Impact of definitive radiotherapy on metabolic response measured with 68Ga-PSMA-PET/CT in patients with intermediate-risk prostate cancer.

PURPOSE: To assess the early metabolic response of the primary tumor using Gallium-68 (68Ga)-labeled-prostate-specific membrane antigen positron emission tomography (68Ga-PSMA-PET/CT), as well as the relationship between PSMA change in the primary tumor and PSA response after definitive radiotherapy (RT), either alone or in combination with androgen deprivation therapy (ADT) in intermediate risk prostate cancer (IR-PCa) patients. METHODS: The clinical data of 71 IR-PCa patients treated with RT alone (36 patients, 50.7%) or RT and ADT (35 patients, 49.3%) were retrospectively analyzed. The difference between pre- and Posttreatment primary tumor PSMA expression and serum PSA values measured 4 months after completion of treatment were compared between treatment arms. Correlation between primary tumor metabolic response and serum PSA changes was analyzed. RESULTS: The median duration between pre- and Posttreatment 68Ga-PSMA-PET/CT for the entire patient population was 6.9 months (range, 5.6-8.4 months), and it was similar in both treatment arms. A decrease in primary tumor maximum standardized uptake value (SUVmax) was seen in 66 patients (93.0%), with a median value of 61.2%, which is significantly lower in patients undergoing RT alone than those undergoing RT and ADT (45.1 ± 30.6% vs. 59.1 ± 24.7%; p = 0.004). The complete metabolic response rate was significantly higher in patients undergoing RT and ADT than those treated with RT alone (40% vs. 0%; p < 0.001). Although moderate and positive correlation between pretreatment SUVmax and oosttreatment SUVmax was observed, there was no significant correlation between SUV change and PSA change. For patients treated with RT and ADT, posttreatment SUVmax was significantly lower and SUV change was significantly higher in patients with PSA nadir than in those without. CONCLUSIONS: Our preliminary results show that RT, with or without ADT, significantly reduces primary tumor SUVmax and serum PSA levels. Nonetheless, our findings indicate that early treatment response using 68Ga-PSMA-PET/CT is not feasible for those treated with RT alone, and it may only be useful in better distinguishing patients with and without PSA nadir for those who received both RT and ADT.

The significance of metabolic response to neoadjuvant androgen deprivation therapy detected with [68Ga]Ga-PSMA-11-PET/CT in high-risk prostate cancer patients treated with definitive radiotherapy.

PURPOSE: We examined the prognostic significance of early changes in primary tumor SUV measured with Gallium-68-labeled prostate-specific membrane antigen positron emission tomography ([68Ga]Ga-PSMA-11-PET/CT) and serum PSA values after neoadjuvant androgen deprivation treatment (nADT) in high-risk prostate cancer (PCa) patients treated with definitive radiotherapy (RT). METHODS: The clinical data and SUV parameters of 71 PCa patients were reviewed retrospectively. The serum PSA and primary tumor SUV values were calculated before and after the start of ADT. Using univariable and multivariable analyses, the prognostic factors predicting biochemical disease free survival (bDFS) and prostate cancer specific survival (PCSS) were investigated. In addition, logistic regression analysis was used to identify predictors of biochemical failure (BF). RESULTS: All but one patient responded with a 98.8% reduction in serum PSA (21.8 ng/mL vs. 0.3 ng/mL; p < 0.001), and 64 patients (91.1%) had a median 66.6% decrease in primary tumor SUV after ADT (13.2 vs. 4.8, p < 0.001). The primary tumor SUV response rate was significantly higher in patients with Gleason score (GS) of 7 than in patients with GS > 7 (59.5% vs. 40.5%; p = 0.04), and it was significantly lower in patients with inadequate treatment response than in those with complete (CR) or partial response (PR) (1.1% vs. 66.1%; p < 0.001). There was a strong and significant correlation (Spearman = 0.41, p < 0.001) and a high concordance (91.5%) between PSA response and SUV response after ADT. With a median follow-up time of 76.1 months, the 5-year bDFS and PCSS rates were 77.2% and 92.2%, respectively. Nineteen patients (26.7%) patients had recurrence at a median of 44.6 months after the completion of RT. In multivariate analysis, lymph node metastasis, GS greater than 7, and SD/PD after nADT were independent predictors of worse bDFS. However, no significant factor for PCSS was identified. In the multivariable logistic regression analysis, advanced age, GS of > 7 disease, lymph node metastasis, and SD or PD after nADT were independent predictors of BF. CONCLUSION: These results imply that the metabolic response measured with [68Ga]Ga-PSMA-11-PET/CT after nADT could be used to predict progression in high-risk PCa patients treated with definitive RT.

Clinical parameters and nomograms for predicting lymph node metastasis detected with 68 Ga-PSMA-PET/CT in prostate cancer patients candidate to definitive radiotherapy.

BACKGROUND: Defining the extent of disease spread with imaging modalities is crucial for therapeutic decision-making and definition of treatment. This study aimed to investigate whether clinical parameters and nomograms predict prostate-specific membrane antigen (PSMA)-positive lymph nodes in treatment-naïve nonmetastatic prostate cancer (PC) patients. MATERIALS AND METHODS: The clinical data of 443 PC patients (83.3% high-risk and 16.7% intermediate-risk) were retrospectively analyzed. Receiver operating characteristic (ROC) curves with areas under the curve (AUC) were generated to evaluate the accuracy of clinical parameters (prostate-specific antigen [PSA], T stage, Gleason score [GS], International Society of Urological Pathology [ISUP] grade) and nomograms (Roach formula [RF], Yale formula [YF], and a new formula [NF]) in predicting lymph node metastasis. The AUCs of the various parameters and clinical nomograms were compared using ROC and precision-recall (PR) curves. RESULTS: A total of 288 lymph node metastases were identified in 121 patients (27.3%) using 68 Ga-PSMA-11-positron emission tomography (PET)/computed tomography (CT). Most PSMA-avid lymph node metastases occurred in external or internal iliac lymph nodes (142; 49.3%). Clinical T stage, PSA, GS, and ISUP grade were significantly associated with PSMA-positive lymph nodes according to univariate logistic regression analysis. The PSMA-positive lymph nodes were more frequently detected in patients with PSA >20 ng/ml, GS ≥7 or high risk disease compared to their counterparts. The clinical T stage, serum PSA level, GS, and ISUP grade showed similar accuracy in predicting PSMA-positive metastasis, with AUC values ranging from 0.675 to 0.704. The median risks for PSMA-positive lymph nodes according to the RF, YF, and NF were 31.3% (range: 12.3%-100%), 22.3% (range: 4.7%-100%), and 40.5% (range: 12.3%-100%), respectively. The AUC values generated from ROC and PR curve analyses were similar for all clinical nomograms, although the RF and YF had higher accuracy compared to NF. CONCLUSION: The clinical T stage, PSA, GS, and ISUP grade are independent predictors of PSMA-positive lymph nodes. The RF and YF can be used to identify patients who can benefit from 68 Ga-PSMA-11 PET/CT for the detection of lymph node metastasis. Together with nomograms, 68 Ga-PSMA-11 PET/CT images help to localize PSMA-positive lymph node metastases and can thus assist in surgery and radiotherapy planning.

The effect of androgen deprivation therapy on 68Ga-PSMA tracer uptake in non-metastatic prostate cancer patients.

PURPOSE: To evaluate the effect of neoadjuvant androgen deprivation treatment (ADT) on prostate-specific membrane antigen (PSMA) tracer uptake demonstrated in 68Ga-PSMA-positron emission tomography (PET/CT) in non-metastatic hormone-naïve prostate cancer (PC) patients. MATERIALS AND METHODS: The clinical data of 108 PC patients who received neoadjuvant ADT were retrospectively analyzed. All patients had a baseline 68Ga-PSMA-PET/CT scan, and a second scan was delivered median of 2.9 months after the initiation of ADT. The maximum standardized uptake value (SUVmax) of primary tumor (SUVp) and metastatic lymph nodes (SUVln) as well as PSA response were assessed between pre- and post-ADT 68Ga-PSMA-PET/CT scans. RESULTS: There were significant decreases in posttreatment serum PSA, SUVp, and SUVln. A decrease in SUVp was seen in 91 patients (84%) with a median value of 66% (range, 5-100%), while 17 patients (16%) had no change in or an increase in PSMA tracer uptake with a median value of 24% (range, 0-198%). Patients with Gleason score (GS) of 7 had significantly higher metabolic response rates compared to other patients. The disease progression was significantly higher only in patients with GS > 7 disease compared to GS 7 disease. The PSA response to ADT was the lowest in patients with ISUP high-grade tumors. A total of 16 patients (15%) had progressive disease, and in 9 patients (8%), radiotherapy decisions were modified according to posttreatment 68Ga-PSMA-PET/CT scans. CONCLUSIONS: The current study includes the largest number of patients analyzed to date and demonstrates that ADT causes a significant decrease in serum PSA values and SUVp and SUVln. The authors demonstrate that 68Ga-PSMA-PET/CT may be used as a quantitative imaging modality after neoadjuvant ADT in hormone-naïve non-metastatic PC patients.

Prognostic values of ADCmean and SUVmax of the primary tumour in cervical cancer patients treated with definitive chemoradiotherapy.

We analysed the correlation of 18F-fluorodeoxyglucose uptake into primary tumours using the maximum standardised uptake value (SUVmax) and the mean apparent diffusion coefficient (ADCmean) values in magnetic resonance imaging (MRI) with the clinical and pathological factors in patients with cervical cancer who were treated with concurrent chemoradiotherapy. The patients were stratified according to the primary tumour pre-treatment ADCmean and SUVmax cut-off values. There were significant correlations between the SUVmax of the primary tumour and tumour size, and the treatment response. The correlation between the ADCmean and FIGO stage, tumour size, and the lymph node metastasis was significant. The SUVmax was significantly and inversely correlated with the ADCmean for cervical cancer (r = -0.44, p <.001). In the multivariate analysis, the primary tumour ADCmean, treatment response and the lymph node metastasis emerged as significant independent predictors of both OS and DFS, and of the primary tumour SUVmax for DFS. Tumour size has a borderline significance for OS. High SUVmax and low ADCmean of the primary tumour are important predictive factors for identifying high-risk patients with cervical cancer who are treated with definitive chemoradiotherapy. These results point to a future role for the diffusion-weighted MRI and for 18F-fluorodeoxyglucose positron emission tomography, not only in the staging of cervical cancer but as an aid in the selection of an adjuvant treatment regimen after chemoradiotherapy for individual patients. Impact statement What is already known on this subject? A negative correlation between primary tumour SUVmax derived from positron emission tomography (PET/CT) and ADCmin derived from diffusion weighted magnetic resonance imaging (DW-MRI) in various cancer types and cervical cancer has been demonstrated. However, the prognostic value of primary tumour SUVmax and ADCmean in cervical cancer patients treated with definitive chemoradiotherapy is not well studied yet. What the results of this study add? The patients with high-risk features (larger tumours, extensive stage, lymph node metastasis) had higher primary tumour SUVmax and lower ADCmean values. Primary tumour ADCmean and lymph node metastasis emerged as significant independent predictors of both overall and disease-free survival. This study demonstrated that the functional biomarkers delivered from PET-CT and DW-MRI are important in predicting the treatment outcomes in the squamous cell carcinoma of cervix treated with definitive chemoradiotherapy, where clinical and radiological findings are very important, since these patients are not staged surgically. What are the implications of these findings for clinical practice and/or further research? Based on these findings, there may be a future role of DW-MRI and FDG/PET-CT not only in the staging of cervical cancer but as an aid in the selection of an adjuvant treatment regimen after chemoradiotherapy (ChRT) for individual patients.

An old enemy not to be forgotten during PET CT scanning of cancer patients: tuberculosis.

AIM OF THE STUDY: Positron emission tomography-computed tomography (PET CT) scan is commonly used in current medical oncology practice as an imaging method. In this study we present data from cancer patients who were followed at our clinic and suspected of having tuberculosis during PET CT scanning. After the biopsy, they were diagnosed with concomitant tuberculosis. MATERIAL AND METHODS: In this study, 14 patients who applied to our clinic and followed up due to cancer, and had PET CT scanning for the preliminary staging or further evaluation, were included. The patients were diagnosed with metastatic or recurrent disease, and their biopsy results revealed tuberculosis. RESULTS: The mean age was 57.8 years with SD (standard deviation) 13.1 years and gender distribution of 78.6% (n = 11) females and 21.4% (n = 3) males. None of the patients had tuberculosis in their personal history (0%). Among the patients, 5 (35.7%) were diagnosed with tuberculosis during the preliminary staging, whereas 9 (64.3%) were diagnosed during the follow-up after the treatment. The median time to tuberculosis diagnosis was 11 months (min-max: 3-24 months) after the treatment. The most commonly involved lymph nodes during PET CT scanning were mediastinal in 8 (64.3%), axillary in 3 (21.4%) and para-aortic in 3 (21.4%) patients. The mean SUVmax (maximum standardised uptake value) of lymph node involved by PET CT scanning was defined as 8.5 (SD 2.6). CONCLUSIONS: Despite all improvements in modern medicine, tuberculosis is still a serious public health problem. It should always be considered in differential diagnosis while evaluating PET CT scanning results of cancer patients, because it may cause false positive results.

Prognostic value of 18F-fluorodeoxyglucose uptake in pelvic lymph nodes in patients with cervical cancer treated with definitive chemoradiotherapy.

PURPOSE: To evaluate the prognostic significance of the maximum standardized uptake (SUVmax) value for pelvic lymph nodes in patients with cervical cancer and its impact on treatment response, disease control, and survival. METHODS: Ninety-three patients with pelvic or para-aortic metastasis detected by PET/CT and treated with definitive chemoradiotherapy were evaluated. The impact of pelvic lymph node SUVmax on prognostic factors and treatment outcomes was assessed. RESULTS: The size and SUVmax of pelvic lymph nodes were significantly correlated (r=0.859; p<0.001). Patients with pelvic and para-aortic lymph node metastases had significantly higher SUVmax values for both primary tumor (23.4±9.2 vs. 18.5±7.3; p=0.01) and pelvic lymph nodes (11.4±4.6 vs. 7.4±3.8; p=0.001). Patients with pelvic lymph node SUVmax≥7.5 had significantly higher primary tumor SUVmax, larger pelvic lymph nodes, higher rates of para-aortic lymph node metastasis, and lower post-therapy complete response rates. Overall survival (OS) and disease-free survival (DFS) rates were significantly higher in patients with SUVmax<7.5 compared to patients with SUVmax≥7.5. In a multivariate analysis, pelvic lymph node SUVmax and post-therapy metabolic response were significant prognostic factors for both OS and DFS for all patients, but no significant prognostic factors were found in pelvic lymph node metastasis only. CONCLUSIONS: Patients with highly FDG-avid pelvic lymph nodes have a higher risk of disease recurrence with worse survival. Identification of these patients may assist in the evaluation of the clinical benefits of additional treatments.

Treatment outcomes of patients with cervical cancer with complete metabolic responses after definitive chemoradiotherapy.

PURPOSE: We sought to evaluate failure patterns and prognostic factors predictive of recurrences and survival in cervical cancer patients who are treated with definitive chemoradiotherapy (ChRT), who have a subsequent complete metabolic response (CMR) with (18) F-fluorodeoxyglucose positron-emission tomography (FDG-PET) after treatment. METHODS: The records of 152 cervical cancer patients who were treated with definitive chemoradiotherapy were evaluated. All patients underwent pre-treatment positron emission tomography (PET-CT), and post-treatment PET-CT was performed within a median of 3.9 months (range, 3.0-9.8 months) after the completion of ChRT. The prognoses of partial response/progressive disease (PR/PD) cases (30 patients, 18 %) and CMR cases (122 patients, %82) were evaluated. Univariate and multivariate analysis effecting the treatment outcome was performed in CMR cases. RESULTS: The median follow-ups for all patients and surviving patients were 28.7 (range, 3.3-78.7 months) and 33.2 months (range, 6.23-78.7 months), respectively. Four-year overall survival (OS) rate was significantly better in patients with CMR compared to patients with PR/PD (66.9 % vs. 12.4 %, p < 0.001, respectively). Patients with PR/PD had higher maximum standardized uptake value (SUVmax) of primary cervical tumor (26.4 ± 10.1 vs. 15.9 ± 6.3; p < 0.001) and larger tumor (6.4 cm ± 2.3 cm vs. 5.0 cm ± 1.4 cm; p < 0.001) compared to patients with CMR. Of the 122 patients with post-treatment CMRs, 25 (21 %) developed local, locoregional, or distant failure. In univariate analysis, tumor size ≥ 5 cm, 'International Federation of Obstetricians and Gynecologists' (FIGO) stage ≥ IIB, and pelvic and/or para-aortic lymph node metastasis were predictive of both overall survival (OS) and disease-free survival (DFS), while histology was predictive of only OS. In multivariate analysis, tumor size, stage and lymph node metastasis were predictive of OS and DFS. CONCLUSION: Although CMR is associated with better outcomes, relapses remain problematic, especially in patients with bulky tumors (≥ 5 cm), extensive stage (≥ IIB) or pelvic and/or para-aortic lymph node metastasis. These findings could support the need for more aggressive treatment or adjuvant chemotherapy regimens.

Kikuchi-Fujimoto disease as a rare cause of benign lymphadenopathy and (18)F-FDG PET/CT findings.

Kikuchi-Fujimoto disease (KFD) is an uncommon benign and self-limited disease, characterized by cervical lymphadenopathy. This disease is generally diagnosed on the basis of an excisional biopsy of affected lymph nodes. However, clinical presentation and histopathological findings of KFD could lead to a wrong initial diagnosis, of tuberculosis, systemic lupus erythymatosus or malignant lymphoma. Laboratory tests are not specific. Imaging modalitites give confusing results. Affected lymph nodes of patients with KFD can exibit (18)F-FDG uptake on PET/CT imaging similar to malignant lymphoma. Therefore, the differential diagnosis of KFD should be considered in patients with cervical and/or generalized lymphadenopathy. Accurate diagnosis of KFD by histology is essential in avoiding unnecessary emotional and mental distress associated with the diagnosis of lymphoma.

Simultaneous occurrence of medullary and differentiated thyroid carcinomas. Report of 4 cases and brief review of the literature.

Simultaneous occurrence of medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) in a single patient is an unusual event. The incidence, cell origin, histopathology features and prognosis of these two carcinomas are considered completely different. The aim of this retrospective study was to describe clinical, pathologic characteristics and the prevalence of diagnosing such patients in our clinic. Between October 2003 and December 2013, 1.420 consecutive patients diagnosed by histology as having differentiated thyroid carcinoma (DTC) and treated with radioactive iodide (RAI) were retrospectively investigated. Of these, 4 patients were diagnosed by histology as having simultaneous MTC and PTC. The clinical and pathology characteristics of these patients are described. The prevalence of simultaneous MTC and PTC of these 4 patients in our clinic was 0.28% of all patients with DTC. The age of the 4 patients ranged from 44 to 63 years and were three females and one male. These patients are currently alive without disease from either of the two types of cancer. In two of these patients, MTC was located in the left and PTC in the right thyroid lobe. One patient had MTC in the right lobe and PTC in both lobes. The remaining patient had both cancers in the left lobe as a mixed tumor. We are able to present the pathology of only 2 of these 4 patients. In these 2 patients MTC was located in the left and PTC in the right thyroid lobe, one of them was female and the other was male, aged 44 and 49, respectively. In conclusion, our results suggested that simultaneous occurrence of MTC and PTC had a prevalence in our clinic of 0.28% among 1420 consecutive patients with DTC or 0.14%, if only the 2 patients in whom we are able to present their pathology slides are considered. Our cases suggest that these two tumors are usually independent and coincidental events in every patient.

Long-term assessment of clinical parameters and positron emission tomography parameters in predicting recurrence in uterine cervical cancer patients receiving definitive chemoradiotherapy.

OBJECTIVE: The objective of this study was to assess the prognostic value of clinical factors and metabolic parameters measured using fluorodeoxyglucose PET (FDG-PET/CT) in predicting disease recurrence, as well as distant metastasis-free survival (DMFS), local recurrence-free survival (LRFS), and overall survival (OS) in patients with uterine cervical cancer who received definitive chemoradiotherapy. METHODS: The clinical data and FDG-PET parameters, including standardized uptake value (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of 194 patients with biopsy-confirmed squamous cell carcinoma of cervical cancer were retrospectively analyzed. Univariate and multivariate analyses were used to ascertain prognostic factors associated with DMFS, LRFS, and OS. RESULTS: With a median follow-up of 12.5 years, 96 patients (49.5%) presented with disease recurrence, at a median of 9.9 months after chemoradiotherapy. Patients who experienced recurrence had significantly higher values for all FDG-PET parameters compared to patients who did not. In multivariate regression analysis, lymph node metastasis, MTV, and SUV mean were significantly correlated with distant metastasis, while local recurrence was only predicted by SUV max . Lymph node metastasis, high MTV, SUV mean , and TLG predicted shorter DMFS, while only the primary tumor SUV max predicted LRFS. Age, regional nodal metastasis, and higher MTV independently predicted shorter OS in multivariate analysis. CONCLUSION: We found that metabolic parameters derived from FDG-PET/CT could serve as surrogates for disease recurrence in patients with cervical cancer who were treated with definitive chemoradiotherapy. Patients at high risk of distant metastasis could be defined using SUV mean and MTV, and for local recurrence, by using SUV max .

Machine learning predicts conventional imaging metastasis-free survival (MFS) for oligometastatic castration-sensitive prostate cancer (omCSPC) using prostate-specific membrane antigen (PSMA) PET radiomics.

PURPOSE: This study investigated imaging biomarkers derived from PSMA-PET acquired pre- and post-metastasis-directed therapy (MDT) to predict 2-year metastasis-free survival (MFS), which provides valuable early response assessment to improve patient outcomes. MATERIALS/METHODS: An international cohort of 117 oligometastatic castration-sensitive prostate cancer (omCSPC) patients, comprising 34 from John Hopkins Hospital (JHH) and 83 from Baskent University (BU), were treated with stereotactic ablative radiation therapy (SABR) MDT with both pre- and post-MDT PSMA-PET/CT scans acquired. PET radiomic features were analyzed from a CT-PET fusion defined gross tumor volume ((GTV) or zone 1), and a 5 mm expansion ring area outside the GTV (zone 2). A total of 1748 PET radiomic features were extracted from these zones. The six most significant features selected using the Chi2 method, along with five clinical parameters (age, Gleason score, number of total lesions, untreated lesions, and pre-MDT prostate-specific antigen (PSA)) were extracted as inputs to the models. Various machine learning models, including Random Forest, Decision Tree, Support Vector Machine, and Naïve Bayesian, were employed for 2-year MFS prediction and tested using leave-one-out and cross-institution validation. RESULTS: Six radiomic features, including Total Energy, Entropy, and Standard Deviation from pre-PSMA-PET zone 1, Total Energy and Contrast from post-PSMA-PET zone 1, and Entropy from pre-PSMA-PET zone 2, along with five clinical parameters were selected for predicting 2-year MFS. In a leave-one-out test with all the patients, random forest achieved an accuracy of 80 % and an AUC of 0.82 in predicting 2-year MFS. In cross-institution validation, the model correctly predicted 2-year MFS events with an accuracy of 75 % and an AUC of 0.77 for patients from JHH, and an accuracy of 78 % and an AUC of 0.80 for BU patients, respectively. CONCLUSION: Our study demonstrated the promise of using pre- and post-MDT PSMA-PET-based imaging biomarkers for MFS prediction for omCSPC patients.

Prostate-Specific Membrane Antigen PET Response Associates with Metastasis-Free Survival After Stereotactic Ablative Radiation in Oligometastatic Prostate Cancer.

Purpose: Emerging data suggest that metastasis-directed therapy (MDT) improves outcomes in patients with oligometastatic castration-sensitive prostate cancer (omCSPC). Prostate-specific membrane antigen positron emission tomography (PSMA-PET) can detect occult metastatic disease, and PSMA response has been proposed as a biomarker for treatment response. Herein, we identify and validate a PSMA-PET biomarker for metastasis-free survival (MFS) following MDT in omCSPC. Methods and Materials: We performed an international multi-institutional retrospective study of patients with omCSPC, defined as ≤3 lesions, treated with metastasis-directed stereotactic ablative radiation who underwent PSMA-PET/computed tomography (CT) before and after (median, 6.2 months; range, 2.4-10.9 months) treatment. Pre- and post-MDT PSMA-PET/CT maximum standardized uptake value (SUVmax) was measured for all lesions, and PSMA response was defined as the percent change in SUVmax of the least responsive lesion. PSMA response was both evaluated as a continuous variable and dichotomized into PSMA responders, with a complete/partial response (at least a 30% reduction in SUVmax), and PSMA nonresponders, with stable/progressive disease (less than a 30% reduction in SUVmax). PSMA response was correlated with conventional imaging-defined metastasis-free survival (MFS) via Kaplan-Meier and Cox regression analysis. Results: A total of 131 patients with 261 treated metastases were included in the analysis, with a median follow-up of 29 months (IQR, 18.5-41.3 months). After stereotactic ablative radiation, 70.2% of patients were classified as PSMA responders. Multivariable analysis demonstrated that PSMA response as a continuous variable was associated with a significantly worse MFS (hazard ratio = 1.003; 95% CI, 1.001-1.006; P = .016). Patients classified as PSMA responders were found to have a significantly improved median MFS of 39.9 versus 12 months (P = .001) compared with PSMA nonresponders. Our study is limited as it is a retrospective review of a heterogenous population. Conclusions: After stereotactic ablative radiation, PSMA-PET response appears to be a radiographic biomarker that correlates with MFS in omCSPC. This approach holds promise for guiding clinical management of omCSPC and should be validated in a prospective setting.

Isolated mediastinal lymph node false positivity of [18F]-fluorodeoxyglucose-positron emission tomography/computed tomography in patients with cervical cancer.

OBJECTIVE: This study aimed to evaluate the degree of mediastinal involvement in patients with cervical cancer with isolated mediastinal [F]-fluorodeoxyglucose-positron emission tomography (FDG-PET) positivity as verified by histopathologic examination. METHODS: Two hundred twenty-eight patients with newly diagnosed cervical cancer and who underwent FDG-PET imaging were analyzed. Twenty-nine patients (17%) had disseminated disease detected with PET/computed tomography (CT). Only 10 patients (4%) had increased FDG uptake in mediastinal lymph nodes alone. Of the 10 patients with mediastinal disease, 2 refused surgical mediastinal lymph node biopsy and did not receive any treatment. Patients with suspected paratracheal or subcarinal lymph node metastasis detected on PET/CT underwent mediastinoscopy, and those with hilar metastasis had video-assisted mediastinal lymphadenectomy. Treatment was delivered according to final staging based on histopathologic confirmation of mediastinal lymph node involvement. RESULTS: The mean (SD) maximum standardized uptake values for primary cervical tumor and mediastinal lymph nodes were 19.7 (10.3) and 7.5 (1.6), respectively. Of 8 patients who underwent mediastinal lymph node confirmation, 6 (75%) were tumor free, demonstrating granulomatous changes, and were treated curatively. No patients had residual or recurrent disease at the primary site, and all but 1 were alive without disease. Two patients with confirmed mediastinal lymph node metastasis were treated palliatively and died between 9 and 11 months after diagnosis. CONCLUSIONS: Positron emission tomography/CT is an important tool for lymphatic staging and evaluation of distant metastases in cervical cancer. However, PET/CT should be interpreted cautiously for isolated mediastinal involvement; surgical evaluation is required for accurate staging and appropriate treatment decisions to achieve better outcomes.

Prognostic value of pretreatment 18F-fluorodeoxyglucose uptake in patients with cervical cancer treated with definitive chemoradiotherapy.

OBJECTIVE: We analyzed the correlation of F-fluorodeoxyglucose (FDG) uptake into primary tumors using the maximum standardized uptake value (SUVmax) and clinicopathological factors of disease. The impact of the pretreatment SUVmax of the primary tumor on survival was investigated. MATERIALS AND METHODS: The records of 149 patients with biopsy-proven cervical cancer treated with definitive chemoradiotherapy (ChRT) were reviewed. All patients underwent pretreatment FDG positron emission tomography with computed tomography, and posttherapy FDG positron emission tomography with computed tomography was performed within a median interval of 4.2 months (range, 3.0-11.2 months) after the completion of chemoradiotherapy. RESULTS: The mean SUVmax in patients with lymph node metastasis was significantly higher than that in patients without metastasis (19.7 ± 8.2 vs 16.4 ± 8.2, respectively; P = 0.01). A significant difference existed between tumor size (<4 vs ≥4 cm) and the primary tumor SUVmax (14.7 ± 6.6 vs 18.7 ± 8.5, respectively; P = 0.02). The primary tumor pretreatment SUVmax for patients with complete remission was significantly lower than that of patients with partial response or progressive disease (15.6 ± 5.7 vs 28.0 ± 9.9, respectively; P < 0.001). The relationship between primary tumor FDG uptake and survival was evaluated by the cutoff value determined by receiver operating characteristic curve analysis. The area under the curve was 0.901 (P < 0.001; 95% confidence interval, 0.848-0.954), and 15.6 was determined as the SUVmax cutoff value. The 4-year actuarial overall survival (OS) and disease-free survival for SUVmax of less than 15.6 compared with SUVmax of 15.6 or greater were 85% vs 34% (P < 0.001) and 80% vs 29%, respectively (P < 0.001). In multivariate analysis, age, SUVmax of 15.6 or greater, and lymph node metastasis were independent prognostic factors of OS, and International Federation of Gynecology and Obstetrics stage IIB or higher, SUVmax of 15.6 or greater, and lymph node metastasis were significant factors for disease-free survival. CONCLUSION: The primary tumor pretreatment SUVmax is correlated with increased tumor size and lymph node involvement at diagnosis, how well the primary tumor responds to treatment, the likelihood of disease recurrence, and OS.

The effect of sodium iodide symporter protein on ablation success in patients with differentiated thyroid cancer.

OBJECTIVE: This study aimed to investigate immunohistochemical staining of sodium iodide symporter (NIS) and its effect on response to I-131 therapy in differentiated thyroid carcinoma patients. METHODS: We evaluated NIS expression, the intracellular distribution of NIS, iodine-131 uptake in residual tissues on post-ablation I-131 whole body scan, and the ablation status after 100 mCi I-131 therapy. We also investigated NIS expression and localization in tumoral paraffin-embedded tissues. RESULTS: In this retrospective study, 35 patients (mean age 44.17 ± 12.9 years, 27 female, 8 male) were studied. Twenty-one of these patients responded to radioiodine therapy, and 14 did not. NIS expression and iodine-131 uptake in residual tissues post-ablation I-131 whole body scan were not statistically significant. When we compared the patients who responded to radioiodine therapy and the poor responder group, NIS expression and iodine-131 uptake in residual tissues did not demonstrate statistically significant difference [(p = 0.308) (p = 0.985) respectively]. 47.6% of the patients in the successful ablation group and 85.7% in the unsuccessful ablation group had intracellular NIS immunostaining. The difference was not statistically significant (p = 0.139). 52.4% of the patients in the successful ablation group and 7% in the unsuccessful ablation group had NIS immunostaining at the basolateral membrane. The difference was statistically significant (p < 0.05). CONCLUSIONS: In conclusion, we did not find any significant difference between successful and unsuccessful ablation groups in terms of NIS expression; however, we concluded that the intracellular (cytoplasmic) localization of NIS is one of the leading causes of ablation failure regardless of NIS expression in DTC patients.

Superscan Appearance of 68Ga PSMA PET/CT in a Patient with Refractory Prostate Cancer.

A 64-year-old male patient with metastatic prostate carcinoma diagnosis received lutetium-177 prostate-specific membrane antigen (PSMA) treatment; however, his disease progressed. Herein, presented the final images of the patient that demonstrated a superscan appearance in the Gallium-68 PSMA positron emission tomography/computed tomography, which is a rare phenomenon.

Long-term outcomes of cervical cancer patients with complete metabolic response after definitive chemoradiotherapy.

OBJECTIVE: We investigated the importance of metabolic parameters measured with 18F-fluorodeoxyglucose positron-emission tomography integrated with computed tomography (FDG-PET/CT) for predicting progression-free survival (PFS) and overall survival (OS) in cervical cancer with complete metabolic response (CMR) after chemoradiotherapy (ChRT). METHODS: The clinical data and PET parameters including standardized uptake value (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of 122 patients having CMR in post-treatment 18F-FDG-PET/CT delivered a median of 3.9 months after ChRT completion were analyzed. RESULTS: With a median follow-up of 8.4 years, 55 patients (45%) presented with disease a median of 19.7 months after ChRT. For SUVp, MTVp, TLGp, SUVln, MTVln, and TLGp, the cut-off values for OS determined by receiver operating curve analysis were 15.8, 48.7 cm³, 552.3, 8.7, 7.0 cm³, respectively. All metabolic PET parameters were significant prognostic factors for OS and PFS in univariate analysis. International Federation of Gynecology and Obstetrics (FIGO) stage was predictive of both OS and PFS, while pelvic and/or para-aortic lymph node metastasis were predictive of OS only. In multivariate analysis, FIGO stage ≥IIB, MTVp ≥49.8 cm³, and TLGp ≥597.4 were predictive of worse OS. Advanced stage, presence of lymph node metastasis, higher TLGp, and larger MTVln were significant factors for poor PFS rates. CONCLUSION: We found that advanced stage and higher TLGp values were significant predictors for poor survival and higher progression rates. Volumetric PET parameters could be used to predict treatment outcomes in patients with CMR after definitive ChRT.

18F-FDG PET/CT Imaging in an Unusual Case of Cutaneous Melanoma Arising From Congenital Melanocytic Nevus in a Two-year-old Girl

Childhood malignant melanoma (MM) is extremely uncommon. We report an unusual case of cutaneous melanoma that developed from a medium-sized congenital melanocytic nevus (CMN) in a two-year-old girl. The patient had a history of CMN on the right hip, and she presented with a new ulcerative area with irregular borders and bleeding on CMN. Histopathological examination of the nevus revealed a MM. 18Florfluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography was performed for metastatic evaluation. The scan demonstrated metastatic increased 18F-FDG uptake in the right external iliac and inguinal lymph nodes.

The use of 18F-FDG positron emission tomography to detect mediastinal lymph nodes in metastatic breast cancer.

BACKGROUND: To assess the predictive value of 18F-fluorodeoxyglucose positron-emission tomography (FDG-PET/CT) in detecting mediastinal lymph node metastasis with histopathologic verification in breast cancer (BC) patients. MATERIALS AND METHODS: Between February 2012 and October 2019, 37 BC patients who underwent histopathological verification for FDG-PET positive mediastinal lymph nodes were retrospectively analyzed. Nine patients (24%) were screened before beginning treatment, while 27 (76%) were screened at the time of disease progression, an average of 39 months after completion of initial treatment. RESULTS: The histopathologic diagnosis revealed lymph node metastasis from BC in 15 patients (40%) and benign disease in 22 patients (60%). The standardized uptake value (SUVmax) of mediastinal lymph nodes was significantly higher in patients with lymph node metastasis compared to those with benign histology (9.0 ± 3.5 vs. 5.9 ± 2.4; P = 0.007). The cut-off value of SUVmax after the ROC curve analysis for pathological lymph node metastasis was 6.4. Two of the 15 patients with mediastinal SUVmax ≤ 6.4 and 13 of the 22 patients with SUVmax > 6.4 had lymph node metastasis. Age and pathological findings were prognostic factors for overall survival in univariate analysis. The treatment decision was changed in 19 patients (51%) after mediastinoscopic evaluation of the entire cohort. CONCLUSIONS: This is the first study to support the need for pathologic confirmation of a positive PET/CT result following evaluation of mediastinal lymph nodes for staging BC, either at initial diagnosis or at the time of progression. Treatment decisions were consequently altered for nearly half of the patients.