Material and Method: Six cases of inoperable primary NSCLC patients were evaluated for tumor response after having received CyberKnife® treatment. The prescribed radiation dose was 45 gray (Gy) in three consecutive fractions for peripherally located tumor and 50 Gy in five fractions within two weeks for centrally located tumor (biological equivalent dose, BED, 112.5 Gy10, and 100 Gy10, respectively). The response to treatment was evaluated from roentgenographic study during follow-up period along with clinical outcome and adverse event.

Results: Overall response after the treatment was demonstrated in five cases with roentgenographic complete response (CR, disappearance of tumor) and partial response (PR, 50% decrease in size) in two and three cases, respectively without any severe adverse event. The treatment planning parameters demonstrated the effectiveness of radiation dose homogeneity and conformity coverage of the target volume.

Conclusion: This preliminary report has provided the effectiveness of treatment plan and local tumor controlled without severe adverse event for primary inoperable NSCLC patients receiving CyberKnife® treatment.

Keywords: CyberKnife®, Stereotactic body radiotherapy, Non-small cell lung cancer