Lung cancer: diagnosis and surgery

Proton therapy in lung cancer: clinical outcomes and technical issues. A systematic review

BACKGROUND AND PURPOSE

To determine whether, according to the currently available literature, proton therapy (PT) has a role in the treatment of non-small-cell lung cancer (NSCLC), to assess its safety and efficacy and to evaluate the main technical issues specifically related to this treatment technique.

MATERIALS AND METHODS

During March 2007, two independent researchers conducted a systematic review of the current data on the treatment of NSCLC with PT.

RESULTS

In total, 113 reports were retrieved, 17 of which were included in the analysis. There were no prospective trials (randomized or non-randomized). Nine uncontrolled single-arm studies were available from three PT centers, providing clinical outcomes for 214 patients in total. These reports were mainly related to stage I-II tumors, with results comparable to those obtained with surgery, without significant toxicity. In addition, two papers were found that compared photon and proton dose distributions, which showed a potential for dose escalation and/or a sparing of the organ at risk with PT. Finally, six studies analyzed dosimetric and technical issues related with PT, mainly underlining the difficulties in designing dose distributions that are representative of the dose actually delivered during treatment.

CONCLUSIONS

Although from a physical point of view PT is a good option for the treatment of NSCLC, limited data are available on its application in the clinical practice. Furthermore, the application of PT to lung cancer does present technical challenges. Because of the small number of institutions involved in the treatment of this disease, number of patients, and methodological weaknesses of the trials it is therefore not possible to draw definitive conclusions about the superiority of PT with respect to the photon techniques currently available for the treatment of NSCLC.

Percutaneous pulmonary radiofrequency ablation: difficulty achieving complete ablations in big lung lesions

The size of both primary and metastatic lung tumours often exceeds 3 cm in diameter at the time of diagnosis. The radiofrequency (RF) electrodes of the three leading companies currently in use are designed for a maximum ablation diameter of 5 cm. Therefore, the tumour to be ablated should not exceed 3 cm in maximum diameter, as a 1 cm safety ablation margin surrounding the tumour should ideally be achieved. A possible solution in treating larger tumours is to create overlapping ablations, a method successfully used in the radiofrequency ablation (RFA) of liver tumours. We report on the percutaneous overlapping ablation of three large lung metastases, 4 cm, 4.5 cm and 5 cm in their longest diameter. The largest of them showed incomplete ablation with residual viable tumour tissue. The overlapping percutaneous RFA of large lung tumours is feasible although the bigger the lesion, the higher the risk of incomplete ablation appears compared with smaller tumours treated by a single ablation.