Background: Despite increasing interest in patient involvement in health care research, researchers may be uncertain about the benefits of involving patients in the design and conduction of clinical studies. We aimed to evaluate the impact of patient involvement on patient recruitment and retention in a clinical study of PET/CT in women with advanced breast cancer. Further, we report our experience regarding the researchers’ attitudes towards involving patients as partners in the research process. Methods: Two patient representatives from the Danish Breast Cancer Organization were invited as partners in the research team. These patient partners were asked to contribute in particular to participator information material and evaluation of ethical aspects of the study. The impact of patient involvement on patient recruitment was evaluated by comparing expected versus actual number of patients recruited, and then relating it to patient recruitment in a similar study at the same institution that did not involve patients as research partners. Results: Having patients as partners in the research team led to a major revision of the participator information material and improved patient recruitment. The expected number of patients was 260, but 380 were actually enrolled within the planned study period, thus 146% of the expected patient recruitment. In the previous study, only 100 of the expected 150 patients were enrolled during a 10-month extended study period, i.e. 67% of the expected number. Patient retention in the current study was high, with 86% of eligible patients attending follow-up scans. We observed initial resistance amongst researchers against inviting patients as team partners. This resistance gradually lessened during the study, and the most reluctant researchers at the beginning of the study later applauded the collaboration and the ideas generated by the patient representatives. Conclusion: Involving patients as partners in the research team resulted in major changes to the participator information material and contributed to higher than expected patient recruitment and retention. Furthermore, we observed a positive change of attitude amongst the researchers towards patient involvement in the research process. Trial registration: Ongoing study: ClinicalTrials.gov (NCT03358589). Previous study: ClinicalTrials.gov (NCT01552655).

Purpose: To prospectively investigate the diagnostic accuracy of [¹⁸F]fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) with dual-time-point imaging, contrast-enhanced CT (ceCT), and bone scintigraphy (BS) in patients with suspected breast cancer recurrence. Patients and Methods: One hundred women with suspected recurrence of breast cancer underwent 1-hour and 3-hour FDG-PET/CT, ceCT, and BS within approximately 10 days. The study was powered to estimate the precision of the individual imaging tests. Images were visually interpreted using a four-point assessment scale, and readers were blinded to other test results. The reference standard was biopsy along with treatment decisions and clinical follow-up (median, 17 months). Results: FDG-PET/CT resulted in no false negatives and fewer false positives than the other imaging techniques. Accuracy of results were similar for 1-hour and 3-hour FDG-PET/CT. For distant recurrence, the area under the receiver operating curve was 0.99 (95% CI, 0.97 to 1) for FDG-PET/CT, 0.84 (95% CI, 0.73 to 0.94) for ceCT, and 0.86 (95% CI, 0.77 to 0.94) for the combined ceCT+BS. Of 100 patients, 22 (22%) were verified with distant recurrence, and 18 of these had bone involvement. Nineteen patients (19%) had local recurrence only. In exploratory analyses, diagnostic accuracy of FDG-PET/CT was better than ceCT alone or ceCT combined with BS in diagnosing distant, bone, and local recurrence, shown by a greater area under the receiver operating curve and higher sensitivity, specificity, and superior likelihood ratios. Conclusion: FDG-PET/CT was accurate in diagnosing recurrence in breast cancer patients. It allowed for distant recurrence to be correctly ruled out and resulted in only a small number of false-positive cases. Exploratory findings suggest that FDG-PET/CT has greater accuracy than conventional imaging technologies in this patient group.

Breast cancer prognosis is steadily improving due to early detection of primary cancer in screening programs and revolutionizing treatment development. In the metastatic setting, therapy improvements render breast cancer a chronic disease. Although FDG-PET/CT has emerged as a highly accurate method for staging metastatic breast cancer, there has been no change in response evaluation methods for decades. FDG-PET/CT has proven high prognostic values in patients with metastatic breast cancer when using quantitative PET methods. It has also shown a higher predictive value than conventional CT when applying the respective response evaluation criteria, RECIST and PERCIST. Response categorization using FDG-PET/CT is more sensitive in detecting progressive and regressive disease, while conventional imaging such as CT and bone scintigraphy deem stable disease more often. These findings reflect the higher accuracy of FDG-PET/CT for response evaluation in this patient group. But does the higher accuracy of FDG-PET/CT translate into a patient benefit when implementing it for monitoring response to palliative treatment? We have evidence of survival benefit from a retrospective study indicating the superiority of using FDG-PET/CT compared with conventional imaging for response evaluation in metastatic breast cancer patients. The survival benefit seems to result from earlier detection of progression with FDG-PET/CT than conventional imaging, leading to an earlier change in treatment with potentially better efficacy of the subsequent treatment line. FDG-PET/CT can be used semiquantitatively as suggested in PERCIST. However, we still need to improve clinically applicable methods based on neural network modeling to better integrate the quantitative information in a smart and standardized way, enabling relevant comparability between scans, patients, and institutions. Such innovation is warranted to support imaging specialists in diagnostic response assessment. Prospective multicenter studies analyzing patients' survival, quality of life, societal and patient costs of replacing conventional imaging with FDG-PET/CT are needed before firm conclusions can be drawn on which type of scan to recommend in future clinical guidelines.