Postmastectomy intensity modulated radiation therapy following immediate expander-implant reconstruction

Abstract 

Background/purpose

To evaluate radiation plans of patients undergoing mastectomy with immediate expander-implant reconstruction followed by postmastectomy radiation therapy (PMRT).

Materials/methods

We identified 41 patients from June 2004 to May 2007 who underwent mastectomy, immediate expander-implant reconstruction, and PMRT with intensity-modulated radiation therapy. We assessed chest wall (CW) coverage and volume of heart and lung irradiated.

Results

In 73% of patients, all CW borders were adequately covered, and in 22%, all but 1 border were adequately covered. The total lung V₂₀ was<20% in 39/41 patients. The mean lung V₂₀ was 13% (range, 3–23%), and the mean heart D_mean was 2.81Gy (range, 0.53–9.60Gy). In patients with left-sided lesions without internal mammary nodes (IMNs) treatment (n=22), the mean lung V₂₀ was 12.6% and the mean heart D_mean was 3.90Gy, and in the patient with IMN treatment, the lung V₂₀ was 18% and heart D_mean was 8.04Gy. For right-sided lesions without IMN treatment (n=12), the mean lung V₂₀ was 12.4% and the mean heart D_mean was 0.90Gy, and in patients with IMN treatment (n=6), these numbers were 17.8% and 1.76Gy. At a median follow-up of 29months, the 30-month actuarial local control was 97%.

Conclusions

In women undergoing immediate expander-implant reconstruction, PMRT can achieve excellent local control with acceptable heart and lung doses. These results can be achieved even when the IMN are being treated, although doses to the heart and lungs will be higher.

Keywords: Postmastectomy radiation, Immediate reconstruction, Lung V₂₀, Heart D_mean