Evaluation of Standard Tangential Irradiation versus Breast Ring Technique Using Three-Dimensional Tools in Cancerous Large Breasts

Abstract

Aims and background

In patients with large breasts, tangential irradiation after lumpectomy is technically difficult. Tangential plans of large breasts comprise a large volume of the lung, axilla and heart, as well as an important volume of the opposite breast and lung.

Methods

Instead of classical positioning of the breast, we encircled the breast with a plastic polyvinyl ring-shaped tube. All five left-sided breast cancer patients underwent CT scan planning with and without the plastic ring in conventional treatment positioning. Skin treatment portals at the midline and mid axilla were marked with radio-opaque markers. The scan volume encompassed the region from just below the diaphragm to the lung apex. Patients' plans were evaluated with regard to dose-volume coverage of the breast planning target volume, ipsilateral lung, contralateral lung, heart and contralateral breast. End points were maximum dose, minimum dose, and mean dose delivered to the target or critical structure.

Results

As expected, the average volume of the left lung treated above a tolerance dose of 2000 cGy was less than 10% in the ringed breast, whereas in the other method without the ring the corresponding lung volume was 30%. The cardiac volume receiving a dose over 4000 cGy was 2% in the ringed breast and 18% in the breast without a ring.

Conclusions

With the use of a simple technique with a fairly low expenditure, acute skin reactions and late cardiac and lung morbidity can be minimized in patients with large breasts.