Radical cyberknife radiosurgery with tumor tracking: an effective treatment for inoperable small peripheral stage I non-small cell lung cancer.
OBJECTIVE
Curative surgery is not an option for many patients with clinical stage I non-small-cell lung carcinoma (NSCLC), but radical radiosurgery may be effective.


METHODS
Inoperable patients with small peripheral clinical stage I NSCLC were enrolled in this study. Three-to-five fiducial markers were implanted in or near tumors under CT guidance. Gross tumor volumes (GTVs) were contoured using lung windows. The GTV margin was expanded by 5 mm to establish the planning treatment volume (PTV). A dose of 42-60 Gy was delivered to the PTV in 3 equal fractions in less than 2 weeks using the CyberKnife radiosurgery system. The 30-Gy isodose contour extended at least 1 cm from the GTV. Physical examination, CT imaging and pulmonary function testing were completed at 6 months intervals for three years following treatment.


RESULTS
Twenty patients with an average maximum tumor diameter of 2.2 cm (range, 1.1 - 3.5 cm) and a mean FEV1 of 1.08 liters (range, 0.53 - 1.71 L) were treated. Pneumothorax requiring tube thoracostomy occurred following CT-guided fiducial placement in 25% of the patients. All patients completed treatment with few acute side effects and no procedure-related mortality. Transient chest wall discomfort developed in 8 of the 12 patients with lesions within 5 mm of the pleura. The mean percentage of the total lung volume receiving a minimum of 15 Gy was 7.3% (range, 2.4% to 11.3%). One patient who received concurrent gefitinib developed short-lived, grade III radiation pneumonitis. The mean percent predicted DLCO decreased by 9% and 11% at 6 and 12 months, respectively. There were no local failures, regional lymph node recurrences or distant metastases. With a median follow-up of 25 months for the surviving patients, Kaplan-Meier overall survival estimate at 2 years was 87%, with deaths due to COPD progression.


CONCLUSIONS
Radical CyberKnife radiosurgery is a well-tolerated treatment option for inoperable patients with small, peripheral stage I NSCLC. Effective doses and adequate margins are likely to have contributed to the optimal early local control seen in this study.
Collins
Brian T
BT
Department of Radiation Medicine, Georgetown University Hospital, Washington, DC, USA. collinsb@gunet.georgetown.edu
Vahdat
Saloomeh
S
Erickson
Kelly
K
Collins
Sean P
SP
Suy
Simeng
S
Yu
Xia
X
Zhang
Ying
Y
Subramaniam
Deepa
D
Reichner
Cristina A
CA
Sarikaya
Ismet
I
Esposito
Giuseppe
G
Yousefi
Shadi
S
Jamis-Dow
Carlos
C
Banovac
Filip
F
Anderson
Eric D
ED
D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053685:Laser Therapy; D008175:Lung Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D009367:Neoplasm Staging; D011183:Postoperative Complications / Q000453:epidemiology; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D017211:Treatment Failure; D016896:Treatment Outcome; D047368:Tumor Burden