Cancers bronchiques : la radiothérapie prophylactique des aires ganglionnaires a-t-elle encore une place ?

[Lung cancer and elective nodal irradiation: A solved issue?]

Lung cancer treatment is a heavy workload for radiation oncologist and that field showed many evolutions over the last two decades. The issue about target volume was raised when treatment delivery became more precise with the development of three-dimensional conformal radiotherapy. Initially based upon surgical series, numerous retrospective and prospective studies aimed to evaluate the risk of elective nodal failure of involved-field radiotherapy compared to standard large field elective nodal irradiation. In every setting, locally advanced non-small cell lung cancer, localized non-small cell lung cancer, localized small cell lung cancer, exclusive chemoradiation or postoperative radiotherapy, most of the studies showed no significant difference between involved-field radiotherapy or elective nodal irradiation with elective nodal failure rate under 5% at 2 years, provided staging had been done with modern imaging and diagnostic techniques (positron emission tomography scan, endoscopy, etc.). Moreover, if reducing irradiated volumes are safe regarding recurrences, involved-field radiotherapy allowed dose escalation while reducing acute and late oesophageal, cardiac and pulmonary toxicities. Consequently, major clinical trials involving radiotherapy initiated in the last two decades and international clinical guidelines recommended omission of elective nodal irradiation in favour of in-field radiotherapy.

[Radiotherapy of lung cancer: Any room left for elective mediastinal irradiation in 2011?]

Traditionally, the target volumes of curative-intent radiotherapy for non-small cell lung cancer include all uninvolved mediastinal nodes. However, an improvement in tumour control requires an increase of the total dose to the macroscopic target volume. This is only achievable if the irradiation of the organs at risk is reduced, i.e. elective irradiation of the mediastinum is omitted. The available data suggest that elective mediastinal irradiation may be safely omitted, provided that an adequate staging procedure, including FDG PET-CT, has been performed.

Complications aiguës et tardives des irradiations thoraciques

Radiotherapy of lung cancer is often complexe because of several organs at risk such as lung, heart, esophagus or spinal cord. An accurate balance needs to be defined between the necessities to reach a local control and to limit the risks of toxicities for each of them. Several parameters were significantly correlated with radiation induced lung toxicities (V13, V20, 30, Mean Dose) and esophagitis (V40 to V60). However no parameters are clearly defined for heart toxicities. The large number of parameters described for lung and esophagus highlights the necessity to perform an overall analysis of the DVHs that could be possible by using Nomal Tissue Complication Probability models.

Traitement des tumeurs de l'apex: un modèle de stratégie multimodale dans les cancers bronchiques localement évolués

Superior sulcus tumors have been individualized among other non-small cell lung cancers because of their characteristic clinical presentation in connection with their local extension to the chest wall and the brachial plexus. For a long time considered as marginally resectable, superior sulcus tumors have been treated since the early 1960's, with a combined approach including preoperative radiotherapy and curative-intent surgery. Surgical resection includes both thoracic, cervical and neurosurgical approach, and aims at obtaining complete resection, which has been identified as a determining prognostic factor in most reported series. Two recent phase II trials showed the benefit, both regarding resectability and local control rates, and survival of combined therapeutic strategies including induction platinum-based chemoradiation, extensive surgical resection, and adjuvant chemotherapy. Adjuvant radiotherapy is not recommended at the time, but needs to be re-evaluated regarding its recent technical optimisation. Similarly to other locally advanced non-small cell lung cancers, exclusive chemoradiation is the standard treatment of unresectable superior sulcus tumors. In this way, radiotherapy has shown to offer a prolonged analgesia in more than 75% of cases, and is associated with concurrent or sequential chemotherapy, with comparable results to those observed in stage III lung cancer. These developments make superior sulcus tumors a therapeutic model for locally advanced non-small cell lung cancer, whereby the benefit of combined multimodal strategies including induction chemoradiation and surgical resection are currently evaluated in phase III trials.