Comparison of time-varying recurrence patterns in breast cancer patients with different molecular subtypes treated from 2008 to 2012 and from 2013 to 2016: a single-center retrospective study

Abstract Purpose: To compare the time-varying recurrence patterns of different molecular subtypes of breast cancer in the contemporary era with those in the past era. Methods: This retrospective study included 14627 consecutive invasive breast cancer patients who underwent surgery from 2008 to 2016 at Fudan University Shanghai Cancer Center. We defined the period from 2013 to 2016 as the contemporary era and that from 2008 to 2012 as the past era. Five subtypes were defined according to the immunohistochemistry results. Emphasis was made on the changing patterns of recurrence for patients with different molecular subtypes changed between the two treatment eras. Kaplan–Meier survival curves were generated, and the hazard function was used to estimate the annual recurrence hazard. Results: By the end of follow-up (median, 68.1 months), 1429 patients (9.77%) experienced recurrence and metastasis. The annual recurrence risks of the entire population and each molecular type in 2013-2016 were reduced compared with those in 2008-2012. Luminal A and triple-negative patients in 2013-2016 showed a significantly lower recurrence hazard curve than those in 2008-2012. The recurrence hazard curve of luminal B (HER2-) and HER2+ subtypes was lower in 2013-2016 than in 2008-2012. The recurrence risk of the luminal B (HER2+) subtype was reduced substantially during 2013-2016, showing a delay of two years.Conclusion: With early detection of disease recurrence and improved treatment strategies, the recurrence patterns of different molecular subtypes of breast cancer have changed. The time-varying recurrence patterns observed during the contemporary era are significant for treatment decision-making and clinical trial planning.