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Analysis of prostate-specific antigen bounce after I(125) permanent seed implant for localised prostate cancer.BACKGROUND AND PURPOSE: To report on the incidence of benign prostate-specific antigen bounce following permanent I(125) prostate brachytherapy, to describe the associations in our population and review the relationship of bounce to subsequent biochemical failure. MATERIALS AND METHODS: From February 2000 to May 2005, 374 patients with localised prostate cancer were treated with I(125) permanent prostate brachytherapy at a single institution. A prospectively collected database was used to identify cases of prostate-specific antigen (PSA) bounce, defined as a rise of 0.2 ng/ml above an initial PSA nadir with subsequent decline to or below that nadir without treatment. The patients who received neo-adjuvant or adjuvant hormone manipulation were excluded. Biochemical failure was determined using the both the ASTRO consensus definition and Phoenix (nadir +2 ng/mL) definition. RESULTS: Two hundred and five patients were identified with a median follow-up of 45 months (24-85). PSA bounce was noted in 79 (37%) men, occurring at a median of 14.8 months (1.7-40.6) following implant. The median peak PSA was 1.8 ng/ml (0.4-7.4) with a bounce magnitude of 0.91 ng/ml (0.2-5.8). When pre- and post-implant factors were assessed for association to bounce, only younger age was statistically significant (p=0.002). The threshold for biochemical failure as defined by the ASTRO consensus definition (1997) was met in 4 (5%) patients after experiencing bounce as opposed to 19 (15%) non-bounce patients (p=0.01). The threshold for Phoenix (nadir +2 ng/mL) was met in 6 (7.5%) patients following bounce versus 22 (17%) of non-bounce patients (p=0.003). Both definitions are prone to false positive calls during bounce. Median PSA velocity during the bounce was 0.08 ng/mL/month (0.02-0.98) and was statistically significantly lower than the median velocity prior to the Phoenix biochemical failure at 0.28 ng/mL/month (0.07-2.04) (p=0.0005). CONCLUSION: PSA bounce is a common finding in our population and is associated with a lower rate of subsequent biochemical failure. The noted differences in PSA velocity will require verification in a future analysis to reduce the influence of median follow-up on this finding. Patients should be advised of the potential of bounce in PSA follow-up after permanent I(125) prostate brachytherapy and physicians involved in follow-up of prostate brachytherapy patients should be aware of this phenomenon, allowing them to commit to appropriate PSA surveillance, avoiding the premature and inappropriate initiation of salvage therapy during PSA bounce.
Patterns of relapse following radiotherapy for differentiated thyroid cancer: implication for target volume delineation.INTRODUCTION: Post-operative residual disease in differentiated thyroid cancer is an indication for external beam radiotherapy (EBRT) especially if there is poor radioiodine uptake by the residual disease. There are no standardized guidelines or consensus in target delineation for radiotherapy in thyroid cancer. AIMS: To determine the pattern of recurrence in patients with well differentiated thyroid cancer who received adjuvant or definitive radiotherapy as well as radioiodine ablation following surgery or biopsy with a view to better defining future target volume delineation for radiotherapy. MATERIALS AND METHODS: Forty-nine patients with differentiated thyroid cancer received radical external beam radiotherapy and radioiodine ablation (3.5GBq) following thyroidectomy or biopsy between 1990 and 2000. Nineteen patients had macroscopic residual (11) or inoperable disease (8), whilst 30 patients had clear (5) or microscopic positive resection margin (24), and 1 patient the resection margin status was unknown. All the patients were deemed high risk for local recurrence or progressive disease. The thyroid bed and regional nodes were irradiated using two radiotherapy techniques: (1) non co-planar lateral fields (NCLF) in coronal plane using 6MV photons to a dose of 45-50Gy in 16 fractions over 22 days and (2) anterior-posterior parallel pair of 6MV photons to a dose of 40-42.5Gy in 16 fractions over 22 days. There was no attempt to irradiate the lymph nodes in that part of the anterior and posterior mediastinum extending from the brachiocephalic veins to the carina. RESULTS: The median follow-up was 5.4 years (range 0.9-12.4 years). The actuarial 5-year cause-specific survival and local control for the whole group was 75.7% and 81.4%, respectively. Of the 4 patients with mediastinal recurrence, all had neck recurrences and two had distant metastases. All the medisastinal recurrences occurred in superior mediastinum (level VII) and all were treated with NCLF in coronal plane radiotherapy technique. Furthermore, mediastinal recurrences did not occur in isolation. The 5-years loco-regional control rate was 89.1% for those with clear or microscopic positive margins and 69.2% for those with macroscopic residual or inoperable disease. Five-year cause specific survival was 58.3% for patients with macroscopic residual or inoperable disease and 91.4% for those with clear or microscopic positive margins. CONCLUSION: The status of postoperative margin relating to bulk of disease influences local control and cause specific survival. Surgical resection in locally advanced thyroid cancer should be performed by an experienced surgeon to achieve macroscopic clearance where possible. The majority of recurrences were loco-regional. The few superior mediastinal recurrences did not occur in isolation. All the mediastinal recurrences occurred in the superior mediastinum (level VII). We recommend the target volume should encompass the thyroid bed and regional neck nodes and the superior mediastinum level VII excluding the lymph nodes on both sides of the trachea within the anterior and posterior mediastinum extending from the brachiocephalic veins to the carina (compartment 4). Thus, this should facilitate dose escalation to improve loco-regional control and avoiding radiation induced mediastinal toxicity.
Report on the early efficacy and tolerability of I(125) permanent prostate brachytherapy from a UK multi-institutional database.AIMS: To report the results of I(125) prostate brachytherapy from a central, prospectively collected database of three UK institutions. MATERIALS AND METHODS: All patients treated with I(125) permanent prostate brachytherapy at the Christie Hospital, Manchester (CHM), Cookridge Hospital, Leeds (CKL) and Mount Vernon Hospital, Northwood, London (MVL) since 2003 have been prospectively registered on a detailed central database. Patient, tumour, pre- and post-implant dosimetry data have been recorded. Urinary toxicity as assessed by the International Prostate Symptom Score, catheterisation and urinary stricture rates after implant have been documented and biochemical failure determined, using both the American Society for Therapeutic Radiology and Oncology (ASTRO) consensus and the Phoenix (nadir + 2 ng/ml) definition. RESULTS: In total, 1535 patients were registered on the database between January 2003 and October 2006, including 432 from CHM, 926 from CKL and 177 from MVL, with a median follow-up of 21 months (range 1-56). Patient and tumour characteristics were similar at all centres. Pre-implant dose indices were comparable between centres, except for the V150, with median values of 51.9, 64.3 and 69.8% at CHM, CKL and MVL, respectively. Median post-implant dose parameters were lower than pre-planned constraints by up to 33.0% at each centre for all values, except at CKL where the V200 was 23.9% higher. The International Prostate Symptom Score increased from a median of 5 at baseline to 18, 6 weeks after implant, but was not significantly different to baseline values by 12 months. Nine per cent of men required catheterisation after implant for a median duration of 53 days, but urinary stricture rates remained low at 1%. Neoadjuvant hormonal manipulation was used in 228 men (15%) for downsizing and 159 (10%) for intermediate/high-risk disease. Collated biochemical failure rates were low at this point of follow-up, with actuarial 2-year ASTRO and Phoenix biochemical failure-free survival rates of 94.4 and 94.5%, respectively, consistent with other large single centre reports. When post-implant dosimetric factors were assessed for a relationship to biochemical failure, no indices consistently predicted for improved ASTRO and Phoenix biochemical failure-free survival rates. CONCLUSIONS: This ongoing collaboration shows that with limited infrastructure (a single industry-sponsored data manager), a large multi-institutional database estimated to represent one-third of implants carried out in the UK during this time can be developed. Patient selection was similar across all centres and adhered to published guidelines. Early biochemical and toxicity outcomes confirm the efficacy and tolerability of I(125) prostate brachytherapy in a large cohort of patients. A further analysis is planned.