Selected-Lesion Stereotactic Radiosurgery (SL-SRS) as a Novel Strategy in the Treatment of Patients With Multiple Brain Metastases.

INTRODUCTION: With the diminishing use of whole-brain radiotherapy (WBRT), there is increasing debate regarding the maximum number of brain metastases that should be treated with stereotactic radiosurgery (SRS). In patients with >10-15 lesions, some groups are proposing a new approach - selected-lesion SRS (SL-SRS) - where only a subset of intracranial lesions are chosen for irradiation. This study is an initial look into this practice. METHODS: This is a cross-sectional exploratory survey study. A survey of 19 questions was created by the International Radiosurgery Research Foundation (IRRF) using open-ended and multiple-choice style questions on SL-SRS practices and indications with the goal of qualitatively understanding how SL-SRS is being implemented worldwide. The survey was distributed to physicians in the United States (US) and internationally who are members of the IRRF and who perform SRS frequently. Ten out of 50 IRRF institutions provided responses reflecting the practices of 16 physicians. RESULTS: SL-SRS is being performed at 8/10 institutions. The most common reasons for using SL-SRS included patients with prior WBRT, patients with progressing systemic disease with central nervous system (CNS)-penetrating or immunotherapies available, specific requests from medical oncology, and cooperative studies using this approach. Lesion size was cited as the most important factor when choosing to irradiate any single lesion. The majority of respondents reported 30 mm and 40 mm as size cutoffs (by largest dimension) for treatment of a lesion in eloquent and non-eloquent locations, respectively. Eloquence of lesion location and attributable symptoms were also considered important. Progression of untreated lesions was the most common reason reported for bringing patients back for additional treatment. CONCLUSION: The responses to this survey show that SL-SRS is being used, allowing for small/asymptomatic brain metastases to be left safely unirradiated. It is currently used in patients who have >10-15 lesions with prior WBRT, those with progression of extracranial disease but with acceptable systemic treatment options, and those with poor functional status. The incorporation of this new approach into clinical trials should be considered for the safe study of the efficacy of new CNS-penetrating systemic therapies.

Brain Metastases With Malignant Peritoneal Mesothelioma: Never Reported Before.

Malignant mesothelioma is a very rare diagnosis. Malignant mesotheliomas arise from surface linings of pleura, peritoneal cavity, or tunica vaginalis and pericardium with pleural malignant mesotheliomas being the most common. The incidence of brain metastases has been very low with malignant pleural mesotheliomas, but to date, there have not been any cases reported of brain metastasis with malignant peritoneal mesotheliomas. We present a patient diagnosed with malignant peritoneal mesothelioma and was successfully treated with immunotherapy for over two years but later presented with brain metastases. Although the patient had a surgical resection followed by brain radiation, he died three months after his diagnosis of brain metastases. Immunotherapy has revolutionized the treatment of malignant mesothelioma, and patients are living longer than before. We present this patient to increase awareness of brain metastases with malignant peritoneal mesothelioma. This case also highlights that we need to investigate different treatment options for brain metastases in patients with malignant mesothelioma as conventional treatment options like surgical resection and brain radiation are not very effective.

Duodenal Adenocarcinoma With Suspected Brain Metastasis.

Duodenal adenocarcinoma (DA) is a rare tumor. We present the case of an 84-year-old lady who presented with episodic emesis with progressive dysphagia to solids and liquids. She also noted a significant weight loss of 31kg over four months. She was reported to have multiple brain masses three months before this admission. A computed tomography (CT) scan showed a heterogeneous mass (8cm) in the left retroperitoneum, inseparable from the duodenum. Additional peritoneal nodules and enlarged retroperitoneal lymph nodes were suspicious for metastases. Esophagogastroduodenoscopy revealed extrinsic compression of the stomach by the tumor. A large friable distal duodenal mass (fourth part) partially obstructed the lumen, which was biopsied. Pathology results demonstrated high-grade dysplasia but did not confirm malignancy. The patient's carcinoembryonic antigen (CEA) was elevated, but cancer antigens (CA)125 and CA19-9 were normal. A percutaneous biopsy of the mass revealed enteric-type adenocarcinoma. Immunohistochemistry showed that the tumor was positive for caudal-type homeobox (CDX)2, negative for special AT-rich sequence-binding protein (SATB)2, and patchy positive for cytokeratin (CK)7 and CK20 staining. The collective evidence suggested a duodenal primary. The patient opted for hospice and died in three days. We lack pathological evidence, but the patient's brain masses were suspicious of metastases. This would be one of the few reported cases of DA with possible brain metastases.

Stereotactic Radiosurgery in a Small Cell Lung Cancer Patient With Numerous Brain Metastases.

Small cell lung cancer (SCLC) is an aggressive form of lung cancer characterized by its propensity to metastasize to the brain. When SCLC patients develop brain metastasis, the standard-of-care treatment is whole-brain radiotherapy (WBRT), with the goal of treating both macroscopic and microscopic tumors. However, WBRT is found to be associated with significant morbidity including cognitive impairment. An emerging alternative to WBRT for SCLC is stereotactic radiosurgery (SRS), supported by a recent multi-institutional series and meta-analysis. However, there is limited evidence on the use of SRS when there are greater than 15 lesions from any histology, much less SCLC, where the risk of microscopic disease is felt to be even higher. Here, we present the case of an adult female with extensive-stage SCLC who developed 23 brain metastases. Due to patient preference, these were treated with SRS to a total dose of 20 Gy in one fraction. The patient did not experience any radiation-induced toxicity, including radionecrosis, and had overall favorable intracranial control using SRS alone at the time of her death, which was due to extracranial disease progression. This case adds to the literature suggesting that SRS could be a reasonable option for patients with SCLC. It illustrates that it might be reasonable to seek to expand on who might be considered a candidate for SRS treatment, with a high number of lesions not necessarily representing imminent widespread intracranial disease progression.

A Rare Case of Neck Sarcomatoid Squamous Cell Carcinoma With Brain Metastases.

Squamous cell carcinoma (SCC) is the second most prominent form of skin malignancy. It occurs most frequently in older males with fair skin complexion that have extensive sun exposure most commonly in their childhood. The metastatic presentation of SCC is rare and is most common in the lung. In this paper, we present the unique case of a 73-year-old patient with sarcomatoid squamous cell carcinoma in their posterior neck that metastasized to the brain.