PULMONARY PERSPECTIVES®: Treatment of Lung Cancer in the High-Risk Patient

During the treatment phase, the patient is typically positioned according to the previously formulated treatment plan. Fiducials are tracked in real time using two ceiling-mounted radiographic fluoroscopes, and these oblique dual images are combined with the CT scan data, using tracking software to direct or readjust the beams of radiation at frequent intervals. For peripheral lesions, 60 Gy is delivered in three fractions; and for central lesions, 48 Gy is delivered in four fractions to minimize toxicity to surrounding critical structures (Pennathur et al. Ann Thorac Surg. 2009;88[5]:1594).

Patients are followed at 3- to 4-month intervals with PET/CT scans. Nodules are assessed for response/progression based on size, mass quality (cavitation, replacement with scar, etc.), and PET avidity. In addition, treatment-related toxicity is assessed with each follow-up visit with pulmonary function testing and quality-of-life assessment.

Early complications of treatment are mainly related to placement of fiducials. In a recent series, 26% of patients developed a pneumothorax requiring tube thoracostomy. Late complications are mainly due to treatment-related toxicity. This is particularly true for central tumors (Pennathur et al. Ann Thorac Surg. 2009;88[5]:1594). In a phase II trial of 70 patients treated with 60 to 66 Gy in three fractions, only 54% of patients with central tumors were free from severe toxicity compared with 83% of patients with peripheral tumors at 2 years. In summary, 8.6% of patients died of treatment-related toxicity (Timmerman et al. J Clin Oncol. 2006[30];24:4833). Therefore, lower doses are required for central tumors, particularly those near larger central airways.

Using this modality, the overall 2-year survival for primary lung cancer (all stages) was 44%. The median overall survival was 22 months. In conclusion, 62% of patients had progression, which was observed at a median time of 9 months. Patients treated with 60-Gy doses (i.e., those with peripheral lesions) showed significantly improved survival and time to disease progression compared with those treated with 20-Gy doses (Pennathur et al. J Thorac Cardiovasc Surg. 2009;137[3]:597).

Conclusion

RFA and SRS each provide a minimally invasive alternative for high-risk patients with pulmonary malignancy. Studies are ongoing in their application to pulmonary metastases and as part of multimodality treatment protocols. As technology improves, RFA delivery probes will be smaller and can potentially be delivered endobronchially. Similarly, tumor-tracking technology in the spontaneously ventilating lung continues to improve, and fiducial placement may soon be unnecessary in SRS. As the technology evolves, the use of these modalities may expand beyond use only for the high-risk patients.

Dr. Brichkov is with the division of thoracic surgery at Maimonides Medical Center in Brooklyn, N.Y. He has disclosed that he has no significant relationships with the companies/organizations whose products or services are discussed within this Pulmonary Perspectives.