Diagnostic Performance of F-18 FDG PET/CT in the Detection of Recurrent Colorectal Cancer: Correlation with Biochemical Markers and Conventional Imaging Modalities.

Background/Objectives: Although the role of PET/CT imaging is well established in oncology, its diagnostic value in routine monitoring for recurrent colorectal cancer (CRC) is still controversial. The aim was to evaluate the diagnostic value of F-18 FDG PET/CT in detecting recurrent CRC in correlation with CEA, CA 19-9 levels, and conventional imaging modalities (CIM). Methods: Between 2009 and 2023, a retrospective study was performed including 134 CRC patients referred for PET/CT imaging on the suspicion of recurrence, based on elevated CEA and/or CA 19-9 and/or equivocal CIM findings. According to our institution's Tumor Board CRC protocol, after the initial treatment, which was dependent on the TNM stage (neoadjuvant therapy, primary resection, or adjuvant treatment), patients underwent a standard 5-year surveillance including CEA and CA 19-9 measurements, CIM, and colonoscopy, every six months. The statistics, including univariate and multivariate analyses were conducted using the IBM SPSS 20.0 statistical software. p-values < 0.05 were considered statistically significant. Results: Recurrent CRC was confirmed in 54/134 (40.3%) patients with elevated tumor markers. PET/CT showed high diagnostic performance in detecting recurrent CRC with sensitivity, specificity, PPV, NPV, and accuracy of 94.4%, 82.5%, 78.5%, 95.7%, and 87.3%, respectively. The CEA showed a high sensitivity of 98.1% but both low specificity and accuracy of 15% and 48.5%, respectively. The sensitivity, specificity, and accuracy for CA 19-9 and CIM for diagnosis of CRC recurrence were 44.4%, 67.5%, 58.2%, and 51.9%, 98.8%, 79.9%, respectively. The AUC for PET/CT, elevated CEA levels, CIM, and elevated CA 19-9 levels was 0.885 (95% CI: 0.824-0.946; p < 0.001), 0.844 (95% CI: 0.772-0.916; p < 0.001), 0.753 (95% CI: 0.612-0.844; p < 0.001), and 0.547 (95% CI: 0.442-0.652; p = 0.358), respectively. Univariate analysis showed that both PET/CT and CIM positive results were highly associated with CRC recurrence (p < 0.001 and p < 0.001, respectively). At the same time, gender, mucinous tumor type, presence of initial lymph node metastasis (N+), and presence of initial distant metastasis (M+) had no significance (p = 0.211, p = 0.158, p = 0.583, and p = 0.201, respectively). Our multivariate analysis showed that independent predictors for CRC recurrence are positive PET/CT scans (p < 0.001), positive CIM results (p = 0.001), and elevated CA 19-9 levels (p = 0.023). Although CA 19-9 was not detected as a statistically significant predictor in the univariate analysis (p = 0.358), in a multivariate analysis it was recognized as a significant predicting factor in detecting the CRC recurrence (p = 0.023). Conclusions: F-18 FDG PET/CT showed high diagnostic efficacy in CRC recurrence detection, in correlation with CEA levels, CA 19-9 levels, and CIM. This imaging modality should be routinely integrated into the post-operative follow-op in patients with elevated tumor markers.

CD4+ CD25+ regulatory T-cells role in tumor microenvironment of the squamous cell carcinoma.

INTRODUCTION: Squamous cell carcinoma (SCC) is the most common skin cancer with a high rate of death. Different lymphocyte populations play an important role in modulating the immune response in the tumor microenvironment. The increase in the proportion of cluster of differentiation (CD)4+ CD25+ regulatory T-cell (Treg) lymphocytes is associated, in different studies, with the increase of the cell multiplication rate. AIM: To analyze the Treg lymphocyte subpopulations and to correlate the results with the presence of the CD8+ cytotoxic T-cell (Tc) lymphocyte population. MATERIALS AND METHODS: Sixty primary skin SCC specimens were incubated with anti-CD8 (clone SP57) rabbit monoclonal antibody and anti-CD25 (clone 4C9) mouse monoclonal antibody. RESULTS: The ratio of the intratumoral∕peritumoral CD4+ CD25+ forkhead box protein p3 (Foxp3) lymphocytes was 0.46, emphasizing that at tumor margins, where tumor aggressiveness is higher, these lymphocytes subpopulations facilitate tumor progression. The comparative analysis of the tumor microenvironment profile revealed that in the case of intratumoral immune response, the number of Tc-type lymphocytes (CD8+) was 3.34 times higher compared to Treg lymphocytes (p<0001). In the peritumoral area, the number of Tc lymphocytes was 5.05 times higher compared to Treg lymphocytes (p<0001). CONCLUSIONS: Treg lymphocytes inhibition may cause the suppression of the antitumoral cell immune response in the tumor environment. We believe that Treg lymphocytes should represent a focus of interest for a new personalized therapy. New studies are needed to better understand the immune response in the tumor microenvironment.

Histopathological correlation of cervical biopsy and tissue after excision in patients with precancerous lesions of the cervix.

INTRODUCTION: Cervical intraepithelial neoplasia (CIN) are precancerous lesion of cervix, with incidence of 1.6 per 1000 for CIN 1 lesion and 1.2 per 1000 for CIN 3 lesion in USA. According to IARC incidence is higher in less developed and developing countries. Taking into account the fact that the sensitivity, specificity and accuracy of Papanicolaou swab and colposcopy vary, the final diagnosis is made by colposcopically guided biopsy and by excisions of the cervix. AIM OF THE STUDY: Comparing the histopathological findings of cervical biopsy and definitive histopathological findings after cervical excision in precancerous lesions of the cervix in relation to the degree of lesion, age and institution, where the biopsy was performed. MATERIALS AND METHODS: The study was retrospective and was conducted on a group of patients who underwent some excision techniques on the cervix after obtaining a histological finding of the cervical biopsy. RESULTS: In a total sample of 168 patients, a correlation of histopathological analysis of biopsy material and excision techniques was observed in 62.5% (105/168). This correlation was statistically significant (χ2 = 5.333, df 1; p = 0.0209). The greater correlation of histopathological material of biopsies and final histopathological material after excisions were obtained in Oncology Institute of Vojvodina (OIV) without statistical significance. CONCLUSION: A statistically significant accuracy of biopsy was noted in examined group of patients.

VALUE OF PROTECTIVE STOMA IN RECTAL CANCER SURGERY.

INTRODUCTION: Anastomotic leakage is the most serious surgical complication in rectal surgery. The aim of this study was to find out whether a protective stoma was capable of lowering the rate of clinical anastomotic leakage and to evaluate the rate of anastomotic leakages requiring resurgery. MATERIAL AND METHODS: A retrospective study included a sample of 149 consecutive patients with rectal cancer who had undergone elective rectal resection with primary anastomosis. After total mesorectal excision, the anastomosis was created using either the single stapling or double stapling anastomotic technique. Anastomotic integrity was verified by transanal air insufflations with the pelvis filled with saline. A protective covering colostomy was added in selected cases and according to the surgeon's preference. RESULTS: A protective stoma was created in 31% of patients. Clinical anastomotic leakage occurred in 6.7% of patients (10/149). Anastomotic leakage occurred in 8.5% of the patients with a protective stoma (4/47) and in 5.9% of those without a protective stoma (6/102), which was not statistically significant. Surgery lasted significantly longer when a stoma had to be created than in case when it was not needed (p=0.024). The overall rate of resurgery due to postoperative surgical complications was 5.3% and in three cases this happened because of anastomotic leakage. All patients with a protective stoma and clinical anastomotic leakage were treated conservatively, compared to 50% of patients without a protective stoma who suffered anastomotic leakage and had to be operated. CONCLUSION: A stoma cannot prevent but it can surely minimize surgical complications related to anastomotic leakage and it does reduce the rate of resurgery.

Concurrent chronic lymphocytic leukemia and merkel cell carcinoma in primary skin tumor and metastatic lymph node.

Association between chronic lymphocytic leukemia and other malignancies has been known for a long time. This epidemiological phenomenon is explained by immunosuppression caused by disease itself or by the applied therapy. Merkel cell carcinoma is a rare malignant tumor of the skin of neuroendocrine origin diagnosed almost exclusively in immunocompromised host. We presented an unique case of coexisting infiltration of chronic lymphocytic leukemia cells within primary cutaneous Merkel cell carcinoma and metastatic lymph node in young HIV-negative female patient.