Preliminary Analysis of a Randomized Clinical Trial Comparing Shoulder-arm Morbidity between Early Breast Cancer Patients Treated with Short Course Image Guided Radiation Therapy and Conventional Post Surgery Radiation Therapy

Purpose: Shoulder/arm morbidity is a known complication of breast cancer surgery and radiotherapy (RT), but the consequences of choosing one RT technology over another for shoulder/arm morbidity are not clearly defined. In this work, we examine early breast cancer patients to compare the incidence of shoulder/arm morbidity, including breast cancer related lymphedema (BCRL) of the arm, between conventional RT and short-course, image-guided RT (IGRT) treatments. Methods: We randomized patients between post-surgery IGRT over 3 weeks and conventional RT over 5 to 7 weeks, as part of the TomoBreast trial (whose primary endpoint was to assess pulmonary and cardiac toxicities). BCRL and shoulder/arm mobility were assessed prior to and between one and three months following RT, using physical function assessment and common terminology criteria for adverse events. Intention to treat analyses used the matched-pairs t-test for continuous measurements and the chi-squared test for categorical data. Results: Analysis of the first 91 evaluable patients found that >80% experienced an increase in the adverse event score in at least one shoulder/arm mobility measurement, and 18% had BCRL symptoms. Arm volume on both sides increased significantly and significant impairment of movement occurred in both limbs. However, there was no significant difference in BCRL incidence or shoulder/arm mobility impairment between the treatment groups. Conclusion: One to three months after treatment, short-course IGRT had not increased shoulder/arm morbidity compared with conventional RT. Although confirmation requires a longer follow-up, the results support the use of a short-course schedule. The incidental finding that morbidity affected the contralateral limb warrants further investigation.