Different Molecular Subtypes of Breast Cancer Have Varied Rates and Patterns of Recurrence

A large retrospective cohort study has found that different molecular subtypes of breast cancer have varying rates and patterns of recurrence following surgery for early-stage disease. The study analyzed the data of 16,462 women who had undergone surgery for breast cancer at the Seoul National University College of Medicine from 2000 to 2018. The study revealed that patients aged 40 or younger had greater variation in recurrence patterns by subtype as compared with older patients. The knowledge of the recurrence pattern may help identify periods of prevalent breast cancer recurrence and optimize the surveillance strategy, the authors stated.

Recurrence Risk in Different Molecular Subtypes

The study revealed that using hormone receptor (HR)-positive (+)/HER2-negative (-) tumors as the reference, HR-/HER2+ breast cancer had the highest risk of ipsilateral recurrence and triple-negative breast cancer had the highest risk of regional and contralateral recurrence. Molecular subtype remained significantly associated with recurrence risk in proportional hazards regression analysis.

Overall, the 10-year freedom from ipsilateral, regional, and contralateral recurrence was 95.9%, 96.1%, and 96.5%, respectively. The results showed that HR-/HER2+ tumors had almost a threefold higher rate of ipsilateral recurrence at 10 years as compared with HR+/HER2- tumors. The risk of regional and contralateral recurrence was two to three times higher with triple-negative tumors. After adjustment for clinicopathologic variables that influence recurrence, older patients had a lower risk of ipsilateral and contralateral recurrence.

Implications for Screening Intervals

The findings have implications for tailored screening intervals and the optimization of the use of breast MRI, a focus of several recent studies. Breast MRI is known to be a useful adjunct in multiple aspects of breast cancer management. However, its exact role and indications are controversial, including for patients with a personal history of cancer. The data currently available on breast MRI suggest that it may be beneficial in certain subsets of patients, including young patients and other high-risk populations.

The study demonstrated that women aged 40 years or younger with HR- breast cancer tended to have higher recurrence rates in the early postoperative periods. As such, young patients with HR-/ERBB2+ [HER2+] or triple-negative breast cancer may benefit from the addition of breast MRI as part of the surveillance in the first 2 to 3 years after surgery.

Conclusion

The study showed that different molecular subtypes of breast cancer have varied rates and patterns of recurrence following surgery for early-stage disease. The knowledge of the recurrence pattern may help identify periods of prevalent breast cancer recurrence and optimize the surveillance strategy. The study has implications for tailored screening intervals and the optimization of the use of breast MRI. Young patients with HR-/ERBB2+ [HER2+] or triple-negative breast cancer may benefit from the addition of breast MRI as part of the surveillance in the first 2 to 3 years after surgery. The authors concluded that validating the study at a multi-institutional level with a large number of patients, taking into account the recent advances in breast cancer treatments, would be necessary to generalize the findings.