Dean A Gant | PubMed Health

PubMed2005

Long-term salvage radiotherapy outcome after radical prostatectomy and relapse predictors.

PURPOSE: We assessed the efficacy of salvage radiotherapy (SRT) and analyzed predictors of biochemical progression-free survival (bPFS) and distant metastasis-free survival in patients with clinically localized disease recurrence after radical prostatectomy. MATERIALS AND METHODS: The records of 114 patients treated with SRT at 2 institutions between 1991 and 2001 were retrospectively reviewed. Time to biochemical recurrence and to distant metastases was analyzed using the Kaplan-Meier estimation. Candidate predictors of bPFS and distant metastasis-free survival were analyzed using the log rank test and Cox regression. Acute and late complications were scored using Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria. RESULTS: At a median followup of 6.3 years (range 1.9 to 13.3) for SRT 4 and 6-year bPFS was 50% (95% CI 42% to 61%) and 33% (95% CI 24% to 43%), respectively. The 6-year actuarial probability of distant metastases after SRT was 14%. Multivariate analysis demonstrated an independent association of increasing Gleason score, lymphovascular invasion and lack of a complete response to SRT with decreased 5-year bDFS. These factors were associated with significantly less 5-year distant metastasis-free survival. Pre-RT prostate specific antigen greater than 2.0 ng/ml was associated with significantly decreased 5-year bDFS and distant metastasis-free survival, although it was not maintained on multivariate analysis. CONCLUSIONS: SRT results in durable prostate specific antigen control in select patients. It is well tolerated with few severe late effects. Increasing Gleason score, lymphovascular invasion and lack of a complete response to SRT are significant risks for disease progression requiring additional management.

Aged↗

PubMed2003

Marker seed migration in prostate localization.

PURPOSE: Marker seed location was analyzed to test the hypothesis that there is no intraseed migration within the prostate, a premise fundamental to the technique of marker seed localization of this organ. Despite increasing interest in the use of implanted seeds as fiducial markers for gland location, there are few data available with which to evaluate the validity of this technique, particularly over the entire course of external beam radiation therapy. METHODS AND MATERIALS: Between May 2001 and December 2001, after obtaining fully informed written consent, 9 patients with early stage prostate cancer were enrolled on an institutionally reviewed protocol. Patients had four to five marker seeds implanted into the prostate under transrectal ultrasound guidance before definitive radiotherapy. The porous gold seeds were each 1.2 x 2.0 mm in dimension. Seed locations from orthogonal radiographs based on the initial simulation and weekly orthogonal films were digitized using a CMS Focus planning system, thereby facilitating the determination of intraseed spacing. The digitization of the isocenter from each orthogonal pair of radiographs was used to determine digitizing error for seed localization. Pubic symphysis, bilateral femoral heads, and isocenter were also digitized and will be analyzed at a later date. RESULTS: Overall, the average migration of all the seeds in the patients was 1.2 +/- 0.2 (SD) mm. The greatest average movement of any seed in any patient was 1.9 mm over the entire 7-week course of radiotherapy. The smallest average movement was 0.6 mm. The greatest change in intraseed spacing in any of the patients during the full course of therapy was 6.6 mm. One seed in 1 patient was lost at the start of the third week of therapy and censored from analysis. Digitizing error in seed localization was calculated to be 0.20 +/- 0.03 (SD) mm. CONCLUSIONS: As an aggregate, there is negligible seed migration within the prostate over the entire course of definitive radiotherapy. However, there are small, detectable movements in individual seed locations, perhaps resulting from topographic changes in the gland secondary to seed placement, anatomic changes in bladder and rectum, or treatment itself. With respect to seed migration, prostate marker seeds represent an accurate and reliable surrogate of gland location during a full course of radiotherapy.

Brachytherapy↗