The inferior performance of [68Ga]Ga-FAPI-04 PET/CT as a diagnostic and theranostic biomarker in [177Lu]Lu-DOTATATE refractory well-differentiated neuroendocrine tumors.

PURPOSE: We aimed to investigate the potential of [68Ga]Ga-FAPI-04 PET/CT as an alternative diagnostic and theranostic tool in well-differentiated NETs refractory to [177Lu]Lu-DOTATATE therapy. METHODS: Patients who received at least two cycles of [177Lu]Lu-DOTATATE therapy for metastatic NETs and progressed under treatment were included. All patients had performed [68Ga]Ga-DOTATATE and [68Ga]Ga-FAPI-04 PET/CT within 3 weeks. The number of PET-positive lesions related to NETs and tumor sites was documented. Mann-Whitney U and chi-square tests were used to compare SUVmax levels of tracers and the number of detected metastases. RESULTS: Twelve patients (7 male, 5 female) who met the eligibility criteria were included in the study. Ten patients had grade 1-2 NET of various origins, and two had paraganglioma and pheochromocytoma. One hundred ninety-eight of 230 lesions (86%) were SSTR positive with a median SUVmax of 16.6 (2.2-76.5), and 88 of 230 lesions (38.2%) were [68Ga]Ga-FAPI-04 positive with a median SUVmax of 5.1 (2.3-21). Median SUVmax level and detected number of tumors were significantly higher in [68Ga]Ga-DOTATATE PET/CT (p=<0.001). [68Ga]Ga-FAPI-04 PET/CT was completely (n:2) or almost completely (n:3) negative in 5 (42%) patients. Two (17%) patients had flip-flop SSTR/FAPI uptake in tumors. In four patients (33%), tumor uptake or the number of PET-positive lesions was inferior in [68Ga]Ga-FAPI-04 PET/CT. In only one patient (8%), tumor uptakes were higher in [68Ga]Ga-FAPI-04 PET/CT. Low-dose [177Lu]Lu-FAPI-46 dosimetry was performed on the FAPI-dominant patient; absorbed radiation doses per GBq were 1.26 Gy, 0.36 Gy, 0.32 Gy, and 0.2 Gy for kidneys, liver, spleen, and total body, respectively. The mean absorbed dose per GBq was 0.33 Gy for liver mass and 0.41 Gy for metastatic lymph nodes. CONCLUSION: Our preliminary results demonstrated that [68Ga]Ga-FAPI-04 PET/CT mainly failed in well-differentiated NETs refractory to [177Lu]Lu-DOTATATE therapy and had a limited role as an alternative diagnostic or theranostic agent. Further investigations with a larger patient population are required to determine the impact of [68Ga]Ga-FAPI-04 PET/CT on NETs.

Comparison of 68GA-FAPI-04 PET/CT and 18F-FDG PET/CT findings in peritonitis carcinomatosa cases.

OBJECTIVE: This study was conducted to compare the diagnostic accuracy of gallium-68-radiolabeled fibroblast activation protein inhibitor (68Ga-FAPI-04), positron emission tomography/computed tomography (PET/CT), and fluorine-18-fluorodeoxyglucose (18F-FDG) PET/CT based on the peritoneal carcinomatosis (PC) index for detecting peritoneal metastases of various cancer types, and to evaluate the potential benefits of FAPI PET/CT in patients with peritoneal metastases. SUBJECTS AND METHODS: This retrospective study included 57 patients with peritoneal metastases between November 2020 and December 2021. All patients underwent 68Ga-FAPI-04 PET/CT and 18F-FDG PET/CT scans within 7 days. RESULTS: Among the 57 patients included, 32 (56.1%) were male and the median age was 54 years (22-86 years). In the visual evaluation made from a total of 13 quadrants on the abdominopelvic peritoneal surfaces, positive findings were observed in 111 quadrants in 39 patients by 18F-FDG PET/CT and in 280 quadrants in 57 patients by 68Ga-FAPI-04 PET/CT (P<0.001). The maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR) values of 68Ga-FAPI-04 PET/CT for the PC lesions were significantly higher than the SUVmax and TBR values of 18F-FDG PET/CT in all patients and in all quadrants (SUVmax 6.45 vs 4.1; P<0.001; TBR 14.9 vs 6.8; P<0.001). CONCLUSION: Gallium-68-FAPI-04 PET/CT showed superior sensitivity compared to 18F-FDG PET/CT in both quantitative and visual evaluations of PC. Considering the low background activity and higher specific activity uptake values, 68Ga-FAPI-04 PET/CT helped improve diagnostic accuracy.

Comparison of [68 Ga]Ga-DOTA-FAPI-04 PET/CT and [18F]FDG PET/CT in colorectal cancer.

AIM: In this study, we aimed to evaluate the diagnostic sensitivity of [68 Ga]Ga-DOTA-FAPI-04 PET/CT in the evaluation of primary or recurrent tumor, and nodal, peritoneal, and distant organ metastases in patients with newly diagnosed or relapsed colorectal cancer (CRC) in comparison with [18F]FDG PET/CT. MATERIALS AND METHOD: Thirty-nine patients with histopathologically confirmed primary or relapsed CRC were included in our study. All patients underwent both [18F]FDG and [68 Ga]Ga-DOTA-FAPI-04 PET/CT imaging in the same week. Primary lesions, lymph nodes, and metastatic lesions were recorded on both scans. SUVmax and background values were measured from the primary and metastatic lesions; tumor-to-background ratio (TBR) was calculated and compared. The results of the operation were compared with PET findings in patients who underwent surgical treatment without neoadjuvant chemotherapy (NAC). RESULTS: The sensitivity and specificity of [68 Ga]Ga-DOTA-FAPI-04 PET/CT in the evaluation of primary tumors were 100%, while the sensitivity of [18F]FDG PET/CT was 100% and its specificity was 85.3%. When evaluated with surgical results in the detection of lymph nodes, [68 Ga]Ga-DOTA-FAPI-04 PET/CT had a sensitivity of 90% and a specificity of 100%, whereas [18F]FDG PET/CT had a sensitivity of 80% and a specificity of 81.8%. The sensitivity and specificity of [68 Ga]Ga-DOTA-FAPI PET/CT for peritoneal implants were 100%, and the sensitivity of [18F]FDG PET/CT was 55%. The SUVmax of primary lesions was higher with [18F]FDG (p < 0.001), while TBR was higher in [68 Ga]Ga-DOTA-FAPI PET/CT than [18F]FDG PET/CT (p: 0.008). SUVmax and TBR of the lymph nodes were significantly higher in [68 Ga]Ga-DOTA-FAPI PET/CT than [18F]FDG PET/CT (p < 0.001 for both). CONCLUSION: [68 Ga]Ga-DOTA-FAPI-04 PET/CT achieved much higher sensitivity and specificity in the detection of primary lesions, and especially the lymph nodes and peritoneal metastases, suggesting that it can be employed in the assessment of primary tumor and metastases in patients with CRC in routine clinical practice.

Nivolumab-Related Dry Mouth and Dry Eye: Cross-Sectional Study.

To evaluate ICIs related dry eye and dry mouth in nivolumab therapy, 24 patients receiving nivolumab (group 1), 30 patients in remission without treatment for 6 months (group 2), 30 healthy participants (group 3) were cross-sectionally examined. Schirmer's 1, 2, TSH blood tests, serological analysis, salivary flow scintigraphy and minor-salivary gland biopsy were performed. Schirmer's tests were performed with anesthetic (1) and without anesthetic (2). Schirmer's scores were lower in group 1 with more frequent reduced tear production (p < 0.001). TSH levels negatively correlated with Schirmer's scores. Functional insufficiency was detected by salivary flow scintigraphy in 7 out of 10 patients with Schirmer's test positivity. In Schirmer's positive patients, lymphocytic sialadenitis was confirmed in 4 patients (focus score > 1) and CD4 T lymphocyte precipitation was observed in 6 patients. Nivolumab therapy may be associated with ICIs related immune sicca.

Role of 68Ga-PSMA PET/CT parameters in treatment evaluation and survival prediction in prostate cancer patients compared with biochemical response assessment.

OBJECTIVE: In this study, we aimed to evaluate the concordance of biochemical treatment response with gallium-68-prostate specific membrane antigen (68Ga-PSMA) positron emission tomography/computed tomography (PET/CT) treatment response in prostate cancer (PCa) and investigate their prognostic effects on survival. MATERIALS AND METHODS: One hundred and fifty-onepatients with PCa, who underwent 68Ga-PSMA PET/CT imaging in our clinic between May 2016 and December 2019, were on treatment, and had pre-treatment and post-treatment imaging studies were included in our study. The treatment patients received and prostate-specific antigen (PSA) levels at the time of PET/CT imaging were recorded. Pre- and post-treatment whole-body metabolic tumor volume (MTVw), whole-body total lesion PSMA (TLPw), percent change in PSA (ΔPSA), ΔMTV, and ΔTLP values were calculated in all patients. Survival time of all patients was measured from the time of initial PET imaging. RESULTS: Median age of patients included in our study was 71 years (range: 51-88). When ΔPSA response and ΔTLP response were evaluated together (r: 0.71, P<0.001 and k: 0.541, P<0.001), statistically significance strong correlation and moderate concordance was observed. ΔPSA response and ΔMTV treatment response had statistically significant moderate correlation and moderate concordance (r: 0.66, P<0.01 and k: 0.454, P<0.001, significantly). Between ΔPSA response and ΔTLP and ΔMTV response had stronger correlation and higher concordance when PSA levels were above 10. Multivariate analyses using multiple Cox regression analysis revealed MTVw1 and ΔMTV parameters to be independent prognostic factors for mortality (P:0.003 and P:0.001, respectively). CONCLUSION: We observed that biochemical response and whole-body volumetric 68Ga-PSMA PET/CT parameter response showed correlation and concordance in all groups with PCa, which was more significant when PSA level was ≥10ng/mL. MTVw1 and ΔMTV parameters obtained via 68Ga-PSMA PET/CT were independent prognostic factors for mortality in PCa. Gallium-68-PSMA PET/CT is a valuable imaging technique for diagnostic purposes as well as follow-up and prognostic evaluation.

The biomechanical and histological effects of platelet-rich plasma on fracture healing.

PURPOSE: Platelet-rich plasma (PRP) includes growth factors and proteins that accelerate and stimulate bone regeneration and tissue recovery. The aim of this study was to evaluate the effects of PRP on fracture healing in terms of biomechanics and histology. METHODS: Seventy female rats were included in this experimental study. They were divided into three groups: Group I (no PRP, n = 30), Group II (PRP added, n = 30) and Group III (control, n = 10). The left femurs of the rats in Groups I and II were osteotomized and fixed by K-wires. Although no additional intervention was performed on Group I rats, PRP was applied to the fracture sites of Group II rats. The remaining ten rats were used as the control group of the biomechanical test (Group III). In the fourth week, nine femurs from Group I and ten femurs from Group II, and in the ninth week, nine femurs from each group were removed, and bone recovery was assessed histologically according to Modified Lane-Sandhu histological scoring criteria. Three-point bending test was applied to femurs for biomechanical evaluation in the ninth week. RESULTS: Histological healing was found to be significantly higher in Group II than in Group I (p < 0.05). Furthermore, biomechanical test results showed that healing quantity and bone strength were significantly better in Group II than in Group I (p < 0.05). CONCLUSION: PRP is a widely studied material in the physiology of fracture healing. The results of this study demonstrated the ameliorative biomechanical effects of PRP on fracture healing, in addition to accelerating the histological union of fractures. In the light of these results, PRP could be a viable alternative to accelerate the healing of fractures, late unions or non-unions. LEVEL OF EVIDENCE: Prospective comparative study, Level II.

Local imaging to interpret tumor size in F18 fluorodeoxyglucose positron emission tomography/CT in lung cancers.

OBJECTIVE: This study aimed to determine the thoracic and extra-thoracic extension of the disease in patients diagnosed with lung cancer and who had whole-body F18-fluorodeoxyglucose positron emission tomography/CT imaging and to investigate whether there is a relationship between tumor size and extrathoracic spread. METHODS: A total of 308 patients diagnosed with lung cancer were included in this study. These 308 patients were first classified as group 1 (SPN 30 mm>longest lesion diameter ≥10 mm) and group 2 (lung mass (longest lesion diameter ≥30 mm), and then the same patients were classified as group 3 (nodular diameter of ≤20 mm) and group 4 (nodular size of >20 mm). Group 1 was compared with group 2 in terms of extrathoracic metastases. Similarly, group 3 was compared with group 4 in terms of frequency of extrathoracic metastases. F18 fluorodeoxyglucose positron emission tomography/CT examination was used to detect liver, adrenal, bone, and supraclavicular lymph node metastasis, besides extrathoracic metastasis. RESULTS: Liver, bone, and extrathoracic metastasis in group 1 was statistically lower than in group 2 (p<0.001, p<0.01, and p=0.03, respectively). Liver, extrathoracic, adrenal, and bone metastasis in group 3 was statistically lower than that in group 4 (p<0.001, p=0.01, and p=0.04, p<0.01, respectively). The extrathoracic extension was observed in only one patient in group 3. In addition, liver, adrenal, and bone metastases were not observed in group 3 patients. CONCLUSION: Positron emission tomography/CT may be more appropriate for cases with a nodule diameter of ≤20 mm. Performing local imaging in patients with a nodule diameter of ≤20 mm could reduce radiation exposure and save radiopharmaceuticals used in positron emission tomography/CT imaging.

Comparing prognostic scoring systems in acute pancreatitis: Bedside Index of Severity in Acute Pancreatitis, WL, and Chinese Simple Scoring System Scores.

OBJECTIVES: Several scoring systems are used to predict prognosis in acute pancreatitis (AP), but their predictive success varies. This study compares the validity of the commonly used Bedside Index of Severity in AP (BISAP) score with the newly developed WL score and the Chinese Simple Scoring System (CSSS) score in predicting mortality and unfavorable prognostic outcomes in AP patients. METHODS: This retrospective descriptive study included all AP patients presenting to the emergency department from June 2, 2019, to June 2, 2022. Patient demographics, vital signs, laboratory values, and imaging findings were recorded, and WL, CSSS, and BISAP scores were calculated. The effectiveness of these scores in predicting adverse outcomes and mortality was compared. RESULTS: Among 357 patients, 53.2% were male, with a median age of 62 years (interquartile range: 48-75). Area under the curve (AUC) values for 7-day outcomes were 0.956 for WL, 0.759 for CSSS, and 0.871 for BISAP; for 30-day outcomes, AUC values were 0.941 for WL, 0.823 for CSSS, and 0.901 for BISAP; and for poor prognostic outcomes, AUC values were 0.792 for WL, 0.769 for CSSS, and 0.731 for BISAP. CONCLUSION: In AP patients, WL, CSSS, and BISAP scores are effective predictors of unfavorable prognosis and mortality. WL score outperforms the CSSS and BISAP scores in predicting 7-day and 30-day mortality and poor prognosis. After WL, BISAP is the second-best system for predicting mortality. For predicting unfavorable prognoses, CSSS is the second-best system after WL. The simplicity of calculating the WL score based on four laboratory parameters makes it a preferable choice.

The prognostic role of whole-body volumetric positron emission tomography/computed tomography parameters in treatment naive colorectal cancer patients with liver metastases.

PURPOSE: The present study aimed to predict the prognostic role of quantitative 18F-fluorodeoxyglucose PET/computed tomography parameters such as maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) obtained from primary tumor, lymph node metastases, and liver metastasis (LM) in patients with colorectal LM (CLM). MATERIAL AND METHOD: The research was designed as a retrospective study and 66 patients with CLM were enrolled between January 2017 and December 2018. Primary tumor SUVmax (PSUVmax), liver SUVmax (LSUVmax), and lymph node SUVmax (LnSUVmax) values obtained from the primary tumor, liver, and lymph nodes were recorded. In addition, total MTV (TMTV) and total TLG (TTLG) values were obtained by summing the values obtained from the primary tumor (PMTV and PTLG), lymph nodes (LnMTV and LnTLG), and liver (LMTV and LTLG). Univariate and multivariate Cox regression analysis was used to measure the effects of prognostic variables on mortality and survival. RESULT: In univariate Cox regression analysis, PMTV (P = 0.001), LnMTV (P = 0.008), LnTLG (P = 0.008), LnSUVmax (P = 0.047), and TTLG (P = 0.038) were identified as prognostic factors for overall survival. No statistically significant relationship was found between MTV and TLG values of LM and overall survival. In multivariate analysis, PMTV (P = 0.022) was identified as an independent prognostic factor. CONCLUSION: In conclusion, our study demonstrated that the PMTV value used in evaluating treatment-naive patients diagnosed with CLM is an independent prognostic factor for survival. Our results need to be confirmed with more studies involving more patients.

Should new organ involvement be included in Response Evaluation Criteria in PSMA Imaging?

PURPOSE: The current study is intended to investigate the effect of new organ involvement on overall survival (OS) and modify the Response Evaluation Criteria in PSMA Imaging (RECIP) by including new organ involvement to RECIP 1.0. MATERIALS AND METHODS: This retrospective study includes 114 patients diagnosed with metastatic castration-resistant prostate cancer (mCRPC) between September 2017 and June 2022 who had received docetaxel treatment and had baseline and post-treatment prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) images. The inclusion criteria were patients with pre- and post-treatment [18F]FDG PET/CT images and whose [18F]FDG PET images were negative. Those whose data were unavailable, who had additional malignancy, or who received abiraterone, enzalutamide, or Lutetium (Lu)-177 treatment were excluded. Age, Gleason score (GS), TPSA (total prostate-specific antigen) levels, surgical history, and OS information were recorded for each patient. RESULTS: The 114 patients herein had a median age of 72.5 (51-91) years and a median GS of 8 (7-10). New lesions were observed in 59 patients (51.7%) and new organ PSMA uptake was observed in 14 patients (12.2%). In the multivariate Cox regression analysis, volume-based treatment response (vTR)-total lesion PSMA (TLP), RECIP PSMA-VOL, modified RECIP (mRECIP) PSMA-VOL, and mRECIP TLP were independent prognostic factors for mortality (p < 0.001, p = 0.006, p = 0.003, and p = 0.003, respectively). The median OS of patients with new organ involvement and new lesion with PSMA uptake was 9.3 months (95% CI 2.1-16.5 months) and 11.8 months (95% CI 7.4-16.2 months), respectively. CONCLUSION: The study concluded that new organ involvement had a shorter OS than new lesion involvement. In the mRECIP that we developed, unlike RECIP, we demonstrated that both PSMA-VOL and TLP value were independent prognostic factors for mortality.

Superiority of 18 F-FDG PET/CT to 68 GA-FAPI PET/CT in Adrenocortical Tumor Imaging.

ABSTRACT: 18 F-FDG PET/CT was performed to evaluate the response to treatment in a 62-year-old female patient who was operated for adrenocortical carcinoma. High FDG uptake was observed in recurrent lesion in the left adrenal gland site and metastatic lesions. In the 68 Ga-FAPI-04 PET/CT study, low FAPI uptake was observed in both recurrences and metastases. In this case, we demonstrated the superiority of 18 F-FDG PET/CT over 68 Ga-FAPI-04 PET/CT in the evaluation of adrenocortical carcinoma.

68 GA-FAPI-04 PET/CT Versus 18 F-FDG PET/CT in Imaging of Malignant Mixed Germ Cell Testicular Tumor.

ABSTRACT: 18 F-FDG PET/CT imaging was performed for restaging in in a 16-year-old boy who was operated on for right testicular tumor and was diagnosed with malignant mixed germ cell tumor. Mild FDG uptake was observed in 2 nodules in both lungs and retroperitoneal lymph node in the abdomen. 68 Ga-FAPI (fibroblast activation protein inhibitor) 04 PET/CT showed moderate uptake of FAPI in lung nodules and retroperitoneal lymph node. In this case, 68 Ga-FAPI-04 PET/CT was shown to be superior to 18 F-FDG PET/CT in the evaluation of malignant mixed germ cell testicular tumor metastases.

The Role of 68Ga FAPI-04 and 18F-FDG PET/CT in Detecting Liver Metastases in Different Types of Cancer.

OBJECTIVE: We compared the diagnostic accuracies of 68Ga FAPI-04 PET/CT and 18F-FDG PET/CT for detecting liver metastases (LMs) in patients with different cancer types. MATERIALS AND METHODS: This retrospective study included 63 patients with liver lesions who underwent 18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT between May 2020 and May 2022. Patients with histopathologically confirmed primary diagnoses, data that could be accessed retrospectively, liver lesions confirmed by biopsy over at least 3-6 months of follow-up (via ultrasonography, CT, magnetic resonance imaging, PET/CT, or laboratory tests) were included. Patients with secondary malignancies or primary liver malignancies, and/or who could not be followed-up, were excluded. RESULTS: Of the 63 total patients, 34 (54%) were female, and the mean age was 61 (30-92) years. There were 582 LMs in 51 patients and 35 benign liver lesions in 20 (12 patients had only benign and 8 both benign and malignant lesions). Of the 582 LMs, 472 (81.1%) evidenced 18F-FDG uptake and 572 (98.2%) 68Ga-FAPI uptake. The diagnostic accuracies of 68Ga-FAPI PET/CT and 18F-FDG PET/CT were 98% and 82%, respectively (p < 0.001; McNemar test). When the LMs were compared, the maximum standardized uptake (SUVmax) value was significantly higher on 18F-FDG PET/CT than 68Ga-FAPI PET/CT (median: 6.0 vs. 5.4; p = 0.016). However, the LM-to-background ratio (TBR) was significantly higher on 68Ga-FAPI PET/CT than 18F-FDG PET/CT (median: 4.1 vs. 2.1; p < 0.001). CONCLUSION: 68Ga-FAPI PET/CT detected more LMs than did 18F-FDG PET/CT, and TBR was significantly higher on 68Ga-FAPI PET/CT than 18F-FDG PET/CT.

Role of volumetric parameters obtained from 68 Ga-PSMA PET/CT and 18F-FDG PET/CT in predicting overall survival in patients with mCRPC receiving taxane therapy.

OBJECTIVE: The aim of this study was to determine the prognostic role of volumetric parameters and Pro-PET scores obtained from 68 Ga-prostate-specific membrane antigen (PSMA) PET/CT and 18F-FDG PET/CT in patients with metastatic castration-resistant prostate cancer (mCRPC) receiving taxane therapy. MATERIALS AND METHODS: The study included 71 patients who underwent simultaneous PSMA and 18F-FDG PET/CT imaging between January 2019 and January 2022, had a Pro-PET score of 3-5 and had received taxane therapy after imaging. 18F-FDG tumor volume (TV-F) and PSMA tumor volume (TV-P) values of the lesions and total lesion glycolysis (TL-G) and total lesion PSMA (TL-P) values of the lesions were calculated on both imaging studies and the effects of these parameters on overall survival (OS) were investigated. RESULTS: The median age of the patients included herein was 71 years (56-89) and the median prostate-specific antigen (PSA) level was 16.4 (0.01-1852 ng/dL). According to the Kaplan-Meier survival analysis, TTV-P ≥ 78.5, TTL-P ≥ 278.8, TTV-F ≥ 94.98, TTL-G ≥ 458.3, TTV-P + F ≥ 195.45, TTL-G + P ≥ 855.78, lymph node (L)TV-FDG ≥ 3.4, LFDG-SUVmax ≥ 3.2, LFDG-SUVmean ≥ 2.25, LFDG-SUVpeak ≥ 2.55, and bone (B)TV-F ≥ 51.15 values were found to be prognostic factors in predicting short OS. Multivariate Cox regression analysis showed that a Vscore ≥ 3 (95% confidence interval [CI]: 7.069-98.251, p < 0.001) and TTL-G + P ≥ 855.78 (95% CI: 4.878-1037.860, p = 0.006) were found to be independent prognostic factors in predicting short OS. CONCLUSION: Volumetric parameters and Pro-PET scores obtained from 68 Ga-PSMA PET/CT and 18F-FDG PET/CT imaging have been shown to have an impact on OS in patients with mCRPC receiving taxane therapy.

18 F-FDG PET/CT parameters for prediction of response to neoadjuvant therapy and prognosis in rectal cancer.

OBJECTIVE: This study aims to investigate the role of F-18 fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) parameters in the prediction of treatment response and the prognosis in locally advanced rectal cancer. METHODS: We investigated the relationship of 18F-FDG PET/CT parameters [rectal metabolic tumor volume (MTV), rectal total lesion glycolysis (TLG), rectal standard uptake value (SUV) max, rectal highest peak SUV, lymph node MTV, lymph node TLG, lymph node highest peak SUV] with the pathological response and disease-free survival (DFS) in 60 patients who received neoadjuvant therapy for a diagnosis of locally advanced rectal cancer. Patients with a total score of 0 were assigned to the low-risk group, patients with a score of 1 were assigned to the intermediate-risk group and patients with a score of 2 were assigned to the high-risk group. RESULTS: The multivariate analysis revealed that, from baseline PET CT parameters, lymph node highest peak SUV strongly predicted the pathological response at a cutoff value of 2.23. DFS was predicted by the lymph node highest peak SUV at a cutoff value of 3.13 and by the MTV value at a cutoff value of 27 cm 3 . The risk scoring performed with regard to rectal MTV and lymph node highest peak SUV values determined a median DFS of 19 months in patients with a risk score of 2, whereas the median DFS was not reached in patients with risk scores of 0 and 1 (P < 0.001). CONCLUSION: This study determined that rectal MTV and lymph node highest peak SUV predicted the response to neoadjuvant therapy and DFS.

Comparison of the role of 18 F-fluorodeoxyglucose PET/computed tomography and 68 Ga-labeled FAP inhibitor-04 PET/CT in patients with malignant mesothelioma.

OBJECTIVE: In this study, we aimed to compare the role of 68 Ga-labeled FAP inhibitor ( 68 Ga-FAPI)-04 PET/computed tomography (CT) and 18 F-fluorodeoxyglucose ( 18 F-FDG) PET/CT in the evaluation of primary tumor and metastases in patients diagnosed with malignant mesothelioma. MATERIALS AND METHODS: Our prospective study included 21 patients with histopathological diagnosis of malignant mesothelioma who underwent both 68 Ga-FAPI-04 PET/CT and 18 F-FDG PET/CT imaging between April 2022 and September 2022. Maximum standardized uptake value (SUVmax), metabolic tumor volume, total lesion glycolysis, tumor-to-background ratio (TBR) and highest SUVpeak (HPeak) values and lesion numbers were calculated from primary and metastatic lesions on FDG and FAPI PET/CT images. Findings obtained from FAPI and FDG PET/CT were compared. RESULTS: More lesions were detected in 68 Ga-FAPI-04 PET/CT compared to 18 F-FDG PET/CT in primary tumor and lymph node metastases. Statistically significantly higher SUVmax and TBR values were found with FAPI PET/CT (primary lesion SUVmax and TBR, P  = 0.001 and P  < 0.001, respectively; lymph node SUVmax and TBR, P  = 0.016 and P  = 0.005, respectively). With FAPI PET/CT, upstage was observed according to tumor-node-metastasis staging in a total of seven patients including three patients with pleural origin, three patients with peritoneal origin and one patient with pericardial origin. CONCLUSION: In addition to the stage change with 68 Ga-FAPI-04 PET/CT in malignant mesothelioma patients, a statistically significant superiority was observed in SUVmax, TBR and volumetric parameters in primary tumors and metastases.

The relationship between CEA and CA 15-3 positivity and metabolic and volumetric 18F-FDG PET/CT parameters in preoperative evaluation of breast cancer.

OBJECTIVE: We aimed to examine the relationship between tumor marker (Cancer Antigen 15-3 [CA15-3] and Carcinoembryonic Antigen [CEA]) positivity and metabolic (standardized uptake value [SUV]) and volume-based (metabolic tumor volume [MTV] and total lesion glycolysis [TLG]) 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) parameters of the primary tumor and lymph node. MATERIAL AND METHODS: Our study group consisted of 91 female patients, who underwent PET/CT between January 2018 and December 2019 in our clinic with a diagnosis of breast cancer. These patients had no distant metastasis or supraclavicular and internal mammarian lymph node metastasis. MTV, TLG, and SUVmax values were obtained from the primary breast lesion and axillary lymph nodes. RESULTS: The mean age of the patients, who participated in the study, was 52,19±14,57, and the median values of the primary tumor MTV, TLG, and total MTV values were found to be statistically significantly higher in those who were CEA positive compared to those who were CEA negative. The median SUVmax value of the axillary lymph node was found to be statistically significantly higher in those who were CEA positive compared to those who were CEA negative (p: 0.004). There was no statistically significant difference between the other parameters. CONCLUSION: There was a statistically significant correlation between CEA positivity in preoperative primary breast cancer and primary tumor volume MTV, TLG, and total MTV values, which are volume-based PET parameters. CEA positivity evaluation may indicate increased tumor load in preoperative. KEY WORDS: Breast Cancer, CEA, CA 15-3, MTV, TLG, FDG PET/CT.

Perirenal Infiltration of Signet Ring Cell Colon Carcinoma Shown by 68Ga-FAPI PET/CT.

ABSTRACT: A soft tissue lesion surrounding the left kidney was detected in 18F-FDG PET/CT performed with suspicion of recurrence in a patient who was operated for descending colon cancer and showed mild FDG uptake. Intense fibroblast activation protein-specific inhibitor (FAPI) uptake in the perirenal soft tissue was observed in 68Ga-FAPI-04 PET/CT. Tru-cut biopsy of the left perirenal lesion revealed signet ring cell colon carcinoma metastasis. This case demonstrated that 68Ga-FAPI-04 PET/CT could be a promising radiopharmaceutical for the evaluation of signet ring cell colon carcinomas.

68Ga-FAPI-04 PET/CT Versus 18F-FDG PET/CT in Malignant Peritoneal Mesothelioma.

ABSTRACT: An 83-year-old man presented with abdominal pain, vomiting, and bloating. His abdominal CT revealed heterogeneous peritoneal thickening in the lower quadrants, which was more prominent in the pelvic region. 18F-FDG PET/CT performed to locate the primary tumor showed irregular peritoneal and omental thickening with low to moderate FDG uptake. 68Ga-FAPI (fibroblast activation protein-specific inhibitor)-04 PET/CT of the patient, whose primary tumor could not be detected using FDG, showed high radiopharmaceutical uptake in the areas of heterogeneous thickening on peritoneal and serosal surfaces. Peritoneal Tru-Cut biopsy revealed malignant tumoral infiltration indicating mesothelioma. This case showed that 68Ga-FAPI-04 PET/CT could be a promising radiopharmaceutical in the evaluation of peritoneal mesothelioma.

Roles of metabolic tumor volume and total lesion glycolysis on 18F-FDG PET/CT, CA19-9 levels, and complete blood count parameters in predicting survival in patients with unresectable or metastatic pancreatic cancer.

AIM: In this study, we aimed to investigate the roles of volume based 18F-FDG PET/CT parameters, CA19-9 levels, and complete blood count parameters in predicting survival in patients with unresectable and/or metastatic pancreatic ductal adenocarcinoma. MATERIALS AND METHOD: Fifty-seven pancreatic cancer patients who were followed in University of Health Sciences Gazi Yasargil Training and Research Hospital between January 2017 and June 2020, declined surgical treatment and/or radiation therapy or had medically inoperable, unresectable, or metastatic disease, and received chemotherapy were included in the study. 18F-FDG PET/CT images of patients were evaluated and calculated metabolic tumor volume (MTV) and total lesion glycolysis (TLG) parameters were compared with CA19-9 levels and complete blood count parameters. Patients were assessed in two groups as survivors and non-survivors. RESULTS: Total MTV and total TLG on 18F-FDG PET/CT were significantly higher among non-survivors than survivors (p: 0.023 and 0.034, respectively). Multivariate Cox regression analysis revealed that TLG higher than 46 g/ml.cm3, MTV higher than 11.02 cm3 (OR 0.987, 95%CI 0.976-0.999, p:0.029 and OR 0.246, 95%CI 0.089- 0.685, p: 0.007, respectively) and elevated MPV (OR:0.785, 95% CI 0,574-0.976, p:0.042) were independent prognostic factors for predicting mortality. CONCLUSION: TLG >46 g/ml.cm3 and MTV >11.02 cm3 in 18F-FDG PET/CT and elevated MPV in complete blood count are independent prognostic factors for predicting mortality in patients with unresectable or metastatic pancreatic cancer who are treated with chemotherapy. KEY WORDS: Pancreatic cancer, Metabolic tumor volume, Total lesion glycolysis, Mean platelet volume.