The psychometric properties revealed that CS-31, CS-16 and CS-10 are valid instruments for assessing HRQL in BC survivors during adjuvant endocrine therapy. All the CS presented adequate internal consistency; satisfactory convergent validity for CS global and for almost all domains, except for Sexual and Couple of CS-16; and known-group validity, with statistical significance between anxiety and depression and worse HRQL. Furthermore, we identified a prospective improvement in HRQL of the baseline for the other time points. The CS were able to predict changes in the FACIT-F, especially the CS-31. To the best of our knowledge, our study is the first one that used the CS to assess HRQL in BC women, especially during adjuvant endocrine therapy.
CS-10 contains a small number of items (32% of the original length), is simple to apply and does not include sexual and couple relationship issues, which can often be embarrassing for respondents. However, the items on this scale are not divided into domains, allowing more restricted analyses. The authors of CS-10 constructed this instrument to a quick menopausal symptom assessment, not specifically to assessment of HRQL , although in the present study, it proved to be valid for this purpose. As for the CS-16 and CS-31, as they are multidimensional, they allow more in-depth analysis of adverse effects and general HRQL. Even though assessments of general HRQL may serve a purpose, knowing details that permeate the HRQL of these women, certainly, can be useful in clinical management. We identified superior psychometric properties of CS-31 over CS-16, which may be related both to the characteristics of sample and to the greater number of items presented in the first. Furthermore, the CS-16 does not include any item related to symptoms in the musculoskeletal system, and aching in muscles and joints is one of the main adverse effects of AI use .
We identified higher scores for anxiety and depression in women with worse HQRL and improvement in HRQL over the study. Recently, Martino and collaborators  identified that after 6 months of treatment with AI, BC patients presented a significantly higher perceived HRQL for both physical and mental components, added to a significant reduction of anxious and depressive symptoms, possibly due to the decline of the physical and psychological effects of recent diagnosis and previous treatments .
Regarding Sexual and Couple domains of CS, as well as Social/Family Well-Being of FACIT-F, the latter which also presents items related to sexual life and couple relation, have not changed over time. Often, the adverse effects of treatment, as well as induced menopause, cause sexual dysfunction among BC survivors, with relevant impact on sexual function . The disturbances in sexual life are among the factors that might deteriorate quality of life in BC patients and survivors . The adjuvant endocrine therapy, especially AI, can cause vaginal atrophy , dryness and dyspareunia , and some urogenital effects, such as vaginal dryness, persist lifelong if untreated . Possibly, the treatment has a more lasting impact on sexuality and a longer follow-up would be necessary to investigate changes in these domains. The main recommendation for the management of sexual health in BC survivors is that a multidisciplinary team needs to include the sexuality as an integral part of treatment, contributing to an improvement of HRQL .
We hypothesized that constructs indirectly related as Sexual and Couple of CS with Social/Family Well-Being of FACIT-F should present moderate correlation. However, this expected correlation has not been achieved by CS-16. Probably, due to the greater number of items investigated, the CS-31 is more sensitive to capture nuances that involve the sexual function and couple relation. It should be noted that sexuality is considered a biopsychosocial concept, and therefore it is believed to be associated with biological and psychosocial factors .
We must recognize that our study has some limitations as a small sample size. Several correlations were weak and could have become significant with larger sample sizes. Even though the CS was not designed for this population, these women are considered BC survivors, i.e. currently free of the disease, and have predominantly adverse effects like to those of other postmenopausal women, although intensified by the AI use. We need to consider that the CS’ target population is women aged 45 to 64 years  and our sample includes women aged 47 to 79 years. For this purpose, we divided women into two age groups (47 to 64 and 65 to 79 years) and observed that age had no effect on the CS scores by performing the Generalized Linear Model (GLzM) analysis (data not shown). In addition, the CS is a self-reported questionnaire, however in this study, all participants replied by interview, which may have inhibited responses to items in the Sexual and Couple domains. Even so, the standardization for this type of application was a methodological care considering that in our sample there were illiterate women.
As pointed out by others , we identified that most of invalid questionnaires were filled by women that were not married or without a partner, referring to a sexually inactive life. In fact, it was the reason for the sample difference between CS-31 and CS-16, considering that the first present more items in these domains. This seems to be a limitation of the multidimensional CS, and adaptations to these instruments are necessary to contemplate all climacteric women, irrespective of their marital status and sexual activity.
The strengths of the current research include that our study has evaluated the psychometric properties of the three CS at the same time and used them to assess HRQL at three time points, with a 2-year follow-up.
Adjuvant endocrine therapy adherence is suboptimal in BC patients. It is negatively associated with treatment adverse events  and associated with increased early tumor recurrence and mortality rates . Potentially, clinical interventions to manage these adverse effects may improve HRQL and BC outcomes . Future studies are necessary to confirm whether the implementation of CS in routine medical oncology is able to contribute to improvements in HRQL and in prognosis of these women. Even so, we suggest that CS-31 is used in outpatient service to investigate HRQL and the CS-10 to early screening of adverse effects or to population studies that seek to investigate HRQL in BC patients in AI use, as it is the fastest to apply. We believe that the use of CS can optimize the attendance time and the health outcomes, since physicians could focus on individual adverse effects and monitor, through graphic summaries, the evolution of these effects after specific interventions.