Lutetium-177-PSMA-617 radioligand therapy in patients with high volume metastatic prostate cancer prior to chemotherapy and new generation androgen deprivation therapy: Clinical Experience.

OBJECTIVE: We aimed to evaluate the efficacy oflutetium-177-prostate-specific membrane antigen-617 (177Lu-PSMA-617) with the luteinizing hormone releasing hormone (LHRH) analogues in the first or in the second-line setting formetastatic castration sensitive patients and metastatic castration resistance after progression with LHRH analogues. SUBJECTS AND METHODS: Sixteen consecutive patients with high volume metastatic prostate cancer undergone 177Lu-PSMA-617 therapy who were refused chemotherapy and were unable to use new generation anti-androgen drugs because of unavailibility of reimbursement, were included in this retrospective study. Prostate specific antigen (PSA) response (>50% decrease), disease control rate (DCR: complete or partial response), progression-free survival (PFS) and overall survival (OS) were calculated to evaluate according to the clinicopathological features of the patients. Treatment response evaluated by 68Ga-PSMA-11 positron emission tomography/computed tomography (PET/CT). RESULTS: Mean age was 74,6 (SD±8,36). Among them, 7 (43,8%) patients has castration resistant disease, while the remaining has castration sensitive disease. Lutetium-177-PSMA-617 was administered to 10 (62,5%) patients as one of the first-line treatment and 6 patients received the treatment after progression on LHRH as a second-line treatment. Considering all patients, PSA response rate and DCR were 50% and 62% respectively. The median PFS and OS (with 95% CI) were 11,2 months (11-15) and 29 months (25,6-32,4), respectively in patients treated with 177Lu-PSMA-617 and LHRH analogues. Clinicopathological features and basal PSA level did not have effect on PSA response rates, DCR, OS and PFS. On the other hand, increment in PFS and OS (with 95% CI) was observed in castration resistant disease and in the second-line therapy; for castration resistant disease 16,5 months (12.3-19.7); 30 months (25.3-32.7), for the second-line therapy 14.5 months (12-20.5); 29 months (NR), respectively but statistically not significant. Serious toxicity was observed in a limited number of patients (18,7%), treatment-related death was not observed. CONCLUSION: Favorable results can be achived with second-line 177Lu-PSMA-617 treatment in terms of OS and PFS, especially in castration-resistant disease, when chemotherapy and new generation ADT's cannot be used.

Should We Completely Exclude Locoregional Therapy for the Primary Tumor from Our Clinical Practice in De Novo Metastatic Breast Cancer?

Locoregional therapy (LRT) for the primary site of breast cancer (BC) is one of the most debated topics in de novo metastatic disease. We have four main randomized controlled trials, three negative and one positive, together with one positive prospectively designed non-randomized study investigating the contribution of LRT to the literature. We aimed to discuss the possible reasons for the positive or negative results of the studies and to identify specific subgroups that may benefit from primary breast surgery.

Dramatic response to crizotinib in a breast cancer patient with ALK gene rearrangement.

Rearrangements of the anaplastic lymphoma kinase (ALK) gene are present in 3-5% of non-small-cell lung cancer (NSCLC), while it was 0.2% in NSCLC tumors. Due to its low frequency, it is extremely challenging to conduct randomized clinical trials of ALK-targeted therapies in NSCLC tumors. In the present case, we describe the first reported case of triple-negative breast cancer (TNBC) harboring the ALK fusion mutation that responded to ALK-targeted therapy after progression with two lines of chemotherapy. Searching for ALK gene rearrangement or other fusion, especially in patients with chemotherapy-resistant TNBC, opens the door to new treatment strategies.

The predictive value of vitamin D follow-up and supplementation on recurrence in patients with colorectal cancer.

Aim: Vitamin D has a role in carcinogenesis and may have effect on recurrence. Thus, we aim to analyze the prognostic effect of vitamin D levels at beginning and follow-up together with the contribution of vitamin D supplementation on patients with colorectal cancer (CRC). Materials & methods: CRC patients who underwent curative surgery were included. Patients' vitamin D values were assessed under four groups according to baseline and follow-up vitamin D values, and whether vitamin D supplementation was used. Survival distributions were compared for vitamin D groups. Results: Patients with a high follow-up vitamin D level and a high vitamin D level after supplementation presented with better disease-free survival and overall survival than patients with low vitamin D and low vitamin D levels after supplementation. Conclusion: Follow-up vitamin D values seems to be a good predictive biomarker and vitamin D supplementation may have a positive effect on survival.

Association of illness perception with chemotherapy-induced nausea and vomiting: a Turkish Oncology Group (TOG) study.

Chemotherapy-induced nausea and vomiting (CINV) may be linked to the psychological status of cancer patients. Therefore, the authors aimed to better understand the underlying risk factors for CINV using the Brief Illness Perception Questionnaire. A total of 238 patients were recruited during three cycles of chemotherapy. Patient, disease and treatment characteristics were noted at the onset of chemotherapy. The Brief Illness Perception Questionnaire was administered face-to-face prior to chemotherapy. The relationship between illness perceptions and CINV was analyzed using Spearman's rank correlation. Positive illness perception parameters, including personal and treatment control, were negatively correlated, whereas negative illness perception parameters, including consequences, timeline, identity, concern and emotions, were positively correlated with CINV after adjusting for age, sex and emetogenic potential of chemotherapy (p < 0.001). Illness perception may be an underlying risk factor for CINV.

Recurrence pattern in the presence of hepatosteatosis in breast cancer: does it facilitate liver metastasis?

Aim: We aimed to investigate the impact of hepatosteatosis (HS) severity on the recurrence pattern of breast cancer and to clarify whether HS causes affinity to recurrence with liver metastasis. Materials & methods: The median follow-up was 80.0 (4-217) months and the mean age was 47.9 ± 11.3 years. Among all, 181 (39.9%) patients were diagnosed with grades 2 and 3 HS. Of total, 158 (34.8%) patients have experienced recurrence. Results: While higher degree of HS was more common in patients presented with liver recurrence (odds ratio; 95% CI: 2.50; 1.27-4.92; p = 0.007), it was lesser in those with other metastatic sites (all were >0.05). Liver-recurrence-free survival was significantly worse in the group with higher degree of HS (hazard ratio; 95% CI: 2.46; 1.4-4.3; p = 0.002) together with younger age (hazard ratio; 95% CI: 2.44; 1.4-4.3; p = 0.002) in multivariate analysis. Conclusion: HS might have produced an affinity for liver metastasis in common types of breast cancer patients in remission independent from metabolic disorders or clinicopathologic features.

Worse patient-physician relationship is associated with more fear of cancer recurrence (Deimos Study): A study of the Palliative Care Working Committee of the Turkish Oncology Group (TOG).

OBJECTIVE: Fear of cancer recurrence (FCR) is an important psychological trauma associated with reduction in the quality of life, disruptions in the level of adjustment, emotional distress and anxiety. The purpose of the study was to evaluate the impact of patient-physician relationship on FCR. METHODS: The study was designed as a multicentre survey study. The cancer survivors, who were under remission, were evaluated with structured questionnaires. Patient-physician relationship (PPR) scale in which higher scores indicate better relationship and FCR inventory was used. RESULTS: Between January and April 2019, 1,580 patients were evaluated. The median age was 57.0 (19-88), and 66% were female. There was high level of FCR scores in 51% of participants. There was a negative correlation between PPR and FCR scores (r = -.134, p < .001). In multivariate analysis, young age, female gender, history of metastasectomy and worse PPR were associated with high levels of FCR. CONCLUSION: It is the first data showing the adverse impact of worse PPR on FCR. The strategies to improve the PPR should be practised. In addition, the cancer survivors, who are under the risk of FCR, should be evaluated and managed.

Durable response after interruption of nivolumab in patients with metastatic renal cell carcinoma: Is renal toxicity a marker to predict the benefit of nivolumab?

INTRODUCTION: Nivolumab is a human IgG4 programmed death-1 immune checkpoint inhibitor antibody. Immune-related toxicity may be associated with higher response even after interruption of nivolumab. CASE REPORT: We reported a case diagnosed with metastatic clear cell renal cell carcinoma and treated with nivolumab as fourth-line therapy. Although nivolumab treatment was stopped after two cycles due to grade 3 renal toxicity, progression-free survival rates of 11 months, that is quite a long time for fourth-line treatment of renal cell carcinoma was observed. MANAGEMENT AND OUTCOME: Therefore, we speculate that when renal toxicity develops, response may continue even after interruption of nivolumab in renal cell carcinoma. DISCUSSION: Nivolumab was approved to be used for second-line treatment of renal cell carcinoma with 4.6 months of median progression-free survival benefit. Higher immune-related toxicity can produce higher efficacy for some instances such as malignant melanoma, lung cancer, and renal cell carcinoma. Renal disturbance during nivolumab treatment is extremely rare, and there are no data on survival after interruption due to renal toxicity of nivolumab without further treatment in renal cell carcinoma. In the present case, we obtained long duration of stable disease, with two cycles of nivolumab after the development of nephrotoxicity. Close follow-up without any treatment until progression may be a treatment choice, because nephrotoxicity can be a sign of benefit and durable response to nivolumab.

Illness perception is a strong parameter on anxiety and depression scores in early-stage breast cancer survivors: a single-center cross-sectional study of Turkish patients.

BACKGROUND: Illness perception has been suggested to have a significant effect on anxiety and depression in cancer patients. In this cross-sectional study, we aimed to evaluate this on Turkish breast cancer patients with follow-up periods up to 12 years. PATIENTS AND METHODS: A total of 225 patients (with 6 months to 12 years follow-up) were recruited in this cross-sectional study. The patients were divided into three groups of follow-up: 6 months-2 years, 2-5 years, and >5 years. Beck Depression Inventory, Beck Anxiety Inventory, Duke-University of North Carolina Functional Social Support Questionnaire, and Brief Illness Perception Questionnaire were used to assess the depression, anxiety, functional social support (FSS), and illness perception, respectively. Statistical significance of the associations was analyzed using Spearman correlation, Student's t, Mann-Whitney U, and ANOVA tests. RESULTS: Rates of moderate-severe anxiety and depression scores were not correlated with follow-up period and disease stage, whereas all these parameters were associated significantly with FSS and age. Parameters of illness perception were also not correlated with follow-up period and stage of disease. However, illness perception scores were noticeably better with increments in FSS. Also, the parameters of illness perception were strongly associated with the depression/anxiety score. CONCLUSION: Illness perception is an important determinant of the depression/anxiety score in Turkish breast cancer patients.

Sorafenib with TACE improves the survival of hepatocellular carcinoma patients with more than 10 cm tumor: a single-center retrospective study.

PURPOSE: Sorafenib, a multikinase inhibitor, is effective in patients with advanced hepatocellular carcinoma (HCC). Transarterial chemoembolization (TACE) is an important palliative treatment for unresectable HCC, but TACE-induced ischemic injury can upregulate angiogenic factors and it might be associated with poor prognosis. The purpose of this study was to evaluate the efficacy of conventional TACE with or without sorafenib in patients with Barcelona Clinic Liver Cancer (BCLC) stage A-B HCC. METHODS: Thirty patients with BCLC stage A or B HCC who had undergone TACE were enrolled in this retrospective study. Child-Pugh score, BCLC staging classification, size and number of lesions were recorded. Sorafenib was given 1 month after TACE to some patients who responded to TACE. Repeated TACE was performed on demand. Tumor response was assessed every 12 weeks. The primary objective of this trial was the progression free survival (PFS). Secondary objectives were overall survival (OS), disease control rate (DCR) and total number of TACE interventions. Kaplan-Meier method was used for the estimation of survival and survival curves were compared with Log-rank test. RESULTS: Twenty-five (83.3%) patients had Child-Pugh A and 5 (16.7%) Child-Pugh B, and 24 (80%) patients had BCLC stage B disease and remanining had stage A disease. Lesion size >10 cm was found in 6 patients and 16/7/7 patients had single/two/multiple lesions, respectively. Mean number of TACE was 2.10±1.369. Seventeen (56.7%) patients used sorafenib after TACE whereas 13 (43.3%) patients were followed without any treatment but received consequent TACEs if needed. PFS of all patients was 10 months (range 3-48); it was 13 months for TACE plus sorafenib group and 9 months for TACE group (p=0.081). In subgroup analysis, TACE plus sorafenib group had better PFS (36 vs 12 months) in patients with tumor size > 10 cm (p=0.025). In the analysis of Child- Pugh A cases, PFS of TACE plus sorafenib group was 23 months while it was 10 months in TACE group (p=0.007). CONCLUSION: Concurrent treatment in Child-Pugh A group HCC with conventional TACE and sorafenib demonstrates a significant efficacy in patients having tumor size >10 cm. In Child-Pugh A group, PFS was superior in the sorafenib plus TACE group than in TACE alone group.

Efficacy of venlafaxine for the relief of taxane and oxaliplatin-induced acute neurotoxicity: a single-center retrospective case-control study.

BACKGROUND: Oxaliplatin and taxane-induced neurosensory toxicity is dose-limiting and mostly presents with acute symptoms that affect the activities of daily living and overall quality of life. The objective of the present study is to assess the relief of acute neuropathy with venlafaxine treatment during the chemotherapy period. PATIENTS AND METHODS: In this retrospective case-control study, from January 2010 to February 2015, patients who experienced treatment with oxaliplatin and taxane-induced acute neurotoxicity were evaluated according to the NCI-CTCAE v. 4.03 grading scale. Neurotoxicity was evaluated using a numeric rating scale (NRS) for pain intensity and experienced relief under the treatment of venlafaxine and using a neuropathic pain symptom inventory scale (NPSI) for the style of complaints. Patients who were diagnosed as mildly depressed according to the HOST anxiety and depression scale and who had grade 1 to 3 sensory neurotoxicity based on the NCI-CTCAE v. 4.03 grading scale, and who also reported ≥ 4/10 on a NRS were eligible. The primary end point was the rate of more than 75 % symptomatic relief under venlafaxine treatment. RESULTS: Two hundred six patients were included (82 % female, median age: 52.7 years). Most patients had breast, gynecologic, and colon cancer (93.4 %). Ninety-one patients who received venlafaxine and 115 patients as the control group were assessed for neurotoxicity every 3 weeks. Based on the NRS, a rate of more than 75 % symptomatic relief was 53.5, 58.3, and 45.2 % in venlafaxine arm versus 0, 0, and 0 % in the control arm in the first, second, and third visits, respectively. Side-effects of venlafaxine (n = 7) were grade 1-2 nausea/vomiting (3.2 %) and asthenia/somnolence (3.2 %) without grade 3-4 events. CONCLUSION: Venlafaxine has a significant clinical activity against taxane-oxaliplatin-induced acute neurosensory toxicity.

Taxane-induced peripheral sensorial neuropathy in cancer patients is associated with duration of diabetes mellitus: a single-center retrospective study.

PURPOSE: The purpose of this study was to determine whether the presence of diabetes mellitus (DM) influences the incidence and severity of peripheral sensory neuropathy (PSN) in patients using taxane therapy. METHODS: A retrospective single-center analysis was conducted: Patients with PSN at baseline were excluded. The incidence of PSN was evaluated retrospectively in patient subgroups who received taxane arm and taxane-plus-platinum-agents combination arm with or without known DM at baseline. RESULTS: Three hundred seventy-four patients were enrolled in this study, 81 (21.6%) of patients had DM at baseline. The incidence of grade 1 PSN (non-DM/DM) in patients receiving taxane-based chemotherapy was 33.4/25.9% and more than grade 2 PSN (non-DM/DM) was 15/34.6%. The rate of neuropathy of non-diabetic patients was 48.8%, while the rate of diabetic patients was 52.8 and 75% in DM duration below 5 years and above 5 years group, respectively. CONCLUSIONS: This retrospective analysis indicates that taxane-based therapy in DM patients whose disease duration is above 5 years appears to affect the incidence and severity of PSN without known baseline neuropathy. The probability of PSN with taxane-based therapy was similar in DM duration below 5 years and non-DM patients.

Atypical presentation of disseminated intravascular coagulation with synchronous peripheral venous thromboembolism and arterial gangrene in a pancreatic cancer patient: a case report.

CONTEXT: Cancer is a prothrombotic state and anticancer therapies are often complicated by vascular events. The risk of developing thromboembolic events is substantially increased in patients with pancreatic cancer. One possible presentation of vascular events in pancreatic cancer is disseminated intravascular coagulation (DIC). CASE REPORT: In our case a patient with a diagnosis of pancreatic cancer initially presented with thrombosis and received low molecular weight heparin (LMWH) in addition to standard chemotherapy regimen. He was thought to have DIC by assessment of clinical and laboratory findings. CONCLUSION: Clinically, thrombosis was first located in the left femoral vein and encountered at right femoral artery after three weeks. This pattern was an unusual presentation of DIC. Subclinical DIC is common in patients presenting with pancreatic cancer and is considered a 'poor' prognostic factor. Acute DIC, on the other hand is a potentially mortal condition.

A perspective: the integration of ctDNA into Response Evaluation Criteria in Solid Tumours 1.1 for phase II immunotherapy clinical trials.

A consensus guideline, iRECIST, was developed by the Response Evaluation Criteria in Solid Tumours (RECIST) working group for the use of the modified RECIST version 1.1 in cancer immunotherapy trials. iRECIST was designed to separate pseudoprogression from real progression. However, this is not the only ambiguous situation. In clinical immunotherapy trials, stable disease may reflect three tumor responses, including real stable disease, progressive disease and responsive disease. The prediction of a "true complete/partial response" is also important. Much data has accumulated showing that ctDNA can guide decisions at this point; thus, integrating ctDNA into the RECIST 1.1 criteria may help to distinguish a true tumor response type earlier in patients treated with immunotherapy; however, prospectively designed validation studies are needed.

68Ga-FAPI PET/CT as an Alternative to 18F-FDG PET/CT in the Imaging of Invasive Lobular Breast Carcinoma.

Accurate staging of invasive lobular carcinoma (ILC), a subtype of breast cancer, is vital for effective clinical management. Although 18F-FDG PET/CT is a commonly used tool, its efficacy varies across different histologic subtypes. To mitigate this challenge, our investigation delves into the potential utility of 68Ga-fibroblast activation protein inhibitor (FAPI) PET/CT as an alternative for staging ILC, aiming to address a significant research gap using a more expansive patient cohort than the smaller samples commonly found in the existing literature. Methods: In this retrospective analysis, women diagnosed with primary ILC of the breast underwent both 18F-FDG PET/CT and 68Ga-FAPI PET/CT. Both modalities were compared across all lesion locations with the used reference standard. The interval between scans was 1 wk, without any intervening treatments. Lesions were categorized visually, and tracer activity was analyzed using SUVmax, tumor-to-background uptake ratio, and uptake ratios. Both modalities were compared across various parameters, and statistical analysis was performed using SPSS 22.0. A P value of less than 0.05 was chosen to determine statistical significance. Results: The study included 23 female ILC patients (mean age, 51 y) with hormone-positive, human epidermal growth factor receptor type 2-negative tumors. Most (65%) had the luminal A subtype. 68Ga-FAPI PET/CT outperformed 18F-FDG PET/CT, with higher tumoral activity and tumor-to-background uptake ratios (P < 0.001). Primary tumors showed significantly increased uptake with 68Ga-FAPI PET/CT (P < 0.001), detecting additional foci, including multicentric cancer. Axillary lymph node metastases were more frequent and had higher uptake values with 68Ga-FAPI PET/CT (P = 0.012). Moreover, 68Ga-FAPI PET/CT identified more lesions, including bone and liver metastases. Pathologic features did not significantly correlate with imaging modalities, but a positive correlation was observed between peritumoral lymphocyte ratio and 68Ga-FAPI PET/CT-to-18F-FDG PET/CT uptake ratios (P = 0.026). Conclusion: This study underscores 68Ga-FAPI PET/CT's superiority over 18F-FDG PET/CT for ILC. 68Ga-FAPI PET/CT excels in detecting primary breast masses, axillary lymph nodes, and distant metastases; can complement 18F-FDG PET/CT in ILC; and holds potential as an alternative imaging method in future studies.

The Effectiveness of Adjuvant PD-1 Inhibitors in Patients With Surgically Resected Stage III/IV Acral Melanoma.

Our aim was to assess the efficacy of adjuvant programmed cell death protein-1 (PD-1) inhibitors and compare the other adjuvant treatments in patients with surgically resected stage III or IV acral melanoma. This study is a multicenter, retrospective analysis. We included 114 patients with stage III or IV acral malignant melanoma who underwent surgery within the past 10 years. We analyzed the effect of adjuvant programmed cell death protein-1 inhibitors on disease-free survival (DFS). The mean follow-up was 40 months, during which 69 (59.5%) patients experienced recurrence. Among the participants, 64 (56.1%) received systemic adjuvant therapy. Specifically, 48.4% received anti-PD-1 therapy, 29.7% received interferon, 14.1% received tezozolomide, and 7.8% received B-Raf proto-oncogene/mitogen-activated protein kinase inhibitors. Patients who received adjuvant therapy had a median DFS of 24 (10.9-37.2) months, whereas those who did not receive adjuvant therapy had a median DFS of 15 (9.8-20.2) months. Multivariate analysis for DFS revealed that the receipt of adjuvant therapy and lymph node metastasis stage were independent significant parameters ( P = 0.021, P = 0.018, respectively). No statistically significant difference was observed for DFS between programmed cell death protein-1 inhibitor treatment and other adjuvant treatments. Regarding overall survival (OS), patients who received adjuvant treatment had a median OS of 71 (30.4-111.7) months, whereas those who did not receive adjuvant treatment had a median OS of 38 (16.7-59.3; P = 0.023) months. In addition, there were no significant differences in OS observed between various adjuvant treatment agents ( P = 0.122). In our study, we have shown that adjuvant therapy had a positive effect on both DFS and OS in patients with stages III-IV acral melanoma who underwent curative intent surgery. Notably, we found no significant differences between anti-PD-1 therapy and other adjuvant therapies.

Comparison of [68Ga]-FAPI PET/CT and [18F]-FDG PET/CT in Multiple Myeloma: Clinical Experience.

OBJECTIVE: In this study, we aimed to compare [68Ga]FAPI PET/CT and [18F]FDG PET/CT imaging to detect lesions in multiple myeloma. METHODS: A total of 14 patients with multiple myeloma who underwent [68Ga]FAPI PET/CT and [18F]FDG PET/CT imaging were included in this retrospective study. SUVmax values of [68Ga]FAPI and [18F]FDG were compared according to lesion locations. Also, lesion localization ability of both imaging methods was compared on the patient basis. RESULTS: In 4 of 14 patients, [68Ga]FAPI PET/CT and [18F]FDG PET/CT have not detected any bone lesions. In 8 of the remaining 10 patients [18F]FDG PET/CT detected bone lesions but in this group, 6 patients showed more higher SUVmax values than [18F]FDG PET/CT in [68Ga]FAPI PET/CT.In contrast, 2 of 8 patients showed more higher SUVmax values than [68Ga]FAPI PET/CT in [18F]FDG PET/CT. Moreover, [68Ga]FAPI PET/CT detected bone lesions in two patients, which werenot detected by [18F]FDG PET/CT. Also, in five patients, [68Ga]FAPI PET/CT showed more bone lesions in comparison with[18F]FDG PET/CT. Only one patient, [18F]FDG PET/CT showed more bone lesions. Three extramedullary involvements were observed in the following locations: lung, presacral lymph node, and soft tissue mass lateral to the right maxillary sinus. Among these involvements, higher SUVmax values were observed in the lung and presacral lymph node with [68Ga]FAPI compared to [18F]FDG. However, the soft tissue mass showed a higher SUVmax value in [18F]FDG than [68Ga]FAPI. CONCLUSIONS: No significant superiority was observed in [68Ga]FAPI PET/CT over [18F]FDG PET/CT in patients with MM. However, [68Ga]FAPI PET/CT can be utilized as a complementary imaging method to [18F]FDG PET/CT in some settings, especially in low-[18F]FDG affinity and inconclusive cases. Considering the favorable aspects of [68Ga]FAPI PET/CT in MM, such as low background activity, absence of non-specific bone marrow, and physiological brain involvement, further studies with a larger sample size should be conducted.

Comparison of 68Ga-FAPI PET/CT and 18FDG PET/CT Modalities in Gastrointestinal System Malignancies with Peritoneal Involvement.

PURPOSE: In this study, we aimed to investigate the utilization of 68Ga-FAPI PET/CT in comparison to 18FDG PET/CT to evaluate the peritoneal involvement of the gastrointestinal malignancies alongside primary lesions and other metastatic foci. PROCEDURES: A total of 37 patients with various gastrointestinal malignancies with accompanying peritoneal involvement who underwent 68Ga-FAPI PET/CT and 18FDG PET/CT imaging between September 2020 and June 2021 were included in this retrospective study. SUVmax values of 68Ga-FAPI and 18FDG were compared according to lesion locations. Also, the lesion localization ability of both imaging was compared in patient basis. RESULTS: Of the 37 patients with peritoneal involvement (23 males and 14 females; median age, 62.8 ± 12.7 years), 35.1% (n = 13) had colorectal cancer, 37.8% (n = 14) gastric cancer, and 27.0% (n = 10) pancreaticobiliary cancer. While 45.9% of them were operated, the remaining did not have surgery. The mean time interval between two studies was 3.2 days (range: 2-6 days). The mean SUVmax value of peritoneal metastases (p < 0.001) was significantly higher with 68Ga-FAPI PET/CT compared to that with 18FDG PET/CT, as in primary lesions (p < 0.001), lymph node metastases (p = 0.006), liver metastases (p = 0.002), and bone metastases (p = 0.018). A total of 185 lesions was detected in the initial assessment with 18FDG PET/CT. Of the total lesions detected with 18FDG PET/CT, 5 of them were evaluated as benign lesions with 68Ga-FAPI PET/CT also in accordance with the reference standard. In addition to 180 lesions detected with 18FDG PET/CT, a total of 37 additional malignant lesions, 12 of which were peritoneal metastases, were detected with 68Ga-FAPI PET/CT. CONCLUSION: 68Ga-FAPI PET/CT was determined to be superior to 18FDG PET/CT in terms of detection of peritoneal involvement with high image quality as well as primary tumor and other metastatic foci. Consequently, 68Ga-FAPI PET/CT can be used as a complementary imaging modality especially for inconclusive 18FDG findings due to the lack of accuracy of 18FDG PET/CT in some of the metastatic regions, especially in the liver.