Single photon emission computerized tomography with capromab pendetide plus computerized tomography image set co-registration independently predicts biochemical failure

Permanent prostate brachytherapy extracapsular radiation dose distributions: analysis of a multi-institutional database

Purpose

Periprostatic brachytherapy doses impact biochemical control. In this study, we evaluate extracapsular volumetric dosimetry following permanent prostate brachytherapy in patients entered in a multi-institutional community database.

Material and methods

In the database, 4547 patients underwent brachytherapy (3094 – ¹²⁵I, 1437 – ¹⁰³Pd and 16 – ¹³¹Cs). Using the originally determined prostate volume, a 5 mm, 3-dimensional peri-prostatic anulus was constructed around the prostate (except for a 2 mm posterior margin), and evaluated in its entirety and in 90° segments. Prostate dosimetric parameters consisted of a V₁₀₀ and D₉₀ while the annular dosimetry was reported as a V₁₀₀.

Results

The intraprostatic V₁₀₀ and D₉₀ for ¹⁰³Pd, and ¹²⁵I were statistically comparable when stratified by isotope and/or monotherapy vs. boost. The overall mean V₁₀₀ for the periprostatic annulus was 62.8%. The mean V₁₀₀ at the base (51.6%) was substantially less than the apex (73.5%) and midgland (65.9%). In addition, for all patients, the anterior V₁₀₀ (45.7%) was less than the lateral (68.8%) and the posterior (75.0%). The geometric V₁₀₀ annular differences were consistent when evaluated by isotope. Overall, the V₁₀₀ was higher in the ¹²⁵I cohort.

Conclusions

The optimal extracapsular brachytherapy dose and radial extent remains unknown, but will prove increasingly important with reductions and/or elimination of supplemental external beam radiation therapy. The large multi-institutional community database demonstrates periprostatic annular doses that are not as robust as those in selected high volume brachytherapy centers, and may be inadequate for optimal biochemical control following monotherapeutic brachytherapy, especially in higher risk patients.

SPECT/CT and tumour imaging

Scintigraphic techniques are sensitive imaging modalities in the diagnosis and follow-up of cancer patients providing the functional and metabolic activity characteristics of the tumour. Hybrid SPECT/CT improves the diagnostic accuracy of these well-established imaging techniques by precise anatomical localization and characterization of morphological findings, differentiation between foci of physiological and pathological tracer uptake, resulting in a significant impact on patient management and more definitive interpretations. The use of SPECT/CT has been studied in a variety of applications in tumour imaging which are reviewed in this article. By combining functional and anatomical information in a single imaging session, SPECT/CT has become a one-stop cancer imaging modality.

Functional imaging for prostate cancer: therapeutic implications

Functional radionuclide imaging modalities, now commonly combined with anatomical imaging modalities computed tomography (CT) or magnetic resonance imaging (single photon emission computed tomography [SPECT]/CT, positron emission tomography [PET]/CT, and PET/magnetic resonance imaging), are promising tools for the management of prostate cancer, particularly for therapeutic implications. Sensitive detection capability of prostate cancer using these imaging modalities is one issue; however, the treatment of prostate cancer using the information that can be obtained from functional radionuclide imaging techniques is another challenging area. There are not many SPECT or PET radiotracers that can cover the full spectrum of the management of prostate cancer from initial detection to staging, prognosis predictor, and all the way to treatment response assessment. However, when used appropriately, the information from functional radionuclide imaging improves, and sometimes significantly changes, the whole course of the cancer management. The limitations of using SPECT and PET radiotracers with regard to therapeutic implications are not so much different from their limitations solely for the task of detecting prostate cancer; however, the specific imaging target and how this target is reliably imaged by SPECT and PET can potentially make significant impact in the treatment of prostate cancer. Finally, although the localized prostate cancer is considered manageable, there is still significant need for improvement in noninvasive imaging of metastatic prostate cancer, in treatment guidance, and in response assessment from functional imaging, including radionuclide-based techniques. In this review article, we present the rationale of using functional radionuclide imaging and the therapeutic implications for each of radionuclide imaging agent that have been studied in human subjects.

The correlation between annular treatment margins and biochemical failure in prostate brachytherapy patients with optimized intraprostatic dosimetry

PURPOSE

To determine whether periprostatic treatment margins correlate with biochemical control in prostate brachytherapy patients with optimized intraprostatic dosimetry.

METHODS AND MATERIALS

Nineteen biochemically failed brachytherapy patients were matched to 74 dosimetric and clinically equivalent nonfailures. The median followup time for the entire study population was 9.4 years. Eligibility requirements included a Day 0 intraprostatic D(90) of 100% or greater and V(100) of 90% or greater, absence of androgen deprivation therapy, and no evidence of distant metastasis in biochemically failed patients. A 5-mm annulus was constructed around the perimeter of each prostate. D(90) and V(100) at the anterior, posterior, superior, inferior, right lateral, and left lateral aspects of the annulus were evaluated for patients with biochemically controlled and failed disease. Biochemical progression-free survival (bPFS) was defined as a prostate-specific antigen level of 0.40ng/mL or less after nadir. D(90) and V(100) parameters were compared between the controlled and failed groups using logistic regression. Predictors of biochemical failure were identified using Cox regression.

RESULTS

No statistically significant differences in prostate-specific antigen level, Gleason score, percent positive biopsies, or intraprostatic dosimetry were observed between the controlled and failed patients. The D(90) and V(100) at the anterior, posterior, superior, inferior, right lateral, and left lateral aspects of the annulus were not statistically different between biochemically controlled and failed groups.

CONCLUSION

In this study, there was no relationship observed between annular dosimetry and biochemical control. It is unlikely that further radial dose intensification would have altered treatment outcome in this population of patients with optimized intraprostatic dosimetry.

Hybrid imaging (SPECT/CT and PET/CT)--improving the diagnostic accuracy of functional/metabolic and anatomic imaging

In-line combined systems, single-photon emission computed tomography (SPECT)/computed tomography (CT) and positron emission tomography (PET)/CT, allow an instant generation of fused images of scintigraphy and CT data. The accumulated clinical data on the use of these systems in various clinical scenarios indicate that this hybrid technology improves the diagnostic accuracy as compared to scintigraphy and CT alone and even to side-by-side interpretation of scintigraphy and CT, which were acquired separately. The improved diagnostic accuracy is reflected by improving image quality of SPECT and PET, detection of more clinically relevant lesions, better localization of disease and differentiation between physiologic and pathologic uptake, characterization of disease by its functional and morphologic appearance before and after therapy and accurate delineation of disease, optimizing biopsy and therapy planning.

A review on the clinical uses of SPECT/CT

In the era when positron emission tomography (PET) seems to constitute the most advanced application of nuclear medicine imaging, still the conventional procedure of single photon emission computed tomography (SPECT) is far from being obsolete, especially if combined with computed tomography (CT). In fact, this dual modality imaging technique (SPECT/CT) lends itself to a wide variety of useful diagnostic applications whose clinical impact is in most instances already well established, while the evidence is growing for newer applications. The increasing availability of new hybrid SPECT/CT devices with advanced technology offers the opportunity to shorten acquisition time and to provide accurate attenuation correction and fusion imaging. In this review we analyse and discuss the capabilities of SPECT/CT for improving sensitivity and specificity in the imaging of both oncological and non-oncological diseases. The main advantages of SPECT/CT are represented by better attenuation correction, increased specificity, and accurate depiction of the localization of disease and of possible involvement of adjacent tissues. Endocrine and neuroendocrine tumours are accurately localized and characterized by SPECT/CT, as also are solitary pulmonary nodules and lung cancers, brain tumours, lymphoma, prostate cancer, malignant and benign bone lesions, and infection. Furthermore, hybrid SPECT/CT imaging is especially suited to support the increasing applications of minimally invasive surgery, as well as to precisely define the diagnostic and prognostic profile of cardiovascular patients. Finally, the applications of SPECT/CT to other clinical disorders or malignant tumours is currently under extensive investigation, with encouraging results in terms of diagnostic accuracy.

Radiotherapy and survival in prostate cancer patients: a population-based study

PURPOSE

To investigate the association of overall and disease-specific survival with the five standard treatment modalities for prostate cancer (CaP): radical prostatectomy (RP), brachytherapy (BT), external beam radiotherapy, androgen deprivation therapy, and no treatment (NT) within 6 months after CaP diagnosis.

METHODS AND MATERIALS

The study population included 10,179 men aged 65 years and older with incident CaP diagnosed between 1999 and 2001. Using the linked Ohio Cancer Incidence Surveillance System, Medicare, and death certificate files, overall and disease-specific survival through 2005 among the five clinically accepted therapies were analyzed.

RESULTS

Disease-specific survival rates were 92.3% and 23.9% for patients with localized vs. distant disease at 7 years, respectively. Controlling for age, race, comorbidities, stage, and Gleason score, results from the Cox multiple regression models indicated that the risk of CaP-specific death was significantly reduced in patients receiving RP or BT, compared with NT. For localized disease, compared with NT, in the monotherapy cohort, RP and BT were associated with reduced hazard ratios (HR) of 0.25 and 0.45 (95% confidence intervals 0.13-0.48 and 0.23-0.87, respectively), whereas in the combination therapy cohort, HR were 0.40 (0.17-0.94) and 0.46 (0.27-0.80), respectively.

CONCLUSIONS

The present population-based study indicates that RP and BT are associated with improved survival outcomes. Further studies are warranted to improve clinical determinates in the selection of appropriate management of CaP and to improve predictive modeling for which patient subsets may benefit most from definitive therapy vs. conservative management and/or observation.