Rate of growth of soft tissue metastases of breast cancer

Abstract

The gross rates of growth of 171 soft tissue metastatic lesions of breast cancer in 54 patients seen at Ellis Fischel State Cancer Hospital were studied. The frequency distributions of these rates are lognormal and are analyzed statistically as such. Both the linear diametric growth rate (LR) and the exponential growth rate, expressed as volumetric doubling times (DT), of 66 untreated lesions were presented as baselines for further study (LR: mean 0.21 mm/day, 95% range of 0.04–1.05; DT: mean 17.1 days, 95% range 3.4–86.1). Rates of growth of simultaneous metastatic lesions of both the same and different sites (e.g., axilla, chest wall, supraclavicular, and other regions) in the same patients were compared. The mean ratios of growth of the paired lesions were close to “one”; however, in 95% of the cases the rates can be differentiated by a factor of one-fifth to seven. In lesions that responded to radiation therapy, hormones, or chemotherapy, the ratios of rate of shrinkage after therapy to the rate of growth before therapy also had means of approximately “one” (95% range of ratios: 0.2–4.2). There is considerable variability of the data presented due to limited numbers of selected lesions that could be measured, the errors of data gathering, and assumptions made during calculations.