Adjuvant endocrine treatment-related adverse effects have a strong impact on patients' quality of life and thereby limit therapy's risk benefit ratio resulting in morbidity and treatment discontinuation. Still, many AI adverse effects remain untreated given that they are unrecognized by conservative methods (e.g., proxy ratings). The ability of complementary patient-reported outcomes (PROs) to provide a more comprehensive assessment of side-effects is to be explored. A cross-sectional study sample of 280 postmenopausal, early stage breast cancer patients was subjected to a comprehensive PRO assessment (FACT-B/+ES) at their after-care appointment. Prevalence and severity of patient-reported physical side-effects and psychosocial burden related to adjuvant AI therapy were compared with prevalences derived from pivotal phase IV trials (ATAC 2005, BIG1-98 2005). Across all symptom categories, highest prevalence rates were found for joint pain (59.6%), hot flushes (52%), lost interest in sexual intercourse (51.4%), and lack of energy (40.3%). Overall, PROs resulted in significantly higher prevalence rates as compared to physician ratings for all symptoms published in pivotal clinical trials except vaginal bleeding and nausea. The treatment duration exerted no significant impact on symptom frequency (P > 0.05). Established prevalence rates of endocrine treatment-related toxicity seem to be underestimated. The incorporation of PRO data should be mandatory or at least highly recommended in clinical treatment planning to arrive at a more accurate assessment of a patient's actual symptom burden enabling improved individualized management of side-effects and mediating the preservation of treatment adherence.

Background Endocrine treatment (ET) is a highly effective breast cancer treatment but can distinctly impair breast cancer patients’ quality of life (QOL). In a patient-reported outcome (PROs) study conducted by the authors in 2011, patients reported higher ET-induced symptom levels than known from the registration trials, and was underestimated. Based on these study results, we investigated the long-term sequelae of ET reported by breast cancer survivors (BCS) in a follow-up study conducted 5–10 years after an earlier assessment. Methods BCS who had participated in the earlier study (n = 436) were approached for study participation either at one of their routine follow-up appointments or via mail; consenting patients were asked to completed the same PRO assessment used in the original study (FACT-B + ES). BCS with relapse/ progressive disease were excluded from the analysis. We compared long-term endocrine symptomatology and overall QOL outcome (i.e. FACT-G and -ES sum score). Results A final sample of 268 BCS was included in the analysis. BCS reported a significant improvement of the overall endocrine symptomatology (baseline mean = 59 vs. follow-up mean = 62, p < 0.001), physical (baseline = 23.9 mean vs. follow-up mean = 24.8, p < 0.01) and functional well-being (baseline mean = 21.7 vs. follow-up mean = 22.7, p = 0.013) and overall QOL (mean baseline = 88.3 vs. mean follow-up = 90.9, p = 0.011). However, the prevalence of particular symptoms, well-known to be ET induced, did not change over time such as joint pain (baseline = 45.5% vs. 44.2%, n.s. difference), lack of energy (36.4% vs 33.8%, n.s. difference), weight gain (36.8% vs. 33.9%, n.s. difference) or vaginal dryness (30.2% vs. 33%, n.s. difference) and the proportion reporting lack of interest in sex increased (40.4% vs. 48.7%, p < 0.05). Conclusion Presented results indicate that BCS recover well in terms of overall endocrine symptomatology and quality of life but experience some clinically relevant and unfavorable ET-related long-term effects.