Publications by authors named "Subha Shankar Das"

5 Publications

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Upfront Use of 177Lu-Labeled PSMA Radioligand Therapy and Treatment Response Assessment in Treatment-Naive Prostate Cancer.

Clin Nucl Med 2021 Sep 13. Epub 2021 Sep 13.

From the Department of Nuclear Medicine, Fortis Memorial Research Institute, Gurgaon, Haryana, India.

Abstract: Prostatic malignancy is the most common type of nonskin cancer and associated with significant morbidity and mortality. Early androgen deprivation therapy (ADT) is the treatment of choice in metastatic prostate cancer, whereas ADT delays progression of disease, but it is associated with significant adverse effects and frequently impairs the quality of life. Therefore, there is growing interest in treatments to postpone ADT while achieving a good progression-free survival. We present a case of oligometastatic prostate cancer, who was treated upfront with 177Lu-labeled PSMA radioligand therapy and demonstrated excellent response to a single dose of 177Lu-PSMA-617.
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http://dx.doi.org/10.1097/RLU.0000000000003890DOI Listing
September 2021

Dosimetric analyses of intra-arterial versus standard intravenous administration of 177Lu-DOTATATE in patients of well differentiated neuroendocrine tumor with liver-dominant metastatic disease.

Br J Radiol 2021 Oct 6;94(1126):20210403. Epub 2021 Aug 6.

Department of Nuclear Medicine, Fortis Memorial Research Institute, Gurgaon, India.

Objective: The aim of the present study was to perform calculation of the absorbed doses to organs at risk and to neuroendocrine tumors and to determine whether hepatic intra-arterial (IA) injection of Lu-DOTATATE Peptide Receptor Radionuclide Therapy (PRRT) would achieve higher intratumoral concentrations than standard intravenous administration of Lu-DOTATATE.

Methods: 29 patients with Grade I-II, inoperable, metastatic gastro-entero-pancreatic neuroendocrine tumor (GEPNET) were prospectively identified and enrolled for the study. 15 patients of GEPNETs with liver-dominant metastatic disease and less than 3 sites of extrahepatic metastatic disease were administered a single dose of Lu-DOTATATE therapy through the selective catheterization of the hepatic artery (IA group). The other 14 patients received a single dose of Lu- DOTATATE through standard intravenous route (IV group). For dosimetry, whole-body γ (anterior and posterior planar acquisitions) and SPECT/CT scans of the abdomen at 2, 24 and 96 h post Lu-DOTATATE administration were acquired. Dosimetric calculations were done using the HERMES software.

Results: The mean dose per unit activity (DpA) in the liver and tumor lesions in the IA group differed significantly ( < 0.05) but differed insignificantly in spleen and kidneys ( > 05) with the IV group. The mean tumor/non-tumor concentration at 96 h was 76.83 ± 7.9 (range 10.2-251.3) in the IA group whereas it was 25.6 ± 5.9 (Range: 12-55) in the IV group. There was an average threefold increase in tumoral concentration over the standard intravenous group.

Conclusion: IA administration of Lu-DOTATATE results in higher concentration and absorbed dose in hepatic metastases in patients of GEPNETs as compared to a single dose of PRRT administered through standard IV route, and thus seems to be a powerful tool to improve the efficacy of PRRT.

Advances In Knowledge: Measurement of the dose received by the tumor lesions and the critical organs is of paramount importance for the prognostication of a radionuclide therapy. Scant data exist on the dosimetric impact of IA administration of the therapy with Lu-DOTATATE on the tumors and other organs, and this study would add an impact towards the better treatment outcome in patients of neuroendocrine tumor with liver-dominant metastatic disease.
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http://dx.doi.org/10.1259/bjr.20210403DOI Listing
October 2021

Invasive Fungal Infection in COVID-19-Recovered Patient Detected on 18F-FDG-Labeled Leukocytes PET/CT Scan.

Clin Nucl Med 2021 Jul 26. Epub 2021 Jul 26.

From the Department of Nuclear Medicine, Fortis Memorial Research Institute, Gurgaon, Haryana, India.

Abstract: Occurrence of invasive fungal infections has gained significant attention during recent times in patients with COVID-19. Patients with severe form of COVID-19, such as those treated in the intensive care unit with prolonged steroid use, are particularly vulnerable to secondary bacterial and fungal infections. Disseminated systemic mycosis is a life-threatening condition, especially in immunocompromised patients. Here, we report a case of a recovered severe COVID-19 patient, who presented with persistent fever. 18F-FDG-labeled leukocyte scan revealed focal accumulation of radiotracer in the small intestine and right lung lower lobe. Subsequently, performed biopsy revealed mucormycosis.
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http://dx.doi.org/10.1097/RLU.0000000000003852DOI Listing
July 2021

Therapeutic efficacy of Ac-PSMA-617 targeted alpha therapy in patients of metastatic castrate resistant prostate cancer after taxane-based chemotherapy.

Ann Nucl Med 2021 Jul 31;35(7):794-810. Epub 2021 May 31.

Department of Medical Oncology, Fortis Memorial Research Institute, Gurugram, Haryana, India.

Objectives: Ac-PSMA-617 therapy has shown good response in many recent studies. We report our experience of targeted alpha therapy with Ac-PSMA-617 in mCRPC patients who have failed therapy with taxanes.

Materials And Methods: Thirty-eight patients with CRPC with progressive disease following at least one taxane-based chemotherapy received Ac-PSMA-617 between July 2017 and Nov 2019. Primary end point was a composite 50% PSA and radiological response. Secondary endpoints were PFS, OS, and changes in QOL. The differences in outcomes between patients with skeletal and lymph-node metastases versus those with visceral metastases were also studied.

Results: A composite response by predetermined criteria was observed in 25 (66%) of 38 patients. The median PFS was 8 months (95% CI 5.3-10.6 months). Median overall survival was 12 months (95% CI 9.1-14.9) with 16 patients alive at the time of censorship. There was no difference in response rates or survival statistics between patients with visceral metastases versus those with only bone and lymph-node metastases (Chi-square 1.51, df 1, Sig 0.218). The most common adverse effect was xerostomia. On the QOL Symptom score, Pain, Fatigue Insomnia, and constipation showed a significant improvement as compared to baseline.

Conclusions: Ac-PSMA-617 is a safe and tolerable treatment option for mCRPC that demonstrates marked anti-tumour activity with improvement in quality of life even in patients of metastatic CRPC who have been previously treated with taxane-based chemotherapy.
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http://dx.doi.org/10.1007/s12149-021-01617-4DOI Listing
July 2021

Incremental Value of Ga-68 Prostate-Specific Membrane Antigen-11 Positron-Emission Tomography/Computed Tomography Scan for Preoperative Risk Stratification of Prostate Cancer.

Indian J Nucl Med 2020 Apr-Jun;35(2):93-99. Epub 2020 Mar 12.

Department of Nuclear Medicine, Fortis Memorial Research Institute, Gurgaon, Haryana, India.

Background: Prostate cancer (PC) is the second-most common cause of cancer.Ga-prostate-specific membrane antigen (PSMA)-11 positron-emission tomography/computed tomography (PET/CT) scan help in accurate staging of PC owing to its high PSMA avidity and specificity. The aim of this prospective observational study was to determine the incremental value of Ga-68 PSMA-11 PET/CT over multiparametric magnetic resonance imaging (mpMRI) in the locoregional staging of intermediate- and high-risk PC using histopathology from radical prostatectomy specimens as a gold standard.

Materials And Methods: This was a prospective study, including 35 patients with biopsy-proven prostate carcinoma. All the patients underwent whole-body Ga-68 PSMA-11 PET/CT scans along with mpMRI including a dedicated pelvic imaging protocol within a time window of ± 10 days. The reference standard was based on histopathological results, postprostatectomy.

Results: All 35 patients showed Ga-68 PSMA-11-avid disease, of which 29 underwent radical prostatectomy, one underwent radiation therapy, and five did not undergo surgery owing to metastases. A total of 52 PC lesions were detected in 29 patients on histopathology. Of 52 lesions, 29 lesions were identified in prostate parenchyma and 23 were extraprostatic lesions on histopathology. Ga-68 PSMA-11 PET/CT detected a total of 45 lesions, of which 29 lesions were located within the prostate parenchyma and 16 were representative of extraprostatic lesions. mpMRI detected a total of 36 lesions, of which 29 lesions were located within the prostate parenchyma and seven were representative of extraprostatic lesions. The overall sensitivity of Ga-PSMA PET/CT and mpMRI in the detection of lesions was 86.2% and 68.6%, respectively. However, the overall specificity was 94.7% and 89.1% for Ga-PSMA and mpMRI, respectively.

Conclusion: Ga-68 PSMA-11 PET/CT provided superior locoregional preoperative staging of PC as compared to mpMRI in intermediate- and high-risk PC patients.
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http://dx.doi.org/10.4103/ijnm.IJNM_189_19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7182336PMC
March 2020
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