Initial brain metastasis velocity: does the rate at which cancers first seed the brain affect outcomes?

External validation of three prognostic scores for brain metastasis velocity in patients treated with intracranial stereotactic radiotherapy

BACKGROUND AND INTRODUCTION

Brain metastasis velocity (BMV) has been proposed as a prognostic factor for overall survival (OS) in patients with brain metastases (BMs). In this study, we conducted an external validation and comparative assessment of the performance of all three BMV scores.

MATERIALS AND METHODS

Patients treated with intracranial stereotactic radiotherapy (SRT) for BM at a single center between 2014 and 2018 were identified. Where possible, all three BMV scores were calculated. Log-rank tests and linear, logistic and Cox regression analysis were used for validation and predictor identification of OS.

RESULTS

For 333 of 384 brain metastasis patients, at least one BMV score could be calculated. In a sub-group of 187 patients, "classic" BMV was validated as categorical (p < 0.0001) and continuous variable (HR 1.02; 95% CI 1.02-1.03; p < 0.0001). In a sub-group of 284 patients, "initial" BMV was validated as categorical variable (high-risk vs. low-risk; p < 0.01), but not as continuous variable (HR 1.02; 95% CI 0.99-1.04; p = 0.224). "Volume-based" BMV could not be validated in a sub-group of 104 patients. On multivariable Cox regression analysis, iBMV (HR 1.85; 95% CI 1.01-3.38; p < 0.05) and cBMV (HR 2.32; 95% CI 1.15 4.68; p < 0.05) were predictors for OS for intermediate-risk patients after first SRT and first DBFs, respectively. cBMV proved to be the dominant predictor for OS for high-risk patients (HR 2.99; 95% CI 1.30-6.91; p < 0.05).

CONCLUSION

This study externally validated cBMV and iBMV as prognostic scores for OS in patients treated with SRT for BMs whereas validation of vBMV was not achieved.

The Impact of Time Interval on Prognosis in Patients with Non-Small Cell Lung Cancer Brain Metastases After Metastases Surgery

BACKGROUND

Non-small cell lung cancer (NSCLC) is a prominent malignancy often linked to the development of brain metastases (BM), which commonly appear at diverse time intervals (TI) following the lung cancer diagnosis. This study endeavors to determine the prognostic significance of the time interval in patients with NSCLC who undergo BM surgery. Through this investigation, we aim to improve our understanding of the factors impacting the prognosis of BM cases originating from NSCLC.

METHODS

We analyzed data from 74 patients (2011-2021) who underwent BM surgery at our institution. The relationship between various clinical, radiological, and histopathological factors, as well as TI and overall survival (OS), was examined.

RESULTS

The median TI from initial NSCLC diagnosis to BM surgery was 19 months (range: 9-36 months). Notably, a shorter TI of less than 23 months was found to be independently associated with postoperative survival (adjusted odds ratio [aOR] 2.87, 95% confidence interval [CI] 1.03-8.02, P = 0.045). Additionally, a shorter TI was independently correlated with the absence of adjuvant chemotherapy for NSCLC (aOR 0.25, 95% CI 0.07-0.83, P = 0.023) and lack of targeted therapy (aOR 0.02, 95% CI 0.00-0.16, P < 0.001). Late-onset BM (TI ≥ 36 months) was observed in 15 cases (20.3%), in this subgroup, patients aged 60 years or older at the time of lung cancer diagnosis exhibited a significant independent correlation with late-onset BM (aOR 7.24, 95% CI 1.59-32.95, P = 0.011). NSCLC patients who underwent adjuvant chemotherapy displayed a notable correlation with late-onset BM (aOR 6.46, 95% CI 1.52-27.43, P = 0.011), while those who received targeted therapy also exhibited an independent association (aOR 2.27, 95% CI 1.70-3.03, P < 0.001).

CONCLUSIONS

Multiple factors contribute to the variability in the onset interval of BM subsequent to NSCLC diagnosis. The occurrence of BM within TI < 23 months following the initial diagnosis of NSCLC was demonstrated as an independent factor associated with an unfavorable prognosis following BM surgery. Furthermore, patients with NSCLC who did not receive adjuvant chemotherapy and lacked targeted therapy were shown to have an elevated likelihood of developing BM after a long progression-free survival.

Validation of the initial brain metastasis velocity in non-small cell lung cancer at a single cancer center

PURPOSE

The initial brain metastasis velocity (iBMV) was recently reported as a survival predictor after brain metastases (BM) in patients treated by stereotactic radiosurgery. In this study, we validated whether iBMV is a prognostic tool, regardless of treatment modality, in patients with non-small cell lung cancer (NSCLC) with metachronous BM.

METHODS

We retrospectively reviewed consecutive 3,792 new lung cancer cases in which no BM was found on magnetic resonance (MR) screening between February 2014 and December 2019, and enrolled 176 NSCLC patients with subsequent BM. Overall survival (OS) was calculated from the date of MR to identify the time from BM to death.

RESULTS

The median iBMV score was 1.9. We used an iBMV score of 2.0 as the cutoff level, as previously reported. An iBMV score ≥ 2.0 was significantly associated with older age, high neutrophil-to-lymphocyte ratio, and Stage IV (P = 0.04, 0.02, and 0.02, respectively). The median OS was 0.92 years. The median OS for patients with iBMV score ≥ 2.0 and < 2.0 were 0.59 years and 1.33 years, respectively (P < 0.001). Multivariate analysis showed that an iBMV score ≥ 2.0, ECOG performance status score of 1-3, Stage IV, and non-adenocarcinoma histology were independent poor prognostic factors (hazard ratio (HR), 1.94; P = 0.0001; HR, 1.53; P = 0.04; HR, 1.45; P = 0.04; and HR, 1.14; P = 0.03, respectively). Patients with iBMV scores of < 2.0 were more likely to undergo craniotomy or stereotactic irradiation.

CONCLUSIONS

An iBMV score ≥ 2.0 is an independent predictor of survival in NSCLC patients with metachronous BM, regardless of the treatment modality.

Time interval between the diagnosis of breast cancer and brain metastases impacts prognosis after metastasis surgery

Purpose

Breast cancer (BC) is the most frequently diagnosed tumor entity in women. Occurring at different time intervals (TI) after BC diagnosis, brain metastases (BM) are associated with poor prognosis. We aimed to identify the risk factors related to and the clinical impact of timing on overall survival (OS) after BM surgery.

Methods

We included 93 female patients who underwent BC BM surgery in our institution (2008–2019). Various clinical, radiographic, and histopathologic markers were analyzed with respect to TI and OS.

Results

The median TI was 45.0 months (range: 9–334.0 months). Fifteen individuals (16.1%) showed late occurrence of BM (TI ≥ 10 years), which was independently related to invasive lobular BC [adjusted odds ratio (aOR) 9.49, 95% confidence interval (CI) 1.47–61.39, p = 0.018] and adjuvant breast radiation (aOR 0.12, 95% CI 0.02–0.67, p = 0.016). Shorter TI (< 5 years, aOR 4.28, 95% CI 1.46–12.53, p = 0.008) was independently associated with postoperative survival and independently associated with the Union for International Cancer Control stage (UICC) III–IV of BC (aOR 4.82, 95% CI 1.10–21.17, p = 0.037), midline brain shift in preoperative imaging (aOR10.35, 95% CI 1.09–98.33, p = 0.042) and identic estrogen receptor status in BM (aOR 4.56, 95% CI 1.35–15.40, p = 0.015).

Conclusions

Several factors seem to influence the period between BC and BM. Occurrence of BM within five years is independently associated with poorer prognosis after BM surgery. Patients with invasive lobular BC and without adjuvant breast radiation are more likely to develop BM after a long progression-free survival necessitating more prolonged cancer aftercare of these individuals.

Prognostic and Predictive Markers of Limited (1-4) Brain Metastases in Patients with Lung Adenocarcinoma After Stereotactic Radiosurgery: A Retrospective Analysis

BACKGROUND

Owing to the complexities of brain metastases (BMs), accurate and reliable prognostic and predictive factors remain critical roadblocks in patients with lung adenocarcinoma (LUAD) BMs who undergo stereotactic radiosurgery (SRS).

METHODS

In total, 132 patients with LUAD BMs who underwent SRS were retrospectively analyzed; Cox proportional hazards analysis of imaging and clinical characteristics was used to identify independent predictors related to overall survival (OS) and progression-free survival (PFS).

RESULTS

Our data indicated that initial brain metastasis velocity (iBMV), Karnofsky performance score (KPS), and Rvol (the sum of peritumoral edema volume/cumulative intracranial tumor volume) could potentially be independent prognostic factors for OS. iBMV ≥2 (P = 0.000), KPS <80 (P = 0.042), and Rvol ≥5.7 (P = 0.017) were strongly associated with unsatisfactory OS. The KPS and BM contrast enhancement were also identified as independent prognostic factors for PFS. A higher KPS (P = 0.004) and homogeneous BM contrast enhancement (P = 0.026) were strongly associated with longer PFS.

CONCLUSIONS

Collectively, iBMV and Rvol are highly related to OS and could be used as potential prognostic indices in patients with LUAD BMs who underwent SRS. Furthermore, we also revealed that the KPS and BM contrast enhancement could be potential indices of PFS in LUAD BMs.

Cerebral metastases

Brain metastases are common and deadly. Over the last 25 years GKNS has been established as an invaluable treatment. It may be used as a primary treatment or after either surgery or WBRT. Patients are assessed using one of a number of available scales. GKNS may be repeated for new metastases and for unresponsive tumors. Prescription doses are usually between 18 and 20Gy. The use of advanced MR techniques to highlight sensitive structures like the hippocampi have extended the efficacy of the treatment. More recently GKNS has been used with different target therapies with improved results. More recently frameless treatments have become more popular in this group of very sick patients. GKNS controls tumors in between 80% and over 95% of cases and may even be used for brainstem tumors.

Stereotactic radiosurgery results for brain metastasis patients with renal cancer: A validity study of Renal Graded Prognostic Assessment and proposal of a new grading index (JLGK2101 Study)

Background and purpose

The Renal Graded Prognostic Assessment (GPA) is relatively new and has not been sufficiently validated using a different dataset. We thus developed a new grading index, the Renal Brain Metastasis Score (Renal-BMS).

Materials and methods

Using our dataset including 262 renal cancer patients with brain metastases (BMs) undergoing stereotactic radiosurgery (SRS) (test series), we validity tested the Renal-GPA. Next, we applied clinical factor-survival analysis to the test series and thereby developed the Renal-BMS. This system was then validated using another series of 352 patients independently undergoing SRS at nine gamma knife facilities in Japan (verification series).

Results

Using the test series, with the Renal-GPA, 95% confidence intervals (CIs) of the post-SRS median survival times (MSTs) overlapped between pairs of neighboring subgroups. Among various pre-SRS clinical factors of the test series, six were highly associated with overall survival. Therefore, we assigned scores for six factors, i.e., "KPS ≥ 80%/<80% (0/3)", "tumor numbers 1-4/≥5 (score; 0/2)", "controlled primary cancer/not (0/2)", "existing extra-cerebral metastases/not (0/3)", "blood hemoglobin ≥ 11.0/<11.0 g/dl (0/1)" and "interval from primary cancer to SRS ≥ 5/<5 years (0/1)". Patients were categorized into three subgroups according to the sum of scores, i.e., 0-4, 5-8 and 9-12. In the test and verification series, post-SRS MSTs differed significantly (p < 0.0001) with no overlaps of 95% CIs among the three subgroups.

Conclusions

The Renal BMS has the potential to be very useful to physicians selecting among aggressive treatment modalities for renal cancer patients with BMs.

Breast cancer subtype predicts clinical outcomes after stereotactic radiation for brain metastases

PURPOSE

We investigated the prognostic ability of tumor subtype for patients with breast cancer brain metastases (BCBM) treated with stereotactic radiation (SRT).

METHODS

This is a retrospective review of 181 patients who underwent SRT to 664 BCBM from 2004 to 2019. Patients were stratified by subtype: hormone receptor (HR)-positive, HER2-negative (HR+/HER2-), HR-positive, HER2-positive (HR+/HER2+), HR-negative, HER2-positive (HR-/HER2+), and triple negative (TN). The Kaplan-Meier method was used to calculate overall survival (OS), local control (LC), and distant intracranial control (DIC) from the date of SRT. Multivariate analysis (MVA) was conducted using the Cox proportional hazards model.

RESULTS

Median follow up from SRT was 11.4 months. Of the 181 patients, 47 (26%) were HR+/HER2+, 30 (17%) were HR-/HER2+, 60 (33%) were HR+/HER2-, and 44 (24%) were TN. Of the 664 BCBMs, 534 (80%) received single fraction stereotactic radiosurgery (SRS) with a median dose of 21 Gy (range 12-24 Gy), and 130 (20%) received fractionated stereotactic radiation therapy (FSRT), with a median dose of 25 Gy (range 12.5-35 Gy) delivered in 3 to 5 fractions. One-year LC was 90%. Two-year DIC was 35%, 23%, 27%, and 16% (log rank, p = 0.0003) and 2-year OS was 54%, 47%, 24%, and 12% (log rank, p < 0.0001) for HR+/HER2+, HR-/HER2+, HR+/HER2-, and TN subtypes, respectively. On MVA, the TN subtype predicted for inferior DIC (HR 1.62, 95% CI 1.00-2.60, p = 0.049). The modified breast-Graded Prognostic Assessment (GPA) significantly predicted DIC and OS (both p < 0.001).

CONCLUSIONS

Subtype is prognostic for OS and DIC for patients with BCBM treated with SRT.

A graded prognostic model for patients surviving 3 years or more (GPM ≥ 3Ys) after stereotactic radiosurgery for brain metastasis

BACKGROUND AND PURPOSE

As more cancer patients with brain metastases (BMs) are surviving longer due to recent advancements in various treatment modalities, we developed a grading system for stereotactic radiosurgery (SRS)-treated BM patients with long survival. This is a Graded Prognostic Model for Patients Surviving 3 Years or More (GPM ≥ 3Ys).

MATERIALS AND METHODS

First, using clinical factor-survival time analysis of 3237 patients in whom gamma knife (GK) SRS was performed by the second author (test cohort), we developed the GPM ≥ 3Ys based on survival ≥3 years as the objective variable. The validity of this model was then tested using another series of 3317 patients independently undergoing GK SRS performed by the third author (verification cohort). Number of patients surviving 3 years or more were 289 (8.9%) and 348 (10.5%), respectively.

RESULTS

Using the test series, among various pre-SRS clinical factors, noted below, five were shown to be highly correlated with survival of ≥3 years. Therefore, we assigned scores for these five factors, i.e., "tumor numbers 1/2-4/≥5 (score; 6/1/0)", "female/male (5/0)", "KPS ≥80%/<80% (5/0)", "primary cancers of breast/lung/gastrointestinal tract/other (score; 1/0/3/0)", "controlled primary cancer/not (8/0)" and "existing extra-cerebral metastases/not (5/0). Patients were categorized into four grades according to the sum of scores, i.e., 0-9, 10-19, 20-29 and 30-36. Post-SRS mean survival times (MSTs) differed significantly (p < 0.0001) with no overlapping of 95% confidence intervals (CIs) among the four grades. Also, in the verification series, MSTs differed significantly (p < 0.0001) with no overlapping of 95% CI among the four grades of the GPM ≥ 3Ys system.

CONCLUSION

Although this was a retrospective study, the GPM ≥ 3Ys system was shown to be very useful to physicians selecting among more aggressive treatment modalities for patients in whom longer survival can be expected.

Upfront radiosurgery plus targeted agents followed by active brain control using radiosurgery delays neurological death in non-small cell lung cancer with brain metastasis

The role of radiosurgery has become further accentuated in the era of targeted agents (TA). Thus, the neurologic outcome of radiosurgery in brain metastasis (BM) of non-small cell lung cancer (NSCLC) was reviewed. We analyzed 135 patients with BM of NSCLC who were administered Cyberknife radiosurgery (CKRS) as either initial or salvage therapy. We evaluated local failure (LF), intracranial failure (IF), and neurological death (ND) due to BM. Primary outcome was neurological death-free survival (NDFS). Median follow-up was 16.2 months. Median CKRS dose of 22 Gy was administered to median 2 targets per patient. Among 99 deaths, 14 (14%) were ND. Upfront treatment for BM included CKRS alone in 85 patients (63%), CKRS + TA in 26 patients (19%), and WBRT in 24 patients (18%). No patients or tumor related factors were associated with ND. However, the type of upfront treatment for BM was significantly associated with ND [HR 0.07 (95% CI 0.01-0.57) for CKRS + TA, HR 0.56 (95% CI 0.19-1.68) for CKRS alone] compared with the WBRT group (P = 0.01). The 2-year NDFS rates for the CKRS + TA, CRKS alone, and WBRT groups were 94%, 87%, and 78%, respectively (P = 0.03). Upfront CKRS showed significantly higher 2-year LF-free survival rate (P < 0.01). IF rate was insignificantly lower in the WBRT group compared with CKRS group (P = 0.38). Upfront CKRS + TA was associated with the best neurological outcome with high NDFS. Active brain control by early delivery of radiosurgery could achieve better neurological outcome in NSCLC with BM.

Three-institution study on applicability of initial brain metastasis velocity for breast cancer brain metastasis patients undergoing stereotactic radiosurgery

PURPOSE

This study aimed to validate whether the recently-proposed prognostic grading system, initial brain metastasis velocity (iBMV), is applicable to breast cancer patients receiving stereotactic radiosurgery (SRS). We focused particularly on whether this grading system is useful for patients with all molecular types, i.e., positive versus negative for EsR, PgR and HER2.

METHODS AND MATERIALS

This was an institutional review board-approved, retrospective cohort study using our database, prospectively accumulated at three gamma knife institutes, during the 20-year-period since 1998. We excluded patients for whom the day of primary cancer diagnosis was not available, had synchronous presentation, lacked information regarding molecular types, and/or had received pre-SRS radiotherapy and/or surgery. We ultimately studied 511 patients categorized into two classes by iBMV scores, i.e., < 2.00 and ≥ 2.00.

RESULTS

The median iBMV score for the entire cohort was 0.97 (IQR 0.39-2.84). Median survival time (MST) in patients with iBMV < 2.00, 15.9 (95% CI 13.0-18.6, IQR 7.5-35.5) months, was significantly longer than that in patients with iBMV ≥ 2.00, 8.2 (95% CI 6.8-9.9, IQR 3.9-19.4) months (HR 1.582, 95% CI: 1.308-1.915, p < 0.0001). The same results were obtained in patients with EsR (-), PgR (-), HER2 (+) and HER2 (-) cancers, while MSTs did not differ significantly between iBMV < 2.00 vs ≥ 2.00 in patients with EsR (+) and PgR (+) cancers.

CONCLUSIONS

This system was clearly shown to be applicable to breast cancer patients with SRS-treated BMs. However, this system is not applicable to patients with hormone receptor (+) breast cancer.

Multidisciplinary patient-centered management of brain metastases and future directions

The incidence of brain metastasis is increasing as improvements in systemic therapy lead to increased survival. This provides new and challenging clinical decisions for patients who are trying to balance the risk of recurrence or progression with treatment-related side effects, and it requires appropriate management strategies from multidisciplinary teams. Improvements in prognostic assessment and systemic therapy with increasing activity in the brain allow for individualized care to better guide the use of local therapies and/or systemic therapy. Here, we review the current landscape of brain-directed therapy for the treatment of brain metastasis in the context of recent improved systemic treatment options. We also discuss emerging treatment strategies including targeted therapies for patients with actionable mutations, immunotherapy, modern whole-brain radiation therapy, radiosurgery, surgery, and clinical trials.

Multi-institutional validation of brain metastasis velocity, a recently defined predictor of outcomes following stereotactic radiosurgery

INTRODUCTION

Brain metastasis velocity (BMV) is a prognostic metric that describes the recurrence rate of new brain metastases after initial treatment with radiosurgery (SRS). We have previously risk stratified patients into high, intermediate, and low-risk BMV groups, which correlates with overall survival (OS). We sought to externally validate BMV in a multi-institutional setting.

METHODS

Patients from nine academic centers were treated with upfront SRS; the validation cohort consisted of data from eight institutions not previously used to define BMV. Patients were classified by BMV into low (<4 BMV), intermediate (4-13 BMV), and high-risk groups (>13 BMV). Time-to-event outcomes were estimated using the Kaplan-Meier method. Cox proportional hazards methods were used to estimate the effect of BMV and salvage modality on OS.

RESULTS

Of 2829 patients, 2092 patients were included in the validation dataset. Of these, 921 (44.0%) experienced distant brain failure (DBF). Median OS from initial SRS was 11.2 mo. Median OS for BMV < 4, BMV 4-13, and BMV > 13 were 12.5 mo, 7.0 mo, and 4.6 mo (p < 0.0001). After multivariate regression modeling, melanoma histology (β: 10.10, SE: 1.89, p < 0.0001) and number of initial brain metastases (β: 1.52, SE: 0.34, p < 0.0001) remained predictive of BMV (adjusted R² = 0.06).

CONCLUSIONS

This multi-institutional dataset validates BMV as a predictor of OS following initial SRS. BMV is being utilized in upcoming multi-institutional randomized controlled trials as a stratification variable for salvage whole brain radiation versus salvage SRS after DBF.

Clinical prognostic factors associated with survival and a survival score for patients with brain metastases

Aim: To identify prognostic factors of survival in patients with brain metastases (BM) and to devise a prognostic score. Patients & methods: In this single-institution retrospective study, we analyzed potential clinical prognostic factors in 1363 patients with BM. Based on the Cox proportional hazard model, we devised a BM score with three classes (score <5, 5-6 and >6). Results: The 1-year overall survival (OS) was 26%. Independent prognostic factors of OS were: age, gender, Karnofski performance status, number of BM, control of primary, presence of extracerebral metastases and type of primary tumor. The 1-year OS was 56% for score <5; 21% for score 5-6 and 4% for score >6 (p < 0.01). Conclusion: The BM score we propose is effective in grouping patients according to their prognosis and can help decision making regarding treatment adjustments.

Applicability and limitations of a recently-proposed prognostic grading metric, initial brain metastasis velocity, for brain metastasis patients undergoing stereotactic radiosurgery

PURPOSE

This study, based on our brain metastasis (BM) patients undergoing stereotactic radiosurgery (SRS) procedures, aimed to validate whether the recently-proposed prognostic grading system, initial brain metastasis velocity (iBMV, scoring the cumulative number of BMs at the time of SRS divided by time [years] since the initial primary cancer diagnosis), is generally applicable.

METHODS

This was an institutional review board-approved, retrospective cohort study using our prospectively accumulated database including 3498 patients who underwent SRS for BMs during the 19.5-year-period between July, 1998 and December, 2017. We excluded four lost to follow-up, 24 for whom the day of primary cancer diagnosis was not available, 665 with synchronous presentation and 651 with pre-SRS radiotherapy and/or surgery, ultimately studying 2150 patients. Patients were categorized into two classes by iBMV scores, i.e., < 2.00 and ≥ 2.00.

RESULTS

In a multivariable model, iBMV was directly associated with a higher risk of death (p < 0.0001). The median survival time of patients with iBMV scores < 2.00, 10.0 (95% CI; 9.2-10.9) months, was longer than that of patients with iBMV scores ≥ 2.00, 6.3 (5.6-6.7) months, showing a significant difference between the two groups (HR 1.599, 95% CI 1.458-1.753, p < 0.0001). The same results were obtained in patients with non-small cell lung, breast, kidney or other cancers. Among 608 patients who underwent repeat SRS for newly-developed BMs, iBMV score categories correlated well with brain metastasis velocity risk groups (p < 0.0001).

CONCLUSIONS

Our present results support the validity of iBMV for predicting survival after SRS.

Impact of regular magnetic resonance imaging follow-up after stereotactic radiotherapy to the surgical cavity in patients with one to three brain metastases

BACKGROUND

Administering stereotactic radiotherapy to the surgical cavity and thus omitting postoperative whole brain radiotherapy (WBRT) is a favored strategy in limited metastatic brain disease. Little is known about the impact of regular magnetic resonance imaging follow-up (MRI FU) in such patient cohorts. The aim of this study is to examine the impact of regular MRI FU and to report the oncological outcomes of patients with one to three brain metastases (BMs) treated with stereotactic radiosurgery (SRS) or hypo-fractionated stereotactic radiotherapy (HFSRT) to the surgical cavity.

METHODS

We retrospectively analyzed patients who received SRS or HFSRT to the surgical cavity after resection of one to two BMs. Additional, non-resected BMs were managed with SRS alone. Survival was estimated by the Kaplan-Meier method. Prognostic factors were examined with the log-rank test and Cox proportional hazards model. Regular MRI FU was defined as performing a brain MRI 3 months after radiotherapy (RT) and/or performing ≥1 brain MRI per 180 days. Primary endpoint was local control (LC). Secondary endpoints were distant brain control (DBC), overall survival (OS) and the correlation between regular MRI FU and overall survival (OS), symptom-free survival (SFS), deferment of WBRT and WBRT-free survival (WFS).

RESULTS

Overall, 75 patients were enrolled. One, 2 and 3 BMs were seen in 63 (84%), 11 (15%) and 1 (1%) patients, respectively. Forty (53%) patients underwent MRI FU 3 months after RT and 38 (51%) patients received ≥1 brain MRI per 180 days. Median OS was 19.4 months (95% CI: 13.2-25.6 months). Actuarial LC, DBC and OS at 1 year were 72% (95% CI: 60-83%), 60% (95% CI: 48-72%) and 66% (95% CI: 53-76%), respectively. A planning target volume > 15 cm³ (p = 0.01), Graded Prognostic Assessment (GPA) score (p = 0.001) and residual tumor after surgery (p = 0.008) were prognostic for decreased OS in multivariate analysis. No significant correlation between MRI FU at 3 months and OS (p = 0.462), SFS (p = 0.536), WFS (p = 0.407) or deferment of WBRT (p = 0.955) was seen. Likewise, performing ≥1 MRI per 180 days had no significant impact on OS (p = 0.954), SFS (p = 0.196), WFS (p = 0.308) or deferment of WBRT (p = 0.268).

CONCLUSION

Our results regarding oncological outcomes consist with the current data from the literature. Surprisingly, regular MRI FU did not result in increased OS, SFS, WFS or deferment of WBRT in our cohort consisting mainly of patients with a single and resected BM. Therefore, the impact of regular MRI FU needs prospective evaluation.

TRIAL REGISTRATION

Project ID: 2017-00033, retrospectively registered.