Clinical impact of the tumor volume doubling time on sarcoma patients with lung metastases

The volume doubling time (VDT) is an accurate and reproducible method for the quantitation of the rate and pattern of tumor growth in individual patients. The purpose of this study is to investigate the tumor VDT using chest CT in individual sarcoma patients with lung metastasis and to determine whether VDT is associated with survival after lung metastasis in bone and soft tissue sarcomas. Forty patients had measurable lung metastases in at least two sequential chest CT images taken at least 14 days apart. The VDT was calculated using the method originally described by Schwartz. The median and mean VDT in all 40 patients was 21.5 and 53 days, respectively. Similarly, the median and average VDT in 29 soft tissue sarcoma patients was 26 and 57 days, respectively. The median and mean VDT in 11 bone sarcoma patients was 13 and 42 days, respectively. The current univariate analysis revealed significantly poorer predictive values for VDT in all 40 sarcoma patients and 29 soft tissue sarcoma patients. A multivariate analysis showed the VDT to be an independent predictor of survival in 29 soft tissue sarcoma patients. These results suggest that patients with a shorter VDT and consequently a more rapid rate of tumor growth have a significantly lower chance for long term survival especially in soft tissue sarcoma. The patients with lung metastasis that have a longer VDT should therefore be considered for aggressive treatment even if the lesions are multiple and/or bilateral.