Clinical Application Of CBCT Guided SBRT In Inoperable Small Size NSCLC Less Than5cm.Treatment Outcome&Toxicities

Introduction:Within the last decade with a better understanding of cancer biology and with the emerging field of molecular imaging, recent scientific and technological advances, Stereotactic body radiation therapy (SBRT) has been a major breakthrough in oncology. Lung cancer being a potentially curable malignancies when still in its early stage, eradication of the primary tumor is a prerequisite to achieve cure with surgery the standard treatment. With some patients are deemed medically inoperable, conventional radiotherapy fails to durably control the primary lung tumor in60%to70%of patients, and SBRT is being sought as an alternative with high curative rates and low toxicity profile.Method:In this study,8NSCLC patients deemed medically inoperable were treated by CBCT guided SBRT at Xiangya First hospital with a dose range48-54Gy in6-9fractions and outcome and toxicity were analyzed prospectively and compare to8patients receiving conventional IMRT treatment.Results:Within a median time follow-up of6months, all patients had good local tumor control, with CR37.5%vs0%(3patients vs0), PR50%vs62.5%(4vs5patients) and SD12.5%vs37.5%(1vs3patients) in the SBRT group and control group respectively, with p-value0.37. Mean total radiation dose was48.75gy±2.12vs60.65gy±4.56(p=0.001), but attaining a higher BED (mean84gy±4.44vs73.4gy±4.12, p=0.006). Coughing was common among all patients with87.5%vs62.5%grade1and12.5%vs37.5%grade2.37.5%vs12.5%grade1pneumonitis,1patient with gradel fatigue and1(12.5%) case each of grade1and2thrombocytopenia.one patients was suspected of grade1atelectsia.Conclusion:Employing SBRT in NSCLC<5cm might be rational with safe delivery methods, good local tumor control and low toxicity profiles comparable to conventional IMRT treatment.