Updates in Postmastectomy Radiation

Ultrasonographic Evaluation of Skin Toxicity Following Radiotherapy of Breast Cancer: A Systematic Review

The present review aimed to systematically review skin toxicity changes following breast cancer radiotherapy (RT) using ultrasound (US). PubMed and Scopus databases were searched according to PRISMA guidelines. The characteristics of the selected studies, measured parameters, US skin findings, and their association with clinical assessments were extracted. Seventeen studies were included with a median sample size of 29 (range 11-166). There were significant US skin changes in the irradiated skin compared to the nonirradiated skin or baseline measurements. The most observed change is skin thickening secondary to radiation-induced oedema, except one study found skin thinning after pure postmastectomy RT. However, eight studies reported skin thickening predated RT attributed to axillary surgery. Four studies used US radiofrequency (RF) signals and found a decrease in the hypodermis's Pearson correlation coefficient (PCC). Three studies reported decreased dermal echogenicity and poor visibility of the dermis-subcutaneous fat boundary (statistically analysed by one report). The present review revealed significant ultrasonographic skin toxicity changes in the irradiated skin most commonly skin thickening. However, further studies with large cohorts, appropriate US protocol, and baseline evaluation are needed. Measuring other US skin parameters and statistically evaluating the degree of the association with clinical assessments are also encouraged.

Postmastectomy Radiation Therapy in Women with T1-T2 Tumors and 1 to 3 Positive Lymph Nodes: Analysis of the Breast International Group 02-98 Trial

PURPOSE

To analyze the impact of postmastectomy radiation therapy (PMRT) for patients with T1-T2 tumors and 1 to 3 positive lymph nodes enrolled on the Breast International Group (BIG) 02-98 trial.

METHODS AND MATERIALS

The BIG 02-98 trial randomized patients to receive adjuvant anthracycline with or without taxane chemotherapy. Delivery of PMRT was nonrandomized and performed according to institutional preferences. The present analysis was performed on participants with T1-T2 breast cancer and 1 to 3 positive lymph nodes who had undergone mastectomy and axillary nodal dissection. The primary objective of the present study was to examine the effect of PMRT on risk of locoregional recurrence (LRR), breast cancer-specific survival, and overall survival.

RESULTS

We identified 684 patients who met the inclusion criteria and were included in the analysis, of whom 337 (49%) had received PMRT. At 10 years, LRR risk was 2.5% in the PMRT group and 6.5% in the no-PMRT group (hazard ratio 0.29, 95% confidence interval 0.12-0.73; P = .005). Lower LRR after PMRT was noted for patients randomized to receive adjuvant chemotherapy with no taxane (10-year LRR: 3.4% vs 9.1%; P = .02). No significant differences in breast cancer-specific survival (84.3% vs 83.9%) or overall survival (81.7% vs 78.3%) were observed according to receipt of PMRT.

CONCLUSION

Our analysis of the BIG 02-98 trial shows excellent outcomes in women with T1-T2 tumors and 1 to 3 positive lymph nodes found in axillary dissection. Although PMRT improved LRR in this cohort, the number of events remained low at 10 years. In all groups, 10-year rates of LRR were relatively low compared with historical studies. As such, the use of PMRT in women with 1 to 3 positive nodes should be tailored to individual patient risks.