[Neoadjuvant radiochemotherapy treatment in locally advanced rectal adenocarcinoma]. / Trattamento radiochemioterapico neoadiuvante negli adenocarcinomi del retto localmente avanzati.

A prospective phase II study was conducted to evacuate toxicity and results of preoperative radiochemotherapy in locoregionally advanced rectal cancer (LARC). A total of 33 patients entered the study and received 45 Gy to the pelvis plus a supplemental boost of 5.4-9 Gy concurrently with 5 FU c.i. at a dose of 225-275 mg/m2. Thirty patients were operated after 5-7 weeks (20 anterior resection and 10 abdominoperineal excision). In 14 patients (47%) a downstaging was observed, 5 patients experienced a complete clearance of the primary tumor. After a median of 14 months (range, 5-27), 23 patients, are alive and well. And 8 patients experienced a disease progression (4 local-regional and 4 distant). Our results provide further evidence of the utility and effectiveness of preoperative radiochemotherapy in LARC.

Light polarization problems.

A method based on the coherency matrix and suitable for dealing with optical phenomena or devices which affect light polarization is explained. A comparison is made with the Mueller calculus, showing the different features of both types of procedures.

Angular distribution of light transmitted by a cylindrical guide.

In this paper the problem of the light transmission through a cylindrical guide is analyzed. Equations are derived that allow us to evaluate the off-axis distribution of rays both with and without optical contact between the light source and the guide. In the latter case a very peculiar behavior is found for values of the refractive index satisfying the condition: [equation]. The over-all transmission of the guide is also evaluated in the various cases.