Prevention of locoregional recurrence and distant metastasis in Japanese breast cancer patients using Japanese standard postoperative radiation fields: Experience at a single institution

Risk factors for recurrence in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative early breast cancer in Japan: a systematic literature review and meta-analysis

BACKGROUND

The clinicopathological factors indicating risk of recurrence are used to guide the choice of perioperative therapy in patients with breast cancer. Although several risk factors for recurrence have been reported in patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) early breast cancer in Japan, there has been no systematic review quantifying potential risk factors.

METHODS

We performed a systematic literature review and meta-analysis using the MEDLINE, Embase, Cochrane CENTRAL, and Japan Medical Abstract Society databases to identify risk factors for recurrence in HR+/HER2- early breast cancer in Japan. The primary outcome was relapse-free or disease-free survival (RFS/DFS), and the secondary outcomes were overall survival and breast cancer-specific survival (BCSS).

RESULTS

Searches identified 42 eligible publications. Meta-analyses identified lymph node metastasis (hazard ratio: 2.76 [95% confidence interval: 1.97-3.88]), large tumor size (1.67 [1.24-2.23]), high histological grade (1.50 [1.04-2.16]), and high nuclear grade (2.02 [1.61-2.54]) as risk factors for RFS/DFS. Lymph node metastasis (2.43 [1.28-4.63]), large tumor size (1.80 [1.24-2.62]), and high histological grade (2.02 [1.44-2.84]) were also risk factors for overall survival, and high progesterone status was a possible favorable prognostic factor for BCSS (0.20 [0.10-0.42]).

CONCLUSIONS

Identified risk factors were consistent with the previous reports, and this study provides quantitative summary of risk factors for HR+/HER2- early breast cancer recurrence in Japan. (PROSPERO Registration ID, CRD42022338391.).

Prevention of locoregional recurrence and distant metastasis in Japanese breast cancer patients using Japanese standard postoperative radiation fields: Experience at a single institution

BACKGROUND

Radiotherapy is an effective local control therapy for breast cancer. Locoregional control is associated with distant metastasis risk and survival after surgery.

AIM

We aimed to evaluate whether Japanese standard postoperative radiotherapy after surgery correlates with disease-free survival (DFS) and overall survival and clarify the characteristics of patients who benefit from it.

METHOD AND RESULTS

This retrospective study included 626 operable breast cancer patients. Tumor characteristics and survival outcomes were compared between patients who received radiotherapy and those who did not. Cox proportional hazard analysis was used to analyze prognostic factors for DFS and perform subgroup analysis. Propensity score matching was used to evaluate the efficacy of radiotherapy using a logistic regression model in patients who received radiotherapy or did not. The median follow-up duration after diagnosis of breast cancer was 63 months. DFS and overall survival were better in the irradiated group (P= .002 and P = .001, respectively). Radiotherapy was more effective for estrogen receptor (ER)-positive disease and for early breast cancer without lymph node metastasis. Multivariate analysis revealed that radiotherapy was a dependent risk factor for recurrence or metastasis.

CONCLUSION

Radiotherapy prevents distant metastasis and recurrence in early breast cancer patients. In particular, ER-positive, node-negative patients benefit from Japanese standard tangent field radiation.