External Validity of a Trial Comprised of Elderly Patients With Hormone Receptor-Positive Breast Cancer

Abstract

Breast cancer trial participants aged 75 years or older do not represent elderly breast cancer patients of corresponding age from the general population, which hampers the external validity of a trial.

Physical activity and survival of postmenopausal, hormone receptor–positive breast cancer patients: Results of the Tamoxifen Exemestane Adjuvant Multicenter Lifestyle study

“…4,15 Furthermore, the TEAM trial included postmenopausal women who generally had a high socioeconomic status and a low comorbidity burden in comparison with the general population. 17 For this reason, it is possible that even patients in the very low physical activity category were still rather active; in this case, differences in outcomes were absent. For comparison, the Nurses' Health Study divided patients into 5 groups according to the number of MET hours of physical activity per week; the lowest category consisted of patients who were active for less than 3 MET hours/week.…”

Variations in compliance to quality indicators by age for 41,871 breast cancer patients across Europe: A European Society of Breast Cancer Specialists database analysis

“…However, the question is if the older patients that were included in these trials are comparable to the general older cancer patients in terms of, for example, tumour characteristics and comorbidity. Therefore, the generalisability of these trial results should be further explored [11]. From these studies, among others, it is clear that the treatment of breast cancer for older women should not be always the same as the treatment for their younger counterparts, at least not for all treatment modalities.…”

“…Moreover, it has been shown that the older subjects who are included in a clinical trial, are not always representative for the general older population [11]. Therefore, the external validity of clinical trial results should be questioned when it concerns older patients.…”

Survival of older patients with metastasised breast cancer lags behind despite evolving treatment strategies – A population-based study

“…Older patients are generally underrepresented in clinical trials [7] and older women who participate in trials tend to have more favourable prognostic patient and tumour characteristics than patients in the general population [8,10]. Consequently, trial results cannot be extrapolated to the general older breast cancer population.…”

“…In addition, older breast cancer patients who are included in clinical trials, have a more favourable prognosis than the general older breast cancer population [10]. It is well known that older breast cancer patients comprise a heterogeneous group due to large differences in comorbidity, functional status and geriatric syndromes between patients [11][12][13].…”