Long-term results of retropubic permanent 125iodine implantation of the prostate for clinically localized prostatic cancer

Genitourinary toxicity in patients receiving TURP prior to hypofractionated radiotherapy for clinically localized prostate cancer: A scoping review

BACKGROUND

When compared with conventional external beam radiotherapy, hypofractionated radiotherapy has led to less treatment sessions and improved quality of life without compromising oncological outcomes for men with prostate cancer. Evidence has shown transurethral prostatic resection prior to brachytherapy and external beam radiotherapy is associated with worsening genitourinary toxicity. However, there is no review of genitourinary toxicity when TURP occurs prior to definitive hypofractionated radiotherapy. In this review, we seek to illustrate the genitourinary outcomes for men with localized prostate cancer who underwent transurethral resection of the prostate prior to receiving definitive hypofractionated radiotherapy. Genitourinary outcomes are explored, and any predictive risk factors for increased genitourinary toxicity are described.

METHODS

PubMed, Medline (Ovid), EMBASE and Cochrane Library were all searched for relevant articles published in English within the last 25 years. This scoping review identified a total of 579 articles. Following screening by authors, 11 articles were included for analysis.

RESULTS

Five studies reported on acute and late toxicity. One article reported only acute toxicity while 5 documented late toxicity only. While most articles found no increased risk of acute toxicity, the risk of late toxicity, particularly hematuria was noted to be significant. Risk factors including poor baseline urinary function, prostate volume, number of prior transurethral prostatic resections, timing of radiotherapy following transurethral prostatic resection, volume of the intraprostatic resection cavity and mean dose delivered to the cavity were all found to influence genitourinary outcomes.

CONCLUSION

For those who have undergone prior TURP hypofractionated radiotherapy may increase the risk of late urinary toxicity, particularly hematuria. Those with persisting bladder dysfunction following TURP are at greatest risk and careful management of these men is required. Close collaboration between urologists and radiation oncologists is recommended to discuss the management of patients with residual baseline bladder dysfunction prior to commencing hypofractionated radiotherapy.

Genitourinary tumors

Memorial Sloan Kettering Cancer Center (MSK) has made many notable contributions to the scientific understanding and care of patients with common urologic cancers. Many of the advances represented paradigm shifts in management and established new standards of care. This review highlights the surgical procedures and treatment strategies originated and pioneered by urologic surgeons and colleagues at MSK during the past 50 years.

Prostate cancer screening and treatment: where have we come from and where are we going?

OBJECTIVE

To evaluate the current prostate cancer screening and treatment paradigm in light of recently published long-term results of major screening and treatment trials.

METHODS

Historical review of the evolution of the diagnosis and treatment of prostate cancer followed by a detailed summary of the findings and differences among the three major screening trials and the three major treatment trials.

RESULTS

Prostate-specific antigen (PSA) testing can identify clinically significant prostate cancer and has produced a significant stage shift and is the likely explanation for the decline in prostate cancer mortality. Unfortunately, PSA testing predominantly identifies low-grade disease that is unlikely to progress during a patient's lifetime leading to substantial diagnosis of indolent disease. Treatment with radical prostatectomy (RP) appears to benefit primarily younger men (aged <65 years) with intermediate-grade disease. Too few men with low-grade disease benefit from RP to justify intervening in all. Unfortunately, high-grade prostate cancer often progresses despite surgery and radiation.

CONCLUSION

The primary PSA testing paradigm is wrong. Rather than attempting to identify all prostate cancers as early as possible, testing objectives should shift towards identifying men likely to harbour clinically significant disease. These are the men who appear to benefit from early diagnosis and intervention, including the earlier use of antiandrogen therapy prior to widespread metastases.

Incorporating biological modeling into patient‐specific plan verification

Purpose

Dose–volume histogram (DVH) measurements have been integrated into commercially available quality assurance systems to provide a metric for evaluating accuracy of delivery in addition to gamma analysis. We hypothesize that tumor control probability and normal tissue complication probability calculations can provide additional insight beyond conventional dose delivery verification methods.

Methods

A commercial quality assurance system was used to generate DVHs of treatment plan using the planning CT images and patient‐specific QA measurements on a phantom. Biological modeling was performed on the DVHs produced by both the treatment planning system and the quality assurance system.

Results

The complication‐free tumor control probability, P₊, has been calculated for previously treated intensity modulated radiotherapy (IMRT) patients with diseases in the following sites: brain (−3.9% ± 5.8%), head‐neck (+4.8% ± 8.5%), lung (+7.8% ± 1.3%), pelvis (+7.1% ± 12.1%), and prostate (+0.5% ± 3.6%).

Conclusion

Dose measurements on a phantom can be used for pretreatment estimation of tumor control and normal tissue complication probabilities. Results in this study show how biological modeling can be used to provide additional insight about accuracy of delivery during pretreatment verification.

A retrospective analysis after low-dose-rate prostate brachytherapy with permanent 125I seed implant: clinical and dosimetric results in 70 patients

Aims and background

To evaluate the biochemical disease-free survival (bDFS) rate after 125I permanent-implant prostate brachytherapy.

Methods

Patients with a diagnosis of prostate adenocarcinoma and adequate PSA follow-up were selected for this retrospective study. Brachytherapy with permanent 125I seeds was performed as monotherapy, with a prescribed dose of 145 Gy to the prostate. Patients were stratified into recurrence risk groups according to the National Comprehensive Cancer Network (NCCN) guidelines. Biochemical failure was defined using the American Society of Therapeutic Radiology and Oncology (ASTRO) guidelines. The post-implant D90 (defined as the minimum dose covering 90% of the prostate) was obtained for each patient. Two cutoff points were used to test the correlation between D90 and bDFS results: 130 Gy and 140 Gy. bDFS was calculated from the implant date to the date of biochemical recurrence. Univariate and multivariate analysis were performed using the SPSS software and included clinical stage, pretreatment PSA, Gleason score (GS), androgen deprivation therapy, D90, and risk groups. In the univariate analysis we used a cutoff point of 5.89 ng/mL for PSA and 5 for GS.

Results

From June 2003 to April 2007, 70 patients were analyzed. The patients' distribution into recurrence risk groups was as follows: 39 patients (56%) in the low-risk group, 23 patients (33%) in the intermediate-risk group, and 8 patients (11%) in the high-risk group. At a median follow-up of 47 months (range, 19–70 months) bDFS was 88.4%, with a global actuarial 5-year bDFS of 86%. Disease-related factors including initial PSA level, GS and risk group were significant predictors of biochemical failure (P = 0.01, P = 0.01, P = 0.006, respectively). In multivariate analysis, risk group (P = 0.005) and GS (P = 0.03) were statistically significant.

Conclusion

Our data are in agreement with those in the literature and, despite the short follow-up, confirm the advantage of brachytherapy for patients at low and intermediate risk of recurrence.

The evolution of brachytherapy for prostate cancer

Brachytherapy (BT), using low-dose-rate (LDR) permanent seed implantation or high-dose-rate (HDR) temporary source implantation, is an acceptable treatment option for select patients with prostate cancer of any risk group. The benefits of HDR-BT over LDR-BT include the ability to use the same source for other cancers, lower operator dependence, and - typically - fewer acute irritative symptoms. By contrast, the benefits of LDR-BT include more favourable scheduling logistics, lower initial capital equipment costs, no need for a shielded room, completion in a single implant, and more robust data from clinical trials. Prospective reports comparing HDR-BT and LDR-BT to each other or to other treatment options (such as external beam radiotherapy (EBRT) or surgery) suggest similar outcomes. The 5-year freedom from biochemical failure rates for patients with low-risk, intermediate-risk, and high-risk disease are >85%, 69-97%, and 63-80%, respectively. Brachytherapy with EBRT (versus brachytherapy alone) is an appropriate approach in select patients with intermediate-risk and high-risk disease. The 10-year rates of overall survival, distant metastasis, and cancer-specific mortality are >85%, <10%, and <5%, respectively. Grade 3-4 toxicities associated with HDR-BT and LDR-BT are rare, at <4% in most series, and quality of life is improved in patients who receive brachytherapy compared with those who undergo surgery.

Prostate deformation from inflatable rectal probe cover and dosimetric effects in prostate seed implant brachytherapy

PURPOSE

Prostate brachytherapy is an important treatment technique for patients with localized prostate cancer. An inflatable rectal ultrasound probe cover is frequently utilized during the procedure to adjust for unfavorable prostate position relative to the implant grid. However, the inflated cover causes prostate deformation, which is not accounted for during dosimetric planning. Most of the therapeutic dose is delivered after the procedure when the prostate and surrounding organs-at-risk are less deformed. The aim of this study is to quantify the potential dosimetry changes between the initial plan (prostate deformed) and the more realistic dosimetry when the prostate is less deformed without the cover.

METHODS

The authors prospectively collected the ultrasound images of the prostate immediately preceding and just after inflation of the rectal probe cover from thirty-four consecutive patients undergoing real-time planning of I-125 permanent seed implant. Manual segmentations of the deformed and undeformed images from each case were used as the input for model training to generate the initial transformation of a testing patient. During registration, the pixel-to-pixel transformation was further optimized to maximize the mutual information between the transferred deformed image and the undeformed images. The accuracy of image registration was evaluated by comparing the displacement of the urethra and calcification landmarks and by determining the Dice index between the registered and manual prostate contours. After registration, using the optimized transformation, the implanted seeds were mapped from the deformed prostate onto the undeformed prostate. The dose distribution of the undeformed anatomy, calculated using the VariSeed treatment planning system, was then analyzed and compared with that of the deformed prostate.

RESULTS

The accuracy of image registration was 1.5 ± 1.0 mm when evaluated by the displacement of calcification landmarks, 1.9 ± 1.1 mm when characterized by the displacement of the centroid of the urethra, and 0.86 ± 0.05 from the determination of the Dice index of prostate contours. The magnitude of dosimetric changes was associated with the degree of prostate deformation. The prostate coverage V100% dropped from 96.6 ± 1.7% on prostate-deformed plans to 92.6 ± 3.8% (p < 0.01) on undeformed plans, and the rectum V100% decreased from 0.48 ± 0.39 to 0.06 ± 0.14 cm³ (p < 0.01). The dose to the urethra increased, with the V150% increasing from 0.02 ± 0.06 to 0.11 ± 0.10 cm³ (p < 0.01) and D1% changing from 203.5 ± 22.7 to 239.5 ± 25.6 Gy (p < 0.01).

CONCLUSIONS

Prostate deformation from the inflation of an ultrasound rectal probe cover can significantly alter brachytherapy dosimetry. The authors have developed a deformable image registration method that allows for the characterization of dose with the undeformed anatomy. This may be used to more accurately reflect the dosimetry when the prostate is not deformed by the probe cover.

Bladder neck contracture

Bladder neck contracture (BNC) is a well-described complication of the surgical treatment of benign and malignant prostate conditions. Nevertheless, etiologies of BNC development are highly dependent on the primary treatment modality undertaken with BNC also occurring after pelvic radiation. The treatment options for BNC can range from simple, office-based dilation procedures to more invasive, complex abdomino-perineal reconstructive surgery. Although numerous strategies have been described, a patient-specific approach is usually necessary in the management of these complex patients. In this review, we highlight various therapeutic maneuvers described for the management of BNC and further delineate a tailored approach utilized at our institution in these complicated patients.

Comparing CTVs for permanent prostate brachytherapy

BACKGROUND AND PURPOSE

To delineate the clinical target volume (CTV) in low dose rate (LDR) brachytherapy for prostate cancer, American Brachytherapy Society (ABS) recommends a CTV = prostate. ESTRO advocates a CTV = prostate + 3 mm excluding rectum and many authors use and recommend other different CTVs. This study aims to: (1) evaluate the appropriateness of these recommendations and (2) test the applicability of seed distributions on the different CTVs and contrast the dosimetric differences.

MATERIALS AND METHODS

Ninety-eight patients treated with (125)I seeds (dose 145 Gy; CTV = prostate) were studied. We established for every patient: (1) risk of extraprostatic extension (EPE), (2) adequacy of original plan to an extended CTV with 3 mm-margin (3) a new planning and seed distribution for this CTV and (4) comparison of dosimetry of both plans.

RESULTS

Mean risk of EPE was 28.46 %. Original plan, when applied to the extended CTV, resulted in unsatisfactory dosimetry. A plan was generated for the 98 extended CTVs meeting all dosimetric specifications.

CONCLUSIONS

The risk of EPE is high enough to consider a 3 mm-margin around prostate necessary for all cases. A CTV = prostate + 3 mm except rectum as ESTRO recommends is feasible and would adjust planning to the most probable extension of the tumor.

Do theoretical potential and advanced technology justify the use of high-dose rate brachytherapy as monotherapy for prostate cancer?

Low-dose rate brachytherapy (LDR-BT), involving implantation of radioactive seeds into the prostate, is an established monotherapy for most low-risk and select intermediate- and high-risk prostate cancer patients. High-dose rate brachytherapy (HDR-BT) is an advanced technology theorized to be more advantageous than LDR-BT from a radiobiological and radiophysics perspective, to the patient himself, and in terms of resource allocation. Studies of HDR-BT monotherapy have encouraging results in terms of biochemical control, patient survival, treatment toxicity and erectile preservation. However, there are still certain limitations that preclude recommending HDR-BT monotherapy for prostate cancer outside the setting of a clinical trial. HDR-BT monotherapy should be considered experimental at present.

Long-term tumor control after brachytherapy for base-of-prostate cancer

PURPOSE

To evaluate the outcomes of patients presenting with cancer at the base of the prostate after brachytherapy as monotherapy.

MATERIAL AND METHODS

We retrospectively reviewed the medical records of all patients who had undergone transperineal ultrasound-guided implantation with (125)I or (103)Pd seeds as monotherapy between March 1998 and December 2006, at our institution. A minimum follow-up interval of 2 years was required for inclusion in our analysis. Dosimetry was assessed using computed tomography 30 days after the implant. Treatment failure was defined as the appearance of biopsy-proved tumor after seed implantation, radiographic evidence of metastases, receipt of salvage therapy, or elevation of the prostate-specific antigen level beyond the nadir value plus 2 ng/mL.

RESULTS

With a median follow-up interval of 89 months (range 25-128 months), all 52 of the identified patients had no evidence of disease progression or biochemical failure. The mean number of cores sampled at the prostate base was 2.84 (median 2); Gleason scores assigned at central review were 6-8 in all patients. Of the 30 patients (58%) for whom dosimetric data were available at day 30, the median V100 values of the right and left base were 92.0% and 93.5%, respectively, and the median D90 values of the right and left base were 148 Gy and 151 Gy, respectively.

CONCLUSION

Permanent prostate brachytherapy as monotherapy results in a high probability of disease-free survival for men with cancer at the base of the prostate.

The impact of prostate edema on cell survival and tumor control after permanent interstitial brachytherapy for early stage prostate cancers

Previous studies have shown that procedure-induced prostate edema during permanent interstitial brachytherapy (PIB) can cause significant variations in the dose delivered to the prostate gland. Because the clinical impact of edema-induced dose variations strongly depends on the magnitude of the edema, the temporal pattern of its resolution and its interplay with the decay of radioactivity and the underlying biological processes of tumor cells (such as tumor potential doubling time), we investigated the impact of edema-induced dose variations on the tumor cell survival and tumor control probability after PIB with the (131)Cs, (125)I and (103)Pd sources used in current clinical practice. The exponential edema resolution model reported by Waterman et al (1998 Int. J. Radiat. Oncol. Biol. Phys. 41 1069-77) was used to characterize the edema evolutions previously observed during clinical PIB for prostate cancer. The concept of biologically effective dose, taking into account tumor cell proliferation and sublethal damage repair during dose delivery, was used to characterize the effects of prostate edema on cell survival and tumor control probability. Our calculation indicated that prostate edema, if not appropriately taken into account, can increase the cell survival and decrease the probability of local control of PIB. The magnitude of an edema-induced increase in cell survival increased with increasing edema severity, decreasing half-life of radioactive decay and decreasing photon energy emitted by the source. At the doses currently prescribed for PIB and for prostate cancer cells characterized by nominal radiobiology parameters recommended by AAPM TG-137, PIB using (125)I sources was less affected by edema than PIB using (131)Cs or (103)Pd sources due to the long radioactive decay half-life of (125)I. The effect of edema on PIB using (131)Cs or (103)Pd was similar. The effect of edema on (103)Pd PIB was slightly greater, even though the decay half-life of (103)Pd (17 days) is longer than that of (131)Cs (9.7 days), because the advantage of the longer (103)Pd decay half-life was negated by the lower effective energy of the photons it emits (∼21 keV compared to ∼30.4 keV for (131)Cs). In addition, the impact of edema could be reduced or enhanced by differences in the tumor characteristics (e.g. potential tumor doubling time or the α/β ratio), and the effect of these factors varied for the different radioactive sources. There is a clear need to consider the effects of prostate edema during the planning and evaluation of permanent interstitial brachytherapy treatments for prostate cancer.

Whitmore, Henschke, and Hilaris: The reorientation of prostate brachytherapy (1970-1987)

PURPOSE

Urologists had performed prostate brachytherapy for decades before New York's Memorial Hospital retropubic program. This paper explores the contribution of Willet Whitmore, Ulrich Henschke, Basil Hilaris, and Memorial's physicists to the evolution of the procedure.

METHODS AND MATERIALS

Literature review and interviews with program participants.

RESULTS

More than 1000 retropubic implants were performed at Memorial between 1970 and 1987. Unlike previous efforts, Memorial's program benefited from the participation of three disciplines in its conception and execution.

CONCLUSIONS

Memorial's retropubic program was a collaboration of urologists, radiation therapists, and physicists. Their approach focused greater attention on dosimetry and radiation safety, and served as a template for subsequent prostate brachytherapy programs.

A systematic evaluation of the dose-rate constant determined by photon spectrometry for 21 different models of low-energy photon-emitting brachytherapy sources

The aim of this study was to perform a systematic comparison of the dose-rate constant (Λ) determined by the photon spectrometry technique (PST) with the consensus value ((CON)Λ) recommended by the American Association of Physicists in Medicine (AAPM) for 21 low-energy photon-emitting interstitial brachytherapy sources. A total of 63 interstitial brachytherapy sources (21 different models with 3 sources per model) containing either (125)I (14 models), (103)Pd (6 models) or (131)Cs (1 model) were included in this study. A PST described by Chen and Nath (2007 Med. Phys. 34 1412-30) was used to determine the dose-rate constant ((PST)Λ) for each source model. Source-dependent variations in (PST)Λ were analyzed systematically against the spectral characteristics of the emitted photons and the consensus values recommended by the AAPM brachytherapy subcommittee. The values of (PST)Λ for the encapsulated sources of (103)Pd, (125)I and (131)Cs varied from 0.661 to 0.678 cGyh(-1) U(-1), 0.959 to 1.024 cGyh(-1)U(-1) and 1.066 to 1.073 cGyh(-1)U(-1), respectively. The relative variation in (PST)Λ among the six (103)Pd source models, caused by variations in photon attenuation and in spatial distributions of radioactivity among the source models, was less than 3%. Greater variations in (PST)Λ were observed among the 14 (125)I source models; the maximum relative difference was over 6%. These variations were caused primarily by the presence of silver in some (125)I source models and, to a lesser degree, by the variations in photon attenuation and in spatial distribution of radioactivity among the source models. The presence of silver generates additional fluorescent x-rays with lower photon energies which caused the (PST)Λ value to vary from 0.959 to 1.019 cGyh(-1)U(-1) depending on the amount of silver used by a given source model. For those (125)I sources that contain no silver, their (PST)Λ was less variable and had values within 1% of 1.024 cGyh(-1)U(-1). For the 16 source models that currently have an AAPM recommended (CON)Λ value, the agreement between (PST)Λ and (CON)Λ was less than 2% for 15 models and was 2.6% for 1 (103)Pd source model. Excellent agreement between (PST)Λ and (CON)Λ was observed for all source models that currently have an AAPM recommended consensus dose-rate constant value. These results demonstrate that the PST is an accurate and robust technique for the determination of the dose-rate constant for low-energy brachytherapy sources.

Technology Insight: Combined external-beam radiation therapy and brachytherapy in the management of prostate cancer

External-beam radiation therapy (EBRT) combined with brachytherapy is an attractive treatment option for selected patients with clinically localized prostate cancer. This therapeutic strategy offers dosimetric coverage if local-regional microscopic disease is present and provides a highly conformal boost of radiation to the prostate and immediate surrounding tissues. Either low-dose-rate (LDR) permanent brachytherapy or high-dose-rate (HDR) temporary brachytherapy can be combined with EBRT; such combined-modality therapy (CMT) is typically used to treat patients with intermediate-risk to high-risk, clinically localized disease. Controversy persists with regard to indications for CMT, choice of LDR or HDR boost, isotope selection for LDR, and integration of EBRT and brachytherapy. Initial findings from prospective, multicenter trials of CMT support the feasibility of this strategy. Updated results from these trials as well as those of ongoing and new phase III trials should help to define the role of CMT in the management of prostate cancer. In the meantime, long-term expectations for outcomes of CMT are based largely on the experience of single institutions, which demonstrate that CMT with EBRT and either LDR or HDR brachytherapy can provide freedom from disease recurrence with acceptable toxicity.

Comparison of two treatment approaches for prostate cancer: intensity-modulated radiation therapy combined with 125I seed-implant brachytherapy or 125I seed-implant brachytherapy alone

The purpose of the present study was to assess the results of two different treatment approaches for clinically localized prostate cancer: intensity‐modulated radiation therapy (IMRT) followed by I125 seed‐implant brachytherapy and I125 seed‐implant brachytherapy alone. We studied our 30 most recent consecutive patients. The sample population consisted of 15 cases treated with IMRT (50.4 Gy) followed by I125 seed‐implant boost (95 Gy), and 15 cases treated with I125 seed implant only (144 Gy). We analyzed established dosimetric indices and various clinical parameters. In addition, we also evaluated and compared the acute urinary morbidities of the two treatment approaches, as assessed by the international prostate symptom score (IPSS). In our series, acute urinary morbidity was slightly increased with IMRT followed by I125 seed‐implant brachytherapy as compared with I125 seed‐implant brachytherapy alone. In addition, we observed no statistically significant correlation between the IPSS and the maximum or mean urethral dose. The combination of IMRT and seed‐implant brachytherapy presents an alternative opportunity to treat clinically localized prostate cancer. The full potential of the procedure needs to be further investigated.

PACS number: 87.53.Tf

Permanent prostate seed brachytherapy: a current perspective on the evolution of the technique and its application

This Review highlights current areas of controversy and development in the field of transperineal permanent prostate seed implantation brachytherapy (PPI), in particular the technological evolution of PPI treatment planning that has led to intra-operative treatment planning and execution, the use of MRI spectroscopy and ultrasonography to target intraprostatic tumor foci, and the introduction of (131)Cs as a new PPI isotope. Here we present a comprehensive review of mature data for PPI monotherapy and PPI combined with supplemental external beam radiation therapy, and a critical discussion of issues pertinent to supplemental EBRT. We also present our current policies in the treatment of prostate cancer at the University of California, San Francisco.

On the need to compensate for edema-induced dose reductions in preplanned (131)Cs prostate brachytherapy

PURPOSE

Surgical trauma-induced edema and its protracted resolution can lead to significant dose reductions in preplanned (131)Cs prostate brachytherapy. The purpose of this work was to examine whether these dose reductions should be actively compensated for and to estimate the magnitude of the additional irradiation needed for dose compensation.

METHODS AND MATERIALS

The quantitative edema resolution characteristics observed by Waterman et al. were used to examine the physical and radiobiologic effects of prostate edema in preplanned (131)Cs implants. The need for dose compensation was assessed using the dose responses observed in (125)I and (103)Pd prostate implants. The biologically effective dose, calculated with full consideration of edema evolution, was used to estimate the additional irradiation needed for dose compensation.

RESULTS

We found that the edema-induced dose reduction in preplanned (131)Cs implants could easily exceed 10% of the prescription dose for implants with moderate or large edema. These dose reductions could lead to a >10% reduction in the biochemical recurrence-free survival for individual patients if the effect of edema was ignored. For a prescribed dose of 120 Gy, the number of 2-Gy external beam fractions needed to compensate for a 5%, 10%, 15%, 20%, and 25% edema-induced dose reduction would be one, four, six, seven, and nine, respectively, for prostate cancer with a median potential doubling time of 42 days. The required additional irradiation increased for fast-growing tumors and/or those less efficient in sublethal damage repair.

CONCLUSION

Compensation of edema-induced dose reductions in preplanned (131)Cs prostate brachytherapy should be actively considered for those implants with moderate or large edema.

Techniques, indications et résultats de la curiethérapie interstitielle par implants permanents dans le cancer localisé de la prostate

Permanent seed brachytherapy as a monotherapy is an appropriate treatment in patients with low risk localized prostate cancer such as intraprostatic cancer, T1-2 stage, PSA less than 10 ng/mL, low tumour volume, well differentiated cancer (Gleason score less than 7), gland size less than 50 mL, no micturition symptoms that could decompensate after implantation. A brachytherapy program needs a specialized multidisciplinary team with the collaboration of urologists, radiotherapists (authorized person to manipulate radioactive elements), and physicists. The 10-year oncologic and morbidity results have been published in the literature and are comparable to those of other standard treatments of localized prostate cancer such as radical prostatectomy and external beam radiation therapy.

The emergence of advanced brachytherapy techniques for common malignancies

The recent advent and integration of sophisticated radiation planning and imaging modalities has improved the quality of brachytherapy treatments, allowing for more conformal radiation delivery. Further investigation and follow-up are necessary to demonstrate improvements in outcome and morbidity with these refined approaches.

Brachytherapy in localized prostatic cancer: 100 years of radium

Contemporary series of brachytherapy in localized prostate cancer show promising early results attributable to improved patient selection and technical refinements in treatment modalities. These innovations consist essentially of precise three-dimensional radioactive dose-distribution planning and source placement, thus solving the problem of possible under-dosage encountered in open brachytherapy.

Permanent prostate brachytherapy: a century of technical evolution

PURPOSE

To summarise the practical aspects of the development of techniques of interstitial permanent prostate brachytherapy (PPB) implantation. Prostate brachytherapy dates back to Pasteau's publication in 1913 describing the insertion of a radium capsule into the prostatic urethra to treat carcinoma of the prostate. Various implantation methods were employed but with unsatisfactory results until the development of the transrectal ultrasound in the 1980s. The subsequent two-stage Seattle technique allowed for a planned homogenous distribution of radioactive sources throughout the gland resulting in biochemical control comparable to surgical and external beam radiotherapy series. With the advent of advanced computer software and improved imaging, the technique has developed accordingly to a single stage procedure with on-table dosimetric assessment. The principles of targeting dose to the prostate while avoiding surrounding organs at risk remain as relevant today as nearly a century ago. There is an array of techniques to consider for the novice PPB provider. Whether the evolution of PPB techniques will translate into improved biochemical control is yet to be seen.

Update on brachytherapy in localized prostate cancer: the importance of dosimetry

PURPOSE OF REVIEW

Prostate brachytherapy has become a common treatment modality for clinical localized adenocarcinoma of the prostate. This is the result of prostate screening and improved technology that currently allows for an outpatient procedure that generally can be accomplished in 1-2 h. The modern technique of prostate brachytherapy includes three components, (1) treatment planning, (2) placement of the sources and (3) an evaluation of the implant quality. In this review, we will focus on the importance of dosimetric quantifiers in predicting freedom from biochemical recurrence.

RECENT FINDINGS

A number of dosimetric quantifiers have been described. These include D90 (dose that covers 90% of the prostate volume) and V100 (fractional volume of the prostate that receives 100% of the prescription dose). The data from four recently reported series are reviewed. Each series looks at various dosimetric cutpoints that predict for freedom from biochemical recurrence making a definitive statement difficult. All series observe a relationship between freedom from biochemical recurrence and one or both of these dosimetric quantifiers.

SUMMARY

It is clear that a dose-response relationship exists following treatment with prostate brachytherapy; in other words, dosimetry matters and poor dosimetry will result in fewer men being cured. The lack of consistency in the reports to date precludes any definitive statements about what constitutes a "good" compared with a "bad" implant. Further prospective data from multi-center trials are required.

Radiation safety aspects of brachytherapy for prostate cancer using permanently implanted sources. A report of ICRP Publication 98

The use of permanent radioactive implants (125I or 103Pd seeds) to treat selected localised prostate cancer patients has been increasing rapidly all over the world for the last 15 years. It is estimated that more than 50,000 patients are treated this way every year in the world, and this number is anticipated to increase in the near future. Although no accidents or adverse effects involving medical staff and/or members of the patient's family have been reported to date, this brachytherapy technique raises a number of radiation safety issues that need specific recommendations from the ICRP. All data concerning the dose received by people approaching patients after implantation have been reviewed. Those doses have been either been measured directly or calculated. The available data show that, in the vast majority of cases, the dose to comforters and carers remains well below the recommended limit of 1 mSv/year. Only the (rare) case where the patient's partner is pregnant at the time of implantation may need specific precautions. Expulsion of sources through urine, semen, or the gastro-intestinal tract is rare. Specific recommendations should be given to patients to allow them to deal adequately with this event. Of note, due to the low activity of an isolated seed and its low photon energy, no incident/accident linked to seed loss has ever been recorded. When performed in the first few months after implantation, cremation of bodies (frequent in some countries) raises several issues related to: (1) the activity that remains in the patient's ashes; and (2) the airborne dose, potentially inhaled by crematorium staff or members of the public. Review of available data shows that cremation can be allowed if 12 months have elapsed since implantation with 125I (3 months for 103Pd). If the patient dies before this delay has elapsed, specific measures must be undertaken. Specific recommendations have to be given to the patient to warn his surgeon in case of subsequent pelvic or abdominal surgery. A 'wallet card' with all relevant information about the implant is useful. In most cases, brachytherapy does make the patient infertile. However, although the therapy-related modifications of the semen reduce fertility, patients must be aware of the possibility of fathering children after such a permanent implantation, with a limited risk of genetic effects for the child. Patients with permanent implants must be aware of the possibility of triggering certain types of security radiation monitors. The 'wallet card' including the main information about the implant (see above) may prove to be helpful in such a case. Considering the available experience after brachytherapy and external irradiation of prostate cancer, the risk of radio-induced secondary tumours appears to be extremely low. The demonstrated benefit of brachytherapy clearly outweighs, by far, the very limited (mainly theoretical)increase in the radiation-induced cancer risk.

Interstitial brachytherapy dosimetry update

In March 2004, the American Association of Physicists in Medicine (AAPM) published an update to the AAPM Task Group No. 43 Report (TG-43) which was initially published in 1995. This update was pursued primarily due to the marked increase in permanent implantation of low-energy photon-emitting brachytherapy sources in the United States over the past decade, and clinical rationale for the need of accurate dosimetry in the implementation of interstitial brachytherapy. Additionally, there were substantial improvements in the brachytherapy dosimetry formalism, accuracy of related parameters and methods for determining these parameters. With salient background, these improvements are discussed in the context of radiation dosimetry. As an example, the impact of this update on the administered dose is assessed for the model 200 (103)Pd brachytherapy source.

The efficacy of conventional external beam, three-dimensional conformal, intensity-modulated, particle beam radiation, and brachytherapy for localized prostate cancer

Technologic advances in radiation treatment planning and delivery have generated popular interest in the different radiation therapy techniques used in treating patients with localized prostate cancer. Throughout the past decade, high-energy (> 4 MV) linear accelerators have largely replaced Cobalt machines in external beam radiation therapy (EBRT) delivery. Conventional EBRT has been used to treat prostate cancer successfully since the 1950s. By switching to computed tomography-based planning, three-dimensional conformal radiation therapy provides better relative conformality of dose than does conventional EBRT. Intensity-modulated radiation therapy (IMRT) has further refined dose conformality by spreading the low-dose region to a larger volume. However, the potential long-term risks of larger volumes of normal tissues receiving low doses of radiation in IMRT are unknown. Particle-beam radiation therapy offers unique dose distributions and characteristics with higher relative biologic effect and linear energy transfer. Transperineal prostate brachytherapy offers the shortest treatment time with equivalent efficacy without significant risk of radiation exposure. The addition of hormonal therapy to radiation therapy has been shown to improve the outcome of radiation therapy.

Intermediate term biochemical-free progression and local control following 125iodine brachytherapy for prostate cancer

PURPOSE

We determined the 10-year biochemical and local control results for I prostate brachytherapy in men followed a minimum of 4 years.

MATERIALS AND METHODS

A total of 279 men with T1-T2 prostate cancer with a minimum followup of 4 years were implanted with I from 1990 to 1998 using the real-time technique. Patients were treated with the implant alone (215 or 72.5%) or with the implant and 6 months of hormone therapy (64 or 27.6%). Of the men 185 (66.3%) agreed to ultrasound guided biopsy (6 to 12 cores) a minimum of 2 years after implantation. All patients with increasing prostate specific antigen (PSA), evidence of local recurrence or a prior positive biopsy underwent repeat biopsy yearly until biopsy became negative or there was clear evidence of biochemical (PSA) progression. The radiation dose delivered to 90% of the gland (D90) was determined 30 days after implantation by computerized tomography based dosimetry. Biochemical failure was defined as 3 consecutive PSA increases. Survival curves were calculated by the Kaplan-Meier method. Cross tabulations were tested by Pearson chi-square analysis. The effect of multiple variables was tested by the log rank test (Cox regression).

RESULTS

Median patient age was 67 years (range 42 to 82) and median followup was 6 years (range 4 to 12). Of the patients 49 (17.6%) experienced failure, for a 10-year freedom from failure (FFF) rate of 78%. Univariate analysis for 10-year FFF demonstrated that initial PSA (p = 0.001), stage (p = 0.002), risk group (p <0.001), hormone therapy (p = 0.013) and D90 (p <0.001) were significant. Multivariate analysis demonstrated that D90 (p <0.001) and risk group (p = 0.013) were the only significant variables. The RR of PSA failure was 3.0 (95% CI 2.0 to 4.4, p <0.001) and 5.6 (95% CI 3.1 to 10, p <0.001) for doses below 140 and 120 Gy, respectively. Of the 185 patients 166 (90%) had a negative post-implantation prostate biopsy. FFF was 85% vs 21% in those with a positive biopsy (p <0.001). Patients with a D90 of at least 140 Gy had a positive biopsy rate of 4.8% compared to 20.5% in those with a lower dose (p <0.001). The RR for positive biopsy at doses less than 140 and 120 Gy was 2.6 (95% CI 1.6 to 4.4, p = 0.002) and 4.3 (95% CI 2.3 to 8.1, p <0.001), respectively.

CONCLUSIONS

These data demonstrate high biochemical and local control in men with T1-T2 prostate cancer treated with I brachytherapy. The delivered radiation dose and risk category are important predictors of success. Patients receiving a dose of at least 140 Gy have a 90% chance of biochemical FFF and a 95.2% likelihood of local control.

Image guided I125 prostate brachytherapy with Hybrid Interactive Mick technique in the community setting: How does it compare?

The aim of this study is to evaluate the target coverage, procedural techniques, and merits of Hybrid Interactive Mick (HIM) I125 transperineal permanent implantation (TPPI) of the prostate performed with 10 urologists in a community hospital. Detailed day 0 post-implant dosimetric evaluations of TPPI procedures were performed on 333 consecutive monotherapy patients treated between September 2000 and November 2003 at a single institution. All patients underwent TPPI with HIM. Pelvic and CXR films were obtained for a manual seed count at day 0 and again > day 90 on 175 patients. The HIM-prostate brachytherapy performed in a community hospital provided median D(90), V100, and V150 values of 157Gy, 94%, and 42.3%, respectively. 18% of patients had seed migration to the lungs while 2% had seed migration to the bladder. Only 7 patients (4%) had 2 or more seeds migrate to the lungs. Procedure times average 38 minutes and number of needles used averaged 18. The post-implant urinary retention rate was 2.1% Use of HIM-prostate brachytherapy in the community setting with multiple urologists reproducibly maintained excellent and consistent dosimetric coverage. Procedure times and number of needles used were minimized, and with careful attention to image-guided technique, seed migration to bladder and lung was also minimized.

Iodine seed prostate brachytherapy: an alternative first-line choice for early prostate cancer

This article on permanent iodine-125 seed prostate brachytherapy reviews the techniques, results, and patient selection issues for early prostate cancer. The long-term 10 y results of brachytherapy from Seattle, and their reproducibility in other centres both in the USA and UK are reported. The use of hormone therapy in brachytherapy and the value of combining external beam radiotherapy with a brachytherapy implant are discussed. Reviewed comparative data show the similarity of biochemical survival in patients treated with brachytherapy, radical prostatectomy, and external beam radiotherapy. The role of brachytherapy as a first-line treatment option for patients with prostate cancer is demonstrated.

Three-dimensional conformal brachytherapy for prostate cancer

Because innovations in radiation treatment planning have dramatically improved the precision of external beam radiotherapy for prostate cancer with the advent of conformal three-dimensional conformal therapy and intensity modulated radiotherapy, similar developments are emerging for prostate brachytherapy. Computer software programs are facilitating the ability to rapidly create conformal treatment plans in the operating room, taking into account the three-dimensional reconstruction of the prostate target and adhering to dose-volume constraints of the normal tissues including the urethra and rectum. Although excellent dose distributions can be achieved with pre-planning techniques, intraoperative planning takes into account the intraoperative geometry of the prostate and the surrounding normal tissues and can consistently produce seed implants with reduced urethral and rectal doses while delivering the intended prescription dose to the target volume. Current developments are pursuing methods to dynamically modify the treatment plan as the implant procedure is ongoing based on the coordinates of the deposited seeds. Such approaches will minimize the possibility of tumor underdosage and further enhance the conformality of prostate brachytherapy.

Measurement of the ultrasound backscatter signal from three seed types as a function of incidence angle: application to permanent prostate brachytherapy

PURPOSE

To measure the relative ultrasound backscatter of different seed types as a function of seed orientation and to evaluate the corresponding images of these seeds.

METHODS AND MATERIALS

Three seed types were evaluated: OncoSeed (standard), EchoSeed (corrugated), and RAPID Strand(RS). Ultrasound images for angles of incidence varying from 90 degrees (perpendicular) to 20 degrees at 5MHz and 7.5MHz were produced by raster scanning the seeds in a degassed water bath. Seed images were visually inspected and analyzed using the integrated-optical-density (IOD) method.

RESULTS

Corrugated seeds appear as contiguous objects over the range of frequencies and orientations examined, whereas standard seeds appear as contiguous objects from 90 degrees to 80 degrees only. The ranges and means of the backscattered IOD ratio of the seeds from 85 degrees to 20 degrees were: (corrugated vs. standard) 1.48 to 3.72 (2.32 +/- 0.62) for 5 MHz and 1.26 to 3.77 (2.19 +/- 0.84) for 7.5 MHz and (corrugated vs. RS) 1.21 to 9.53 (2.98 +/- 2.48) for 5 MHz and 1.008 to 10.86 (2.79 +/- 3.08) for 7.5 MHz. Backscattered signal increase ranged from 1.66 dB to 20.7 dB for the corrugated seed as compared to the other seeds.

CONCLUSIONS

Corrugated seeds produce greater backscatter signal and a more readily identifiable seed image over a large range of seed orientation as compared with standard brachytherapy seeds.