The Impact of Post-Mastectomy Chest-Wall Radiation on Overall Survival for Intermediate-Risk Breast Cancer Patients: A National Cancer Data Base Analysis

Comparison of treatment plans between static jaw and jaw tracking techniques in postmastectomy intensity-modulated radiation therapy

This study reports a dosimetric comparison between treatment plans using static jaw and jaw tracking techniques in intensity-modulated radiation therapy (IMRT) for postmastectomy radiation therapy (PMRT). Seventeen patients treated for left-sided breast cancer with implant-based reconstruction were subjected to IMRT plans. Another group of 22 patients treated for left-sided breast cancer without reconstruction was also subjected to IMRT plans. The plans were generated using the Eclipse treatment planning system with static jaw and jaw tracking techniques. The dose-volume histograms and dosimetric indices, such as mean dose (D_mean), V_{20 Gy}, V_{10 Gy}, and V_{5 Gy} (volumes receiving 20, 10, and 5 Gy at the least, respectively), and generalized equivalent uniform dose for organs at risk (OARs) were analyzed. A significant difference in the value of the dosimetric indices between the static jaw and jaw tracking plans was observed. For jaw tracking plans, the D_mean of the heart for the patients with implant-based reconstruction reduced from 11.6 ± 1.1 Gy to 10.0 ± 1.8 Gy, whereas the V_{5 Gy} reduced from 92.0 ± 4.5% to 85.1 ± 8.4%. The D_mean of the heart for patients without reconstruction reduced from 11.0 ± 2.3 Gy to 9.8 ± 2.6 Gy, whereas the V_{5 Gy} reduced from 81.4 ± 13.6% to 66.7 ± 17.4%. The dosimetric indices of OARs in the jaw tracking plans were significantly lower than those of the OARs in the static jaw plans. The jaw tracking technique was more effective for patients without reconstruction than for those with implant-based reconstruction.

Immediate breast reconstruction has no impact on the oncologic outcomes of patients treated with post-mastectomy radiation therapy: a comparative analysis based on propensity score matching

PURPOSE

To investigate the impact of immediate breast reconstruction (iBR) on patients treated with post-mastectomy radiation therapy (PMRT) using propensity score matching (PSM).

METHODS

After a retrospective review of patients treated with PMRT between 2008 and 2017, we included 153 patients who underwent iBR and 872 patients who did not undergo iBR. Among the 153 patients who underwent iBR, 34 received one-stage iBR with autologous tissue and 119 received two-stage iBR. Conventional fractionated PMRT with a total dose of 50-50.4 Gy in 25-28 fractions was performed in all patients. Propensity scores were calculated via logistic regression.

RESULTS

Patients who underwent iBR were younger, had early stage disease, and had more frequent hormone receptor-positive tumor than those who did not undergo iBR. After PSM, 127 patients from each group with well-balanced characteristics were selected. With a median follow-up of 67.5 months, iBR led to better 6-year disease-free survival rates compared to no iBR before PSM (84.8% vs. 71.4%, p = 0.003); after PSM, there was no significant difference (84.8% vs. 75.5%, p = 0.130). On multivariable analysis in the matched cohort, iBR was not associated with inferior disease-free survival (hazard ratio, 0.67; p = 0.175). In the sensitivity analysis, iBR was not associated with a lower disease-free survival across all prognostic groups. The 5-year cumulative incidence of iBR failure was 15.0%.

CONCLUSION

In patients with adverse pathologic factors planning to receive PMRT, iBR did not compromise oncologic outcomes. In addition, iBR can be considered in patients treated with PMRT with several clinicopathologic risk factors.