Analysis of cardiac adverse events following postmastectomy hypofractionated radiotherapy

Predictive Factors Increasing the Risk of Radiation Toxicity in Patients with Early Breast Cancer

OBJECTIVES

Radiation induces adverse events on healthy tissues which may be augmented by certain factors. This study aimed to assess patients; tumor and treatment-related factors which increase the risk of radiation-induced toxicity in breast cancer patients.

METHODS

This prospective study included postmenopausal early breast cancer patients treated at the clinical oncology department, Assiut University, Egypt between January 2015 and December 2018. Patients treated with mastectomy followed by conventional radiotherapy (25x 2 Gy) and either concurrent or sequential letrozole. Acute and late radiation toxicity was scored according to EORTC/RTOG and risk factors were analyzed.

RESULTS

A total of 75 patients were included in the study. After a median follow-up of 24 months, 12 patients had > grade 2 acute dermatitis, 5 patients had > grade 2 cardiac toxicity and 3 patients had > grade 2 lung toxicity. Multivariate analysis revealed that trastuzumab use was associated with a decrease risk of acute dermatitis (p= 0.01) but boost irradiation was significantly associated with increased risk of acute dermatitis (p= 0.01). Late toxicity > grade 2 was observed in 6 patients, 14 patients, and 2 patients for skin, heart, and lung respectively.

CONCLUSION

The use of boost irradiation was associated with increased risk of acute dermatitis, in the contrary; the use of trastuzumab seemed to be protective as observed in this study.

Trends and Patterns of Utilization of Hypofractionated Postmastectomy Radiotherapy: A National Cancer Database Analysis

BACKGROUND

The acceptance of hypofractionated radiotherapy in treating breast cancer in the breast conservation therapy setting has stimulated interest in hypofractionated postmastectomy radiotherapy (PMRT). We assessed national trends and patterns of utilization of hypofractionated PMRT.

PATIENTS AND METHODS

Women 18 years of age or older with breast cancer treated with mastectomy and PMRT to the chest wall with or without regional lymph nodes from 2004 to 2014 were identified from the National Cancer Database. A standard fractionation cohort was defined as patients receiving 180 to 200 cGy per fraction to a total dose of 4500 to 7000 cGy over 5 to 7 weeks, and a hypofractionation cohort was defined as those receiving 250 to 400 cGy per fraction to a total dose of 3000 to 6000 cGy over 2 to 5 weeks. Multivariable logistic regression was used to determine factors associated with hypofractionated PMRT use.

RESULTS

We identified 113,981 patients who met study criteria. Overall, hypofractionated PMRT use was low (1.1%) although utilization increased over time (P ≤ .001). Older age, greater comorbidity, further distance from treatment facility, treatment at academic facilities, less extensive disease, and recent treatment year were statistically significant predictors of hypofractionation use compared with standard fractionation. Conversely, breast reconstruction and receipt of chemotherapy were negative predictors.

CONCLUSION

Because of the absence of high-level evidence to support its use, hypofractionated PMRT was uncommonly utilized in the United States from 2004 to 2014, although a small increase in use was noted over time. Findings from this study might be useful in designing future studies, and might serve as a baseline for evaluation of future changes in practice patterns.

Improvement of survival with postmastectomy radiotherapy in patients with 1-3 positive axillary lymph nodes: A systematic review and meta-analysis of the current literature

In breast cancer with >4 positive axillary lymph nodes, it is common practice to deliver radiotherapy to the affected site following mastectomy. However, less is known regarding the benefits this may confer on women with 1-3 positive lymph nodes. In this meta-analysis, we aimed to assess whether post-mastectomy radiotherapy (PMRT) was beneficial for such patients. A literature review was conducted using the PubMed and Ovid databases. Selected studies were analysed and data regarding overall survival (OS) and locoregional recurrence (LRR) rates were extracted. Statistical analysis was then conducted in order to develop a combined risk ratio (RR) for both OS and LRR in the setting of PMRT in women with breast cancer with 1-3 positive lymph nodes. PMRT in women with 1-3 positive lymph nodes significantly reduced the risk of LRR, with a RR of 0.3 [95% confidence interval (CI): 0.23-0.38] and also showed a minor benefit in terms of OS (RR=1.03, 95% CI: 1.00-1.07). Therefore, in breast cancer patients with 1-3 positive lymph nodes, PMRT significantly reduced the risk of LRR and was associated with a minor OS benefit. Until the results of ongoing randomised controlled trials are published, PMRT should be recommended in this group of patients following a careful multidisciplinary discussion.