ABSTRACT
PURPOSE: Recent work has demonstrated the return of hormone sensitivity after palliative chemotherapy in androgen independent prostate cancer. We wished to establish whether a similar phenomenon existed in patients with no exposure to chemotherapy. MATERIALS AND METHODS: A review of "hormone resistant" patients who had received salvage brachytherapy for localized prostate cancer after previous external beam radiotherapy was undertaken. Three patients with subsequent biochemical relapse responded to the rechallenge with hormonal treatment. RESULTS: The series of patients presented here demonstrates this phenomenon occurs after salvage brachytherapy with no exposure to chemotherapy. Recovery of sensitivity is demonstrated both to androgen deprivation and to androgen receptor antagonism. The recovery of hormone sensitivity was surprisingly durable, ranging from eight months to over twenty-one months. CONCLUSIONS: Hormone sensitivity may be recovered after salvage brachytherapy. Potential mechanisms underlying these observations are discussed and the likely central role of the activity of the androgen receptor highlighted. The relevance of these findings to the management of advanced prostate cancer is considered including thoughts on the practice of intermittent anti-androgen therapy.
Subject(s)
Brachytherapy/methods , Neoplasm Recurrence, Local/radiotherapy , Prostatic Neoplasms/radiotherapy , Aged , Androgen Antagonists/adverse effects , Humans , Male , Middle Aged , Prostate-Specific Antigen/blood , Prostatic Neoplasms/drug therapy , Receptors, Androgen/physiology , Salvage TherapyABSTRACT
PURPOSE: Recent work has demonstrated the return of hormone sensitivity after palliative chemotherapy in androgen independent prostate cancer. We wished to establish whether a similar phenomenon existed in patients with no exposure to chemotherapy. MATERIALS AND METHODS: A review of hormone resistant patients who had received salvage brachytherapy for localized prostate cancer after previous external beam radiotherapy was undertaken. Three patients with subsequent biochemical relapse responded to the rechallenge with hormonal treatment. RESULTS: The series of patients presented here demonstrates this phenomenon occurs after salvage brachytherapy with no exposure to chemotherapy. Recovery of sensitivity is demonstrated both to androgen deprivation and to androgen receptor antagonism. The recovery of hormone sensitivity was surprisingly durable, ranging from eight months to over twenty-one months. CONCLUSIONS: Hormone sensitivity may be recovered after salvage brachytherapy. Potential mechanisms underlying these observations are discussed and the likely central role of the activity of the androgen receptor highlighted. The relevance of these findings to the management of advanced prostate cancer is considered including thoughts on the practice of intermittent anti-androgen therapy.
Subject(s)
Aged , Humans , Male , Middle Aged , Brachytherapy/methods , Neoplasm Recurrence, Local/radiotherapy , Prostatic Neoplasms/radiotherapy , Androgen Antagonists/adverse effects , Prostate-Specific Antigen/blood , Prostatic Neoplasms/drug therapy , Receptors, Androgen/physiology , Salvage TherapyABSTRACT
OBJECTIVE: The aim of the study was to assess the diagnostic performance of co-registered single photon emission computed tomography (SPECT)/computed tomography (CT) compared to Iodine-123 whole body gamma camera (WBGC) imaging and to SPECT alone in patients with differentiated thyroid cancer. METHODS: WBGC and SPECT/CT (n=85) imaging of the neck and thorax was performed in 79 consecutive patients. Three experienced observers reviewed: i) WBGC images followed by ii) SPECT alone, and iii) co-registered SPECT/CT. Foci of increased radioiodine uptake were classified on a five-point scale. Biopsy, other imaging modalities, and clinical follow-up served as the reference standard. RESULTS: Twenty-two patients had local recurrence or metastatic thyroid cancer (11 were radioiodine negative), 9 had remnant thyroid tissue, and 54 had no evidence of disease. When classifying equivocal, probably, and definitely malignant findings as positive for malignancy, the sensitivity, specificity, positive predictive value, and negative predictive value were as follows: 41, 68, 31, and 77% for WBGC imaging; 45, 89, 59, and 82% for WBGC plus SPECT imaging; and 50, 100, 100, and 85% for WBGC plus SPECT/CT imaging respectively. The specificity was improved by the addition of SPECT (P=0.0002) and SPECT/CT (P<0.0001) than to WBGC imaging. SPECT/CT was also more specific than WBGC plus SPECT imaging (P=0.016). In a study-based analysis, SPECT/CT provided additional diagnostic information in 42% (36/85) of cases. SPECT/CT provided further characterization in 70% (63/90) of foci and improved the diagnostic confidence of all three observers. CONCLUSION: The addition of SPECT/CT significantly improved the diagnostic information over Iodine-123 WBGC imaging and WBGC plus SPECT imaging alone.
