Reactive axillary lymph nodes after COVID-19 mRNA vaccination: comparison of mRNA vs. attenuated whole-virus vaccines.

OBJECTIVE: To compare the incidence and natural course of reactive axillary lymph nodes (RAL) between mRNA and attenuated whole-virus vaccines using Deauville criteria. METHODS: In this multi-institutional PET-CT study comprising multiple vaccine types (Pfizer-BioNTech/Comirnaty, Moderna/Spikevax, Sinovac/CoronaVac and Janssen vaccines), we evaluated the incidence and natural course of RAL in a large cohort of oncological patients utilizing a standardized Deauville scaling system (n=522; 293 Female, Deauville 3-5 positive for RAL). Univariate and multivariate analyses were conducted to evaluate the predictive value of clinical parameters (absolute neutrophil count [ANC], platelets, age, sex, tumor type, and vaccine-to-PET interval) for PET positivity. RESULTS: Pfizer-BioNTech/Comirnaty and Moderna vaccines revealed similar RAL incidences for the first 20 days after the second dose of vaccine administration (44% for the first 10 days for both groups, 26% vs. 20% for 10-20 days, respectively for Moderna and Pfizer). However, Moderna recipients revealed significantly higher incidences of RAL after 20 days compared to Pfizer-BioNTech/Comirnaty, with nodal reactivity spanning up to the 9th week post-vaccination (15% vs. 4%, respectively P  < 0.001). No RAL was observed in patients who received either a single dose of J&J vaccine or two doses of CroronaVac. Younger patients showed increased likelihood of RAL, otherwise, clinical/demographic parameters were not predictive of RAL ( P  = 0.014 for age, P  > 0.05 for additional clinical/demographic parameters). CONCLUSION: RAL based on strict PET criteria was observed with mRNA but not with attenuated whole-virus vaccines, in line with higher immunogenicity and stronger protection offered by mRNA vaccines.

Comparison between body composition parameters and response to neoadjuvant chemotherapy by using pre-treatment PET CT in locally advanced breast cancer.

PURPOSE: To compare the adipose and muscle tissue areas in patients who responded differently to neoadjuvant chemotherapy. METHODS: One hundred and eighty six patients diagnosed with breast cancer who underwent neoadjuvant chemotherapy between January 2015- October 2019 and were operated after the treatment were retrospectively included in the study. Pathological results were divided into five groups using the Miller-Payne grading systems. Grade 1 indicating no significant reduction in malignant cells; Grade 2: a minor loss of malignant cells (≤ 30 %); Grade 3: reduction in malignant cells between 30 % and 90 %; Grade 4: disappearance of malignant cells >90 %; Grade 5: no malignant cells identifiable. Pre-treatment PET CT scans were evaluated, and calculation of body composition parameters were performed on a single axial section passing through the L3 vertebrae. Spearman's correlation test was used to analyze the correlation between SAT, VAT, MT parameters and pathological responses. RESULTS: There was no strong correlation between the 5 groups separated according to neoadjuvant chemotherapy treatment response and tissue distributions. However, that there was a very low correlation found between superficial adipose tissue and pathological response (r=, 156). CONCLUSION: In conclusion, our results have provided a very low correlation between SAT and more than 30 % response. More research is required to evaluate the role of the body fat and muscle parameters in response to neoadjuvant chemotherapy in larger patient populations.

The utility of FDG-PET/CT as an effective tool for detecting recurrent colorectal cancer regardless of serum CEA levels.

PURPOSE: Tumor recurrence of colorectal cancers (CRC) is generally followed up by analyses of the serum carcinoembryonic antigen (CEA) levels. However, recent evidence suggests that tumor recurrence can also be visualized by 18F-fluoro-deoxyglucose emission tomography/computed tomography (FDG-PET/CT) in patients with normal CEA levels. We retrospectively evaluated the diagnostic performance of FDG-PET/CT in patients with suspected recurrence of CRC by comparing PET/CT performance in patients with normal CEA levels with PET/CT performance in patients with elevated CEA levels. METHODS: A total of 235 patients with CRC who had been treated with surgery and/or chemotherapy/radiotherapy underwent PET/CT for the detection of tumor recurrence. The patients [96 females and 139 males; age (mean ± SD) 59.9 ± 12.6 years; range 18-85] were divided into 2 groups based on whether their CEA levels were normal (<5 ng/ml) (Group 1, n = 118) or elevated (>5 ng/ml) (Group 2, n = 117). All of the patients had suspected recurrence based on raised CEA levels, clinical symptoms, and/or tumor detection using other imaging modalities. RESULTS: Of the 235 patients, 172 (73.1 %) had disease recurrence confirmed by a pathological examination (either biopsy or surgical exploration) or clinical follow-up studies. The FDG-PET/CT study yielded a true positive in detecting recurrence in 169 (71.9 %) patients, a true negative in 53 (22.5 %) patients, a false negative in 3 (1.2 %) patients and a false positive in 10 (4.2 %) patients. CRC recurrence was detected in 64.4 % (76/118) and 88 % (103/117) patients in Group 1 and Group 2 with FDG-PET/CT, respectively. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of the FDG-PET/CT study for establishing recurrence were 100, 84, 89.4, 100 and 93.2 %, respectively, for Group 1; by contrast, these parameters were 97.1, 84.6, 98, 78.5 and 95.7 %, respectively, for Group 2. The number of patients with hepatic and extra-hepatic metastases, such as lung and abdominal lymph node metastasis, detected with FDG-PET/CT was significantly different in Group 1 than in Group 2; however, the number of patients with local recurrence and peritoneal implants detected with FDG-PET/CT was not different between the two groups. CONCLUSIONS: FDG-PET/CT can accurately detect tumor recurrence in patients with suspected recurrent CRC, even for patients with normal CEA levels.

Diagnostic value of PET/CT is similar to that of conventional MRI and even better for detecting small peritoneal implants in patients with recurrent ovarian cancer.

OBJECTIVE: The aim of this study was to evaluate the diagnostic value of 2-(fluorine-18)-fluoro-2-deoxy-D-glucose ((18)F-FDG) PET/CT in comparison with MRI for the detection of recurrent ovarian cancer. METHODS: Forty-seven patients with suspected ovarian cancer recurrence after total ablative or cytoreductive surgery, as well as neoadjuvant or adjuvant chemotherapy, who had undergone (18)F-FDG PET/CT imaging were recruited for the present study. All patients also underwent MRI within a month of (18)F-FDG PET/CT for the same purpose. Recurrent cancer in the abdomen and pelvis was evaluated in each of the 47 patients and classified as either distant metastasis or local pelvic recurrence involving the vaginal stump, peritoneal implants, supradiaphragmatic region, and/or abdominal and pelvic lymph nodes. Special attention was paid to peritoneal implants. These were divided into five groups according to size of the implants: less than 0.5 cm (group 1), 0.5-1 cm (group 2), 1-2 cm (group 3), 2-3 cm (group 4), and larger than 3 cm (group 5). PET/CT findings were compared with abdominopelvic MR findings. Statistical analysis was carried out using the Wilcoxon signed rank test. RESULTS: Thirty-nine of 47 patients were found to have recurrent ovarian cancer. Both PET/CT and MRI were negative for recurrence in six patients. Overall sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of PET/CT were 97.5, 100, 100, 87.5, and 97.8%, respectively, whereas those of MRI were 95, 85.7, 97.4, 75, and 93.6%, respectively. For the peritoneal implants in groups 2 and 3, the sensitivity, negative predictive value, and diagnostic accuracy values of PET/CT were significantly better than those of MRI (P<0.05). CONCLUSION: The present study revealed that PET/CT is similar to conventional MRI for the detection of recurrent ovarian cancer. PET/CT has greater accuracy in the detection of small-to-medium-sized (<2 cm) peritoneal implants compared with MRI. This may affect surgical decision making.