Endoscopic resection followed by adjuvant radiotherapy for sinonasal intestinal-type adenocarcinoma: Retrospective analysis of 30 consecutive patients.

BACKGROUND: Intestinal-type adenocarcinoma (ITAC) is a rare and locally aggressive occupation-related tumor. Currently, endoscopic-assisted resection and advances in irradiation modalities (3D conformal radiotherapy/intensity-modulated radiation therapy [IMRT]) are emerging as an alternative to traditional open surgery and conventional radiotherapy. METHODS: Retrospective analysis of 30 consecutive patients affected with sinonasal ITAC, primarily treated by an endoscopic approach followed by 3D conformal radiotherapy/IMRT at a single institution, from 2003 to 2010. RESULTS: The 5-year overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), and recurrence-free survival (RFS) were 72.7% ± 9.6%, 78% ± 9.5%, 67.9% ± 10.7%, and 69.2% ± 9.4%, respectively (mean follow-up, 48 months). No major complications or serious toxicities were observed. Prognostic factors were stage of disease at diagnosis, development of recurrences, status of surgical margins, grading, tumoral pattern of growth, and proliferative index (Ki-67). CONCLUSION: The low morbidity of endoscopic approaches, the acceptable toxicity of modern irradiation modalities, and these promising survival rates, indicate that this treatment strategy might be considered a safe, minimally invasive, and maximally effective option for treating selected sinonasal ITAC.

Experimental method to obtain scattering contribution in portal dose images.

A method for evaluating scattered dose contribution in portal images acquired under clinical conditions (phantom-device distance of 30 cm) is presented. This method is based on radiographic film and ionisation chamber measurements and is valid for homogenecus polystyrene phantoms and square fields of different size. The portal imaging device consisted of a radiographic film placed between slabs of polystyrene under full build-up conditions (1.5 cm for 6 MV beam and 3 cm for 18 MV and 1 cm of polystyrene backscatter material. First the primary dose image in the portal plane P(i,j) is obtained using a projection algorithm, then the scattered dose image S(i,j) is found by subtracting the primary dose image in the portal plane P(i,j) from the total dose image acqu red in the portal plane T(i,j). The ratio S(i,j)/T between the scattered dose distribution and the dose value measured on the bearn axis in the portal plane was found to be uniform within the radiation field for all the geometrical configuration of phantoms and fields studied. Under these conditions the mean value of the scatter fraction S/T evaluated within a ROI centred on the bearn axis accurately describes the scatter fraction distribution S(i,j)/T within the whole radiation field. S/T ranges from 7.4% to 31.1% in the 6 MV beam and from 8.9% to 30.8% in the 18 MV beam. Finally an analytical method to evaluate the ratio S/T has been developed from the experimental results. It comprises phantom, accelerator head and portal imaging device contributions and depends on field size and phantom thickness.