Does Local Recurrence of Prostate Cancer After Radiation Therapy Occur at the Site of Primary Tumor? Results of a Longitudinal MRI and MRSI Study

Department of Radiology and Biomedical Imaging, University of California San Francisco, California, USA.
International journal of radiation oncology, biology, physics (Impact Factor: 4.26). 02/2012; 82(5):e787-93. DOI: 10.1016/j.ijrobp.2011.11.030
Source: PubMed


To determine if local recurrence of prostate cancer after radiation therapy occurs at the same site as the primary tumor before treatment, using longitudinal magnetic resonance (MR) imaging and MR spectroscopic imaging to assess dominant tumor location.
This retrospective study was HIPAA compliant and approved by our Committee on Human Research. We identified all patients in our institutional prostate cancer database (1996 onward) who underwent endorectal MR imaging and MR spectroscopic imaging before radiotherapy for biopsy-proven prostate cancer and again at least 2 years after radiotherapy (n = 124). Two radiologists recorded the presence, location, and size of unequivocal dominant tumor on pre- and postradiotherapy scans. Recurrent tumor was considered to be at the same location as the baseline tumor if at least 50% of the tumor location overlapped. Clinical and biopsy data were collected from all patients.
Nine patients had unequivocal dominant tumor on both pre- and postradiotherapy imaging, with mean pre- and postradiotherapy dominant tumor diameters of 1.8 cm (range, 1-2.2) and 1.9 cm (range, 1.4-2.6), respectively. The median follow-up interval was 7.3 years (range, 2.7-10.8). Dominant recurrent tumor was at the same location as dominant baseline tumor in 8 of 9 patients (89%).
Local recurrence of prostate cancer after radiation usually occurs at the same site as the dominant primary tumor at baseline, suggesting supplementary focal therapy aimed at enhancing local tumor control would be a rational addition to management.

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Available from: Elnasif Arrayeh, Oct 07, 2015
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    • "CTV HR to at least 145 Gy to ensure comparable tumor control as in clinical practice. Several studies have demonstrated that local recurrence of prostate cancer after radiotherapy usually occurs at the site of the primary tumor [37] [38] [39]. Although it is not clear if a dose escalation in low-risk prostate cancer patients is necessary, given the current high local control, our study shows that focal dose escalation is possible while reducing the dose to OAR. "
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    ABSTRACT: We investigated the application of a differential target- and dose prescription concept for low-dose-rate prostate brachytherapy (LDR-BT), involving a re-distribution of dose according to risk of local failure and treatment-related morbidity. Our study included 15 patients. Multi-parametric MRI was acquired prior to LDR-BT for gross tumor volume (GTV) delineation. Trans-rectal ultrasound (US) images were acquired during LDR-BT for prostate gland- (CTVProstate) and organs at risk delineation. The GTV contour was transferred to US images after US/MRI registration. An intermediate-risk target volume (CTVProstate) and a high-risk target volume (CTVHR=GTV+5mm margin) were defined. Two virtual dose plans were made: Planrisk-adapt consisted of a de-escalated dose of minimum 125Gy to the CTVProstate and an escalated dose to 145-250Gy to the CTVHR; Planref included the standard clinical dose of minimum 145Gy to the CTVProstate. Dose-volume-histogram (DVH) parameters were expressed in equivalent 2Gy fractionation doses. The median D90% to the GTV and CTVHR significantly increased by 44Gy and 17Gy, respectively when comparing Planrisk-adapt to Planref. The median D10% and D30% to the urethra significantly decreased by 9Gy and 11Gy, respectively and for bladder neck by 18Gy and 15Gy, respectively. The median rectal D2.0cm(3) had a significant decrease of4Gy, while the median rectal D0.1cm(3) showed an increase of 1Gy. Our risk adaptive target- and dose prescription concept of prescribing a lower dose to the whole gland and an escalated dose to the GTV using LDR-BT seed planning was technically feasible and resulted in a significant dose-reduction to urethra and bladder neck. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    Radiotherapy and Oncology 06/2015; 115(3). DOI:10.1016/j.radonc.2015.05.015 · 4.36 Impact Factor
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    • "Cold areas were found to correlate with positive post-treatment biopsies [17]. While failures after primary radiotherapy and/or brachytherapy could be due to a more challenging delineation of the base and apex on planning CT or US, other studies have reported that more than 90% of patients with a proven local failure recur in an area that overlaps with the site of the primary index lesion [14] [18] [19]. The latter observations may suggest that inadequate radiation dose was delivered initially to the primary index site and thus, leading to local failures. "
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    ABSTRACT: Even in the current era of dose-escalated radiotherapy for prostate cancer, biochemical recurrence is not uncommon. Furthermore, biochemical failure is not specific to the site of recurrence. One of the major challenges in the management of prostate cancer patients with biochemical failure after radiotherapy is the early discrimination between those with locoregional recurrence only and those with metastatic disease. While the latter are generally considered incurable, patients with locoregional disease may benefit from emerging treatment options. Ultimately, the objective of salvage therapy is to control disease while ensuring minimal collateral damage, thereby optimizing both cancer and toxicity outcomes. Advances in functional imaging, including multiparametric prostate MRI, abdominopelvic lymphangio-MRI, sentinel node SPECT-CT and/or whole-body PET/CT have paved the way for salvage radiotherapy in patients with local recurrence, microscopic nodal disease limited to the pelvis or oligometastatic disease. These patients may be considered for salvage reirradiation using different techniques: prostate low-dose or high-dose rate brachytherapy, pelvic and/or lomboaortic image-guided radiotherapy with elective nodal irradiation, focal nodal or bone stereotactic body radiation therapy (SBRT). An individualized approach is recommended. The decision about which treatment, if any, to use will be based on the initial characteristics of the disease, relapse patterns and the natural history of the rising prostate specific antigen (PSA). Preliminary results suggest that more than 50% of patients who have undergone salvage reirradiation are biochemically relapse-free with very low rates of severe toxicity. Large prospective studies with a longer follow-up are needed to confirm the promising benefit/risk ratio observed with salvage brachytherapy and or salvage nodal radiotherapy and/or bone oligometastatic SBRT when compared with life-long palliative hormones.
    Cancer/Radiothérapie 09/2014; 18(5-6). DOI:10.1016/j.canrad.2014.07.153 · 1.41 Impact Factor
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    • "Intermediate T2 signal intensity at the site of the prior tumour may represent local recurrence. T2-weighted imaging alone lacks specificity and is insufficient to reliably diagnose local recurrence [36, 37, 41–43]. Multi-parametric MRI (two or more functional imaging tests) is better than T2-weighted imaging alone for the diagnosis of local recurrence [36, 37, 41–43]. "
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    ABSTRACT: Radiotherapy (RT) is an integral component in the management of many abdominal and pelvic malignancies. Imaging follow-up in patients who have received RT is performed to assess for treatment response, evaluate for tumour recurrence and to diagnose complications related to treatment. The purpose of this pictorial review is to depict the expected imaging findings and potential complications following RT in the genitourinary (GU) tract using an organ-based approach and to review the diagnosis of locally recurrent tumour in the GU tract following RT. Some GU malignancies, namely cervical and prostatic carcinoma, can be treated with radical RT with intent to cure. More frequently, the GU tract is indirectly treated as a result of RT to adjacent cancers. Expected imaging findings, RT-related complications and the diagnosis of recurrent tumour following RT in the GU tract often necessitate a multi-modality imaging approach, the incorporation of functional imaging techniques and an organ-based approach for diagnosis.
    Insights into Imaging 11/2013; 5(1). DOI:10.1007/s13244-013-0295-z
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