Based on the emerging data from many institutional reports as well as prospective randomized clinical trials, the American Society for Therapeutic Radiology and Oncology (ASTRO) developed a Consensus Summary Statement on postmastectomy radiation therapy (PMRT).
The key elements to this consensus statement are:
Reduction in the recurrence rate of clinically detectable local-regional disease by PMRT is evident.
The most recent randomized controlled trials, including two well-designed trials using modern radiation techniques, have shown a moderate and statistically significant improvement in survival.
Consultation with a radiation oncologist should occur in postmastectomy node-positive patients. Patients with 4 or more positive lymph nodes should receive radiation therapy to improve local control and perhaps survival as well. Greater benefit was seen in patients with 1-3 positive nodes and in patients with smaller tumor burdens.
In all patients, the chest wall should be treated.
The treatment of internal mammary nodes remains controversial.
A supraclavicular field can be used to encompass the axillary apex and supraclavicular area in selected node-positive patients (particularly those with 4 or more positive nodes). A posterior axillary radiation field may be considered in patients with incomplete axillary dissection.
Effort should be made to minimize the dose to heart and lung.
The optimal sequencing of chemotherapy and PMRT remains uncertain.