[Current management of brain metastases]

The development and validation of a nomogram for predicting brain metastases in lung squamous cell carcinoma patients: an analysis of the Surveillance, Epidemiology, and End Results (SEER) database

Background

The incidence of brain metastasis (BM) in patients suffering from lung squamous cell carcinoma (LUSC) is lower than that in patients suffering from non-squamous cell carcinoma (NSCC) and there are few studies on BM of LUSC. The purpose of this investigation was to ascertain the risk factors of LUSC, as well as to establish a nomogram prognostic model to predict the incidence of BM in patients with LUSC.

Methods

Patients diagnosed with LUSC between 2010 and 2015 were identified from the Surveillance, Epidemiology, and End Results (SEER) database and the patient data were collated. All patients diagnosed from 2010–2012 were allocated into the training cohort, and the remaining patients diagnosed from 2013–2015 formed the test cohort. Using factors that were screened out through logistic regression analyses, the nomogram in the training cohort was established. It was then evaluated for discrimination and calibration using the test cohort. The performance of the nomogram was assessed by quantifying the area under the receiver operating characteristic (ROC) curve and evaluating the calibration curve.

Results

A total of 26,154 LUSC patients were included in the study. The training cohort consisted of 16,543 patients and there were 8611 patients in the test cohort. Age, marital status, insurance status, histological grade, tumor location, laterality, stage of the cancer, number of metastatic organs, chemotherapy, surgery, and radiotherapy were highly correlated with the incidence of BM. The area under the ROC curve (AUC) of the nomogram for the training cohort and the test cohort were 0.810 [95% confidence interval (CI): 0.796 to 0.823] and 0.805 (95% CI: 0.784 to 0.825), respectively. The slope of the calibration curve was close to 1.

Conclusions

The nomogram was able to accurately predict the incidence of BM. This may be beneficial for the early identification of high-risk LUSC patients and the establishment of individualized treatments.

HOXB9 enhances the ability of lung cancer cells to penetrate the blood-brain barrier

Even after multimodal therapy, the prognosis is dismal for patients with brain metastases from non-small cell lung cancer (NSCLC). Although the blood-brain barrier (BBB) limits tumor cell penetration into the brain parenchyma, some nevertheless colonize brain tissue through mechanisms that are not fully clear. Here we show that homeobox B9 (HOXB9), which is commonly overexpressed in NSCLC, promotes epithelial-to-mesenchymal transition (EMT) and tumor migration and invasion. Animal experiments showed that HOXB9 expression correlates positively with the brain metastatic potential of human NSCLC cells, while brain metastatic cells derived through in vivo selection showed greater HOXB9 expression than their cells of origin. Comparable results were obtained after immunohistochemical analysis of clinical primary NSCLC and matched brain metastasis samples obtained after surgery. Using an in vitro BBB model, knockdown and overexpression experiments showed that HOXB9-dependent expression of MMP9 in NSCLC cells leads to reduced expression of junctional proteins in cultured human vascular endothelial cells and enhanced transmigration of tumor cells. These data indicate that HOXB9 enables NSCLC cells to break away from the primary tumor by inducing EMT, and promotes brain metastasis by driving MMP9 production and degradation of intercellular adhesion proteins in endothelial cells comprising the BBB.

Photodynamic therapy adjuvant to surgery in metastatic carcinoma in brain

Cerebral metastases occur in 15-40% of cancers and their incidence is increasing. We have studied the use of fluorescence image-guided surgery and repetitive photodynamic therapy in 14 metastatic brain cancers.

METHODS

Case note review of prospectively collected data on patients who were treated with PDT at the time of surgery for brain metastases. Patients were consented for the surgery and PDT. Patients were given 2 mg/kg body weight of Photofrin IV 48 h before the surgery and 20 mg/kg 5-aminolevulenic acid orally 3h before surgery. Following resection of the tumor using fluorescence, microsurgical and image guidance techniques, the post-excision cavity is filled with a balloon using 0.32% intralipid solution and up to five consecutive PDT treatments were given using 100 J/cm(2) Diode Laser 630 nm. Patients were followed up clinically and by brain imaging every 3 months till their death.

RESULTS

Seven were lung in origin and seven of variable sources. One patient with lung metastases died of unrelated cause while the remaining six had remained free from brain disease till their death. Two of the remaining seven patients died of local brain recurrence, one bowel after 4 weeks and one of unknown primary after 70 weeks.

CONCLUSION

Adjuvant repetitive PDT seems to offer an excellent local control of metastatic brain carcinomas with about 79% of patients succumb to the primary and only two out of fourteen died of brain recurrence with the best results obtained in lung cancer.

A rare bone-leptomeningeal metastasis from an adrenal cortical carcinoma

We report a rare bone-leptomeningeal metastasis from an adrenal cortical carcinoma (ACC). ACC is a rare malignancy and represents one of the most unusual sources of intracranial metastases (0-0.2%); the localization to the skull bone and meninges is uncommon. A 45-year-old man underwent surgery for a non-functioning ACC; 4 months later he developed a soft left frontal mass. The CT scans and MRI showed a large tumor with bone and leptomeningeal involvement. Despite chemotherapy, the lesion increased in volume, which led to local pain and right hemiparesis. Thus, the patient underwent excision of the mass; histopathological diagnosis confirmed that it was an ACC metastasis. The patient underwent standard radiation therapy after surgery. At post-operative follow-up, the patient was in a good neurological condition with no radiological evidence of a cranial recurrence; however, there was a voluminous abdominal regrowth of the primary tumor. To our knowledge, this is the second case of bone and leptomeningeal metastasis arising from an ACC. This patient report confirms the effectiveness of aggressive surgery for management of large intracranial metastases, particularly those that arise from primary tumors that are resistant to radiotherapy and chemotherapy. In our opinion, surgery represents the most appropriate treatment for voluminous intracranial metastasis - even when there are no neurological signs.