Thymic hyperplasia after high-dose chemotherapy and autologous stem cell transplantation: Incidence and significance in patients with breast cancer

OBJECTIVE. The purpose of this study was to determine the incidence and cli nical significance of thymic hyperplasia after high-dose chemotherapy and a utologous stem cell transplantation for treatment of metastatic or high-ris k primary (with at least four positive lymph nodes) breast cancer. MATERIALS AND METHODS. We retrospectively reviewed clinical records and CT scans of 102 breast cancer patients treated with high-dose chemotherapy and autologous stem cell transplantation. Patients were 26-63 years old (mean, 46 years). The length and width of the thymus gland were measured on seria l CT scans obtained before and after treatment. Moderate thymic hyperplasia was recorded if a focal or diffuse increase was seen in the oblong, triang ular soft-tissue opacity conforming to the configuration of the normal glan d within the anterior mediastinum after therapy. Minimal hyperplasia was re corded when a minimal increase was seen in soft-tissue attenuation conformi ng to the configuration of the normal bilobed thymus gland within the anter ior mediastinum, but no discrete mass was visible. RESULTS. CT showed no thymic hyperplasia in 91 (89%) of the 102 patients. C T showed thymic hyperplasia in the other 11 patients (11%). Three patients (3%) had moderate hyperplasia, and eight patients (8%) had minimal hyperpla sia. When comparing patients with and without hyperplasia, we found no diff erence in mean age or survival. CONCLUSION. Thymic hyperplasia is rare after high-dose chemotherapy and aut ologous stem cell transplantation in adult patients with metastatic or high -risk primary breast cancer. In this population, thymic hyperplasia does no t appear to correlate with survival.