Dose distribution in 3-dimensional conformal radiotherapy for prostate cancer: comparison of two treatment techniques (six coplanar fields and two dynamic arcs).

PURPOSE: To compare dose distribution for two techniques of 3-dimensional conformal radiotherapy (RT): 6-field technique (6F) and 2-dynamic arc therapy (2DA). METHODS AND MATERIALS: Thirty nonmetastatic prostate cancer patients were included. In each patient, two treatment plans were prepared: with six coplanar fields (45 degrees , 90 degrees , 135 degrees , 225 degrees , 270 degrees , 315 degrees ) and with two dynamic lateral 100 degrees -wide arcs (40-140 degrees , 220-320 degrees ). Dose-volume histograms (DVHs) were computed and mean area under curve (AUC) values were calculated for the DVHs of Planning Target Volume (PTV), rectum, urinary bladder and femoral heads. Doses given to 30% of rectum (DR(30)), to 60% of rectum (DR(60)), to 50% of bladder (DB(50)), to 50% of femoral head (DF(50)) and to 95% of PTV (DPTV(95)) were reported as a percentage of the total dose. RESULTS: Mean DR(30) and DR(60) for 6F and 2DA were 75.8%, 51.5% and 72.2%, 37.2%, respectively. Mean DB(50) for 6F and 2DA were 68% and 64.2%, respectively. Mean right DF(50) for 6F and 2DA were 35.4% and 45.5%, respectively. Mean DPTV(95) for 6F and 2DA were 99% and 99.2%, respectively. Mean AUCs of DVHs of rectum and urinary bladder were significantly higher for 6F (this was more evident for small PTV and in the intermediate dose range). Mean AUC of DVHs of PTV and femoral heads were significantly higher for 2DA. CONCLUSIONS: Both 6F and 2DA offer good dose distribution for PTV. 2DA allows for significantly better sparing of rectum and urinary bladder with slightly worse femoral head dose distribution. Further study is warranted in order to establish the clinical relevance of these differences.

Breast cancer bone metastases: an epidemiologic study in selected radiation departments.

AIMS: To quantify radiation treatments for bone metastases from breast cancer in three Sicilian provinces (Messina, Catania, Ragusa) with respect to the general population and the incidence and prevalence of breast cancer in this macro-area in a 8-year period. METHODS: All bone metastasis patients treated using radiotherapy in 8 radiation departments operating in the provinces of Messina, Catania and Ragusa were collected. Among these, metastases from breast carcinoma were analyzed according to year of irradiation. An analysis of breast cancer incidence and prevalence with respect to inhabitants in this macro-area was conducted using literature and census data. RESULTS: From January 2004 to December 2011, irradiation was delivered in 4419 bone metastasis patients. Among these, 1617 had a primary breast cancer with a median treatment per year of 206.5 (range, 164-251); 211 patients were treated in 2004 and 206 in 2011. In 2004, there were 1,048,957 female residents in the three provinces and 1,065,422 in 2011. The reported breast cancer incidence and prevalence in Sicily was respectively 100.79/100,000 and 908.54/100,000 in 2004 and 108.41/100,000 and 1091.29/100,000 in 2010. CONCLUSIONS: There has been an increase in both incidence and prevalence of breast cancer in Sicily. Nevertheless, it seems that there was no increment in skeletal-related events requiring irradiation in such patients in eastern Sicily radiation departments.