap software and statistical analyzes were performed on the software R (R Core Team (2022). Qualitative variables were compared between groups using the Chi-square or exact Chi-square test and for quantitative variables the non-parametric Mann-Whitney test was used. Multivariable analysis was performed using Poisson regression. P < 0.05 was considered significant. Analyzes were performed in SAS 9.4. Results: From June 2021 to May 2023, a total of 461 women with ER+ early-stage breast cancer from 12 Brazilian institutions were included in this analysis. The mean age was 56.0 years (range 22-93 ), 47.7% were non-white and 38.7% were premenopausal. A total of 233 women (50.6%) had private insurance and the remaining were treated in public institutions. Median duration of ET use was 2.78 years (range 6 months- 9.61 years).Only 249 (54%) out of 461 patients who accepted to participate in this study declared to have sexual intercourse in the previous 4 weeks before evaluation and composes the population of this analysis. Sexual disfunction according results of FSFI questionnaire was found in 113 (53.3%) participants. Age was significantly associated with sexual dysfunction with women > 40 years-old having higher rates (95.3%) compared with versus younger patients (4.71% p=0.0069). Patients without sexual dysfunction had significantly higher EORTC QLQ C30 Global health status, Physical Functioning, Emotional Functioning, Sexual Functioning and Sexual Enjoyment scores than those with sexual dysfunction (p = 0.0060, p = 0.0242, p = 0 .0353, p = 0.0002 and p < 0.0001 respectively). ET duration between 2 and 5 years vs < 2 years, higher vs lower education level, EORTC QLQ-BR23 breast symptom and sexual functioning higher scores were significantly associated with the occurrence of sexual dysfunction in multivariated analysis (p < 0.05). Conclusion: In our study, only 54% of women evaluated had sexual intercourse in the previous four weeks and from those women 53.3% reported sexual dysfunction. Factors related to sexual dysfunction were higher education level, ET duration between 2 and 5 years, breast symptom and sexual functioning higher scores. div style=margin-top:10px; margin-bottom:20px;>Characteristic with adjusted prevalence ratios for the occurrence of sexual disfunction XX XX PR: prevalence ratio, EORTC: European Organisation for Research and Treatment of Cancer Citation Format: Daniele Assad-Suzuki, Fernanda Moura, Danielle Santos, Sulene Oliveira, Cristiano Souza, Heloísa Resende, Andrea Shimada, Anna Luiza Galvão, Bruno Souza, Amanda Castro, Monalisa Andrade, Yuri Beckedorff, Maria Cristina Magalhães, Carlos Paiva, Angelica Rodrigues, Daniela Pereira, Daniela Rosa, Romualdo Barroso-Sousa. Sexual dysfunction among Brazilian women with early breast cancer on adjuvant endocrine therapy (ET) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-11-05.

BackgroundQuality of life in patients with breast cancer is an important outcome. This paper presents an extensive overview on the topic ranging from descriptive findings to clinical trials.MethodsThis was a bibliographic review of the literature covering all full publications that appeared in English language biomedical journals between 1974 and 2007. The search strategy included a combination of key words 'quality of life' and 'breast cancer' or 'breast carcinoma' in titles. A total of 971 citations were identified and after exclusion of duplicates, the abstracts of 606 citations were reviewed. Of these, meetings abstracts, editorials, brief commentaries, letters, errata and dissertation abstracts and papers that appeared online and were indexed ahead of publication were also excluded. The remaining 477 papers were examined. The major findings are summarized and presented under several headings: instruments used, validation studies, measurement issues, surgical treatment, systemic therapies, quality of life as predictor of survival, psychological distress, supportive care, symptoms and sexual functioning.ResultsInstruments-Several valid instruments were used to measure quality of life in breast cancer patients. The European Organization for Research and Treatment of Cancer Core Cancer Quality of Life Questionnaire (EORTC QLQ-C30) and its breast cancer specific complementary measure (EORTC QLQ-BR23) and the Functional Assessment Chronic Illness Therapy General questionnaire (FACIT-G) and its breast cancer module (FACIT-B) were found to be the most common and well developed instruments to measure quality of life in breast cancer patients. Surgery-different surgical procedures led to relatively similar results in terms of quality of life assessments, although mastectomy patients compared to conserving surgery patients usually reported a lower body image and sexual functioning. Systemic therapies-almost all studies indicated that breast cancer patients receiving chemotherapy might experience several side-effects and symptoms that negatively affect their quality of life. Adjuvant hormonal therapies also were found to have similar negative impact on quality of life, although in general they were associated with improved survival. Quality of life as predictor of survival-similar to known medical factors, quality of life data in metastatic breast cancer patients was found to be prognostic and predictive of survival time. Psychological distress-anxiety and depression were found to be common among breast cancer patients even years after the disease diagnosis and treatment. Psychological factors also were found to predict subsequent quality of life or even overall survival in breast cancer patients. Supportive care-clinical treatments to control emesis, or interventions such as counseling, providing social support and exercise could improve quality of life. Symptoms-Pain, fatigue, arm morbidity and postmenopausal symptoms were among the most common symptoms reported by breast cancer patients. As recommended, recognition and management of these symptoms is an important issue since such symptoms impair health-related quality of life. Sexual functioning-breast cancer patients especially younger patients suffer from poor sexual functioning that negatively affect quality of life.ConclusionThere was quite an extensive body of the literature on quality of life in breast cancer patients. These papers have made a considerable contribution to improving breast cancer care, although their exact benefit was hard to define. However, quality of life data provided scientific evidence for clinical decision-making and conveyed helpful information concerning breast cancer patients' experiences during the course of the disease diagnosis, treatment, disease-free survival time, and recurrences; otherwise finding patient-centered solutions for evidence-based selection of optimal treatments, psychosocial interventions, patient-physician communications, allocation of resources, and indicating research priorities were impossible. It seems that more qualitative research is needed for a better understanding of the topic. In addition, issues related to the disease, its treatment side effects and symptoms, and sexual functioning should receive more attention when studying quality of life in breast cancer patients.

Safety of adjuvant CDK4/6 inhibitors during the COVID-19 pandemic.

Locally advanced prostate cancer generally refers to those patients with clinical stages T3-4 disease. Patients with locally advanced cancer frequently are included in clinical trials that examine treatment for patients at high risk for relapse based on presenting prostate-specific antigen, high Gleason score, or advanced clinical stage. There is a growing body of evidence that suggests that men with localized prostate cancer benefit from high-dose radiation therapy delivered with three-dimensional conformal radiation therapy, intensity-modulated radiation therapy, or proton beam therapy. Most importantly, neoadjuvant and adjuvant androgen-deprivation therapy have significantly improved outcomes in men with locally advanced or high-risk prostate cancer. Although questions remain regarding the optimal timing and duration of adjuvant hormonal therapy, a combination of long-term androgen deprivation started before radiation therapy and continued for 2 years represents a North American standard of care for this patient population.

Young age is a known factor associated with suboptimal adherence to endocrine therapy (ET) for adjuvant breast cancer (BC) treatment. This study was aimed at assessing nonadherent behaviors and associated factors among young women with early-stage hormone receptor-positive BC. As part of a multicenter, prospective cohort of women with a diagnosis of BC at or under the age of 40years, participants were surveyed 30months after their diagnosis about adherent behaviors. Among those who reported taking ET, adherence was measured with a 3-item Likert-type scale: Do you ever forget to take your ET? If you feel worse when you take your ET, do you stop taking it? Did you take your ET exactly as directed by your doctor over the last 3months? Women reporting at least 1 nonadherent behavior were classified as nonadherers. Variables with a P value<.20 were included in a multivariable logistic model. Among 384 women, 194 (51%) were classified as nonadherers. Univariate factors that retained significance in the multivariable model included educational level (odds ratio [OR], 0.50 for high vs low; P=.04), level of social support according to the Medical Outcome Study Social Support Survey (OR, 0.98 per 1 point; P=.01), and confidence with the decision regarding ET measured on a 0 to 10 numerical scale (OR, 0.63 for high vs low; P=.04). Findings from this study could help to identify young patients at higher risk for nonadherence. Interventions adapted to the level of education and aimed at reinforcing support and patients' confidence in their decision to take ET could improve adherence and associated outcomes in this population.

Breast cancer in young women (<40 years) is a rare and complex clinical and psychosocial condition, which deserves multidisciplinary and personalized approaches. In young women with hormone-receptor positive disease, 5 years of adjuvant tamoxifen, with or without ovarian suppression/ablation, is considered the standard endocrine therapy. The definitive role of adjuvant aromatase inhibitors has still to be elucidated: the upcoming results of the Tamoxifen and EXemestane Trial (TEXT) and Suppression of Ovarian Function Trial (SOFT) trials will help understanding if we can widen our current endocrine therapeutic options. The optimal duration of adjuvant endocrine therapy in young women also remains an unresolved issue. The recently reported results of the ATLAS and aTToM trials represent the first evidence of a beneficial effect of extended endocrine therapy in premenopausal women and provide an important opportunity in high-risk young patients. In the metastatic setting, endocrine therapy should be the preferred choice for endocrine responsive disease, unless there is evidence of endocrine resistance or need for rapid disease and/or symptom control. Tamoxifen in combination with ovarian suppression/ablation remains the 1st-line endocrine therapy of choice. Aromatase inhibitors in combination with ovarian suppression/ablation can be considered after progression on tamoxifen and ovarian suppression/ablation. Fulvestrant has not yet been studied in pre-menopausal women. Specific age-related treatment side effects (i.e., menopausal symptoms, change in body image and weight gain, cognitive function impairment, fertility damage/preservation, long-term organ dysfunction, sexuality) and the social impact of diagnosis and treatment (i.e., job discrimination, family management) should be carefully addressed when planning long-lasting endocrine therapies in young women with hormone-receptor positive early and advanced breast cancer.

Background: The 21-gene Recurrence Score (Oncotype DX) is a genomic assay that provides prognostic information for distant recurrence risk and is predictive of adjuvant chemotherapy benefit in hormone receptor (HR)-positive, HER-2 negative early-stage breast cancer (EBC). The Breast Cancer Index (BCI) is another molecular gene expression-based assay that evaluates the utility of extending adjuvant endocrine therapy (ET) from 5 to 10 years and predicts risk of distant recurrence. In January 2021, the National Comprehensive Cancer Network (NCCN) Guidelines added BCI to guide duration of adjuvant ET as a category 2A recommendation. The goal of this study was to evaluate the association between BCI and RS in terms of their predicted benefit for adjuvant therapy and risk of distant recurrence. We also assessed the association of various anatomic and biologic tumor features with BCI. Methods: We performed a retrospective chart review of all patients with HR-positive EBC who had a BCI and Oncotype DX performed between 2007-2021. Demographics, tumor characteristics and BCI and RS results were extracted from the electronic medical record. Patients were categorized by BCI predictive of extended ET (formerly BCI high) versus not (formerly BCI low) and RS of low (0-10), intermediate (11-25) and high (26-100). Numerical values for distant recurrence risk were recorded for both BCI and Oncotype DX tests. Multivariable regression models were used to assess the relationship between BCI and Oncotype DX as well as factors associated with each. Results: We identified 153 women with HR-positive EBC with both RS and BCI performed. The median age of the population was 57 years and 25% were premenopausal. 32% (n=49) had a BCI result predictive of benefit from extended adjuvant ET. When comparing patients with BCI predictive of extended ET versus those with BCI not predictive of extended ET, there was no association between BCI and RS based on multivariate logistic regression models, p=0.7. A similar distribution of RS was observed between patients who had a BCI result predictive of benefit from extended ET versus not predictive. Among 49 patients with a BCI predictive of extended ET, 35% had high RS, 63% intermediate RS and 2% low RS. Among 104 patients with a BCI not predictive of extended ET, 24%, 73% and 3% had high, intermediate, and low RS, respectively. Multivariate regression models revealed an association between poorly differentiated tumors and BCI result predictive of extended ET, p=0.002. No associations were observed between BCI and menopausal status, ER%, PR%, tumor size or lymph node positivity. Regarding risk of recurrence, there was an association between BCI and Oncotype DX in terms of their predicted numerical risk of recurrence, p&amp;lt; 0.001. Higher percentage of PR positivity, poorly differentiated tumors, and lymph node positivity were associated with a higher risk of recurrence on the BCI. Conclusions: In our patient population selected to have Oncotype DX and BCI performed, we found no association between the two genomic assays in terms of their predictive benefit. However, there was an association between Oncotype DX and BCI in terms of their prognostic ability. Given the increased use of BCI since its inclusion in national guidelines, it is important to understand its relationship with other genomic assays especially when used to guide clinical decisions and estimate prognosis. Citation Format: Rima Patel, Nicole Casasanta, Zhiqiang Li, Melanie Kier, Julia Blanter, Sophie Sohval, Malin Hovstadius, Catherine Wu, Marc Fink, Xiang Zhou, Brittney Zimmerman, Krystal Cascetta, Rong Chen, William Oh, Amy Tiersten. Correlating Predicted Adjuvant Therapy Benefit and Risk of Recurrence between Breast Cancer Index (BCI) and 21-gene Oncotype DX Recurrence Score (RS) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-04-09.

Patients with hormone-receptor positive, early-stage breast cancer are at considerable risk for late recurrence. Previous randomized clinical trials have shown that extending adjuvant tamoxifen to ten vs. five years improves disease-free survival (and overall survival in one trial). Adding five years of an aromatase inhibitor (AI) after five years of tamoxifen has also been shown to significantly improve disease-free survival in postmenopausal patients. Benefit from extending adjuvant AI therapy beyond five years in patients who have received five years of an AI or tamoxifenàAI has also been recently demonstrated in several clinical trials but the absolute benefit appears small and the ideal duration of the extended therapy is still a topic of debate. Over the past decade, efforts have focused on identifying predictors of risk of late recurrence and predictors of benefit from extended endocrine therapy. Clinicopathologic factors and circulating tumor cells can predict risk of late recurrence but not benefit from extended ET. Several commercially available genomic classifiers can further stratify risk of late recurrence, and some have also been found to predict benefit from extended ET. Their clinical utility for tailoring the use of extended endocrine therapy continues to evolve. Citation Format: Eleftherios (Terry) Mamounas, Kathryn Ruddy. Duration of endocrine therapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr CC1-2-1.

Supplementary Data from Determinants and Effectiveness of Extending the Duration of Adjuvant Hormone Therapy beyond 5 Years in Patients with Breast Cancer

Objective: To analyze the presence of osteoporosis and osteopenia in post-menopausal breast cancer patients receiving hormonal therapy.&#x0D; Study Design: Comparative Cross-sectional Study.&#x0D; Place and Duration of Study: Oncology Department, Combined Military Hospital Rawalpindi Pakistan, from Dec 2020 to May 2021.&#x0D; Methodology: This study was conducted on 200 post-menopausal female breast cancer patients who had been taking Aromatase inhibitors for more than six months. All the study participants underwent a dual-energy X-ray absorptiometry (DEXA) scan to measure bone mineral density. As a result, they were classified as having osteoporosis or osteopenia based on bone mineral density. In addition, age, duration of therapy, tumour stage and molecular subtypes of breast cancer were correlated with the presence of osteopenia/osteoporosis in the study participants.&#x0D; Results: A total of 200 post-menopausal patients with breast cancer using hormonal therapy for more than six months were included in the final analysis. The mean age of the patients was 56.331 ± 6.744 years. In addition, 55 (22.5%) patients had normal bone mineral density, 92 (46%) had osteopenia, while 53 (26.5%) had osteoporosis on a dual-energy X-ray absorp- tiometry (DEXA) scan. Molecular subtypes of the tumour, the advancing age of patients and the long duration of hormonal therapy were statistically significantly associated with the presence of osteopenia/osteoporosis (p-value &lt;0.05) in our study participants.&#x0D; Conclusion: Considerable number of post-menopausal patients with advanced breast cancer taking hormonal therapy showed the presence of osteopenia and osteoporosis. Molecular subtyping, the advanced age of patients and the long duration of hormonal therapy significantly predicted.........

The endocrine therapy for breast cancer could be traced back to the excision of the metastatic breast cancer by oophorectomy in a premenopausal women performed by Beatson in 1896. After the development of more than 100 years, endocrine therapy plays an important role in adjuvant therapy, the rescuing treatment of its recurrence due to metastasis, and the new adjuvant endocrine therapy for breast cancer. Through analyzing the changes in the 4 aspects of endocrine treatment of breast cancer, i.e., the original simple excision of the endocrine organs, tamoxifen, drug-induced ovarian castration and the 3th generation aromatase inhibitor, the characteristics of different ages of endocrine therapy can be summarized, which would provide the reference for the new developmental trend of this therapy.

For patients with hormone receptor–positive (HR+) breast cancer, the recommended duration of adjuvant endocrine therapy ranges from 5 to 10 years. For

e12505 Background: Adjuvant endocrine therapy (AET) improves long-term survival for hormone-sensitive breast cancer; However, suboptimal adherence is prevalent, with many women failing to follow prescribed dosage and frequency. Long-term adherence patterns to AET are poorly understood. Additionally, there is a lack of data regarding the adherence to AET among Moroccan women and the factors that may influence it. Objectives: The primary objective of the study was to assess the adherence rate to AET in patients with HR-positive early breast cancer being treated at Hassan II University Hospital of Fez, Morocco. Secondary objectives included determining factors associated with poor adherence and assessing the adverse events associated with AET and their prevalence. Methods: We conducted a cross-sectional study involving 335 breast cancer patients undergoing AET. Eligible patients, who had received at least one dispensing of AET, participated in the study through a direct questionnaire survey after providing signed consent. The questionnaire comprised sections covering patient demographics, clinical data (stage, type of AET, duration of therapy), side effects or symptoms related to AET, other factors that may impact adherence. Adherence to AET was assessed at three points of measurement: 1 year, 3 years, and ≥ 5 years after the initiation of therapy. The study was carried out with respect to the Moroccan regulation in effect. Results: The study included 335 cases with an average age of 54 years. Participants were predominantly illiterate (62%) and post-menopausal (50.7%). Most were classified as stage II UICC (53.5%). Mastectomy was performed in the majority (74%). Neo(adjuvant) CMT was given to 79.4%, and adjuvant radiotherapy to 86.9%. Tamoxifen was administered to 55.4%, and aromatase inhibitors to 44.6%. Medical castration was associated with 12.5%, and 35 patients switched AET over time. Only 12.8% exceeded 5 years of AET during recruitment. Adherence assessment revealed an overall adherence rate of 53.4%. Notably, 67.2% claimed never to forget their medication, and about 20% temporarily stopped it, primarily due to lack of information. Most participants used a reminder strategy, notably alarms (43.3%). Treatment tolerance varied, with hot flushes and arthralgia being predominant side effects. Statistical analyses found a significant link between treatment lasting over 5 years and non-adherence (p = 0.003). However, the use of an alarm as a reminder strategy strengthened adherence (p = 0.021). No statistically significant differences were noted in other variables. Conclusions: Despite the benefits, ensuring adjuvant hormone therapy adherence is challenging. Our analysis, estimating a 53.4% global adherence, found that only treatment duration and recall strategy significantly correlated with adherence.