Causes and consequences of delayed diagnosis in breast cancer screening with a focus on mammographic features and tumour characteristics

Abstract

PurposeTo study the prevalence, causes and consequences of delayed breast cancer diagnosis in the screening population. MethodsThis retrospective study was performed in women who underwent biennial screening mammography between January 1, 2009 and June 30, 2019. Patients were divided into 3 groups; screen-detectedbreast cancer (SDC) without a diagnostic delay, a primary diagnostic delay(i.e. missed cancer at previous screening round)and a delay in diagnostic work-up after recall. Women with a true interval cancer (IC; i.e. not visible on prior examinations) were excluded. Outcome parameters included mammographic and tumour characteristics, lymph node status and surgical treatment. ResultsIn our sample of 4491 women with breast cancer (4292 SDC and 199 ‘missed’ IC), respectively, a total of 1112 women experienced a diagnostic delay of ≥ 4 months. Compared to women without a diagnostic delay (n = 2720), the 176 women with a delay in diagnostic work-up showed overall similar mammographic abnormalities (P = 0.052). These groups show similar distributions in invasive tumours, tumour stage and lymph node status (P = 0.25, P = 0.95 and P = 0.93, respectively). Women with a primary diagnostic delay (n = 936) showed less calcifications (P < 0.001), and more masses with calcifications and architectural distortions on mammography (P = 0.01 and P = 0.04, respectively). Moreover, this group comprised larger tumours (P < 0.001) and lymph node metastases (P < 0.001), and more often underwent mastectomy (P < 0.001). ConclusionsA primary diagnostic delay in breast cancer diagnosis results in less favourable tumour characteristics and relatively more mastectomies compared to no delay in breast cancer diagnosis and a delay in diagnostic work-up after recall.