Complete response in a frail patient with high-grade B-cell lymphoma to only one cycle of R-CHOP or to prolonged COVID-19?

BACKGROUND: COVID-19 infection increases mortality in hematological malignancies. In a large meta-analysis, patients aged 60 years and older had a significantly higher risk of death than patients under 60 years of age [1]. Furthermore, a high risk of death and reduced survival in patients receiving B cell depletion therapy with prolonged COVID-19 infection was reported in a recent study [2]. High-grade B-cell lymphomas are classified as morphologically aggressive lymphomas with the presence of a high mitotic index and Ki-67 proliferation rates. They demonstrate aggressive behavior clinically as well as morphologically, and COVID-19 infection is an important factor that increases mortality in these patients. Herein, we present an elderly patient with a diagnosis of high-grade B-cell lymphoma, in whom a complete response was observed after prolonged COVID-19 infection. CASE SUMMARY: An 81-year-old female patient received her first cycle of R-CHOP (rituximab, cyclophosphamide, vincristine, and prednisolone) treatment after being diagnosed with high- grade B-cell lymphoma. After being discharged from the hospital, the patient was referred to the emergency department with complaints of fever and fatigue when she came for the second cycle of chemotherapy. Her COVID-19 PCR test was found positive. She was admitted to the infectious diseases service and favipiravir treatment was started. On the 24th day of hospitalization, it was decided to perform interim FDG-PET/CT (Fluorodeoxyglucose - Positron Emission Tomography/Computed Tomography) scan at a time that her PCR (Polymerase Chain Reaction) test was still positive. A complete metabolic response was detected in her imaging. On the 26th day, the PCR test became negative and the patient was transferred to the oncology service and received the second cycle of R-CHOP treatment. CONCLUSION: Our case emphasizes that antitumor effect could be seen in a patient with SARS-CoV-2 infection and a hematologic malignancy. It also highlights being alert to prolonged COVID-19 infection in patients receiving B-cell depletion therapy.

Predictive factors of tumor sink effect: Insights from 177Lu-Prostate-specific membrane antigen therapy.

OBJECTIVE: Tumor sink effect (TSE) has been defined as; decreased uptake in healthy tissue with increased tumor sequestration of the radiopharmaceuticals. It enables us to give high tumoral radiation doses while resulting in lower absorbed radiation to critical organs. However, the factors which influence this effect are yet to be defined. In this study, we have investigated the predictive factors of the tumor sink effect in a group of patients who received 177Lu-Prostate-specific membrane antigen (PSMA) therapy due to progressive metastatic castration-resistant prostate cancer (mCRPC). METHODS: We have retrospectively analyzed the pre-therapy 68Ga-PSMA positron-emission tomography (PET)-computed tomography (CT) and post-therapy planar whole-body scans of 65 patients who received at least two cycles of 7.4 GBq of 177Lu-PSMA therapy. All patients with mCRPC were referred to our department after multiple treatment lines. Age, previous therapies, International Society of Urological Pathology (ISUP) score, and pre-therapy serum tumor marker levels were recorded. Post 177Lu-PSMA therapy images were analyzed for TSE. 68Ga-PSMA PET-CT images were used for the calculation of SUVmax in malignant and healthy tissues as well as metabolic tumor volume (MTV) and total lesion PSMA index (TLPI). RESULTS: Based on the post-therapy scans, TSE was seen in 17/65 (26.2%) patients. In univariate analysis, patients with TSE had higher pre-therapy PSA, PSA velocity, and ALP (p < 0.0001). In relation to PET parameters, patients with TSE had higher 68Ga-PSMA MTV, 68Ga-PSMA TLPI and lower pretherapy renal SUVmax (p < 0.0001)), pretherapy liver SUVmax (p:0.012), pretherapy parotid gland SUVmax (p:0.032), and pretherapy parotid gland SUVmean (p:0.038). In the multivariant analysis, 68Ga-PSMA TLPI, pre-therapy PSA, and PSA velocity were found to be statistically significant. When analyzed according to Youden index, pretherapy PSA level of 133 ng/ml (sensitivity 0.765 and 0.875), PSA velocity of 246 ng/ml/year (sensitivity 0.765 and 0.833), and 68Ga-PSMA TLPI of 2969 g (sensitivity 0.765 and 0.875) was found to be the best cut-off points to predict TSE. CONCLUSION: The tumor sink effect was seen in 26.2% of patients. 68Ga- PSMA TLPI, pre-therapy PSA, and PSA velocity was found to be the predictors of TSE. Accurate prediction of TSE may lead to increased tumoral doses while sparing healthy organs. Clinical trials that consider this effect as a part of a dose algorithm may further increase therapeutic efficacy.

The role of Tc-99m MIBI scintigraphy in clinical T1 renal mass assessment: Does it have a real benefit?

INTRODUCTION: Despite the increasing accuracy of imaging modalities, the rate of benign renal tumors misclassified as malignant before surgery still non-negligible. Tc-99m sestamibi was demonstrated to be a possible reliable agent in discriminating oncocytoma from renal cell carcinoma (RCC). We aimed to study the efficacy of Tc-99m MIBI tumor scintigraphy in evaluating clinical T1 renal masses. METHODS AND MATERIALS: Between July 2017 and March 2019, patients with clinical T1 renal mass underwent preoperative Tc-99m sestamibi tumor scintigraphy. Tc-99m sestamibi tumor scintigraphy findings were correlated with the postoperative pathology results. RESULTS: A total of 90 renal masses were included in the study. Male to female ratio was 67/23. The mean age and tumor size were 55.5 ± 11.4 years and 4 ± 1.4 cm, respectively. In pathological evaluation, 20% (18/90) of masses were reported as benign (10 oncocytomas, 4 angiomyolipomas (AML), 2 chronic sclerosis, 1 fibroma and 1 hydatid cyst). While Tc-99m sestamibi uptake was positive in all oncocytomas; 6 patients with chronic sclerosis, fibroma, hydatid cyst and angiomyolipoma pathologies had no uptake. Except for 5 chromophobe cell RCC and 3 oncocytic papillary RCC masses, malignant lesions had no uptake. In predicting benign pathology, Tc-99m sestamibi tumor scintigraphy had positive and negative predictive value of 60% and 91.3%, respectively. The mean Tc-99m 2-methoxy isobutyl isonitrile lesion/normal renal parenchyma ratio of benign and malignant lesions was 0.6 and 0.37, respectively. A relative uptake of 0.49 was an acceptable cutoff point to discriminate oncocytomas from all other pathologies. CONCLUSION: Tc-99m sestamibi tumor scintigraphy has a beneficial role in the assessment of clinical T1 renal mass. Masses with negative uptake harbor high probability of being malignant. While evaluating masses with positive uptake, it should be kept in mind that some malignant pathologies may demonstrate similar results.

Clinical Impact of PET Imaging in Patients With Metastatic Prostate Cancer.

Prostate cancer (Pca) is the most common cancer and the second leading cause of death among men. Although conventional bone scans and abdominal CT are preferred in most of the guidelines and clinical trials, PET/CT has already started to become the inevitable part of Pca management because of its higher sensitivity and specificity. Radiotracers used for PET imaging show different molecular aspects of the disease process. Although Ga-prostate-specific membrane antigen offers the highest sensitivity and specificity, other PET radiotracers such as F-FDG and Ga-DOTATATE still have a role in patients with prostate-specific membrane antigen-negative diseases such as Pca with neuroendocrine differentiation. In this pictorial essay, we have presented a series of patients with metastatic Pca who had PET images with different radiotracers and discussed the clinical role of this imaging modality in patient management.