The spontaneous regression or remission (SR) of cancer, often described as the partial or complete disappearance of a malignant tumor in the absence of all medical treatment and therapy, is a well-documented phenomenon. With efforts ongoing to establish cancer treatments that limit undesirable outcomes and adverse effects, these uncommon occurrences of SR carry significant implications for novel therapies and warrant further investigation. While several case studies have reported instances of SR in gastrointestinal (GI) malignancies, a comprehensive review of previous manifestations of SR in the GI tract remains lacking. The inclusion criteria for the rare phenomenon are also in need of an appropriate update that takes recent scientific advancements and emerging new medical technologies into account. Our analysis of 390 cases of SR in the GI tract focuses primarily on neoplasms of the hepatobiliary system and proposes an updated version of the older inclusion criteria for spontaneous regression.

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The Spontaneous Regression of Primary Gastrointestinal Malignancies: An Observational Review

The COVID-19 pandemic has forced people to significantly change their lifestyles and attitudes, and has greatly burdened healthcare delivery systems worldwide. The redistribution of the medical delivery system to maintain normal medical care while responding generously to COVID-19 is a continuing challenge that weighs heavily on medical institutions. Among imaging modalities, chest X-rays and computed tomography (CT) examinations have clearly made a large contribution to treatment of COVID-19. In contrast, it is difficult to express the standpoint of nuclear medicine examinations in a straightforward manner, as the greatest emphasis in this modality has been on how necessary medical care can continue to be provided. Many clinical reports of nuclear medicine examinations related to COVID-19 have been published, and knowledge continues to accumulate. This review provides a summary of the current state of oncology and cardiology positron emission tomography (PET) examinations related to COVID-19, and includes preparation of the nuclear medicine department, trends in PET examinations, specific imaging findings on 18F-fluorodeoxyglucose (FDG) PET/CT, imaging of complications of COVID-19, PET tracers other than FDG, and the effects of vaccines on PET imaging findings.

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Oncology and cardiology positron emission tomography/computed tomography faced with COVID-19: A review of available literature data

Abstract Early in the COVID-19 pandemic, it emerged that the risk of severe outcomes was greater in patients with co-morbidities, including cancer. The huge effort undertaken to fight the pandemic, affects the management of cancer care, influencing their outcome. Despite the high fatality rate of COVID-19 disease in cancer patients, rare cases of temporary or prolonged clinical remission from cancers after SARS-CoV-2 infection have been reported. We have reviewed sixteen case reports of COVID-19 disease with spontaneous cancer reduction of progression. Fourteen cases of remission following viral infections and two after anti-SARS-CoV-2 vaccination. The immune response to COVID-19, may be implicated in both tumor regression, and progression. Specifically, we discuss potential mechanisms which include oncolytic and priming hypotheses, that may have contributed to the cancer regression in these cases and could be useful for future options in cancer treatment. 

/pdf/spontaneous-cancer-remission-after-covid-19-insights-from-ifbduq5e.pdf

Spontaneous cancer remission after COVID-19: insights from the pandemic and their relevance for cancer treatment

Spontaneous regression of metastatic renal cell carcinoma (mRCC) is a rare event, often associated with an activation of innate immunity by various triggers. SARS-CoV-2 infection induces a strong inflammatory response in some patients and a cytokine storm is one of the main causes of severe morbidity and mortality associated with the virus. Here, we describe two cases of patients with histologically and radiologically proven mRCC whose treatment was delayed due to COVID-19 and who experienced spontaneous tumour regression following the infection. Both patients reported here had predominantly pulmonary and mediastinal involvement and underwent nephrectomy. The interval between the diagnosis of COVID-19 and the detection of tumour regression was 3 and 4 months, respectively. Although approved vaccines and other measures are clearly the best way to prevent COVID-19-associated morbidity and mortality in cancer patients, we hypothesize that innate immunity activation by the infection can contribute to tumour regression in special circumstances.

Lukas Fiser

Papers

Spontaneous Regression of Metastatic Renal Cell Carcinoma after SARS-CoV-2 Infection: A Report of Two Cases.