[An analysis of 20 consecutive patients treated with stereotactic body radiotherapy on Novalis Tx(®) for stage I non-small-cell lung cancer].

PURPOSE

Recent clinical results of dose escalation with stereotactic body radiation therapy to increase local tumour control for patients with stage I non-small-cell lung cancer who either refuse surgery or are medically inoperable resulted in making it a standard treatment in this setting. This treatment technique was implemented at the Paul-Strauss Centre, Strasbourg, in 2010. The objective of this study is to describe and analyze the data of the first 20 treated patients.

PATIENTS AND METHODS

From October 2010 to May 2012, 20 patients were treated with this technique for T1N0M0 or T2N0M0 lung tumour. The indication was proposed by the multidisciplinary thoracic oncology team meeting, and approved by the technical committee of the Department of Radiotherapy. After the realization of a dosimetric CT Scan (4DCT or three phases-free breathing and deep breath-hold inspiration and expiration) and after performing a ((18)F)-FDG PET scan in the treatment position, all patients were treated on Novalis Tx(®) linear accelerator, with arctherapy or modulated intensity radiotherapy (IMRT). A protocol has been defined for the prescribed dose, depending on the size and location of the tumor, central or peripheral. The patients underwent follow-up during treatment and at 1 month, 3-4 months, 6 and 9 months to assess outcomes and toxicities.

RESULTS

The mean age was 72.6 years (52-89). Seventeen patients had one or more pulmonary comorbidities. The mean delivered dose was 59.9 Gy (40-70) in 4 Gy to 17.5 Gy fractions. The mean gross tumour volume was 14.9 mL (median 7.2, 0.9 to 73.5) and the mean planning target volume was 77.8 mL (median 49.5; 17-300). The mean initial SUV max was 7.7 (1.8 to 16.7). Dose constraints and planning target volume coverage recommended by the protocol were achieved in the majority of cases. The mean lung V20 was 7.63% (1.2 to 17.7) and the mean dose delivered to the planning target volume was 94.6% (88-99). The duration of treatment was 21 days (median: 23; 8-27), and no change or interruption of prescribed treatment has occurred. Median follow-up was 6.6 months, and crude rates of objective response for patients evaluated were 85% (11/13 patients) at 3 months and 100% at 6 and 9 months. The complete response rate at 3 and 6 months were 0 (0/13 patients) and 50% (5/10 patients). Two patients had metastatic disease in the 6 months following treatment. Concerning pulmonary toxicity at 3 months, 6 patients developed G2 radiation pneumonitis and three patients G3, with positive evolution.

CONCLUSION

The analysis of the results of this series, comparable with those described in literature, shows that lung stereotactic radiotherapy is an effective and well-tolerated treatment for inoperable patients. The extension of the indications could be envisaged based on the results of ongoing trials.