Radiation therapy for brain metastases

Initial Age and Performans Status: Predicators for Re-Irradiation Ability in Patients with Relapsed Brain Metastasis after Initial Stereotactic Radiotherapy

BACKGROUND

Brain metastases (BMs) frequently occur in cancer patients, and stereotactic radiation therapy (SRT) is a preferred treatment option. In this retrospective study, we analyzed patients treated by SRT for a single BM during their first SRT session and we compared two subgroups: "Cohort 1" with patients did not undergo cerebral re-irradiation and "Cohort 2" with patients received at least one subsequent SRT session for cerebral recurrence.

METHODS

We included patients who received SRT for a single BM between January 2010 and June 2020. Cohort 1 comprised 152 patients, and Cohort 2 had 46 patients.

RESULTS

Cohort 2 exhibited younger patients with higher Karnofsky performance status (KPS). Median overall survival was considerably longer in Cohort 2 (21.8 months) compared to Cohort 1 (6.1 months). Local and cerebral recurrence rates were significantly higher in Cohort 2 (p < 0.001), attributed to patient selection and longer survival. The combined score of age and KPS proved to be a predictive factor for survival, with patients under 65 years of age and KPS > 80 showing the best survival rates in the overall population.

CONCLUSION

This retrospective study highlights that the combined score of age and KPS can predict better survival, especially for patients under 65 years with a KPS score above 80. Further research involving larger and more diverse populations is essential to validate and expand upon these findings.

Long-Term Results of Stereotactic Radiotherapy in Patients with at Least 10 Brain Metastases at Diagnosis

PURPOSE

to evaluate an SRT approach in patients with at least 10 lesions at the time of BM initial diagnosis.

METHODS

This is a monocentric prospective cohort of patients treated by SRT, followed by a brain MRI every two months. Subsequent SRT could be delivered in cases of new BMs during follow-up. The main endpoints were local control rate (LCR), overall survival (OS), and strategy success rate (SSR). Acute and late toxicity were evaluated.

RESULTS

Seventy patients were included from October 2014 to January 2019, and the most frequent primary diagnosis was non-small-cell lung cancer (N = 36, 51.4%). A total of 1174 BMs were treated at first treatment, corresponding to a median number of 14 BMs per patient. Most of the patients (N = 51, 72.6%) received a single fraction of 20-24 Gy. At 1 year, OS was 62.3%, with a median OS of 19.2 months, and SSR was 77.8%. A cumulative number of 1537 BM were treated over time, corresponding to a median cumulative number of 16 BM per patient. At 1-year, the LCR was 97.3%, with a cumulative incidence of radio-necrosis of 2.1% per lesion. Three patients (4.3%) presented Grade 2 toxicity, and there was no Grade ≥ 3 toxicity. The number of treated BMs and the treatment volume did not influence OS or SSR (p > 0.05).

CONCLUSIONS

SRT was highly efficient in controlling the BM, with minimal side effects. In this setting, an SRT treatment should be proposed even in patients with ≥10 BMs at diagnosis.

Comparative study of dynamic conformal arc therapy and volumetric modulated arc therapy for treating single brain metastases: A retrospective analysis of dosimetric and clinical outcomes

Background and purpose

Stereotactic radiation therapy (SRT) is commonly used to treat brain metastases (BMs). This retrospective study compared two SRT techniques, dynamic conformal arc therapy (DCAT) and volumetric modulated arc therapy (VMAT), for single BM treatments.

Material and methods

Data of patients treated between January 2010 and June 2020 were considered. Patients with multiple BMs, resected BMs, reirradiation, whole-brain radiation therapy and brainstem metastases were excluded. We focused our analysis on 97 patients who received 23.1 Gy in three fractions. Acute toxicities and follow-up outcomes were recorded. Dosimetric data were analyzed in two subgroups (PTV ≤ 10 cc and PTV > 10 cc).

Results

DCAT and VMAT were used in 70 (72.2 %) and 27 (27.8 %) patients, respectively. Acute toxicities were not significantly different between groups (p = 0.259), and no difference was detected in the incidence rate of radionecrosis, local recurrence and cerebral recurrence (p > 0.999, p > 0.999 and p = 0.682, respectively). PTV coverage was better with DCAT for small volumes (PTV ≤ 10 cc). Mean conformity index (CI) was significantly higher with VMAT and mean gradient index (GI) was significantly lower with DCAT whatever volume subgroups (p < 0.001). DCAT had more heterogeneous plans and VMAT required more monitor units. DCAT resulted in reduced low and intermediate doses, whereas VMAT led to decreased high doses.

Conclusion

DCAT and VMAT are two effective and safe SRT techniques for BMs treatment. In the era of re-irradiation, it is important to reduce the doses delivered to healthy tissues. Further prospective studies are needed to validate these findings.

Role of radiotherapy in the management of brain oligometastases

The management of patients with brain oligometastases is complex and relies on specific reasoning compared to extracranial oligometastases. The levels of evidence are still low because patients with brain oligometastases are frequently excluded from randomized clinical trials. Stereotactic radiotherapy should be preferred in this indication over whole brain irradiation, both for patients with metastases in place and for those who have undergone surgery. The decision of local treatment and its timing must be a multidisciplinary reflection taking into account the histological and molecular characteristics of the tumor as well as the intracranial efficacy of the prescribed systemic treatments. Great caution must be observed when using stereotactic radiotherapy and concomitant systemic treatments because interactions are still poorly documented. We present the recommendations of the French society of radiation oncology on the management of brain oligometastatic patients with radiotherapy.

Radiotherapy in the management of synchronous metastatic lung cancer

Metastatic lung cancer classically portends a poor prognosis. The management of metastatic lung cancer has dramatically changed with the emergence of immune checkpoint inhibitors, targeted therapy and due to a better understanding of the oligometastatic process. In metastatic lung cancers, radiation therapy which was only used with palliative intent for decades, represents today a promising way to treat primary and oligometastatic sites with a curative intent. Herein we present through a literature review the role of radiotherapy in the management of synchronous metastatic lung cancers.

Stereotactic Radiation Therapy of Single Brain Metastases: A Literature Review of Dosimetric Studies

Stereotactic radiotherapy (SRT) plays a major role in treating brain metastases (BMs) and can be delivered using various equipment and techniques. This review aims to identify the dosimetric factors of each technique to determine whether one should be preferred over another for single BMs treatment. A systematic literature review on articles published between January 2015 and January 2022 was conducted using the MEDLINE and ScienceDirect databases, following the PRISMA methodology, using the keywords "dosimetric comparison" and "brain metastases". The included articles compared two or more SRT techniques for treating single BM and considered at least two parameters among: conformity (CI), homogeneity (HI) and gradient (GI) indexes, delivery treatment time, and dose-volume of normal brain tissue. Eleven studies were analyzed. The heterogeneous lesions along with the different definitions of dosimetric indexes rendered the studied comparison almost unattainable. Gamma Knife (GK) and volumetric modulated arc therapy (VMAT) provide better CI and GI and ensure the sparing of healthy tissue. To conclude, it is crucial to optimize dosimetric indexes to minimize radiation exposure to healthy tissue, particularly in cases of reirradiation. Consequently, there is a need for future well-designed studies to establish guidelines for selecting the appropriate SRT technique based on the treated BMs' characteristics.

Hypofractionated postoperative stereotactic radiotherapy for large resected brain metastases

PURPOSE

The aim of the present retrospective study was to report outcomes after hypofractionated stereotactic radiotherapy (HSRT) for resected brain metastases (BM).

PATIENTS AND METHODS

We reviewed results of patients with resected BM treated with postoperative HSRT (3×7.7Gy to the prescription isodose 70%) between May 2013 and June 2020. Local control (LC), distant brain control (DBC), overall survival (OS), leptomeningeal disease relapse (LMDR), and radiation necrosis (RN) occurrence were reported.

RESULTS

Twenty-two patients with 23 brain cavities were included. Karnofsky Performance status (KPS) was≥70 in 77.3%. Median preoperative diameter was 37mm [21.0-75.0] and median planning target volume (PTV) was 23 cm³ [9.9-61.6]. Median time from surgery to SRT was 69 days [7-101] and 48% of patients had a local relapse on pre-SRT imaging. Median follow-up was 17.5 months [1.6-95.9]. One and two-year LC rates were 60.9 and 52.2% respectively. One and 2-year DBC rates were 45.5 and 40.9%. Median OS was 16.5 months. Four patients (18.2%) presented LMDR during follow-up. RN occurred in 6 patients (27.2%). Three factors were associated with OS: ECOG-PS (P=0.009), KPS (P=0.04), and cystic metastasis before surgery (P=0.037). Several factors were related to RN occurrence: PTV diameter and volume, Normal brain V21, V21 and V24 isodoses volumes.

CONCLUSION

HSRT is the most widely used scheme for larger brain cavities after surgery. The optimal dose and scheme remain to be defined as well as the optimal delay between postoperative SRT and surgery. Dose escalation may be necessary, especially in case of subtotal resection.