Postprostatectomy Intensity-modulated Radiation Therapy Research Articles

Comparative Toxicity and Dosimetric Profile of Whole-Pelvis Versus Prostate Bed-Only Intensity-Modulated Radiation Therapy After Prostatectomy

To assess whether whole-pelvis (WP) intensity modulated radiation therapy (IMRT) for prostate cancer (PCa) after prostatectomy is associated with increased toxicity compared to prostate-bed only (PB) IMRT. All patients (n= 67) undergoing postprostatectomy IMRT to 70.2 Gy at our institution from January 2006 to January 2009 with minimum 12-month follow-up were divided into WP (n= 36) and PB (n= 31) comparison groups. WP patients received initial pelvic nodal IMRT to 45 Gy. Pretreatment demographics, bladder and rectal dose-volume histograms, and maximum genitourinary (GU) and gastrointestinal (GI) toxicities were compared. Logistic regression models evaluated uni- and multivariate associations between pretreatment demographics and toxicities. Pretreatment demographics including age and comorbidities were similar between groups. WP patients had higher Gleason scores, T stages, and preoperative prostate-specific antigen (PSA) levels, and more WP patients underwent androgen deprivation therapy (ADT). WP minimum (Dmin) and mean bladder doses, bladder volumes receiving more than 5 Gy (V5) and V20, rectal Dmin, and PB bladder and rectal V65 were significantly increased. Maximum acute GI toxicity was Grade 2 and was increased for WP (61%) vs. PB (29%) patients (p= 0.001); there was no significant difference in acute Grade ≥2 GU toxicity (22% WP vs. 10% PB; p= 0.193), late Grade ≥2 GI toxicity (3% WP vs. 0% PB; p= 0.678), or late Grade ≥2 GU toxicity (28% WP vs. 19% PB; p= 0.274) with 25-month median follow-up (range, 12-44 months). On multivariate analysis, long-term ADT use was associated with Grade ≥2 late GU toxicity (p= 0.02). Despite dosimetric differences in irradiated bowel, bladder, and rectum, WP IMRT resulted only in clinically significant increased acute GI toxicity in comparison to that with PB IMRT, with no differences in GU or late GI toxicity.

Preservation of Sexual Function after High Dose Post-Prostatectomy Intensity Modulated Radiation Therapy (IMRT)

Preservation of Sexual Function after High Dose Post-Prostatectomy Intensity Modulated Radiation Therapy (IMRT)

Preliminary Report of the Effect of High-Dose Adjuvant Intensity Modulated Radiation Therapy on the Sural Nerve Graft for Cavernosal Nerve Sacrifice After Radical Prostatectomy

A sural nerve graft may replace a killed cavernosal nerve. The effect of intensity-modulated radiation therapy (IMRT) on function of the graft has not been reported. Between 1998 and 2001, 8 patients (9 nerve grafts) were treated with postoperative IMRT (mean dose, 70 Gy). Two patients had neoadjuvant Lupron 30 mg 2 months prior to radiation. Potency was defined as ability to achieve spontaneous erection sufficient for vaginal penetration. Median follow-up was 31.6 months. Five patients (62.5%) who had erectile function after prostatectomy preserved spontaneous erectile function after radiation. Of these, 3 patients had both nerves resected (two receiving unilateral grafts and one receiving bilateral grafts) and 2 others had one graft and one nerve preserved. The impotent patients were impotent after surgery. High-dose postprostatectomy IMRT does not place sural nerve grafts at greater risk for failure. Larger numbers of patients are needed to confirm these encouraging, preliminary findings.

Evaluation of acute GI and GU toxicity with postprostatectomy intensity-modulated radiation therapy (IMRT) with endorectal balloon immobilization

Evaluation of acute GI and GU toxicity with postprostatectomy intensity-modulated radiation therapy (IMRT) with endorectal balloon immobilization

Clinical experience with intensity-modulated radiation therapy (IMRT) for prostate cancer with the use of rectal balloon for prostate immobilization

The implementation of intensity-modulated radiation therapy (IMRT) is the result of advances in imaging, radiotherapy planning technologies, and computer-controlled linear accelerators. IMRT allows both conformal treatment of tumors and conformal avoidance of the surrounding normal structures. The first patient treated with Peacock IMRT at Baylor College of Medicine took place in March 1994. To date, more than 1500 patients have been treated with IMRT; more than 700 patients were treated for prostate cancer. Our experience in treating prostate cancer with IMRT was reviewed. Patient and prostate motions are important issues to address in delivering IMRT. The Vac-Lok bag-and-box system, as well as rectal balloon for immobilization of patient and prostate gland, respectively, are employed. Treatment planning also plays a very important role. IMRT as a boost after conventional external beam radiotherapy is not our treatment strategy. To derive maximal benefits with this new technology, all patients received full course IMRT. Three separate groups of patients receiving (1) primary IMRT, (2) combined radioactive seed implant and IMRT, and (3) post-prostatectomy IMRT were addressed. Overall, toxicity profiles in these patients were very favorable. IMRT has the potential to improve treatment outcome with dose escalation while minimizing treatment-related toxicity.

Intensity modulated radiation therapy (IMRT) following prostatectomy: more favorable acute genitourinary toxicity profile compared to primary IMRT for prostate cancer

Purpose: To report our initial experience on postprostatectomy IMRT (PPI), addressing acute genitourinary (GU) toxicity in comparison to primary IMRT (PI) for prostate cancer. Methods and Materials: From April 1998 to December 1999, 40 postprostatectomy patients were treated with intensity modulated radiation therapy (IMRT) to a median prescribed dose of 64 Gy (mean dose of 69 Gy). The Radiation Therapy Oncology Group (RTOG) scoring system was used to assess acute GU toxicity. Target volume and maximum and mean doses were evaluated. The mean doses to the bladder and irradiated bladder volume receiving >65 Gy were assessed. These were compared to those of 125 patients treated with PI to a prescribed dose of 70 Gy (mean dose of 76 Gy). Results: The acute GU toxicity profile is more favorable in the PPI group with 82.5% of Grade 0–1 and 17.5% of Grade 2 toxicity compared to 59.2% and 40.8%, respectively, in the PI group ( p < 0.001). There was no Grade 3 or higher toxicity in either group. The target volume was larger in the PPI group, while the maximum and mean doses to the target were higher in the PI group. The mean dose delivered to the bladder was higher in the PPI group. The irradiated bladder volume receiving >65 Gy was significantly larger in the PI group ( p < 0.001). Conclusions: PPI can be delivered with acceptable acute GU toxicity. The larger PPI target volume may be related to the difficulty in delineating prostatic fossa. Despite a larger target volume and a higher mean dose to the bladder, PPI produced a more favorable acute GU toxicity profile. This may be related to a combination of lower mean and maximum doses and smaller bladder volumes receiving >65 Gy in the PPI group, as well as urethral rather than bladder irradiation. The findings have implications in the evaluation of IMRT treatment plan for prostate cancer, whereby the irradiated bladder volumes above 65 Gy may be more meaningful than the mean dose to the bladder. Longer term toxicity results are awaited.