Radiotherapy alone in breast cancer. Analysis of tumor and lymph node radiation doses and treatment-related complications. The experience of the Gustave-Roussy Institute and the Princess Margaret Hospital.

This retrospective analysis was conducted on breast cancer patients treated by radiotherapy alone at The Princess Margaret Hospital and at the Institut Gustave-Roussy. These patients had either operable tumors, but were unfit for general anesthesia, or had inoperable tumors due to local contraindications to surgery. Previous results showed that a radiation dose increase of 15 Gy can decrease the relative risk of tumor or lymph node recurrence twofold. In this third report, the same data were analyzed to determine the treatment-related complication rates and to correlate these to the radiation dose levels. Overall results were analyzed on 453 patients, but detailed analyses on complications were conducted on 372 patients not developing local recurrence in the first 6 months of follow-up. Each complication was graded on a 3-level previously defined scale. Most frequent complications were skin changes of different degrees, which were usually asymptomatic. More disabling complications were arm edema, impaired shoulder mobility, rib fractures and brachial plexopathy. The incidence of disabling complications was low. The only factor significantly increasing the risk of complications was the radiation dose level to the tumor and axilla. Technical factors such as overlapping fields should also be taken into account. As the more effective control of tumor and lymph nodes obtained in patients treated with higher radiation doses is counterbalanced by an increase in the complication rate, the dose to be delivered for each patient should be carefully chosen according to individual risk factors.