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ABSTRACT: To evaluate the relationship between the dose and volume of radiation to proximal penile structures and the development of erectile dysfunction after external beam radiotherapy (RT) for localized prostate adenocarcinoma.
The study cohort comprised 28 patients who were enrolled our in-house three-dimensional conformal RT dose escalation protocol. The patients were treated to 78 Gy between 1995 and 1998. This protocol included a planned quality-of-life questionnaire to assess sexual function 2 years after completing RT. All the study patients were potent before RT. The median follow-up was 66 months (range 39-95). Penile base contents were outlined retrospectively in restored treatment plans. The dose-volume histograms (DVHs) for the corpus spongiosum (penile bulb), corpora cavernosum and crura, and total penile structure (corpus spongiosum plus corpora cavernosum and crura) were calculated. Statistical significance was defined as p < 0.05. The Bonferroni correction was used to adjust for multiple comparisons. Power calculations showed that our study sample would detect radiation- induced impotence with a very high power. We also estimated that a relatively small difference of 10-15% in the DVHs between the potent and impotent patients could be detected.
At 2 years after RT, 10 patients (35.7%) reported new-onset erectile dysfunction and were unable to attain firm enough erections to have intercourse. Only hypertension was observed to affect erectile dysfunction after external beam RT. We found no statistically significant correlation among age, diabetes, or heavy alcohol consumption and post-RT potency. The mean radiation dose +/- standard deviation delivered to the corpus spongiosum, corpora cavernosa and crura, and total penile structure was, respectively, 42.2 +/- 8.4 Gy, 36.3 +/- 8.0 Gy, and 38.2 +/- 7.5 Gy. t test comparisons were performed between DVHs of post-RT potent and impotent patients on multiple cutpoints. No dose-volume effect was found. Analysis of the DVHs when the patients were subdivided into normotensive and hypertensive groups also showed no dose-volume response.
Our analysis did not show statistically significant correlations between potency preservation and radiation dose to the proximal penis. The entire etiology of radiation- induced erectile dysfunction remains unclear and further research is needed.
International Journal of Radiation OncologyBiologyPhysics 07/2004; 59(4):1039-46. · 4.11 Impact Factor
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ABSTRACT: To assess patient-reported prostate cancer-specific quality of life 2 and 3 years after radiotherapy to the prostate in a randomized dose-escalation trial of 70 versus 78 Gy conducted from 1993 to 1998.
Two years after completing radiotherapy, a questionnaire that assessed bladder, rectal, and sexual function was sent to 301 patients in the study. Three years after treatment, a second questionnaire was sent to the 175 patients with adequate follow-up.
Three years after radiotherapy, urinary incontinence was reported by 35% of patients, but only 6% required the use of a pad or other protective device. Patients reported increased leakage with a full bladder (urge incontinence) between the 2 and 3-year questionnaires (42% versus 50%; P = 0.03). At 3 years, 33% of patients reported rectal bleeding compared with 47% at 2 years (P = 0.006). Patients in the 78-Gy arm reported more frequent bowel movements at 3 years and less change in bowel function at 2 years than patients in the 70-Gy arm. Before radiotherapy, 84% of patients reported erections adequate for intercourse at least a few times during the previous year. After 2 and 3 years, this had decreased to 49% and 41%, respectively (P <0.02).
By patient-reported questionnaire, 78 Gy produced an increase in bowel movement frequency and no increase in bladder or sexual side effects at 3 years compared with 70 Gy. Comparing the results 2 and 3 years after radiotherapy, the symptoms of rectal bleeding had improved, erectile function had decreased, and urinary urge incontinence had increased.
Urology 10/2003; 62(4):707-13. · 2.43 Impact Factor
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ABSTRACT: Traditionally, portal images have been used for verification of patient setup. More recently, direct prostate localization using ultrasound imaging has become available. The aim of this study was to use both modalities to measure daily setup error and prostate organ motion and their respective contributions to the overall uncertainty of prostate target localization.
Thirty-five patients treated for prostate cancer with intensity-modulated radiotherapy (IMRT) between February 6 and July 2, 2001 underwent daily B-mode acquisition and targeting (BAT) ultrasound localization and weekly orthogonal portal imaging.
A total of 243 pairs of orthogonal portal films and the corresponding daily BAT images were reviewed. The mean shift +/- standard deviation in the right-left (RL), AP, and superinferior (SI) directions was 0.035 +/- 2.8 mm, -0.23 +/- 3.0 mm, and -0.013 +/- 2.0 mm, respectively, for portal films and -0.82 +/- 3.2 mm, -1.4 +/- 6.4 mm and -1.7 +/- 6.4 mm, respectively, for BAT images taken on the same day as the portal films. The mean prostate organ motion measurements were -0.89 +/- 3.3 mm (RL), -1.3 +/- 5.7 mm (AP), and -1.6 +/- 6.4 mm (SI). Without BAT localization, organ motion would have caused the clinical target volume to move outside the planning target volume margin in 23.3-41.8% of the treatments. Margins necessary to achieve complete coverage of the clinical target volume > 95% of the time without BAT would have been 5.3, 10.4 and 10.4 mm in the RL, AP, and SI dimensions, respectively.
Prostate organ motion appears to predominate over setup error as the major component of variation in target localization. Without the use of BAT ultrasound prostate imaging, misses of the prostate can occur in a high percentage of treatments, despite patient setup verification with portal images. Relatively large planning target volume margins in the AP and SI dimensions may be necessary to overcome this.
International Journal of Radiation OncologyBiologyPhysics 08/2003; 56(5):1218-24. · 4.11 Impact Factor
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ABSTRACT: Childhood rhabdomyosarcoma (RMS) has a relatively good prognosis. Outcome for adults with this disease is poorly documented due to its rarity.
The clinicopathologic features, treatment methods, and disease outcome were reviewed retrospectively for 82 adults with locoregional RMS treated between 1960 and 1998. Patients with distant metastasis at diagnosis were excluded. Actuarial univariate and multivariate statistical methods were used to evaluate outcome.
Patient ages ranged from 17 to 84 years (median, 27 years). Histologic subtypes were embryonal (34%), pleomorphic (43%), and alveolar (23%). Anatomic sites of origin were head and neck (52%), trunk (26%), and extremity (7%). Tumor size was 5 cm or smaller in 51% of patients. Regional lymph node metastasis was present in 33% of patients at presentation. Treatment consisted of radiation alone in 11%, radiation and surgery in 18%, radiation and chemotherapy in 34%, and all three modalities in 37%. With a median follow-up of 10.5 years, the 10-year actuarial disease-free and overall survival rates were 41% and 40%, respectively. The 10-year actuarial local, lymph node, and metastatic control rates were 75%, 82%, and 53%, respectively. The major determinant of metastatic control and survival was primary tumor size (< or = 5 vs. > 5 cm). Local control was satisfactory (10-year rate of 87%) for sites other than parameningeal (50% at 10 years). Patients whose disease responded to chemotherapy had a significantly better metastasis free period (72% at 10 years) than those whose disease failed to respond (19% at 10 years).
Adult RMS is a highly malignant tumor with a significant incidence of metastatic recurrence. Continuing investigation of new and potentially more effective chemotherapy is crucial. Local control is satisfactory for sites other than parameningeal where new radiation technologies such as intensity-modulated therapy may be necessary to safely deliver adequate doses.
Cancer 08/2002; 95(2):377-88. · 4.77 Impact Factor
