The Role of Lithium in Management of Endocrine Tumors-A Comprehensive Review

Valproate and lithium: Old drugs for new pharmacological approaches in brain tumors?

Beyond its use as an antiepileptic drug, over time valproate has been increasingly used for several other therapeutic applications. Among these, the antineoplastic effects of valproate have been assessed in several in vitro and in vivo preclinical studies, suggesting that this agent significantly inhibits cancer cell proliferation by modulating multiple signaling pathways. During the last years various clinical trials have tried to find out if valproate co-administration could enhance the antineoplastic activity of chemotherapy in glioblastoma patients and in patients suffering from brain metastases, demonstrating that the inclusion of valproate in the therapeutic schedule causes an improved median overall survival in some studies, but not in others. Thus, the effects of the use of concomitant valproate in brain cancer patients are still controversial. Similarly, lithium has been tested as an anticancer drug in several preclinical studies mainly using the unregistered formulation of lithium chloride salts. Although, there are no data showing that the anticancer effects of lithium chloride are superimposable to the registered lithium carbonate, this formulation has shown preclinical activity in glioblastoma and hepatocellular cancers. However, few but interesting clinical trials have been performed with lithium carbonate on a very small number of cancer patients. Based on published data, valproate could represent a potential complementary therapeutic approach to enhance the anticancer activity of brain cancer standard chemotherapy. Same advantageous characteristics are less convincing for lithium carbonate. Therefore, the planning of specific phase III studies is necessary to validate the repositioning of these drugs in present and future oncological research.

Lithium in Cancer Therapy: Friend or Foe?

Lithium, a trace element important for fetal health and development, is considered a metal drug with a well-established clinical regime, economical production process, and a mature storage system. Several studies have shown that lithium affects tumor development by regulating inositol monophosphate (IMPase) and glycogen synthase kinase-3 (GSK-3). Lithium can also promote proliferation and programmed cell death (PCD) in tumor cells through a number of new targets, such as the nuclear receptor NR4A1 and Hedgehog-Gli. Lithium may increase cancer treatment efficacy while reducing side effects, suggesting that it can be used as an adjunctive therapy. In this review, we summarize the effects of lithium on tumor progression and discuss the underlying mechanisms. Additionally, we discuss lithium's limitations in antitumor clinical applications, including its narrow therapeutic window and potential pro-cancer effects on the tumor immune system.

Parathyroid Imaging: Past, Present, and Future

The goal of parathyroid imaging is to identify all sources of excess parathyroid hormone secretion pre-operatively. A variety of imaging approaches have been evaluated and utilized over the years for this purpose. Ultrasound relies solely on structural features and is without radiation, however is limited to superficial evaluation. 4DCT and 4DMRI provide enhancement characteristics in addition to structural features and dynamic enhancement has been investigated as a way to better distinguish parathyroid from adjacent structures. It is important to recognize that 4DCT provides valuable information however results in much higher radiation dose to the thyroid gland than the other available examinations, and therefore the optimal number of phases is an area of controversy. Single-photon scintigraphy with 99mTc-Sestamibi, or dual tracer 99mTc-pertechnetate and 99mTc-sestamibi with or without SPECT or SPECT/CT is part of the standard of care in many centers with availability and expertise in nuclear medicine. This molecular imaging approach detects cellular physiology such as mitochondria content found in parathyroid adenomas. Combining structural imaging such as CT or MRI with molecular imaging in a hybrid approach allows the ability to obtain robust structural and functional information in one examination. Hybrid PET/CT is widely available and provides improved imaging and quantification over SPECT or SPECT/CT. Emerging PET imaging techniques, such as 18F-Fluorocholine, have the exciting potential to reinvent parathyroid imaging. PET/MRI may be particularly well suited to parathyroid imaging, where available, because of the ability to perform dynamic contrast-enhanced imaging and co-registered 18F-Fluorocholine PET imaging simultaneously with low radiation dose to the thyroid. A targeted agent specific for a parathyroid tissue biomarker remains to be identified.

Challenges in Treating Cancer Patients With Unstable Psychiatric Disorder

In this review, we first present a case of chronic myeloid leukemia with acute psychosis, and then we will discuss the incidence of cancer in patients with psychotic disorders, the manifestations of new-onset psychosis, and the prevalence of preexisting psychosis in cancer patients, coupled with their impact on the treatment, diagnosis, and prognosis of cancer. This was a case that presented with acute psychosis and was found to have an elevated white blood cell count upon admission to an inpatient psychiatric unit. He was diagnosed with chronic myeloid leukemia and successfully managed with imatinib/dasatinib therapy. Psychiatrically, he was stabilized on two long-acting injectable medications to help maintain adherence. We were able to eliminate his active psychotic symptoms and return him to normal functioning in affect and thinking, achieving sustained compliance with treatment. We identified multiple inconsistencies in screening for cancer of all types in these patients, masking of signs and symptoms that would typically clue physicians to the presence of cancers, underreporting of symptoms, and disparate access to healthcare resources in patients with mental disorders when compared to the general population. Treatment of cancer in these patients as compared to the general population has also been shown to be incongruent, which will be elaborated upon. Psychiatric interventions, as well as supportive measures, for treating patients who are facing challenges during active cancer treatment will be discussed.

MRE11 as a molecular signature and therapeutic target for cancer treatment with radiotherapy

MRE11, the core of the MRE11/RAD50/NBS1 complex, is one of key DNA damage response proteins. Increasing evidence suggests that its expression in cancer cells is critical to developing radioresistance; as such, MRE11 is an emerging marker for targeted radiosensitization strategies. Elevated MRE11 in tumor tissues has been associated with poor survival in patients undergoing radiotherapy, although in some cancer types, the opposite has been noted. The recent discovery of ionizing radiation-induced truncation of MRE11, which decreases its efficacy, may explain some of these paradoxical findings. The progress of research on the biological modulation of MRE11 expression is also discussed, with the potential application of small molecule or large molecule inhibitors of MRE11 for enhancing radiosensitivity. Current research has further highlighted both nuclease and non-nuclease activities of MRE11 in cancer cells treated with ionizing radiation, and differentiation between these is essential to verify the targeting effects of radiosensitizing agents. These updates clarify our understanding of how MRE11 expression may be utilized in future stratification of cancer patients for radiotherapy, and how it may be leveraged in shaping novel radiosensitization strategies.

Lithium-Associated Hyperparathyroidism Followed by Catatonia

Objective

To familiarize the medical community with the less common adverse effects of lithium on parathyroid function, we present a case of lithium-associated hyperparathyroidism followed by the development of new-onset catatonia in a patient with schizoaffective disorder.

Methods

To allow for the safe resumption of lithium, the patient received laboratory screening of serum lithium, blood urea nitrogen, serum creatinine, calcium, and thyroid-stimulating hormone levels. The hypercalcemia was evaluated by measuring parathyroid hormone (PTH), ionized calcium, and 25-hydroxy vitamin D levels.

Results

A 58-year-old man with longstanding schizoaffective disorder was admitted for worsening psychotic symptoms following noncompliance with his risperidone and lithium regimen. Exploratory laboratory tests (hospital day 5) showed an elevated PTH level of 72 (reference, 15-65) pg/mL, ionized calcium level of 1.4 (reference, 1.03-1.23) mmol/mL, and a serum calcium level of 11.3 (reference, 8.4-10.5) mg/dL. After the discontinuation of lithium (day 6), anergia (day 7), mutism, and posturing (day 10) developed. Worsening catatonic symptoms of negativism and poor oral intake necessitated dehydration management with intravenous isotonic saline (day 24). The hypercalcemia persisted for 6 weeks. Treatment with cinacalcet (day 43) rapidly normalized the serum calcium levels (day 44). The catatonia, depression, and psychosis began resolving when clozapine (day 50) and electroconvulsive therapy (day 59) were initiated. PTH levels did not normalize until day 82.

Conclusion

This report describes a case of prolonged hyperparathyroidism and hypercalcemia following treatment with lithium. Catatonia is unusual in patients with lithium-associated hyperparathyroidism but this report suggests that in settings yet to be determined, it is related to hypercalcemia of this syndrome.