Radiation Therapy for Early-Stage Breast Cancer
Lastly, patients with collagen vascular diseases are reputed to tolerate radiation poorly, with several series reporting very serious and exaggerated normal-tissue consequences from radiation. Thus, patients with collagen vascular disease should be approached with caution if breast-conservation therapy is being considered.
Patients with a history of prior therapeutic radiation, such as those previously treated for Hodgkins Disease with mantle radiation therapy, are not considered candidates for breast-conservation therapy.
Currently, most patients with early-stage breast cancer, that is any patient with a T1N0 tumor 1.0 cms or greater in diameter, will ordinarily receive systemic chemotherapy. If the above criteria of wide-local excision with a negative margin have been satisfied, our policy has been to postpone radiation until the completion of all chemotherapy.
This permits adequate and uncompromised dosing of chemotherapy agents. We have found that the toxicity of combining chemotherapy and radiation is deleterious to the cosmetic result from local radiation as well as to the adequate and full dosing of current chemotherapy regimens. As Adriamycin takes an increasingly central position in the treatment of even early-stage breast cancer, the possibility of combined modality treatment is eliminated because concurrent administration of Adriamycin with radiation is contraindicated.
The patient usually commences radiation therapy 3-6 weeks after completion of the last cycle of chemotherapy. Longer intervals are associated with decreased local control. Therapy must be custom-planned for each patient prior to commencing actual radiation treatments. At Memorial Sloan-Kettering Cancer Center, this includes fabricating a custom upper-body mold to assure reproducible torso, head and arm position on a daily basis.
A liquid styrofoam substance is utilized that expands and conforms to the patient’s desired body position and hardens to permit daily utilization of this mold for radiation setup. We feel that this type of immobilization is superior to devices that are interchanged between patients. Slight variations in arm position and rotations in the torso can dramatically alter the position of the breast upon the patient’s chest wall.
Once the custom mold has been fabricated, the radiation oncologist will thoroughly examine the patient to determine the periphery of the breast tissue. We utilize solder wire to mark the periphery of the breast tissue.