Fractionated Stereotactic Radiation Therapy for Pituitary Adenomas: An alternative escalating protocol of hypofractionated stereotactic radiotherapy delivering 35Gy in 5 fractions

PURPOSE

Evaluate efficacy and toxicity of hypofractionated stereotactic radiotherapy (HSRT) for patients treated for pituitary adenoma (PA) with an alternative HSRT escalating protocol delivering 35Gy in 5 fractions.

MATERIAL AND METHODS

From June 2007 to March 2017, 29 patients with pituitary adenoma were treated in Antoine Lacassagne Cancer Centre with an alternative HSRT protocol. Prescribed dose was 35Gy in 5 fractions of 7Gy. Radiographic responses were assessed by annual MRI. Hormone blood samples were evaluated each year after HSRT.

RESULTS

A total of 29 patients aged between 23 and 86 years (median 54 years) were included. Twelve patients received HSRT for recurrent cases and 12 received postoperative adjuvant HSRT, 5 patients did not have surgery. After a median follow-up period of 47 months local control rate was 96%. One patient presented an out-field tumor regrowth 73 months after HSRT. The majority of PA were endocrine-active (18 patients, 62%). After HSRT, 8 patients (44%) presented complete response on initial secretion, 4 patients (23%) presented partial response on initial secretion. Four patients (14%) presented grade 2 or more acute radiation toxicities. One grade 4 visual disorder was observed for one patient.

CONCLUSIONS

HSRT delivering 35Gy in 5 fractions represents a feasible treatment and shows promising results to reduce hormonal overproduction and to improve local control in PA.

Papilledema secondary to vestibular schwannoma: An atypical case without intracranial hypertension

In most cases, vestibular schwannomas with papilledema are associated with intracranial hypertension secondary to hydrocephalus (obstructive or communicating). We describe the atypical case of a 39-years-old man who presented with bilateral papilledema revealing a vestibular schwannoma, but without hydrocephalus and with normal intracranial pressure. Ophtalmologic signs were completely resolved after tumor removal. The pathophysiological mechanism generally described to explain bilateral papilledema in such cases is tumor-induced hyperproteinorachia. However, in the absence of hydrocephalus or intracranial hypertension, this case raises the question of the mechanisms involved in the visual impairment related to vestibular schwannoma.

Orbital exenteration and conjunctival melanoma: a 14-year study at the Jules Gonin Eye Hospital

Purpose

To report our 14-year experience with orbital exenteration and assess risk factors for poor prognosis by focusing on conjunctival melanoma.

Patients and method

A retrospective study was conducted in our tertiary care centre (Jules Gonin Eye Hospital, Lausanne, Switzerland) between 2003 and 2017. Inclusion criteria were patients aged  ≥18 years with a follow-up >12 months, without metastatic spread at the time of surgery. Data recorded were age, gender, tumour histology, surgical technique, postoperative complications, surgical margin status, local recurrence, postoperative radiation beam therapy and metastatic status.

Results

Twenty-five patients with a mean age of 63.2 years (38–92) were included. Conjunctival melanoma was the most frequently identified tumour (n = 14, 56%) followed by conjunctival squamous cell carcinoma (n = 4, 16%), sebaceous carcinoma (n = 3, 12%), choroidal melanoma (n = 2, 8%) and basal cell carcinoma (n = 2, 8%). Eighteen tumours (72%) originated from the conjunctival tissue. Clear surgical margins were achieved in 21 (84%) patients. Fourteen (56%) patients experienced distant metastases and died from metastatic spread after a mean follow-up of 52.3 months (6–120). The 1-, 3- and 5-year overall survival (OS) was 96%, 72% and 60%, respectively. In the univariate analysis, positive surgical margins, local recurrence and metachronous metastases were associated with a decreased OS (p = 0.002, p = 0.005 and p = 0.007, respectively). In the multivariate analysis, positive surgical margins and metachronous metastases were also associated with a decreased OS (p = 0.02 and p = 0.042, respectively). Conjunctival melanoma was not associated with a poorer prognosis (p = 0.280).

Conclusion

Free surgical margins are needed to increase OS. To achieve clearer surgical margins, neoadjuvant targeted therapies/immunotherapies may be considered.

DOCK4 promotes loss of proliferation in glioblastoma progenitor cells through nuclear beta-catenin accumulation and subsequent miR-302-367 cluster expression

Glioblastomas (GBM) are lethal primitive brain tumours characterized by a strong intra-tumour heterogeneity. We observed in GBM tissues the coexistence of functionally divergent micro-territories either enriched in more differentiated and non-mitotic cells or in mitotic undifferentiated OLIG2 positive cells while sharing similar genomic abnormalities. Understanding the formation of such functionally divergent micro-territories in glioblastomas (GBM) is essential to comprehend GBM biogenesis, plasticity and to develop therapies. Here we report an unexpected anti-proliferative role of beta-catenin in non-mitotic differentiated GBM cells. By cell type specific stimulation of miR-302, which directly represses cyclin D1 and stemness features, beta-catenin is capable to change its known proliferative function. Nuclear beta-catenin accumulation in non-mitotic cells is due to a feed forward mechanism between DOCK4 and beta-catenin, allowed by increased GSK3-beta activity. DOCK4 over expression suppresses selfrenewal and tumorigenicity of GBM stem-like cells. Accordingly in the frame of GBM median of survival, increased level of DOCK4 predicts improved patient survival.

MET immunolabelling is a useful predictive tool for MET gene amplification in glioblastoma

AIMS

MET gene amplification is rare in glioblastoma (GBM) and represents a potential target for MET inhibitors. An immunohistochemical screening may be useful to identify MET amplification. The aim of our study was to establish how MET immunolabelling correlates with MET amplification.

METHODS

Three cohorts including 108 GBM (cohort 1, prospective), 104 GBM (cohort 2, retrospective) and 52 GBM (cohort 3, prospective) were investigated for MET expression by immunohistochemistry. MET amplification was assessed by comparative genomic hybridization on microarray (CGH-array) in all cohorts and by fluorescent in situ hybridization (FISH) in cohorts 2 and 3. Active form of MET was assessed using p-MET (Y1349) immunohistochemistry.

RESULTS

Diffuse MET amplification detectable by CGH-array was associated with diffuse, strong MET immunolabelling (four cases in cohort 1 and one case in cohort 2). Focal MET amplification detectable only by FISH was observed in small foci of strongly immunopositive cells in two GBM (cohort 2). In both cohorts, MET amplification was never detected in GBM devoid of strongly immunopositive cells. MET overexpression, observed in 23% of unamplified GBM, was associated with a predominant weak-to-moderate staining intensity and with necrosis (P < 0.005). p-MET was detected in all MET-amplified GBM and in perinecrotic areas of nonamplified GBM. A strong MET immunostaining intensity, at least focal and distant from necrosis, showed 100% sensitivity and 84% specificity for predicting MET amplification in cohort 3.

CONCLUSIONS

MET amplification is characterized by strongly immunopositive cells. Only GBM showing strong MET immunostaining is appropriate for the assessment of MET amplification.