COVID-19 vaccine related hypermetabolic lymph nodes on PET/CT: Implications of inflammatory findings in cancer imaging.

We observed several patients presenting 2-[18F]FDG uptake in the reactive axillary lymph node at PET/CT imaging, ipsilateral to the site of the COVID-19 vaccine injection. Analog finding was documented at [18F]Choline PET/CT. The aim of our study was to describe this source of false positive cases. All patients examined by PET/CT were included in the study. Data concerning patient anamnesis, laterality, and time interval from recent COVID-19 vaccination were recorded. SUVmax was measured in all lymph nodes expressing tracer uptake after vaccination. Among 712 PET/CT scans with 2-[18F]FDG, 104 were submitted to vaccination; 89/104 patients (85%) presented axillary and/or deltoid tracer uptake, related to recent COVID-19 vaccine administration (median from injection: 11 days). The mean SUVmax of these findings was 2.1 (range 1.6-3.3). Among 89 patients with false positive axillary uptake, 36 subjects had received chemotherapy due to lymph node metastases from somatic cancer or lymphomas, prior to the scan: 6/36 patients with lymph node metastases showed no response to therapy or progression disease. The mean SUVmax value of lymph nodal localizations of somatic cancers/lymphomas after chemotherapy was 7.8. Only 1/31 prostate cancer patients examined by [18F]Choline PET/CT showed post-vaccine axillary lymph node uptake. These findings were not recorded at PET/CT scans with [18F]-6-FDOPA, [68Ga]Ga-DOTATOC, and [18F]-fluoride. Following COVID-19 mass vaccination, a significant percentage of patients examined by 2-[18F]FDG PET/CT presents axillary, reactive lymph node uptake. Anamnesis, low-dose CT, and ultrasonography facilitated correct diagnosis. Semi-quantitative assessment supported the visual analysis of PET/CT data; SUVmax values of metastatic lymph nodes were considerably higher than post-vaccine lymph nodes. [18F]Choline uptake in reactive lymph node after vaccination was confirmed. After the COVID-19 pandemic, nuclear physicians need to take these potential false positive cases into account in daily clinical practice.

Effect of the COVID-19 pandemic on surgery for indeterminate thyroid nodules (THYCOVID): a retrospective, international, multicentre, cross-sectional study.

BACKGROUND: Since its outbreak in early 2020, the COVID-19 pandemic has diverted resources from non-urgent and elective procedures, leading to diagnosis and treatment delays, with an increased number of neoplasms at advanced stages worldwide. The aims of this study were to quantify the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic; and to evaluate whether delays in surgery led to an increased occurrence of aggressive tumours. METHODS: In this retrospective, international, cross-sectional study, centres were invited to participate in June 22, 2022; each centre joining the study was asked to provide data from medical records on all surgical thyroidectomies consecutively performed from Jan 1, 2019, to Dec 31, 2021. Patients with indeterminate thyroid nodules were divided into three groups according to when they underwent surgery: from Jan 1, 2019, to Feb 29, 2020 (global prepandemic phase), from March 1, 2020, to May 31, 2021 (pandemic escalation phase), and from June 1 to Dec 31, 2021 (pandemic decrease phase). The main outcomes were, for each phase, the number of surgeries for indeterminate thyroid nodules, and in patients with a postoperative diagnosis of thyroid cancers, the occurrence of tumours larger than 10 mm, extrathyroidal extension, lymph node metastases, vascular invasion, distant metastases, and tumours at high risk of structural disease recurrence. Univariate analysis was used to compare the probability of aggressive thyroid features between the first and third study phases. The study was registered on ClinicalTrials.gov, NCT05178186. FINDINGS: Data from 157 centres (n=49 countries) on 87 467 patients who underwent surgery for benign and malignant thyroid disease were collected, of whom 22 974 patients (18 052 [78·6%] female patients and 4922 [21·4%] male patients) received surgery for indeterminate thyroid nodules. We observed a significant reduction in surgery for indeterminate thyroid nodules during the pandemic escalation phase (median monthly surgeries per centre, 1·4 [IQR 0·6-3·4]) compared with the prepandemic phase (2·0 [0·9-3·7]; p<0·0001) and pandemic decrease phase (2·3 [1·0-5·0]; p<0·0001). Compared with the prepandemic phase, in the pandemic decrease phase we observed an increased occurrence of thyroid tumours larger than 10 mm (2554 [69·0%] of 3704 vs 1515 [71·5%] of 2119; OR 1·1 [95% CI 1·0-1·3]; p=0·042), lymph node metastases (343 [9·3%] vs 264 [12·5%]; OR 1·4 [1·2-1·7]; p=0·0001), and tumours at high risk of structural disease recurrence (203 [5·7%] of 3584 vs 155 [7·7%] of 2006; OR 1·4 [1·1-1·7]; p=0·0039). INTERPRETATION: Our study suggests that the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic period could have led to an increased occurrence of aggressive thyroid tumours. However, other compelling hypotheses, including increased selection of patients with aggressive malignancies during this period, should be considered. We suggest that surgery for indeterminate thyroid nodules should no longer be postponed even in future instances of pandemic escalation. FUNDING: None.

Impact of coronavirus disease 2019 pandemic on breast cancer surgery using the National Database of Japan.

Various countries have reported a decrease in breast cancer surgeries during the coronavirus disease 2019 (COVID-19) pandemic; however, inconsistent results have been reported in Japan. This study revealed changes in the number of surgeries during the pandemic using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) from January 2015 to January 2021, where insurance claims data from Japan as a whole are comprehensively accumulated. The number of breast-conserving surgeries (BCS) without axillary lymph node dissection (ALND) significantly decreased in July (- 846; 95% confidence interval (CI) - 1190 to - 502) and October 2020 (- 540; 95% CI - 861 to - 218). No decrease was observed for other types of surgery, BCS with ALND, and mastectomy with or without ALND. In the age-specific subgroup analysis, significant and transient reduction in BCS without ALND was observed in all age groups (0-49, 50-69, and ≥ 70 years). The number of BCS without ALND significantly decreased for a relatively short period in the early pandemic stages, suggesting reduced surgery for patients with a relatively low stage of cancer. Some patients with breast cancer might have been left untreated during the pandemic, and an unfavorable prognosis would be a concern.

The location of unilateral axillary lymphadenopathy after COVID-19 vaccination compared with that of metastasis from breast cancer without vaccination.

PURPOSE: Unilateral axillary lymphadenopathy is known to occur after coronavirus disease (COVID-19) vaccination. Post-vaccination lymphadenopathy may mimic the metastatic lymph nodes in breast cancer, and it is challenging to distinguish between them. This study investigated whether the localization of axillary lymphadenopathy on magnetic resonance imaging (MRI) could be used to distinguish reactive lymphadenopathy after COVID-19 vaccines from metastatic nodes. MATERIALS AND METHODS: We retrospectively examined preoperative MRI images of 684 axillae in 342 patients who underwent breast cancer surgery from June to October 2021. Lymphadenopathy was defined as cortical thickening or short axis ≥ 5 mm. The axilla was divided into ventral and dorsal parts on the axial plane using a perpendicular line extending from the most anterior margin of the muscle group, including the deltoid, latissimus dorsi, or teres major muscles, relative to a line along the lateral chest wall. We recorded the presence or absence of axillary lymphadenopathy in each area and the number of visible lymph nodes. RESULTS: Of 80 axillae, 41 and 39 were included in the vaccine and metastasis groups, respectively. The median time from the last vaccination to MRI was 19 days in the vaccine group. The number of visible axillary lymph nodes was significantly higher in the vaccine group (median, 15 nodes) than in the metastasis group (7 nodes) (P < 0.001). Dorsal lymphadenopathy was observed in 16 (39.0%) and two (5.1%) axillae in the vaccine and metastasis groups, respectively (P < 0.001). If the presence of both ventral and dorsal lymphadenopathy is considered indicative of vaccine-induced reaction, this finding has a sensitivity of 34.1%, specificity of 97.4%, and positive and negative predictive values of 93.3％ and 58.5%, respectively. CONCLUSION: The presence of deep axillary lymphadenopathy may be an important factor for distinguishing post-vaccination lymphadenopathy from metastasis. The number of axillary lymph nodes may also help.

Multispectral optoacoustic tomography to differentiate between lymph node metastases and coronavirus-19 vaccine-associated lymphadenopathy.

INTRODUCTION: Worldwide mass vaccination for COVID-19 started in late 2020. COVID-19 vaccines cause benign hypermetabolic lymphadenopathies. Clinical stratification between vaccine-associated benign lymphadenopathies and malignant lymphadenopathies through ultrasound, MRI or FDG PET-CT is not feasible. This leads to unnecessary lymph node biopsies, excisions and even radical lymph node dissections. Therefore, to avoid unnecessary surgeries, we assessed whether noninvasive multispectral optoacoustic tomography (MSOT) enables a better differentiation between benign and malignant lymphadenopathies. PATIENTS AND METHODS: All patients were vaccinated for COVID-19. We used MSOT to image deoxy- and oxyhaemoglobin levels in lymph nodes of tumour patients to assess metastatic status. MSOT imaging results were compared with standard ultrasound and pathological lymph node analysis. We also evaluated the influences of gender, age and time between vaccination and MSOT measurement of lymph nodes on the measured deoxy- and oxyhaemoglobin levels in patients with reactive lymph node changes. RESULTS: Multispectral optoacoustic tomography was able to identify cancer-free lymph nodes in vivo without a single false negative (33 total lymph nodes), with 100% sensitivity and 50% specificity. A statistically significant higher deoxyhaemoglobin content was detected in patients with tumour manifestations in the lymph node (p = 0.02). There was no statistically significant difference concerning oxyhaemoglobin (p = 0.65). Age, sex and time between vaccination and MSOT measurement had statistically non-significant impact on deoxy- and oxyhaemoglobin levels in patients with reactive lymph nodes. CONCLUSION: Here, we show that MSOT measurement is an advantageous clinical approach to differentiate between vaccine-associated benign lymphadenopathy and malignant lymph node metastases based on the deoxygenation level in lymph nodes.

COVID-19 Vaccine-Associated Lymphadenopathy Mimicking Regrowth of Axillary Lymph Node Metastasis of Lung Adenocarcinoma.

We encountered a woman with re-enlarged axillary lymph nodes during a computed tomography (CT) scan for surveillance of lung adenocarcinoma with axillary lymph node metastasis at the initial diagnosis that had shrunk with standard chemotherapy. We first suspected cancer recurrence and considered a change in the chemotherapeutic regimen. However, after careful history taking regarding the timing of her Coronavirus Disease 2019 (COVID-19) vaccination, and subsequent careful, close follow-up, radiological shrinkage suggested a strictly benign cause. Especially in lung cancer with a medical history of axillary lymph node involvement, cliniciansshould be aware that vaccine-associated lymphadenopathy can mimic cancer recurrence and sometimesprompt serious misjudgment regarding a current treatment course and strategy.

Evaluation of clinically involved lymph nodes with deformable registration in breast cancer radiotherapy.

OBJECTIVES: Modern radiotherapy (RT) techniques require careful delineation of the target. There is no particular RT contouring guideline for patients receiving neoadjuvant chemotherapy (NACT). In this study, we examined the distribution of pre-chemotherapy clinically positive nodal metastases. METHODS: We explored the coverage rate of the RTOG breast contouring guideline by deformable fusion of 18-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) scan. We retrospectively evaluated neoadjuvant chemotherapy patients. All PET-CT images were imported into the planning software. We combined the planning CT and the CT images of PET-CT with rigid and then a deformable registration. We manually contoured positive lymph nodes on the CT component of the PET-CT data set and transferred them to planning CT after fusion. We evaluated whether previously contoured lymphatic CTVs, according to the RTOG breast atlas, include GTV-LNs. RESULTS: All breast cancer patients between October 2018 and February 2021 were evaluated from the electronic database. There were 142 radiologically defined positive lymph nodes in 31 patients who were irradiated after NACT. Most LNs (70%) were in the level I axilla. Only 71.1% (n:101) of the whole lymph nodes in 10 patients were totally covered, 22.5% (n:32) partially covered and 6.4% %(n:9) totally undercovered. CONCLUSIONS: The extent of regional nodal areas in the RTOG atlas may be insufficient to cover positive lymph nodes adequately. For patients with nodal involvement undergoing neoadjuvant chemotherapy, PET-CT image fusions can be helpful to be sure that positive lymph nodes are in the treatment volume. ADVANCES IN KNOWLEDGE: RTOG contouring atlas may be insufficient to cover all involved lymph nodes after NACT. For patients with nodal involvement undergoing neoadjuvant chemotherapy, PET-CT image fusions may help to be sure that positive lymph nodes are in the treatment volume.

Axillary adenopathy detected on breast MRI following COVID-19 vaccination: outcomes and follow-up recommendations.

This retrospective study presents 110 patients with suspected COVID-19 vaccine-related axillary adenopathy on breast MRI. Our study aimed to assess the outcomes of axillary adenopathy detected on breast MRI performed within one year after COVID-19 vaccination. The median time between the COVID-19 vaccine and breast MRI was shorter in patients with detected adenopathy compared to patients without detected adenopathy (6 weeks [2-17] versus 15 [7-24] weeks, p < 0.001). Unilateral axillary adenopathy detected on breast MRI had a low malignancy rate (3.3%), and no cases of malignant axillary adenopathy were diagnosed without a known breast cancer in the ipsilateral breast. Our findings suggest that unilateral axillary adenopathy identified on breast MRI ipsilateral to a recent COVID-19 vaccination can be considered benign in the absence of a suspicious breast finding or known breast cancer. Regardless of vaccine status and timing, unilateral axillary adenopathy detected on MRI evaluation with a known malignancy or suspicious breast finding should be considered suspicious. This will avoid unnecessary scheduling constraints, patient anxiety, and cost, without delaying diagnosis of metastatic breast cancer.

Axillary Lymphadenopathy in the COVID-19 Era: What the Radiologist Needs to Know.

Axillary lymphadenopathy caused by the high immunogenicity of messenger RNA (mRNA) COVID-19 vaccines presents radiologists with new diagnostic dilemmas in differentiating vaccine-related benign reactive lymphadenopathy from that due to malignant causes. Understanding axillary anatomy and lymphatic drainage is key to radiologic evaluation of the axilla. US plays a critical role in evaluation and classification of axillary lymph nodes on the basis of their cortical and hilar morphology, which allows prediction of metastatic disease. Guidelines for evaluation and management of axillary lymphadenopathy continue to evolve as radiologists gain more experience with axillary lymphadenopathy related to COVID-19 vaccines. General guidelines recommend documenting vaccination dates and laterality and administering all vaccine doses contralateral to the site of primary malignancy whenever applicable. Guidelines also recommend against postponing imaging for urgent clinical indications or for treatment planning in patients with newly diagnosed breast cancer. Although conservative management approaches to axillary lymphadenopathy initially recommended universal short-interval imaging follow-up, updates to those approaches as well as risk-stratified approaches recommend interpreting lymphadenopathy in the context of both vaccination timing and the patient's overall risk of metastatic disease. Patients with active breast cancer in the pretreatment or peritreatment phase should be evaluated with standard imaging protocols regardless of vaccination status. Tissue sampling and multidisciplinary discussion remain useful in management of complex cases, including increasing lymphadenopathy at follow-up imaging, MRI evaluation of extent of disease, response to neoadjuvant treatment, and potentially confounding cases. An invited commentary by Weinstein is available online. ©RSNA, 2022.

FDG PET/CT radiomics as a tool to differentiate between reactive axillary lymphadenopathy following COVID-19 vaccination and metastatic breast cancer axillary lymphadenopathy: a pilot study.

OBJECTIVES: To evaluate if radiomics with machine learning can differentiate between F-18-fluorodeoxyglucose (FDG)-avid breast cancer metastatic lymphadenopathy and FDG-avid COVID-19 mRNA vaccine-related axillary lymphadenopathy. MATERIALS AND METHODS: We retrospectively analyzed FDG-positive, pathology-proven, metastatic axillary lymph nodes in 53 breast cancer patients who had PET/CT for follow-up or staging, and FDG-positive axillary lymph nodes in 46 patients who were vaccinated with the COVID-19 mRNA vaccine. Radiomics features (110 features classified into 7 groups) were extracted from all segmented lymph nodes. Analysis was performed on PET, CT, and combined PET/CT inputs. Lymph nodes were randomly assigned to a training (n = 132) and validation cohort (n = 33) by 5-fold cross-validation. K-nearest neighbors (KNN) and random forest (RF) machine learning models were used. Performance was evaluated using an area under the receiver-operator characteristic curve (AUC-ROC) score. RESULTS: Axillary lymph nodes from breast cancer patients (n = 85) and COVID-19-vaccinated individuals (n = 80) were analyzed. Analysis of first-order features showed statistically significant differences (p < 0.05) in all combined PET/CT features, most PET features, and half of the CT features. The KNN model showed the best performance score for combined PET/CT and PET input with 0.98 (± 0.03) and 0.88 (± 0.07) validation AUC, and 96% (± 4%) and 85% (± 9%) validation accuracy, respectively. The RF model showed the best result for CT input with 0.96 (± 0.04) validation AUC and 90% (± 6%) validation accuracy. CONCLUSION: Radiomics features can differentiate between FDG-avid breast cancer metastatic and FDG-avid COVID-19 vaccine-related axillary lymphadenopathy. Such a model may have a role in differentiating benign nodes from malignant ones. KEY POINTS: • Patients who were vaccinated with the COVID-19 mRNA vaccine have shown FDG-avid reactive axillary lymph nodes in PET-CT scans. • We evaluated if radiomics and machine learning can distinguish between FDG-avid metastatic axillary lymphadenopathy in breast cancer patients and FDG-avid reactive axillary lymph nodes. • Combined PET and CT radiomics data showed good test AUC (0.98) for distinguishing between metastatic axillary lymphadenopathy and post-COVID-19 vaccine-associated axillary lymphadenopathy. Therefore, the use of radiomics may have a role in differentiating between benign from malignant FDG-avid nodes.

Post-vaccination SARS-CoV-2 axillary adenopathy. Differences with axillary metastases from breast cancer.

The differential diagnosis of the metastatic axillary lymphadenopathies of breast cancer with which they occur secondary to the Pfizer-BioNTech vaccine against COVID-19, is imperative. In a series of cases, we analyzed the characteristics of unilateral axillary lymphadenopathy in patients after Pfizer-BioNTech vaccination. Axillary lymphadenopathy were observed ipsilateral to the vaccination arm. The axillary ultrasound defined these as reactive and that they disappeared in 3 weeks. The pathological findings were benign. The anamnesis, the place and date of vaccination and the radiological findings, play an essential role to carry out a correct differential diagnosis and follow-up of these adenopathies.

El diagnóstico diferencial de las adenopatías axilares metastásicas del cáncer de mama con las que se producen secundarias a la vacuna de Pfizer-BioNTech contra la COVID-19 es imperioso. Analizamos una serie de casos con las características de las adenopatías axilares unilaterales tras la administración de la vacuna de Pfizer-BioNTech. Se observaron adenopatías axilares homolaterales al brazo de vacunación. La ecografía axilar las definió como reactivas y que desaparecían en 3 semanas. Los hallazgos anatomopatológicos fueron de benignidad. La anamnesis, el lugar y la fecha de vacunación, así como los hallazgos radiológicos, desempeñan un papel esencial para realizar un correcto diagnóstico deferencial y el seguimiento de estas adenopatías.

Lymph node metastasis as the initial symptom of a germ cell tumor in an adult: A case report.

RATIONALE: Germ cell tumors in the head and neck are very rare. In cases of germ cell tumors, it is uncommon for lymph node metastasis to be the only and initial symptom, and this can easily lead to a misdiagnosis. Herein, we report about a 28-year-old woman with lymph node metastasis, in whom a primary tumor appeared in the nasal cavity. PATIENT CONCERNS: A 28-year-old woman presented with enlarged left submandibular lymph nodes. No other mass was found on whole-body screening using positron emission tomography-computed tomography. DIAGNOSIS: After partial submandibular lymphadenectomy was performed, histopathological and immunohistochemical examinations revealed a metastatic germ cell tumor. However, it was difficult to further classify and affirm the origin. INTERVENTIONS: As the patient was receiving four cycles of bleomycin, etoposide, and cisplatin chemotherapy, a primary tumor emerged in the nasal cavity, which was finally confirmed as an immature teratoma of a high World Health Organization histological grade and Norris grade 3. This tumor was found to contain similar components to lymph nodes with respect to histopathological and immunohistochemical characteristics, especially the immature neural tubes or nervous tissue in the nasal cavity. Fortunately, the patient recovered well with no signs of relapse, and the size of residual lymph nodes remained unchanged after she received another four cycles of bleomycin, etoposide, and cisplatin chemotherapy and two cycles of doxorubicin and ifosfamide (AI) chemotherapy. OUTCOMES: Unfortunately, 11 months later, during the coronavirus disease pandemic, the patient died owing to respiratory failure and pulmonary infection. CONCLUSIONS: In cases of malignant tumor in the submandibular lymph nodes of adults, the metastasis of a germ cell tumor should be considered an important differential diagnosis even if a primary tumor does not emerge. In this case, adequate postoperative chemotherapy is necessary.

Time for Resolution of COVID-19 Vaccine-Related Axillary Lymphadenopathy and Associated Factors.

BACKGROUND. The variable clinical course of subclinical lymphadenopathy detected on breast imaging after COVID-19 vaccination creates management challenges and has led to evolving practice recommendations. OBJECTIVE. The purpose of this study was to assess the duration of axillary lymphadenopathy ipsilateral to COVID-19 vaccination detected by breast imaging and to assess factors associated with the time until resolution. METHODS. This retrospective single-center study included 111 patients (mean age, 52 ± 12 years) with unilateral axillary lymphadenopathy ipsilateral to mRNA COVID-19 vaccine administration performed within the prior 8 weeks that was detected on breast ultrasound performed between January 1, 2021, and October 1, 2021, and who underwent follow-up ultrasound examinations at 4- to 12-week intervals until resolution of the lymphadenopathy. Patient information was extracted from medical records. Cortical thickness of the largest axillary lymph node on ultrasound was retrospectively measured and was considered enlarged when greater than 3 mm. Multivariable linear regression analysis was used to identify independent predictors of time until resolution. RESULTS. The mean cortical thickness at the initial ultrasound examination was 4.7 ± 1.2 mm. The lymphadenopathy resolved a mean of 97 ± 44 days after the initial ultrasound examination, 127 ± 43 days after the first vaccine dose, and 2.4 ± 0.6 follow-up ultrasound examinations. A significant independent predictor of shorter time to resolution was Pfizer-BioNTech (rather than Moderna) vaccination (ß = -18.0 [95% CI, -34.3 to -1.7]; p = .03]. Significant independent predictors of longer time to resolution were receipt of the second dose after the initial ultrasound examination (ß = 19.2 [95% CI, 3.1-35.2]; p = .02) and greater cortical thickness at the initial ultrasound examination (ß = 8.0 [95% CI, 1.5-14.5]; p = .02). Patient age, history of breast cancer, and axillary symptoms were not significantly associated with time to resolution (all p > .05). CONCLUSION. Axillary lymphadenopathy detected with breast ultrasound after COVID-19 mRNA vaccination lasts longer than reported in initial vaccine clinical trials. CLINICAL IMPACT. The prolonged time to resolution supports not delaying screening mammography because of recent COVID-19 vaccination. It also supports the professional society recommendation of a follow-up interval of at least 12 weeks when vaccine-related lymphadenopathy is suspected.

Multifocal Urinary Tract Metastasis of Colorectal Carcinoma.

INTRODUCTION: Secondary urinary tract tumors are uncommon findings and mainly evolve by direct invasion from adjacent organs. Actual metastatic involvement often develops in the urinary bladder, while the upper urinary tract is infrequently affected. In addition, the lungs, breast, and prostate gland are the usual primary sites. Colorectal carcinoma (CRC) may spread to the ureter directly or seeds via vascular or lymphatic channels. It may pose struggles in the differential diagnosis because CRC shares standard pathologic features with the primary adenocarcinoma of the urinary tract. CASE PRESENTATION: We describe the case of an 81-year-old man who was referred to our hospital with a distal ureteral tumor that was treated by a ureteronephrectomy. The histopathological and genetic analysis established the diagnosis of metastatic CRC along with 3 metastases in the renal pelvis. CONCLUSION: This rare case highlights the limitations of conventional histological processing, including immunohistochemistry, and it underlines the role of molecular investigations in certain circumstances.

Quantitative ultrasound image analysis of axillary lymph nodes to differentiate malignancy from reactive benign changes due to COVID-19 vaccination.

PURPOSE: The aim of this study is to assess the potential of quantitative image analysis and machine learning techniques to differentiate between malignant lymph nodes and benign lymph nodes affected by reactive changes due to COVID-19 vaccination. METHOD: In this institutional review board-approved retrospective study, we improved our previously published artificial intelligence model, by retraining it with newly collected images and testing its performance on images containing benign lymph nodes affected by COVID-19 vaccination. All the images were acquired and selected by specialized breast-imaging radiologists and the nature of each node (benign or malignant) was assessed through a strict clinical protocol using ultrasound-guided biopsies. RESULTS: A total of 180 new images from 154 different patients were recruited: 71 images (10 cases and 61 controls) were used to retrain the old model and 109 images (36 cases and 73 controls) were used to evaluate its performance. The achieved accuracy of the proposed method was 92.7% with 77.8% sensitivity and 100% specificity at the optimal cut-off point. In comparison, the visual node inspection made by radiologists from ultrasound images reached 69.7% accuracy with 41.7% sensitivity and 83.6% specificity. CONCLUSIONS: The results obtained in this study show the potential of the proposed techniques to differentiate between malignant lymph nodes and benign nodes affected by reactive changes due to COVID-19 vaccination. These techniques could be useful to non-invasively diagnose lymph node status in patients with suspicious reactive nodes, although larger multicenter studies are needed to confirm and validate the results.

Axillary Lymph Node Swelling After COVID-19 Booster Vaccination: Japanese Case Report and Literature Review.

BACKGROUND/AIM: COVID-19 has been a global pandemic for more than 2 years, and vaccination against COVID-19 using an mRNA vaccine is widespread. The COVID-19 vaccination can cause specific side-effects, such as axillary lymph node swelling; therefore, breast oncologists should pay attention to such occurrences. Initially, only two COVID-19 vaccinations were planned; however, in some countries third or fourth vaccines have been administered. Here, we present a female case who developed axillary lymph node swelling after her third vaccination. We have also reviewed the literature regarding this side-effect after a third or fourth COVID-19 vaccination. CASE REPORT: A 64-year-old woman who came to our clinic regarding a mammography abnormality in her left breast. She had no palpable mass, but a left breast mass was shown by mammography, and ultrasonography and magnetic resonance imaging indicated a hamartoma. At 2 months after her second COVID-19 vaccination when she underwent these tests, she had no axillary lymph node swelling. We planned a follow-up after 6 months. At her next visit, by chance, she underwent ultrasonography 14 days after she received a third COVID-19 vaccination, and a swollen axillary lymph node was observed. CONCLUSION: Axillary lymph node swelling can occur after a third COVID-19 vaccination. Therefore, breast oncologists will have to consider this side-effect of COVID-19 vaccination when diagnosing breast tumors.

Timing and Duration of Axillary Lymph Node Swelling After COVID-19 Vaccination: Japanese Case Report and Literature Review.

BACKGROUND/AIM: COVID-19 vaccination is now performed in most of the world to limit the spread of the disease. The first mRNA vaccine was approved in clinical settings and has specific side effects including axillary lymph node swelling, which can be misdiagnosed as breast cancer metastasis. The timing of axillary lymph node swelling and its duration are unclear. Here, we present a Japanese case and review of the existing literature. CASE REPORT: We report the case of a 67-year-old woman with breast calcification. She had regular follow ups in our hospital for this calcification and received ultrasonography of the breast and axilla at every visit. She visited 6 months before having her COVID-19 vaccination, and 7 days and 6 months after the first COVID-19 vaccination. She had a swollen axillary lymph node 7 days after the first vaccination, which although it was improved, remained for 6 months. CONCLUSION: Axillary lymph node swelling occurred 7 days after vaccination and remained up to 6 months after it.

DENEB: Development of new criteria for curability after local excision of pathological T1 colorectal cancer using liquid biopsy.

According to the current international guidelines, high-risk patients diagnosed with pathological T1 (pT1) colorectal cancer (CRC) who underwent complete local resection but may have risk of developing lymph node metastasis (LNM) are recommended additional intestinal resection with lymph node dissection. However, around 90% of the patients without LNM are exposed to the risk of being overtreated due to the insufficient pathological criteria for risk stratification of LNM. Circulating tumor DNA (ctDNA) is a noninvasive biomarker for molecular residual disease and relapse detection after treatments including surgical and endoscopic resection of solid tumors. The CIRCULATE-Japan project includes a large-scale patient-screening registry of the GALAXY study to track ctDNA status of patients with stage II to IV or recurrent CRC that can be completely resected. Based on the CIRCULATE-Japan platform, we launched DENEB, a new prospective study, within the GALAXY study for patients with pT1 CRC who underwent complete local resection and were scheduled for additional intestinal resection with lymph node dissection based on the standard pathologic risk stratification criteria for LNM. The aim of this study is to explore the ability of predicting LNM using ctDNA analysis compared with the standard pathological criteria. The ctDNA assay will build new evidence to establish a noninvasive personalized diagnosis in patients, which will facilitate tailored/optimal treatment strategies for CRC patients.

The Impact of the COVID-19 Pandemic on Colorectal Cancer Patients in a Tertiary Center in Romania. Single Center Retrospective Study.

Background: The novel coronavirus, SARS-COV-2, was first reported in Wuhan, China in the end of 2019. To curb its spread, social distancing measures and new safety regulations were implemented which led to major disruptions in colorectal cancer care. It is however unknown how it influenced the Romanian colorectal cancer care. Methods and Material: We assessed the demographical, clinical, intraoperative and pathological data of our colorectal cancer patients, 302 in total, between 15.03.2019-14.03.2021. The first year's data was considered as the control group and the second one, the study (pandemic) group. Results: We observed a 12% decrease in colorectal cancer hospitalizations in the first year, 38,6% in the first six months. The rate of emergency admissions, colo/ileostomy formatting procedures, palliative resections, clinical metastasis was higher in the pandemic group. More advanced locoregional invasion, a higher tumor stage, higher rate of vascular, perineural invasion, positive resection margin, and a higher lymph node yield was seen after the restrictions were implemented. Conclusion: The COVID-19 pandemic and the response against it had a major effect on the colorectal cancer care in our country. The outcomes of these worse clinical and pathological findings are unknown, but it is important to do further research in this field. We think colorectal cancer care should have an absolute priority in future pandemics.