Patterns of relapse and late toxicity after resection and whole-brain radiotherapy for solitary brain metastases

New Radiobiological Principles for the CNS Arising from Space Radiation Research

Traditionally, the brain has been regarded as a relatively insensitive late-reacting tissue, with radiologically detectable damage not being reported at doses < 60 Gy. When NASA proposed interplanetary exploration missions, it was required to conduct an intensive health and safety evaluation of cancer, cardiovascular, and cognitive risks associated with exposure to deep space radiation (SR). The SR dose that astronauts on a mission to Mars are predicted to receive is ~300 mGy. Even after correcting for the higher RBE of the SR particles, the biologically effective SR dose (<1 Gy) would still be 60-fold lower than the threshold dose for clinically detectable neurological damage. Unexpectedly, the NASA-funded research program has consistently reported that low (<250 mGy) doses of SR induce deficits in multiple cognitive functions. This review will discuss these findings and the radical paradigm shifts in radiobiological principles for the brain that were required in light of these findings. These included a shift from cell killing to loss of function models, an expansion of the critical brain regions for radiation-induced cognitive impediments, and the concept that the neuron may not be the sole critical target for neurocognitive impairment. The accrued information on how SR exposure impacts neurocognitive performance may provide new opportunities to reduce neurocognitive impairment in brain cancer patients.

Sector Irradiation vs. Whole Brain Irradiation After Resection of Singular Brain Metastasis-A Prospective Randomized Monocentric Trial

To minimize recurrence following resection of a cerebral metastasis, whole-brain irradiation therapy (WBRT) has been established as the adjuvant standard of care. With prolonged overall survival in cancer patients, deleterious effects of WBRT gain relevance. Sector irradiation (SR) aims to spare uninvolved brain tissue by applying the irradiation to the resection cavity and the tumor bed. 40 were randomized to receive either WBRT (n = 18) or SR (n = 22) following resection of a singular brain metastasis. Local tumor control was satisfactory in both groups. Recurrence was observed earlier in the SR (median 3 months, 1–6) than in the WBRT cohort (median 8 months, 7–9) (HR, 0.63; 95% CI, 0.03–10.62). Seventeen patients experienced a distant intracranial recurrence. Most relapses (n = 15) occurred in the SR cohort, whereas only two patients in the WBRT group had new distant tumor manifestation (HR, 6.59; 95% CI, 1.71–11.49; p = 0.002). Median overall survival (OS) was 15.5 months (range: 1–61) with longer OS in the SR group (16 months, 1–61) than in the WBRT group (13 months, 3–52), without statistical significance (HR, 0.55; 95% CI, 0.69–3.64). Concerning neurocognition, patients in the SR group improved in the follow-up assessments, while this was not observed in the WBRT group. There were positive signals in terms of QOL within the SR group, but no significant differences in the global QLQ and QLQ-C30 summary scores were found. Our results indicate comparable efficacy of SR in terms of local control, with better maintenance of neurocognitive function. Unsurprisingly, more distant intracranial relapses occurred.

Clinical Trial Registration:ClinicalTrials.gov, identifier NCT01667640.

Dosimetric differences between cesium-131 and iodine-125 brachytherapy for the treatment of resected brain metastases

Purpose

To compare treatment plans and evaluate dosimetric characteristics of permanent cesium-131 (¹³¹Cs) vs. iodine-125 (¹²⁵I) implants used in brain brachytherapy.

Material and methods

Twenty-four patients with ¹³¹Cs implants from a prospective phase I/II trial were re-planned with ¹²⁵I implants. In order to evaluate the volume of brain tissue exposed to radiation therapy (RT), the dose volume histogram was generated for both radioisotopes. To evaluate the dosimetric differences of the two radioisotopes we compared homogeneity (HI) and conformity indices (CI), and dose covering 100% (D₁₀₀), 90% (D₉₀), 80% (D₈₀), and 50% (D₅₀) of the clinical target volume (CTV).

Results

At the 100%, 90%, 80%, and 50% isodose lines, the ¹³¹Cs plans exposed less mean volume of brain tissue than the ¹²⁵I plans (p < 0.001). The D₁₀₀, D₉₀, D₈₀, and D₅₀ were smaller for ¹³¹Cs (p < 0.001). The HI and CI for ¹³¹Cs vs. ¹²⁵I were 19.71 vs. 29.04 and 1.31 vs. 1.92, respectively (p < 0.001).

Conclusions

Compared to ¹²⁵I, ¹³¹Cs exposed smaller volumes of brain tissue to equivalent doses of radiation and delivered lower radiation doses to equivalent volumes of the CTV. ¹³¹Cs exhibited a higher HI, indicating increased uniformity of doses within the CTV. Lastly, ¹³¹Cs presented a CI closer to 1, indicating that the total volume receiving the prescription dose was closer to the desired CTV volume. These results suggest that ¹³¹Cs is dosimetrically superior to ¹²⁵I and may explain the reason for the 0% incidence of radiation necrosis (RN) in our previously published prospective study using ¹³¹Cs.

Post-operative stereotactic radiosurgery of brain metastases: A single-center retrospective review of clinical outcomes

Aim:

We sought to retrospectively report our outcomes using post-operative stereotactic radiosurgery (SRS)/stereotactic radiotherapy (SRT) in place of whole-brain radiation therapy (WBRT) following resection of brain metastases from our hospital-based community practice.

Materials and Methods:

A retrospective review of 23 patients who underwent post-operative SRS at our single institution from 2013 to 2017 was undertaken. Patient records, treatment plans and diagnostic images were reviewed. Local failure, distant intracranial failure and overall survival were studied. Categorical variables were analyzed using Fisher’s exact tests. Continuous variables were analyzed using Mann–Whitney tests. The Kaplan–Meier method was used to estimate survival times.

Results:

16 (70%) were single-fraction SRS, whereas the remaining 7 patients received a five-fraction treatment course. The median single-fraction dose was 16 Gy (range, 16–18). The median total dose for fractionated treatments was 25 Gy (range, 25–35). Overall survival at 6 and 12 months was 95 and 67%, respectively. Comparison of SRS versus SRT local control rates at 6 and 12 months revealed control rates of 92 and 78% versus 29 and 14%, respectively. Every patient with dural/pial involvement at the time of surgery had distant intracranial failure at the 12-month follow-up.

Findings:

Single-fraction frameless SRS proved to be an effective modality with excellent local control rates. However, the five-fraction SRT course was associated with an increased rate of local recurrence. Dural/pial involvement may portend a high risk for distant intracranial disease; therefore, it may be prudent to consider alternative approaches in these cases.

Cesium-131 brachytherapy for recurrent brain metastases: durable salvage treatment for previously irradiated metastatic disease

OBJECTIVE Managing patients whose intraparenchymal brain metastases recur after radiotherapy remains a challenge. Intraoperative cesium-131 (Cs-131) brachytherapy performed at the time of neurosurgical resection may represent an excellent salvage treatment option. The authors evaluated the outcomes of this novel treatment with permanent intraoperative Cs-131 brachytherapy. METHODS Thirteen patients with 15 metastases to the brain that recurred after stereotactic radiosurgery and/or whole brain radiotherapy were treated between 2010 and 2015. Stranded Cs-131 seeds were placed as a permanent volume implant. Prescription dose was 80 Gy at 5-mm depth from the resection cavity surface. The primary end point was resection cavity freedom from progression (FFP). Resection cavity freedom from progression (FFP), regional FFP, distant FFP, median survival, overall survival (OS), and toxicity were assessed. RESULTS The median duration of follow-up after salvage treatment was 5 months (range 0.5-18 months). The patients' median age was 64 years (range 51-74 years). The median resected tumor diameter was 2.9 cm (range 1.0-5.6 cm). The median number of seeds implanted was 19 (range 10-40), with a median activity per seed of 2.25 U (range 1.98-3.01 U) and median total activity of 39.6 U (range 20.0-95.2 U). The 1-year actuarial local FFP was 83.3%. The median OS was 7 months, and 1-year OS was 24.7%. Complications included infection (3), pseudomeningocele (1), seizure (1), and asymptomatic radionecrosis (RN) (1). CONCLUSIONS After failure of prior irradiation of brain metastases, re-irradiation with intraoperative Cs-131 brachytherapy implants provides durable local control and limits the risk of RN. The authors' initial experience demonstrates that this treatment approach is well tolerated and safe for patients with previously irradiated tumors after failure of more than 1 radiotherapy regimen and that it results in excellent response rates and minimal toxicity.

Current treatment options of brain metastases and outcomes in patients with malignant melanoma

The prognosis for patients with melanoma who have brain metastases is poor, a median survival does not exceed 4-6 months. There are no uniform standards of treatment for patients with melanoma brain metastases (MBMs). The most preferred treatment approaches include local therapy - surgical resection and/or stereotactic radiosurgery (SRS). The role of whole brain radiotherapy (WBRT) as an adjuvant to local therapy is controversial. WBRT remains a palliative approach for those patients who have multiple MBMs with contraindications for surgery or SRS, or/and poor performance status, or/and very widespread extracranial metastases. Corticosteroids have been used in palliative treatment of MBMs as relief from symptoms related to intracranial pressure and edema. In recent years, the development of new systemic therapeutic strategies has been observed. Various modalities of systemic treatment include chemotherapy, immunotherapy and targeted therapy. Also, multimodality management in different combinations is a common strategy. Decisions regarding the use of specific treatment modalities are dependent on patient's performance status, and the extent of both intracranial and extracranial disease. This review summarizes current treatment options, indications and outcomes in patients with brain metastases from melanoma.

Surgical Technique and Clinically Relevant Resection Cavity Dynamics Following Implantation of Cesium-131 (Cs-131) Brachytherapy in Patients With Brain Metastases

BACKGROUND

Cesium-131 (Cs-131) brachytherapy is used to reduce local recurrence of resected brain metastases. In order to ensure dose homogeneity and reduce risk of radiation necrosis, inter-seed distance and cavity volume must remain stable during delivery.

OBJECTIVE

To investigate the efficacy of the "seeds-on-a-string" technique with intracavitary fibrin glue in achieving cavity volume stability.

METHODS

We placed intra-operative Cs-131 brachytherapy in 30 cavities post-resection of brain metastases. Seeds-on-a-string were placed like barrel staves within the cavity with fibrin glue. Serial MRI imaging occurred post-operatively. Pre-operative tumor volumes were compared with post-operative cavity volumes to evaluate volume stability. Thirty patients who underwent post-resective stereotactic radiosurgery (SRS) were used as a control group for volumetric comparison.

RESULTS

Cs-131 and SRS patients exhibited consistent cavity shrinkage over the median 110-day follow-up (p<.001), with total median shrinkage of 56.5% (Cs-131) and 84.8% (SRS). During the first month when ~88% of Cs-131 dosage is delivered, however, there was non-significant volume decrease in the Cs-131 group (median 22.0%; p=.063), while SRS patients showed significantly more shrinkage (46.7%; p=.042). No events of radiation necrosis occurred in either group.

CONCLUSION

Cs-131 patients exhibited significantly less cavity shrinkage than SRS patients during the first critical month with 88% Cs-131 dose delivery. This significant difference in shrinkage suggests that the intracavitary seeds-on-a-string technique facilitates increased cavity stability, promoting more homogenous dose delivery.

Phase I/II study of resection and intraoperative cesium-131 radioisotope brachytherapy in patients with newly diagnosed brain metastases

OBJECT

Resected brain metastases have a high rate of local recurrence without adjuvant therapy. Adjuvant whole-brain radiotherapy (WBRT) remains the standard of care with a local control rate > 90%. However, WBRT is delivered over 10-15 days, which can delay other therapy and is associated with acute and long-term toxicities. Permanent cesium-131 ((131)Cs) implants can be used at the time of metastatic resection, thereby avoiding the need for any additional therapy. The authors evaluated the safety, feasibility, and efficacy of a novel therapeutic approach with permanent (131)Cs brachytherapy at the resection for brain metastases.

METHODS

After institutional review board approval was obtained, 24 patients with a newly diagnosed metastasis to the brain were accrued to a prospective protocol between 2010 and 2012. There were 10 frontal, 7 parietal, 4 cerebellar, 2 occipital, and 1 temporal metastases. Histology included lung cancer (16), breast cancer (2), kidney cancer (2), melanoma (2), colon cancer (1), and cervical cancer (1). Stranded (131)Cs seeds were placed as permanent volume implants. The prescription dose was 80 Gy at a 5-mm depth from the resection cavity surface. Distant metastases were treated with stereotactic radiosurgery (SRS) or WBRT, depending on the number of lesions. The primary end point was local (resection cavity) freedom from progression (FFP). Secondary end points included regional FFP, distant FFP, median survival, overall survival (OS), and toxicity.

RESULTS

The median follow-up was 19.3 months (range 12.89-29.57 months). The median age was 65 years (range 45-84 years). The median size of resected tumor was 2.7 cm (range 1.5-5.5 cm), and the median volume of resected tumor was 10.31 cm(3) (range 1.77-87.11 cm(3)). The median number of seeds used was 12 (range 4-35), with a median activity of 3.82 mCi per seed (range 3.31-4.83 mCi) and total activity of 46.91 mCi (range 15.31-130.70 mCi). Local FFP was 100%. There was 1 adjacent leptomeningeal recurrence, resulting in a 1-year regional FFP of 93.8% (95% CI 63.2%-99.1%). One-year distant FFP was 48.4% (95% CI 26.3%-67.4%). Median OS was 9.9 months (95% CI 4.8 months, upper limit not estimated) and 1-year OS was 50.0% (95% CI 29.1%-67.8%). Complications included CSF leak (1), seizure (1), and infection (1). There was no radiation necrosis.

CONCLUSIONS

The use of postresection permanent (131)Cs brachytherapy implants resulted in no local recurrences and no radiation necrosis. This treatment was safe, well tolerated, and convenient for patients, resulting in a short radiation treatment course, high response rate, and minimal toxicity. These findings merit further study with a multicenter trial.

Evaluation of results of linac-based radiosurgery for brain metastases from primary lung cancer

AIM

The purpose of our review was to evaluate results of radiosurgery for patients with brain metastases from lung cancer.

BACKGROUND

Lung cancer is the leading cause of death from cancer and the most common source of brain metastases. Radiosurgery allows the precise focal delivery of a high single radiation dose to brain metastases and results in high rates of local control.

MATERIALS AND METHODS

83 patients were treated between 2006 and 2008. We evaluated local control and outcome after radiosurgery and identified prognostic factors.

RESULTS

Median survival in the whole group was 7.8 months from radiosurgery and 11 months from diagnosis. Median survival in classes I, II and III was 13.2, 8.2 and 2.2 months. For 94% of patients symptoms improved or stabilised at the first follow-up visit and this status did not change during 7.1 months. According to the univariate analysis, factors associated with improved survival included: RPA class 1 compared with RPA 2 and 3, RPA class 2 compared with RPA 3, KPS > 70, control of the primary disease, radiosurgery performed more than once, level of haemoglobin >7 mmol/1, absence of extracranial metastases, volume of the biggest lesion <11 cm(3). The multivariate analysis confirmed a significant influence on survival for the following factors: RPA class 1 as compared with RPA 3, KPS > 70, absence of extracranial metastases, multiplicity of radiosurgery.

CONCLUSIONS

Stereotactic radiosurgery is a safe and effective treatment. It proved to be effective and safe in older patients. Selection of patients who are likely to benefit most should be based on prognostic factors. KPS proved to be the most important prognostic factor. In the RPA III group (patients with KPS < 70) survival time was similar to that achieved after symptomatic medical management.

Prognostic significance of Ki67 proliferation index, HIF1 alpha index and microvascular density in patients with non-small cell lung cancer brain metastases

BACKGROUND

Survival upon diagnosis of brain metastases (BM) in patients with non-small cell lung cancer (NSCLC) is highly variable and established prognostic scores do not include tissue-based parameters.

METHODS

Patients who underwent neurosurgical resection as first-line therapy for newly diagnosed NSCLC BM were included. Microvascular density (MVD), Ki67 tumor cell proliferation index and hypoxia-inducible factor 1 alpha (HIF-1 alpha) index were determined by immunohistochemistry.

RESULTS

NSCLC BM specimens from 230 patients (151 male, 79 female; median age 56 years; 199 nonsquamous histology) and 53/230 (23.0%) matched primary tumor samples were available. Adjuvant whole-brain radiation therapy (WBRT) was given to 153/230 (66.5%) patients after neurosurgical resection. MVD and HIF-1 alpha indices were significantly higher in BM than in matched primary tumors. In patients treated with adjuvant WBRT, low BM HIF-1 alpha expression was associated with favorable overall survival (OS), while among patients not treated with adjuvant WBRT, BM HIF-1 alpha expression did not correlate with OS. Low diagnosis-specific graded prognostic assessment score (DS-GPA), low Ki67 index, high MVD, low HIF-1 alpha index and administration of adjuvant WBRT were independently associated with favorable OS. Incorporation of tissue-based parameters into the commonly used DS-GPA allowed refined discrimination of prognostic subgroups.

CONCLUSION

Ki67 index, MVD and HIF-1 alpha index have promising prognostic value in BM and should be validated in further studies.

A phase 2 trial of stereotactic radiosurgery boost after surgical resection for brain metastases

PURPOSE

To evaluate local control after surgical resection and postoperative stereotactic radiosurgery (SRS) for brain metastases.

METHODS AND MATERIALS

A total of 49 patients (50 lesions) were enrolled and available for analysis. Eligibility criteria included histologically confirmed malignancy with 1 or 2 intraparenchymal brain metastases, age≥18 years, and Karnofsky performance status (KPS)≥70. A Cox proportional hazard regression model was used to test for significant associations between clinical factors and overall survival (OS). Competing risks regression models, as well as cumulative incidence functions, were fit using the method of Fine and Gray to assess the association between clinical factors and both local failure (LF; recurrence within surgical cavity or SRS target), and regional failure (RF; intracranial metastasis outside of treated volume).

RESULTS

The median follow-up was 12.0 months (range, 1.0-94.1 months). After surgical resection, 39 patients with 40 lesions were treated a median of 31 days (range, 7-56 days) later with SRS to the surgical bed to a median dose of 1800 cGy (range, 1500-2200 cGy). Of the 50 lesions, 15 (30%) demonstrated LF after surgery. The cumulative LF and RF rates were 22% and 44% at 12 months. Patients who went on to receive SRS had a significantly lower incidence of LF (P=.008). Other factors associated with improved local control include non-small cell lung cancer histology (P=.048), tumor diameter<3 cm (P=.010), and deep parenchymal tumors (P=.036). Large tumors (≥3 cm) with superficial dural/pial involvement showed the highest risk for LF (53.3% at 12 months). Large superficial lesions treated with SRS had a 54.5% LF. Infratentorial lesions were associated with a higher risk of developing RF compared to supratentorial lesions (P<.001).

CONCLUSIONS

Postoperative SRS is associated with high rates of local control, especially for deep brain metastases<3 cm. Tumors≥3 cm with superficial dural/pial involvement demonstrate the highest risk of LF.

Involved field radiation therapy after surgical resection of solitary brain metastases--mature results

BACKGROUND

Whole brain radiation therapy (WBRT) reduces local recurrence in patients after surgical resection of brain metastases without improving overall survival. Involved field radiation therapy (IFRT) has been used at our center to avoid delayed neurotoxicity associated with WBRT in well-selected patients with surgically resected single brain metastases. The purpose of this study was to evaluate the long-term outcomes of these patients.

METHODS

Thirty-three consecutive patients with single brain metastases from a known primary tumor were treated with gross total resection followed by IFRT between 2006 and 2011. The postoperative surgical bed was treated to 40.05 Gy in 15 fractions of 2.67 Gy with conformal radiation therapy. Patients received serial MRIs and neurological exams in follow-up. Surgery, WBRT, or stereotactic radiosurgery was performed as salvage treatment when necessary.

RESULTS

The median follow-up was 16 months (range: 2-65 months). Local control, distant brain recurrence-free survival, and overall survival at 12 and 24 months were 90.3% and 85.8%, 60.7% and 51.4%, and 65.6% and 61.5%, respectively. Overall, 5 (15%) patients developed recurrence at the resection cavity, and 13 (39%) patients experienced recurrence at a new intracranial site. Two patients received WBRT, 8 stereotactic radiosurgery, 2 surgery, and 2 both chemotherapy and IFRT as salvage. Four patients died from CNS disease progression.

CONCLUSION

For patients with newly diagnosed single brain metastases treated with surgical resection, postoperative IFRT to the resection cavity achieves reasonable rates of local control and is an excellent alternative to WBRT.

Stereotactic radiosurgery boost to the resection bed for oligometastatic brain disease: challenging the tradition of adjuvant whole-brain radiotherapy

Object

Whole-brain radiation therapy (WBRT) has been the traditional approach to minimize the risk of intracranial recurrence following resection of brain metastases, despite its potential for late neurotoxicity. In 2007, the authors demonstrated an equivalent local recurrence rate to WBRT by using stereotactic radiosurgery (SRS) to the operative bed, sparing 72% of their patients WBRT. They now update their initial experience with additional patients and more mature follow-up.

Methods

The authors performed a retrospective review of all cases involving patients with limited intracranial metastatic disease (≤ 4 lesions) treated at their institution with SRS to the operative bed following resection. No patient had prior cranial radiation and WBRT was used only for salvage.

Results

From November 2000 to June 2009, 52 patients with a median age of 61 years met inclusion criteria. A single metastasis was resected in each patient. Thirty-four of the patients each had 1 lesion, 13 had 2 lesions, 3 had 3 lesions, and 2 had 4 lesions. A median dose of 1500 cGy (range 800–1800 cGy) was delivered to the resection bed targeting a median volume of 3.85 cm3 (range 0.08–22 cm3). With a median follow-up of 13 months, the median survival was 15.0 months. Four patients (7.7%) had a local recurrence within the surgical site. Twenty-three patients (44%) ultimately developed distant brain recurrences at a median of 16 months postresection, and 16 (30.7%) received salvage WBRT (8 for diffuse disease [> 3 lesions], 4 for local recurrence, and 4 for diffuse progression following salvage SRS). The median time to WBRT administration postresection was 8.7 months (range 2–43 months). On univariate analysis, patient factors of a solitary tumor (19.0 vs 12 months, p = 0.02), a recursive partitioning analysis (RPA) Class I (21 vs 13 months, p = 0.03), and no extracranial disease on presentation (22 vs 13 months, p = 0.01) were significantly associated with longer survival. Cox multivariate analysis showed a significant association with longer survival for the patient factors of no extracranial disease on presentation (p = 0.01) and solitary intracranial metastasis (p = 0.02). Among patients with no extracranial disease, a solitary intracranial metastasis conferred significant additional survival advantage (43 vs 10.5 months, p = 0.05, log-rank test). No factor (age, RPA class, tumor size or histological type, disease burden, extent of resection, or SRS dose or volume) was related to the need for salvage WBRT.

Conclusions

Adjuvant SRS to the metastatic intracranial operative bed results in a local recurrence rate equivalent to adjuvant WBRT. In combination with SRS for unresected lesions and routine imaging surveillance, this approach achieves robust overall survival (median 15 months) while sparing 70% of the patients WBRT and its potential acute and chronic toxicity.

Gamma Knife radiosurgery to the surgical cavity following resection of brain metastases

OBJECT

This study evaluated the efficacy of postoperative Gamma Knife surgery (GKS) to the tumor cavity following gross-total resection of a brain metastasis.

METHODS

A retrospective review was conducted of 700 patients who were treated for brain metastases using GKS. Forty-seven patients with pathologically confirmed metastatic disease underwent GKS to the postoperative resection cavity following gross-total resection of the tumor. Patients who underwent subtotal resection or who had visible tumor in the resection cavity on the postresection neuroimaging study (either CT or MR imaging with and without contrast administration) were excluded. Radiographic and clinical follow-up was assessed using clinic visits and MR imaging. The radiographic end point was defined as tumor growth control (no tumor growth regarding the resection cavity, and stable or decreasing tumor size for the other metastatic targets). Clinical end points were defined as functional status (assessed prospectively using the Karnofsky Performance Scale) and survival. Primary tumor pathology was consistent with lung cancer in 19 cases (40%), melanoma in 10 cases (21%), renal cell carcinoma in 7 cases (15%), breast cancer in 7 cases (15%), and gastrointestinal malignancies in 4 cases (9%). The mean duration between resection and radiosurgery was 15 days (range 2-115 days). The mean volume of the treated cavity was 10.5 cm3 (range 1.75-35.45 cm3), and the mean dose to the cavity margin was 19 Gy. In addition to the resection cavity, 34 patients (72%) underwent GKS for 116 synchronous metastases observed at the time of the initial radiosurgery.

RESULTS

The mean radiographic follow-up duration was 14 months (median 10 months, range 4-37 months). Local tumor control at the site of the surgical cavity was achieved in 44 patients (94%), and tumor recurrence at the surgical site was statistically related to the volume of the surgical cavity (p=0.04). During follow-up, 34 patients (72%) underwent additional radiosurgery for 140 new (metachronous) metastases. At the most recent follow-up evaluation, 11 patients (23%) were alive, whereas 36 patients had died (mean duration until death 12 months, median 10 months). Patients who showed good systemic control of their primary tumor tended to have longer survival durations than those who did not (p=0.004). At the last clinical follow-up evaluation, the mean Karnofsky Performance Scale score for the overall group was 78 (median 80, range 40-100).

CONCLUSION

Radiosurgery appears to be effective in terms of providing local tumor control at the resection cavity following resection of a brain metastasis, and in the treatment of synchronous and metachronous tumors. These data suggest that radiosurgery can be used to prevent recurrence following gross-total resection of a brain metastasis.

Management of metastatic melanoma patients with brain metastases

Brain metastases seem to be an almost inevitable complication in patients with metastatic melanoma. Except for the rare patients who can undergo successful surgical resection of brain metastases, current management strategies do not appear adequate and result in a poor outcome (median survival, 2-4 months). In recent small series, stereotactic radiosurgery or gamma-knife treatment has suggested improvement in local control compared with whole brain radiation therapy. We have recently shown prolonged survival (11.1 months) using a multimodality treatment approach in 44 sequential patients with melanoma brain metastases. A subsequent study demonstrated that the outcome of biochemotherapy for metastatic melanoma is not affected by the presence or absence of brain metastases. Our results suggest that the outcome of patients with melanoma brain metastases can be improved using a multidisciplinary management strategy.

Stereotactic radiosurgery of the postoperative resection cavity for brain metastases

PURPOSE

The purpose of this study was to analyze results of adjuvant stereotactic radiosurgery (SRS) targeted at resection cavities of brain metastases without whole-brain irradiation (WBI).

METHODS AND MATERIALS

Patients who underwent SRS to the tumor bed, deferring WBI after resection of a brain metastasis, were retrospectively identified.

RESULTS

Seventy-two patients with 76 cavities treated from 1998 to 2006 met inclusion criteria. The SRS was delivered to a median marginal dose of 18.6 Gy (range, 15-30 Gy) targeting an average tumor volume of 9.8 cm(3) (range, 0.1-66.8 cm(3)). With a median follow-up of 8.1 months (range, 0.1-80.5 months), 65 patients had follow-up imaging assessable for control analyses. Actuarial local control rates at 6 and 12 months were 88% and 79%, respectively. On univariate analysis, increasing values of conformality indices were the only treatment variables that correlated significantly with improved local control; local control was 100% for the least conformal quartile compared with 63% for the remaining quartiles. Target volume, dose, and number of sessions were not statistically significant.

CONCLUSIONS

In this retrospective series, SRS administered to the resection cavity of brain metastases resulted in a 79% local control rate at 12 months. This value compares favorably with historic results with observation alone (54%) and postoperative WBI (80-90%). Given the improved local control seen with less conformal plans, we recommend inclusion of a 2-mm margin around the resection cavity when using this technique.

Gamma-Knife radiosurgery in the management of melanoma patients with brain metastases: A series of 106 patients without whole-brain radiotherapy

PURPOSE

To assess retrospectively a strategy that uses Gamma-Knife radiosurgery (GKR) in the management of patients with brain metastases (BMs) of malignant melanoma (MM).

METHODS

GKR without whole-brain radiotherapy (WBRT) was performed for patients with Karnofsky Performance Status (KPS) of 60 or above who harbored 1 to 4 BMs of 30 mm or less and was repeated as often as needed. Survival was assessed in the whole population, whereas local-control rates were assessed for patients with follow-up longer than 3 months.

RESULTS

A total of 221 BMs were treated in 106 patients; 61.3% had a single BM. Median survival from the time of GKR was 5.09 months. Control rate of treated BMs was 83.7%, with 14% of complete response (14 BMs), 42% of partial response (41 BMs), and 43% of stabilization (43 BMs). In multivariate analysis, survival prognosis factors retained were KPS greater than 80, cortical or subcortical location, and Score Index for Radiosurgery (SIR) greater than 6. On the basis of KPS, BM location, and age, a score called MM-GKR, predictive of survival in our population, was defined.

CONCLUSION

Gamma-Knife radiosurgery provides a surgery-like ability to obtain control of a solitary BM and could be consider as an alternative treatment to the combination of GKR+WBRT as a palliative strategy. MM-GKR classification is more adapted to MM patients than are SIR, RPA and Brain Score for Brain Metastasis.

Radiotherapy and chemotherapy of brain metastases

The authors have reviewed the results, the indications and the controversies regarding radiotherapy and chemotherapy of patients with newly diagnosed and recurrent brain metastases. Whole-brain radiotherapy, radiosurgery, hypofractionated stereotactic radiotherapy, brachytherapy and chemotherapy are the available options. New radiosensitizers and cytotoxic or cytostatic agents are being investigated. Adjuvant whole brain radiotherapy, either after surgery or radiosurgery, and prophylactic cranial irradiation in small-cell lung cancer are discussed, taking into account local control, survival, and risk of late neurotoxicity. Increasingly, the different treatments are tailored to the different prognostic subgroups, as defined by Radiation Therapy Oncology Group RPA Classes.

Therapeutic management of brain metastasis

This review focuses on the management of brain metastases. The four main modes of therapy are discussed: whole brain radiation therapy (WBRT), surgery, radiosurgery, and chemotherapy. Young patients with limited extracranial disease may benefit from surgical resection of a single brain metastasis, and from radiosurgery (or stereotactic radiotherapy) if two to four brain metastases are present. Whether WBRT after surgery or radiosurgery is beneficial is uncertain. Therefore, two approaches can be justified in patients with a good prognosis: WBRT after surgery or radiosurgery, or alternatively, observation with MRI follow-up after surgery or radiosurgery. A hyperfractionated radiation scheme is then to be preferred to limit late toxicity of WBRT. Patients with extensive extracranial tumour activity or impaired quality of life may benefit from radiosurgery (one to four brain metastases), or from shorter WBRT schedules. We propose a decision tree on the various ways to treat brain metastasis.

Management of brain metastases in patients with melanoma

PURPOSE OF REVIEW

Melanoma is the third most common metastatic brain tumor in the United States and is a major cause of morbidity and mortality. The development of more effective therapies for melanoma brain metastases is a major unmet clinical need and is summarized in this review.

RECENT FINDINGS

Management strategies include symptomatic treatment with corticosteroids and anticonvulsants, and definitive therapy in the form of whole-brain radiation therapy, surgical resection, stereotactic radiosurgery, and systemic therapy. The data on whole-brain radiation therapy show little impact on survival, but there is evidence that it may improve neurologic deficits. Surgery may provide a survival advantage in combination with whole-brain radiation therapy in the management of a single brain melanoma metastasis, compared with whole-brain radiation therapy alone. Stereotactic radiosurgery may offer a survival advantage (in a select group of patients with limited disease) when used alone or in combination with whole-brain radiation therapy, compared with whole-brain radiation therapy alone. Fotemustine, temozolomide, and thalidomide are three agents with high central nervous system penetration that are being actively investigated as part of systemic therapy.

SUMMARY

The currently available therapeutic options offer palliative relief of symptoms in most patients and a survival advantage in selected patients with melanoma and brain metastases. An urgent need exists to further define these treatments in the context of randomized trials, several of which are under way in the United States and abroad.

The treatment of brain metastases from malignant melanoma

Metastasis to the CNS develops in nearly half of patients with advanced melanoma; in 15% to 20% of these patients, the CNS is the first site of relapse. While systemic therapy for metastatic melanoma produces objective responses in 15% to 50% of patients, the available drugs do not penetrate well into the CNS, and these patients rarely benefit from systemic therapy. Although brain metastasis may be treated with surgery and/or stereotactic radiosurgery (SRS) when disease is limited to approximately one to three lesions, treatment for patients with large or multiple metastases is limited to whole brain irradiation (WBRT). While formal response and survival analyses of the impact of WBRT in melanoma have not been reported, the estimated median survival time for unselected patients with CNS metastases is only 2 to 4 months, with 1-year survival rates of less than 13%. In a selected population of patients with limited CNS involvement, surgical resection alone or in combination with WBRT appears to prolong median survival. More recently, SRS has been shown to be an effective local treatment for selected patients with brain metastases. In several retrospective reports of patients with melanoma CNS metastases, treatment with surgical resection alone or in combination with WBRT has been demonstrated to prolong median survival. More recently, SRS has been shown to be an effective local treatment for selected patients with brain metastases. In several retrospective reports, patients with CNS metastases from melanoma treated with a combination of WBRT plus SRS or SRS alone had median survivals and rates of control in the CNS superior to published reports for traditional WBRT. Most of these patients died from progressive extracranial disease with locally controlled CNS disease. Investigation of the contribution of newer systemic agents to the control of melanoma metastatic to the CNS has been based on the identification of drugs that have antitumor activity and the ability to cross the blood-brain barrier. Fotemustine is a nitrosourea that produced similar activity in CNS metastasis as in systemic disease, with a response rate of about 25%. Temozolomide (TMZ) is an oral alkylating agent that acts via the same mechanism as dacarbazine (DTIC), the most active single agent in melanoma. TMZ, which is highly active in brain tumors, has also been associated with activity in systemic and CNS metastases in melanoma patients, also in the 25% range. Efforts are underway to assess the additive benefit of TMZ and other drugs to WBRT or focused radiotherapy in this disease.

Dose-response relationships for radiotherapy of brain metastases: role of intermediate-dose stereotactic radiosurgery plus whole-brain radiotherapy

The effects of intermediate-dose radiotherapy consisting of whole-brain radiotherapy (WBRT, 10 fractions of 3 Gy) plus stereotactic radiosurgery (SRS) were studied prospectively. Twenty-five adult patients with 31 brain metastases received WBRT plus linear accelerator (LINAC)-based single dose SRS with fixed treatment parameters (10 Gy at the isocenter, target volume enclosed by the 90% isodose). Median age was 63 years, median Karnofsky performance status 80%, and median diameter of brain metastases 2.4 cm. Fifteen patients had non-small-cell lung cancer. Because of some early deaths, only 26 lesions could be evaluated for response. We observed 1 complete and 15 partial remissions. Median time to progression inside or outside the SRS volume was 4.5 months. Actuarial local control of SRS-treated lesions was 61% at 1 year. At that time, only 37% of patients were free from new lesions outside the SRS volume. Median survival and cause-specific survival were 2.3 and 4.5 months, respectively (1-year survival rate 8% and 21%). Ten patients died of progressive brain metastases, 13 from extracranial disease progression (unknown cause of death in 2 cases). Comparable to SRS studies with higher doses, the majority of brain failures occurred outside the SRS volume and more patients died of extracranial progression than of uncontrolled brain metastases. Failure to improve survival can be explained by the high percentage of patients with extracranial metastases (52%). However, the present results appear less favorable than those of previous studies of SRS with 15 Gy to 16 Gy (1-year actuarial local control rates of 66-89%). Therefore, we recommend SRS with 15 Gy to 16 Gy for patients whose favorable prognostic factors justify a boost after WBRT.

Validation of the RTOG recursive partitioning analysis (RPA) classification for brain metastases

PURPOSE

The Radiation Therapy Oncology Group (RTOG) previously developed three prognostic classes for brain metastases using recursive partitioning analysis (RPA) of a large database. These classes were based on Karnofsky performance status (KPS), primary tumor status, presence of extracranial system metastases, and age. An analysis of RTOG 91-04, a randomized study comparing two dose-fractionation schemes with a comparison to the established RTOG database, was considered important to validate the RPA classes.

METHODS AND MATERIALS

A total of 445 patients were randomized on RTOG 91-04, a Phase III study of accelerated hyperfractionation versus accelerated fractionation. No difference was observed between the two treatment arms with respect to survival. Four hundred thirty-two patients were included in this analysis. The majority of the patients were under age 65, had KPS 70-80, primary tumor controlled, and brain-only metastases. The initial RPA had three classes, but only patients in RPA Classes I and II were eligible for RTOG 91-04.

RESULTS

For RPA Class I, the median survival time was 6. 2 months and 7.1 months for 91-04 and the database, respectively. The 1-year survival was 29% for 91-04 versus 32% for the database. There was no significant difference in the two survival distributions (p = 0.72). For RPA Class II, the median survival time was 3.8 months for 91-04 versus 4.2 months for the database. The 1-year survival was 12% and 16% for 91-04 and the database, respectively (p = 0.22).

CONCLUSION

This analysis indicates that the RPA classes are valid and reliable for historical comparisons. Both the RTOG and other clinical trial organizers should currently utilize this RPA classification as a stratification factor for clinical trials.

Late radiation toxicity after whole brain radiotherapy: the influence of antiepileptic drugs

This retrospective study had the following aims: (a) calculation of actuarial rate of late radiation toxicity after whole-brain radiotherapy (WBRT), (b) correlation of clinical symptoms with changes of computed tomography (CT) scans, and (c) analysis of potentially predictive factors with special regard to concomitant treatment with antiepileptic drugs. We analyzed 49 adult patients, selected from a preexisting data base. Inclusion criteria were as follows: no previous brain irradiation; WBRT without boost; CT, clinical, and neurologic examination before and more than 3 months after completion of WBRT. Uni- and multivariate tests of various patient- and treatment-related parameters as possible predictive factors for clinical symptoms of late radiation toxicity (scored according to the RTOG/EORTC system) as well as cerebral atrophy and white matter abnormalities were performed. Median age was 54 years. Patients were treated for brain metastases (n = 37), primary cerebral lymphoma (n = 2), primary brain tumors (n = 7), or with prophylactic intention (n = 3). Carbamazepine was given to 15 patients, phenytoin to 12, and barbiturate to 7, respectively; 42 patients also received corticosteroids. The median dose of WBRT was 30 Gy (range 27-66 Gy). Median fraction size was 3 Gy (1-3 Gy). Nine patients received two fractions per day. The biologically effective dose (BED) according to the linear-quadratic model ranged between 90 and 141 Gy (median, 120 Gy; alpha/beta value, 1 Gy). Median follow-up was 10 months (range, 4-130 months). In 16 cases, symptoms of late radiation toxicity grade I-III appeared. Actuarial rates were 32% after 1 year, 49% after 2 years, and 83% after 5 years. Actuarial rates of cerebral atrophy were 50% after 1 year and 84% after 2 years (white matter abnormalities: 25% and 85%, respectively). There was a significant correlation between atrophy and white matter abnormalities, but not between CT changes and clinical symptoms. CT changes were dependent on BED, absence of barbiturate use, and preexisting cerebral atrophy. Clinical symptoms usually were dependent on BED too, but treatment with carbamazepine was more important in the multivariate model. Neither other drugs nor other factors influenced late radiation toxicity. A detailed analysis showed that most carbamazepine-treated symptomatic patients took the drug during WBRT as well as during follow-up. Actuarial rates of grade I-III symptoms were 18% versus 50% after 1 year with or without carbamazepine. Even after exclusion of carbamazepine-treated patients, CT changes and clinical symptoms did not correlate. In conclusion, a BED <120 Gy was associated with a lower rate of late radiation toxicity after WBRT. The anticonvulsant drug carbamazepine showed a surprisingly clear influence on clinical symptoms of late radiation toxicity; that might be explained by the fact that the side effects of long-term drug treatment are indistinguishable from mild or moderate true radiation sequelae, rather than that it has a role in the pathogenesis of radiation-induced changes.

[Stereotactic one-time irradiation (radiosurgery). The methods, indications and results]

BACKGROUND

Stereotaxy is a method to determine a point in the patient's body by an external coordinate system which is attached to the patient. Radiosurgery uses this method for precise delivery of a high single radiation dose to the patient. The aim is to destroy the tissue in the target and to spare surrounding unaffected normal tissue by a steep dose gradient.

METHODS

Three techniques of percutaneous radiosurgery are available: radiosurgery with ion beams with a cyclotron, spherical arrangement of cobalt-60 sources, the so-called gamma knife, and an adapted linear accelerator. The availability and the good clinical experience lead to a wide spread use of linear accelerator for radiosurgery in recent years. A subsequent development is fractionated stereotactic radiotherapy which combines the precision of radiosurgery with the radiobiological advantage of fractionation.

RESULTS

Only a few indications for radiosurgery are proven by statistically valid studies. One of these is the treatment of small arteriovenous malformation, where obliteration rates of 80% to 100% are reported with only minor toxicity. However, the obliteration rate is reduced significantly in large arteriovenous malformations. A local control rate of 90% is obtained after radiosurgery of brain metastases which is comparable to the results of microsurgical resection followed by adjuvant whole brain radiotherapy. An ongoing EORTC study evaluates the role of adjuvant whole brain radiotherapy after radiosurgery. The survival of the patients with brain metastases is limited by the existence of progressive extracerebral disease. The role of radiosurgery in the treatment of benign tumors is currently evaluated in clinical studies which include: vestibular schwannomas, meningiomas, chordomas and chondrosarcomas and pituitary adenomas. Most of the published studies include only small tumors because radiosurgery is limited by the risk of radionecrosis of adjacent normal tissue, which shows a steep dose volume response relationship. Recent developments of stereotactic radiotherapy include the use of mini-multileaf-collimators and clinical studies on stereotactic radiotherapy of extracranial targets.

CONCLUSIONS

Stereotactic irradiation is a well established treatment technique for intracranial tumors and arteriovenous malformations. Methods are available that allow optimization of dose distributions to irregularly shaped tumors for single dose as well as fractionated stereotactic irradiations by linear accelerator. Therefore the therapeutic potential of this technique has increased and enables also the extracerebral application in controlled clinical studies.