Inclusion Criteria:  Subjects who are receiving treatment in the MGH Breast Cancer Center who are enrolled in a DF/HCC-regulated targeted therapy trial for the treatment of early or metastatic breast cancer or patients being treated with a targeted therapy that may alter their risk of developing edema or BCRL will be eligible. Subjects that will be eligible for the study include: Females between 18 and 80 years of age With a history of breast cancer 4 weeks or more post-surgery With or without edema Undergoing treatment with targeted therapy for early or metastatic disease.  Exclusion Criteria:  - Patients who cannot attain 90 degrees of shoulder abduction (position of measurement with Perometer).