Acute morbidity related to treatment volume during 3D-conformal radiation therapy for prostate cancer

Intensity-Modulated Radiotherapy of Pelvic Lymph Nodes in Locally Advanced Prostate Cancer: Planning Procedures and Early Experiences

“…For example, according to Gallagher et al, less than 78 cm 3 of the small intestine should receive more than 45 Gy, and less than 17 cm 3 should receive 50 Gy (22). The acute adverse effect outcome of the present IMRT series (28% of both Grade 2 GI and GU adverse effects) compare well with our previous CRT experience using the same prescription dose level, in which 40% of the CRT patients had acute Grade 2 GI and 35% had acute Grade 2 GU adverse effects (6,24). Also the late adverse effect rates observed at the first follow-up consultations after treatment seem reasonable, in particular for the GI effects.…”

“…For prostate cancer patients at high risk for involvement of pelvic lymph nodes, the Radiation Therapy Oncology Group (RTOG) 9413 trial documented an improved progression-free survival for these patients if the pelvic lymph nodes were irradiated (5). Compared with localized fields, however, pelvic irradiation carries the risk of increasing adverse effects rates, in particular for the intestine (5)(6)(7)(8). Although the typical shape of the lymph node target calls for use of IMRT (with the planning target volume very close to the intestine), relatively few institutions have yet reported on the application of IMRT for this subset of prostate cancer patients (9)(10)(11)(12)(13)(14).…”

Time patterns of changes in biomarkers, symptoms and histopathology during pelvic radiotherapy

“…This confirms other studies showing histopathological signs of inflammation to be more intense at week 2 of RT compared to week 6 [14] and GI toxicity symptoms to be worst at the end of RT [13,22,23]. The discrepancy in time profiles between symptoms and biopsies may be partly explained by the fact that the biopsies are from superficial layers of the bowel, while deeper tissues were not examined.…”

“…Fifteen had started maximal androgen blockade (MAB) before RT according to departmental routines previously described [22]. All patients were treated with a four-field conformal box technique, 2 Gy fractions 5 days/wk, to a total of 70 Gy (one patient to 72 Gy).…”

“…Seven patients were treated with a slightly larger field, with the craniocaudal upper limit in the L5-S1 interspace and the lower limit at the ischial tuberosity. The Gross Tumour Volume (GTV) was contoured by the responsible oncologist on 5 mm thick and 5 mm intervals' slices on Computer Tomography scans, defined as the volume within the outer wall contour of prostate and seminal vesicles, as appropriate [22]. Clinical Target Volume (CTV) was generated by adding 5 mm margins on GTV, and the Planning Target Volume (PTV) additionally 15 mm wider than CTV, except towards rectum, where 10 mm margins were applied [22].…”