Prognostic Modeling in Pathologic N1 Breast Cancer Without Elective Nodal Irradiation After Current Standard Systemic Management

Radiation Oncologists' Views on Adjuvant Radiotherapy for Early-Stage Breast Cancer in the Elderly: Comparisons between Japan and the United States

PURPOSE

To understand perspective on breast cancer using a survey.

MATERIALS & METHODS

Questionnaire was distributed to 304 Japanese radiation oncologists (RadOncs) (response rate: 64.1%). Result was compared with a similar US survey.

RESULTS

In a scenario with an 81-year-old patient with comorbidities, while most US RadOncs chose to tell that radiation might not be necessary, 2% of Japanese chose it. In a scenario with a healthy 65-year-old breast cancer patient with lumpectomy, while most US RadOncs chose to discuss omission of radiation, 24.5% of Japanese chose it.

CONCLUSIONS

Differences were observed on radiotherapy for older early-stage breast cancer.

The Role of Post-Mastectomy Radiotherapy in T1-2N1 Breast Cancer Patients: Propensity Score Matched Analysis

This study aimed to evaluate the role of post-mastectomy radiotherapy (PMRT) in T1-2N1 breast cancer. Between 2006 and 2014, a total of 504 patients with T1-2N1 breast cancer were analyzed. PMRT was administered to 71 patients, and 1:2 propensity score matching (PSM) was performed between the PMRT and non-PMRT groups. Loco-regional control (LRC), disease-free survival (DFS), and overall survival (OS) rates were compared according to PMRT status. Thirteen and one loco-regional recurrences were observed in the PMRT and non-PMRT groups, respectively. Before PSM, the 8-year LRC, DFS, and OS rates in the non-PMRT and PMRT groups were 98.5% and 96.5% (p = 0.426), 89.7% and 91.2% (p = 0.700), and 91.5% and 92.1% (p = 0.679), respectively. Corresponding rates were 95.6% and 96.5% (p = 0.365), 84.1% and 91.2% (p = 0.185), and 88.4% and 92.1% (p = 0.276), respectively, after PSM. Multivariate analysis showed that three lymph node metastases were prognostic for LRC and DFS rates and LVI for OS rate. Arm lymphedema developed in 32.4% of patients who received PMRT, which was significantly higher than the non-PMRT group (p < 0.001). Contributions of PMRT for improvement of treatments outcomes in T1-2N1 breast cancer patients were not evident, while the incidence of arm lymphedema significantly increased after PMRT. Further prospective trials are required to re-evaluate the role of PMRT.

Comparison of Breast Conserving Surgery Followed by Radiation Therapy with Mastectomy Alone for Pathologic N1 Breast Cancer Patients in the Era of Anthracycline Plus Taxane-Based Chemotherapy: A Multicenter Retrospective Study (KROG 1418)

PURPOSE

We compared the oncologic outcomes of breast-conserving surgery plus radiation therapy (BCS+RT) and modified radical mastectomy (MRM) under anthracycline plus taxane-based (AT) regimens and investigated the role of adjuvant radiation therapy (RT) in patients with pathologic N1 (pN1) breast cancer treated by mastectomy.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 2,011 patients with pN1 breast cancer who underwent BCS+RT or MRM alone at 12 institutions between January 2006 and December 2010. Two-to-one propensity score matching was performed for balances in variables between the groups.

RESULTS

The median follow-up duration for the total cohort was 69 months (range, 1 to 114 months). After propensity score matching, 1,074 patients (676 in the BCS+RT group and 398 in the MRM-alone group) were analyzed finally. The overall survival, disease-free survival, locoregional failure-free survival, and regional failure-free survival (RFFS) curves of the BCS+RT group vs. MRM-alone group were not significantly different. The subgroup analysis revealed that in the group with both lymphovascular invasion (LVI) and histologic grade (HG) III, the BCS+RT showed significantly superior RFFS (p=0.008). Lymphedema (p=0.007) and radiation pneumonitis (p=0.031) occurred more frequently in the BCS+RT group than in the MRM-alone group, significantly.

CONCLUSION

There are no differences in oncologic outcomes between BCS+RT and MRM-alone groups under the AT chemotherapy regimens for pN1 breast cancer. However, BCS+RT group showed superior RFFS to MRM-alone group in the patients with LVI and HG III. Adjuvant RT might be considerable for pN1 breast cancer patients with LVI and HG III.

Clinical Significance of Lymph-Node Ratio in Determining Supraclavicular Lymph-Node Radiation Therapy in pN1 Breast Cancer Patients Who Received Breast-Conserving Treatment (KROG 14-18): A Multicenter Study

This study evaluated the clinical significance of the lymph-node ratio (LNR) and its usefulness as an indicator of supraclavicular lymph-node radiation therapy (SCNRT) in pN1 breast cancer patients with disease-free survival (DFS) outcomes. We retrospectively analyzed the clinical data of patients with pN1 breast cancer who underwent partial mastectomy and taxane-based sequential adjuvant chemotherapy with postoperative radiation therapy in 12 hospitals (n = 1121). We compared their DFS according to LNR, with a cut-off value of 0.10. The median follow-up period was 66 months (range, 3–112). Treatment failed in 73 patients (6.5%) and there was no significant difference in DFS between the SCNRT group and non-SCNRT group. High LNR (>0.10) showed significantly worse DFS in both univariate and multivariate analyses (0.010 and 0.033, respectively). In a subgroup analysis, the effect of SCNRT on DFS differed significantly among patients with LNR > 0.10 (p = 0.013). High LNR can be used as an independent prognostic factor for pN1 breast cancer patients treated with partial mastectomy and postoperative radiotherapy. It may also be useful in deciding whether to perform SCNRT to improve DFS.

Axillary Lymph Node Dissection Does Not Improve Post-mastectomy Overall or Disease-Free Survival among Breast Cancer Patients with 1-3 Positive Nodes

Purpose

Axillary lymph node dissection (ALND) may be avoidable for breast cancer patients with 1-2 positive lymph nodes (LN) after breast-conserving therapy. However, the effects of ALND after mastectomy remain unclear because radiation is not routinely used. Herein, we compared the benefits of post-mastectomy ALND versus sentinel node biopsy (SNB) alone for breast cancer patients with 1-3 metastatic LNs.

Materials and Methods

A total of 1,697 patients with pN1 disease who underwent mastectomy during 2000-2015 were identified from an institutional database. Outcomes were compared using the inverse probability of treatment weighted method.

Results

Patients who underwent SNB tended to have smaller tumors, a lower histology grade, a lower number of positive LNs, and better immunohistochemical findings. After correcting all confounding factors regarding patient, tumor, and adjuvant treatment, the SNB and ALND groups did not differ in terms of overall survival (OS) and disease-free survival (DFS), distant metastasis and locoregional recurrence. The 10-year DFS and OS rates were 83% and 84%, respectively, during a median follow-up period of 93 months.

Conclusion

ALND did not improve post-mastectomy survival outcomes among patients with N1 breast cancer, even after adjusting for all histopathologic and treatment-related factors.

Which Patients with Left Breast Cancer Should be Candidates for Heart-Sparing Radiotherapy?

Purpose

This study aimed to identify risk factors that have significant interaction with radiation exposure to the heart, and thus to determine candidates for heart-sparing radiotherapy (RT) among women with left breast cancer.

Methods

We identified 4,333 patients who received adjuvant RT following breast-conserving surgery for ductal carcinoma in situ or invasive breast cancer from 1996 to 2010. Incidence rates of cardiovascular disease were compared between left-sided and right-sided RT, and stratified by age and risk factors such as body mass index (BMI), smoking, hyperlipidemia, hypertension, diabetes, administration of anthracycline, and trastuzumab.

Results

In all patients, the cumulative incidence of cardiovascular disease was greater in patients treated with left-sided RT than in those treated with right-sided RT, but the difference was not significant (p=0.428). Smoking (hazard ratio [HR], 5.991; 95% confidence interval [CI], 2.109-17.022; p=0.002) and hyperlipidemia (HR, 5.567; 95% CI, 3.235-9.580; p<0.001) were the most powerful risk factors for cardiovascular disease. There was no significant factor that further increased the risk of cardiovascular disease after left breast RT compared to right breast RT.

Conclusion

Although hyperlipidemia and smoking are risk factors for cardiovascular disease, they have not been proven to increase the risk of RT-related cardiovascular disease in Korean women.

Postmastectomy Radiotherapy in Patients with pT1-2N1 Breast Cancer Treated with Taxane-Based Chemotherapy: A Retrospective Multicenter Analysis (KROG 1418)

PURPOSE

The purpose of this study was to evaluate the impact of postmastectomy radiotherapy (PMRT) on loco-regional recurrence-free survival (LRRFS), disease-free survival (DFS), and overall survival (OS) in pT1-2N1 patients treated with taxane-based chemotherapy.

MATERIALS AND METHODS

We retrospectively reviewed the medical data of pathological N1 patients who were treated with modified radical mastectomy and adjuvant taxane-based chemotherapy in 12 hospitals between January 2006 and December 2010.

RESULTS

We identified 714 consecutive patients. The median follow-up duration was 69 months (range, 1 to 114 months) and the 5-year LRRFS, DFS, and OS rates were 97%, 94%, and 98%, respectively, in patients who received PMRT (PMRT [+]). The corresponding figures were 96%, 90%, and 96%, respectively, in patients who did not receive PMRT (PMRT [-]). PMRT had no significant impact on survival. Upon multivariable analysis, only the histological grade (HG) was statistically significant as a prognostic factor for LRRFS and DFS. In a subgroup analysis of HG 3 patients, PMRT (+) showed better DFS (p=0.081).

CONCLUSION

PMRT had no significant impact on LRRFS, DFS, or OS in pT1-2N1 patients treated with taxane-based chemotherapy. PMRT showed a marginal benefit for DFS in HG 3 patients. Randomized studies are needed to confirm the benefit of PMRT in high risk patients, such as those with HG 3.