The (in)effectiveness of staging exams in asymptomatic breast cancer patients

Background: During breast cancer follow-up, there is no data suggesting that, besides annual mammography, laboratory and imaging tests in asymptomatic patients lead to survival benefit. However, most available data come from a period of fewer quality of diagnostic procedures and less efficacy of treatment for advanced breast cancer. In our centre, in the absence of disease recurrence after 5 years of follow-up, and when endocrine therapy ends, we transfer the surveillance of breast cancer patients for primary care physicians. Before that, by protocol, we use to request as staging exams a bone scan, a chest x-ray and liver ultrasound, or a thoracoabdominal computed tomography, as well as the quantification of CA15.3, in order to detect asymptomatic cancer recurrence before discharge. This study aimed to evaluate the effectiveness of that strategy in detecting asymptomatic disease and its impact on patients’ outcomes, compared to those who recurred symptomatically during the following 5 years of surveillance. Methods: A retrospective cohort study of all adult patients admitted to our institution due to breast cancer in stage I-III during 2008 was performed. We included those who were asymptomatic and considered for discharge after 5 years of follow-up. Laboratory and imaging tests done at that time were reviewed. We also looked for symptomatic disease recurrence in the following 5 years of surveillance, with median follow-up of 43 months (95% CI 24.6-61.4), after discharge. Data were analyzed using descriptive statistics and survival was estimated by Kaplan-Meier method. Survival between groups was compared using log-rank test. Hazard ratios and respective 95% CI were estimated using Cox-regression models. Statistical significance was set at P Results: A total of 576 patients met inclusion criteria, 99.7% female (574/576), with median age of 59 years (IQR, 18). Disease was staged as IA in 48.5% of patients (279/575). At discharge, 75.2% of patients (433/576) did staging exams, and the remaining did not according to clinical criteria defined by the attending physician (mainly age, comorbidities and stage IA). Exams were positive in 2.1% of patients screened (9/433), due to bone metastasis detection in 88.9% (8/9). For these 9 patients, median PFS was 30 months (95% CI 0.0-76.7) and 5-year OS was 62.5%. During surveillance after discharge, 4.4% of patients (24/549) presented disease recurrence, 3.1% (17/549) with distant metastasis. From those, 70.6% (12/17) had visceral metastasis and 29.4% (5/17) had recurrent disease limited to bone. For these 17 patients, median PFS was 16 months (95% CI 5.3-26.7) and 2-year OS was 50.1%. For bone metastasis patients, median PFS was not different between asymptomatic and symptomatic group (p=0.378); but median OS was not reached in asymptomatic patients and was of 34 months in symptomatic patients (p=0.029). We did not find predictive factors for PFS or OS by multivariable Cox-regression analysis. Conclusion: In our cohort, asymptomatic recurrence detection rate was low, mainly presented as bone metastasis. Nevertheless, it seemed to impact positively on OS, compared to those who presented symptomatic bone disease. Disease recurrence due to visceral metastasis was detected, more frequently, in symptomatic patients. New trials are needed to reassess the question concerning staging exams in asymptomatic breast cancer patients. It would also be interesting to perform a cost-effectiveness analysis of that approach. Citation Format: Andreia Cruz, Ana Rita Lopes, Maria Leitao, Sarah Lopes, Sofia Patrao, Maria Cassiano, Cristina Oliveira, Miguel Abreu, Julio Oliveira, Joana Bordalo Sa, Ana Rodrigues, Marta Ferreira, Rosario Couto, Ines Pousa, Claudia Vieira, Ana Ferreira, Susana Sousa, Deolinda Pereira. The (in)effectiveness of staging exams in asymptomatic breast cancer patients [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-03-01.