Cellular and molecular features related to exceptional therapy response and extreme long-term survival in glioblastoma

Glioblastoma Multiforme (GBM) remains the most common malignant primary brain tumor with a dismal prognosis that rarely exceeds beyond 2 years despite extensive therapy, which consists of maximal safe surgical resection, radiotherapy, and/or chemotherapy. Recently, it has become clear that GBM is not one homogeneous entity and that both intra-and intertumoral heterogeneity contributes significantly to differences in tumoral behavior which may consequently be responsible for differences in survival. Strikingly and in spite of its dismal prognosis, small fractions of GBM patients seem to display extremely long survival, defined as surviving over 10 years after diagnosis, compared to the large majority of patients. Although the underlying mechanisms for this peculiarity remain largely unknown, emerging data suggest that still poorly characterized both cellular and molecular factors of the tumor microenvironment and their interplay probably play an important role. We hereby give an extensive overview of what is yet known about these cellular and molecular features shaping extreme long survival in GBM.

Long-term volumetric analysis of vestibular schwannomas following stereotactic radiotherapy: Practical implications for follow-up

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Pseudoprogression may be a late phenomenon after radiosurgery.

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Loss of central contrast enhancement is not predictive of tumor control.

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No decision of salvage therapy should be made until the 6th year post-treatment.

Background and purpose

Transient tumor swelling is a well-known phenomenon following radiotherapy for vestibular schwannomas (VS). We analyzed the long-term volumetric changes of VS after LINAC radiosurgery, in order to determine a time interval during which a true tumor progression can be distinguished from a pseudoprogression.

Methods

Among 63 patients with VS treated by one fraction or fractionated radiotherapy, we selected 52 of them who had a minimal follow-up of 5 years. Maximal axial diameter and three-dimensional tumor volume were measured on each MRI scan. Volume changes were interpreted using different error margins ranging from 10 to 20%. Patients were categorized according to the tumor evolution pattern over time.

Results

Median follow-up was 83 months. One tumor (1.9%) remained stable and 26.9% had continuous shrinkage. Applying an error margin of 13%, a transient tumor enlargement was observed in 63.5% of patients, with a first peak at 6–12 months and a late peak at 3–4 years. A true progression was suspected in 4 (7.7%) patients, tumor regrowth starting after the 3rd or 4th year post-treatment. Only one patient required salvage radiotherapy.

Conclusion

Transient swelling of VS following radiotherapy is generally an early phenomenon but may occur late. In the first 5 years, a true tumor progression cannot be differentiated from a pseudoprogression. A significant tumor expansion observed on 3 sequential MRI scans after the 3rd year may be suggestive of treatment failure. Long-term follow-up is therefore mandatory and no decision of salvage treatment should be made until the 6th year.

Randomized Clinical Trial on Reduction of Radiotherapy Dose to the Elective Neck in Head and Neck Squamous Cell Carcinoma: Results on the Quality of Life

PURPOSE

A randomized trial was initiated to investigate whether a reduction of the dose to the elective nodal sites would result in less toxicity and improvement in Quality of Life (QoL) without compromising tumor control. This paper aimed to compare QoL in both treatment arms.

METHODS

Two-hundred head and neck cancer patients treated with radiotherapy (RT) or chemo-RT were randomized (all stages, mean age: 60 years, M/F: 82%/18%). The elective nodal volumes of patients randomized in the experimental arm were treated up to a 40 Gy equivalent dose. In the standard arm, the elective nodal volumes were treated up to a 50 Gy equivalent dose. The QoL data were collected using The European Organization for Research and Treatment of Cancer (EORTC) core questionnaire QLQ-C30 and the EORTC Head and Neck Cancer module (H&N35).

RESULTS

A trend toward less decline in QoL during treatment was observed in the 40 Gy arm compared to the 50 Gy arm. Statistically significant differences for global health status, physical functioning, emotional functioning, speech problems, and trouble with social eating in favor of the 40 Gy arm were observed. A clinically relevant better outcome in the 40 Gy arm was found for physical functioning at the end of therapy.

CONCLUSION

QoL during RT for head and neck cancer tends to be less impaired in the 40 Gy arm. However, reducing the dose only on the elective neck does not result in clinically relevant improvement of QoL. Therefore, additional treatment strategies must be examined to further improve the QoL of HNSCC patients.

Surgical bed stereotactic radiotherapy of brain metastases: Clinical outcome and predictors of local and distant brain failure

PURPOSE

To retrospectively analyze the outcomes of stereotactic radiotherapy (SRT) targeted at surgical bed of brain metastases (BM) and identify patterns of local/distant brain relapses (LR/DBR).

PATIENTS/METHODS

Seventy patients were treated with SRT between 2008-2017. Marginal dose prescription on the 70% isodose line depended on the maximal diameter of the target volume and range between 15-18Gy for single fraction radiosurgery and 23.1-26Gy in 3-5 fractions for fractionated SRT.

RESULTS

At 12 months, the overall survival (OS) was 69% [CI _95%=59%-81%]. At 6 and 12 months, the cumulative incidence functions (CIF) of local relapse were 4% [1%-13%] and 15% [8%-26%], respectively. According to univariate analysis, factors associated with LR were an initial volume larger than 7cc (hazard ratio: 4.6 [1.0-20.8], P=0.046) and a positive resection margin [hazard ratio: 3.6 [1.1-12.0], P=0.037. DBR occurred in 54.3% of patients with a median time of 8 months. None of the variables tested (histology, location or number of lesions) were found correlated with the DBR. Leptomeningeal disease occurred in 12.9% of cases. Salvage whole brain radiotherapy (WBRT) was required in 45.7% of patients and delayed by a median time of 9.6 months. Symptomatic radionecrosis (RN) occurred in 7.1%.

CONCLUSIONS

Adjuvant SRT was an effective and well-tolerated treatment to control the postoperative risk of recurrence of BM without compromising OS. Positive resection margins and large volumes were predictors factor of local relapse.

P03.02 Risk of leptomeningeal dissemination in patients treated with postoperative stereotactic radiotherapy of brain metastases

Background

There is a body of evidence that the risk of leptomeningeal dissemination (LMD) is increased in the postoperative stereotactic radiotherapy (SRT) of brain metastases (BM) compared to adjuvant whole brain radiotherapy (WBRT). The proposed mechanism is an iatrogenic tumor dissemination into the cerebrospinal fluid at time of surgery. Including a wider volume of meningeal wall and the entire surgical track in the definition of the postoperative SRT clinical target volume (CTV) to decrease LMD is still controversial. The aim of this study was to retrospectively analyze the outcome of adjuvant SRT targeted at resection cavities of BM without previous WBRT.

MATERIAL / METHODS

We reviewed 70 patients treated with postoperative SRT for BM. Stereotactic planning computed tomography and planning MRI were imported into iPlan RT image software for image registration and TV delineation. The CTV consisted of any residual enhancement and all resected cavity including a safety margin of 1 to 2 mm. Only in cases of superficial initial tumor with meningeal contact was the CTV enlarged to the adjacent meningeal wall, but never included edema or the entire surgical track. Patients underwent regular follow-up MRI. The cumulative incidence rates of LMD was retrospectively calculated as well as patterns of failure.

RESULTS

The most common histological type was non small cell lung cancer in 61.4%. There were 38.6% infratentorial locations and 37.2 % superficial lesions. En bloc resection was achieved in 60% and compete resection in 75.7%. After a median imaging follow up time of 16.7 months, 54.3% of patients experienced distant brain failure. LMD occurred in 9 of 70 patients (12.9 %) at a median time of 10.7 months. Survival without LMD was 88% at 1 year (IC 95% 79%-97%) and 82% at 2years (IC 95% 72%-94%). In three quarter of cases, LMD interested superficial lesions. In univariate analysis, survival rates without LMD at 1 year for superficial and deep lesions were 88 % and 94 %, respectively (p=0.49). We report only one recurrence in the surgical track (1.42%).

CONCLUSION

The risk of LMD was comparable to the literature (11–17%). Superficial lesions were slightly more likely to relapse in the meninges, but it was non-significant. The risk of recurrence in the surgical track is negligible. Our results do not support the current guidelines recommending the systematic inclusion of the surgical track and the related meninges in the CTV.

P03.03 Dynamics of brain metastasis cavities between resection and adjuvant stereotactic radiotherapy and impact of the delay on local control

BACKGROUND

Adjuvant stereotactic radiotherapy (SRT) to the surgical cavity of brain metastases (BM) improves the local control. An early post-operative irradiation is desirable to limit the risk of recurrence while delaying it might reduce the risk of radionecrosis by reducing the size of the target volume (TV) thanks to the cavity constriction. The purpose of our study was to examine cavity dynamics after resection to determine if delaying SRT influences cavity size as well as local progression (LP).

MATERIAL AND METHODS

We reviewed 70 BM resection cavities treated with adjuvant SRT. A preoperative, immediate postoperative and at the time of SRT, 3D T1-weigthed MRI, were available for all patients. The volumes were retrospectively calculated with the PACS software Telemis® version 4 and the iPlan RT image software. For all cavities, the TV was obtained by expanding the cavity by a median margin of 2mm to account for microscopic spread. The surgical track and edema areas were not included in the TV. The dynamic evolution of cavities and LP according to the delay of SRT were analyzed.

RESULTS

The median time from surgery to SRT was 27 days (3–99). The median preoperative and SRT cavity volumes were 7.2 cc (ranges: 0.5–29.5) and 8 cc (ranges: 0.8–31), respectively. After margin expansion, the TV was increased to a median of 14.8 cc. The volumetric cavity changes were an increase by 2 cc in 35 %, whereas only 22.5 % decreased by 2 cc and 42.5% cavities were stable (defined as a change ≤2 cc). We noted that 11% of volume change were attributable to the delay (r2 = 0.11). forty-seven patients were treated within a delay of 30 days and experienced early LP in 10.6 % against 20 % beyond 30 days (p= 0.6).

CONCLUSION

In the interval between surgery and SRT, BM cavities dynamics are inconstant and unpredictable in function of time. Furthermore, delaying SRT may compromise local control, though the difference was not statistically significant due to the small size of our population. A preoperative SRT strategy looks more promising by alleviating the problem of time and reducing the volume of irradiated brain.

The opinion of general practitioners on the treatment of prostate and breast cancer in elderly people: results of a survey based on clinical models

AIMS

Several publications have reported age-related differences in the management of people with cancer. Most data have been derived retrospectively from hospital or cancer-centre databases. The aim of the present study was to identify major decisional factors observed in general practitioner (GP) practices, outside the hospital setting, regarding the clinical management of patients with prostate and breast cancer.

MATERIALS AND METHODS

During three national GP meetings in Belgium, questionnaires presenting two simulated patient cases were presented to GPs who were asked two questions: one regarding further staging and referral of the case and the second regarding the treatment of the case. A total of 678 questionnaires were distributed. GPs received two randomly selected cases each: a breast cancer history and a prostate cancer history. Three variables were assessed simultaneously: age, performance status and medical history (comorbidity).

RESULTS

The analysis indicated that elderly patients were more likely to be referred for non-curative treatment (OR 13.71; 95% CI 5.67-33.12; P < 0.0001 for prostate cancer and OR 17.67; 95% CI 4.04-77.31; P < 0.0001 for breast cancer). The other variables (performance status and medical history) did not affect treatment orientation. However, GPs were prepared to seek assistance from oncologists in both cases, irrespective of the patient's age.

CONCLUSION

Age seems to be more important among GPs in deciding how to manage cancer patients than performance status and comorbidity. This is a very common prejudice. They are, nevertheless, inclined to refer people with cancer to oncologists independently of the patient's age.

[Selection and delineation of lymph node target volumes in head and neck neoplasms]

This article reviews all clinical and pathological data available in the literature supporting the concept of selectivity in the neck nodes to be included in the Clinical Target Volume for head and neck squamous cell carcinoma. Using the terminology of neck node levels and the guidelines for the surgical delineation of these levels proposed by the Committee for Head and Neck Surgery and Oncology of the American Academy for Otolaryngology-Head and Neck Surgery, recommendations are proposed for both the selection and the delineation of lymph node target volumes.