C. Durdux

Radiothérapie adaptative du carcinome bronchique non à petites cellules

Anatomical changes and tumor regression during thoracic radiotherapy may alter the treatment volumes. These modifications are not taken into account into set-up or motion margins used for treatment planning. Their dosimetric impact could be significant and a better understanding of the changes occurring during the 6 to 7 weeks of treatment could be useful in order to define quantitative thresholds before a new treatment planning is needed. Margins could also be reduced in order to better spare organs at risk and perform targeted dose escalation. This review assesses the potential of morphologic and metabolic imaging during treatment for adaptive radiotherapy in non-small cell lung cancer.

Cancers bronchiques non à petites cellules : facteurs prédictifs de survenue de pneumopathie radique

PURPOSE To evaluate the predictors of acute radiation pneumonitis after conformal thoracic radiotherapy in the treatment of locally advanced non-small cell lung cancer. PATIENTS AND METHODS Forty-seven consecutive patients were treated with conformal thoracic irradiation for locally advanced non-small cell lung cancer and retrospectively analysed. The mean total dose of radiotherapy was 65 Gy with respiratory gating in 19 cases. Neoadjuvant and concomitant chemotherapy was performed in 33 patients (70%) and 41 patients (87%) respectively. RESULTS Eleven patients (23%) had an acute radiation pneumonitis, resulting in death for one patient. In univariate analysis, age, sex, pretherapeutic value of forced expiratory volume, non-gated radiotherapy and type of concomitant chemotherapy did not appear as contributing factors in contrast to the administration of neoadjuvant gemcitabine (P=0.03). The occurrence of acute radiation pneumonitis was significantly associated with non-tumour lung volumes irradiated to 13 Gy (V13, P=0.04), 20 Gy (V20, P=0.02) and 25 Gy (V25, P=0.006), the mean lung dose (P=0.008) and lung normal tissue complication probability (P=0.004). In multivariate logistic regression analysis, the occurrence of acute radiation pneumonitis was significantly associated with age above 75 years (odds ratio [OR]=16.72 ; P=0.02) and with administration of neoadjuvant gemcitabine (OR=18.08, P=0.04). CONCLUSION Acute radiation pneumonitis is a common acute side effect of the conformal thoracic radiotherapy of locally advanced non-small cell lung cancer, requiring close post-treatment follow-up, particularly for elderly patients. The use of gemcitabine before radiation should be avoided. The benefits and risks of conformal thoracic radiotherapy must be carefully analyzed in view of the dosimetric parameters obtained.