Quantification Of Tumor Volume Changing Pattern And Its Influencing Factors After Radiotherapy For Non-small Cell Lung Cancer

Purpose: This research was to investigate the regular pattern variation of tumor aftertreating with Intensity-Modulated Radiation therapy and analyze possible factorswhich influence the change of tumor volume after radiotherapy, in order to provide atheoretical basis about when and how to schedule further treatment.Methods and Materials: Between September2009and November2012, patientswith non-small cell lung cancer treated with IMRT in author’s hospital were enrolledin this study. Collected chest computed tomography (CT）images before and afterradiotherapy retrospectively and used volume measurement software, Image J, tomeasured primary tumor volume respectively. Then compared the differences oftumor volume between every adjacent month, analyzed the possible influencingfactors which may affect the change of tumor volume and then studied the influenceof the volume changes on the overall survival.Results: A total of41NSCLC patients treated with IMRT were enrolled in this study.Tumor volume has regularly changed within6months after radiotherapy. There wasobvious reduce in the absolute volume and relative volume of first month afterradiotherapy and that in the end of radiotherapy(t were5.684,2.715, p were＜0.001,0.014). And tumor volume remained stable until the sixth month afterradiotherapy, without obvious increasing trend. The group with Consolidationchemotherapy after radiotherapy and the group without consolidation chemotherapygroup also reached the very same variation. But taking consolidation chemotherapy ornot was the independent factors of increased tumor within6months after radiotherapy(P=0.017). At the end of this study, it was found that the median survival time (MST)in the41trials was9months, the1-and2-year overall survival rates were58.7%and42.3%respectively. Better survival was significantly more pronounced in tumorradiation dose≥66Gy and not increased tumor size within6months after radiotherapy(P were＜0.001,0.002). For the group with radiation dose＜66Gy andthe group with radiation dose≥66Gy, the MST were5.5months vs11months, the1-and2-year OS were16.7%vs77.8%and0%vs58.6%. For the group with volumeincreased (9trials) and the group without volume increased (14trials), the MST were10months vs15months, the1-year OS were55.6%vs88.9%.Conclusion: Tumor volume was significantly reduced in the first month afterradiotherapy and remained stable until the sixth month after radiotherapy. Takingconsolidation chemotherapy or not was the independent factors of increased tumorwithin6months after radiotherapy. Tumor radiation dose and the increase of tumorvolume within6months after radiotherapy were important influencing factorsinfluencing prognosis of patients with NSCLC.