Tumour Volume and Dose Influence Outcome after Surgery and High-dose Photon Radiotherapy for Chordoma and Chondrosarcoma of the Skull Base and Spine

Prognostic nomogram in middle-aged and elderly patients with chordoma: A SEER-based study

BACKGROUND

Chordoma is a bone tumor that tends to occur in middle-aged and elderly people. It grows relatively slowly but is aggressive. The prognosis of middle-aged and elderly patients with chordoma is quite different from that of young patients with chordoma.

OBJECTIVES

The purpose of the research was to construct a nomogram to predict the Individualized prognosis of middle-aged and elderly (age greater than or equal to 40 years) patients with chordoma.

METHODS

In this study, we screened 658 patients diagnosed with chordoma from 1983 to 2015 in the Surveillance, Epidemiology, and End Results (SEER) database. We determined the independently prognostic factors that affect the survival of patients by univariate and multivariate Cox proportional hazards model. Based on the independent prognostic factors, we constructed a nomogram to predict the overall survival (OS) rates of middle-aged and elderly patients with chordoma at 3 and 5 years. The validation of this nomogram was completed by evaluating the calibration curve and the C-index.

RESULTS

We screened a total of 658 patients and divided them into two cohort. Training cohort had 462 samples and validation cohort had 196 samples. The multivariate Cox proportional hazards model of the training group showed an association of age, tumor size, histology, primary site, surgery, and extent of disease with OS rates. Based on these results, we constructed the corresponding nomogram. The calibration curve and C-index showed the satisfactory ability of the nomogram in terms of predictive ability.

CONCLUSION

Nomogram can be an effective prognostic tool to assess the prognosis of middle-aged and elderly patients with chordoma and can help clinicians in medical decision-making and enable patients to receive more accurate and reasonable treatment.

A case report of Sustained triumph: 15-year recurrence-free survival following surgical resection of a cervical chordoma in a 15-year-old girl

Introduction and importance

Chordoma of the cervical spine is a rare condition associated with poor long-term outcomes. This is mainly attributed to its pathological involvement of vital structures such as the cervical roots and vertebral artery (VA). Although the most appropriate management in these cases is total en bloc excision, attaining complete resection is relatively challenging due to the vicinity of the critical anatomical structures mentioned above.

Case description

A 15-year-old female with middle cervical spine chordoma was treated by a multidisciplinary team involving neurosurgery and head and neck surgeons utilizing anterior and posterior approaches followed by high-beam X-ray radiotherapy. Histopathological examination matched the description of a chordoma. Fifteen years after the initial excision, the patient maintained her normal neurological function without local recurrence or metastasis.

Clinical discussion

The patient underwent surgery in two stages. A posterior approach for C3, C4, and C5 laminectomies was performed in the first stage, with the second stage involving head and neck surgery for complete resection of the tumor. The patient also underwent radiotherapy 3 months after surgery for a total duration of 1 month. The patient is currently 30 years old with no evidence of chordoma recurrence.

Conclusion

Patients afflicted with cervical chordomas often find themselves undergoing multiple operations due to high recurrence rates. Fortunately, the utilization of en bloc resection coupled with adjuvant radiotherapy presents a hopeful treatment modality that can serve to substantially reduce recurrence rates, increase survival rates, and ultimately enhance the quality of life.

Intensity-modulated radiotherapy for the management of primary and recurrent chordomas: a retrospective long-term follow-up study

Background

Chordomas have a high risk of recurrence. Radiotherapy (RT) is required as adjuvant therapy after resection. Sufficient radiation doses for local control (LC) can be achieved using either particle therapy, if this technology is available and feasible, or intensity-modulated radiotherapy.

Materials and methods

57 patients (age, 11.8-81.6 years) with chordomas of the skull base, spine and pelvis who received photon radiotherapy between 1995 and 2017 were enrolled in the study. Patients were treated at the time of initial diagnosis (68.4%) or during recurrence (31.6%). 44 patients received adjuvant radiotherapy and 13 received definitive radiotherapy. The median total dose to the physical target volume was 70 Gy equivalent dose in 2 Gy fractions (EQD2) (range: 54.7-82.5) in 22-36 fractions.

Results

LC was 76.4%, 58.4%, 46.7% and 39.9% and overall survival (OS) was 98.3%, 89%, 76.9% and 47.9% after 1, 3, 5 and 10 years, respectively, with a median follow-up period of 6.5 years (range, 0.5-24.3 years). Age, dose and treatment concept (post-operative or definitive) were significant prognostic factors for OS. Primary treatment, macroscopic tumour at RT and size of the irradiated volume were statistically significant prognostic factors for LC.

Conclusion

Photon treatment is a safe and effective treatment for chordomas if no particle therapy is available. The best results can be achieved against primary tumours if the application of curative doses is possible due to organs at risk in direct proximity. We recommend high-dose radiotherapy, regardless of the resection status, as part of the initial treatment of chordoma, using the high conformal radiation technique if particle therapy is not feasible.

Outcomes of Patients Treated in the UK Proton Overseas Programme: Central Nervous System Group

AIMS

In 2008, the UK National Health Service started the Proton Overseas Programme (POP), to provide access for proton beam therapy (PBT) abroad for selected tumour diagnoses while two national centres were being planned. The clinical outcomes for the patient group treated for central nervous system (CNS), base of skull, spinal and paraspinal malignancies are reported here.

MATERIALS AND METHODS

Since the start of the POP, an agreement between the National Health Service and UK referring centres ensured outcomes data collection, including overall survival, local tumour control and late toxicity data. Clinical and treatment-related data were extracted from this national patient database. Grade ≥3 late toxicities were reported following Common Terminology Criteria for Adverse Events (CTCAE) v 4.0 definition, occurring later than 90 days since the completion of treatment.

RESULTS

Between 2008 and September 2020, 830 patients were treated within the POP for the above listed malignancies. Overall survival data were available for 815 patients and local control data for 726 patients. Toxicity analysis was carried out on 702 patients, with patients excluded due to short follow-up (<90 days) and/or inadequate toxicity data available. After a median follow-up of 3.34 years (0.06-11.58), the overall survival was 91.2%. The local control rate was 85.9% after a median follow-up of 2.81 years (range 0.04-11.58). The overall grade ≥3 late toxicity incidence was 11.97%, after a median follow-up of 1.72 years (0.04-8.45). The median radiotherapy prescription dose was 54 GyRBE (34.8-79.2).

CONCLUSIONS

The results of this study indicate the safety of PBT for CNS tumours. Preliminary clinical outcomes following PBT for paediatric/teen and young adult and adult CNS tumours treated within the POP are encouraging, which reflects accurate patient selection and treatment quality. The rate of late effects compares favourably with published cohorts. Clinical outcomes from this patient cohort will be compared with those of UK-treated patients since the start of the national PBT service in 2018.

A Dosiomics Analysis Based on Linear Energy Transfer and Biological Dose Maps to Predict Local Recurrence in Sacral Chordomas after Carbon-Ion Radiotherapy

Carbon Ion Radiotherapy (CIRT) is one of the most promising therapeutic options to reduce Local Recurrence (LR) in Sacral Chordomas (SC). The aim of this work is to compare the performances of survival models fed with dosiomics features and conventional DVH metrics extracted from relative biological effectiveness (RBE)-weighted dose (D_RBE) and dose-averaged Linear Energy Transfer (LET_d) maps, towards the identification of possible prognostic factors for LR in SC patients treated with CIRT. This retrospective study included 50 patients affected by SC with a focus on patients that presented a relapse in a high-dose region. Survival models were built to predict both LR and High-Dose Local Recurrencies (HD-LR). The models were evaluated through Harrell Concordance Index (C-index) and patients were stratified into high/low-risk groups. Local Recurrence-free Kaplan-Meier curves were estimated and evaluated through log-rank tests. The model with highest performance (median(interquartile-range) C-index of 0.86 (0.22)) was built on features extracted from LET_d maps, with D_RBE models showing promising but weaker results (C-index of 0.83 (0.21), 0.80 (0.21)). Although the study should be extended to a wider patient population, LET_d maps show potential as a prognostic factor for SC HD-LR in CIRT, and dosiomics appears to be the most promising approach against more conventional methods (e.g., DVH-based).

Dosimetric parameters associated with the long-term oncological outcomes of Gamma Knife surgery for sellar and parasellar tumors in pediatric patients

OBJECTIVE

The authors aimed to investigate the dosimetric parameter and the minimally required dose associated with long-term control of sellar and parasellar tumors after Gamma Knife surgery (GKS) in children.

METHODS

A retrospective analysis was performed on pediatric patients younger than 19 years of age who were diagnosed with sellar and parasellar tumors and received GKS at the authors' institution from 1998 to 2019. Cox proportional hazards regression analyses were used to investigate the dosimetric parameters associated with treatment outcome. The Kaplan-Meier method was used to analyze tumor control rates after GKS.

RESULTS

Overall, 37 patients with 40 sellar and parasellar tumors, including 22 craniopharyngiomas and 12 pituitary adenomas, had a mean follow-up of 85.8 months. The gross target volume was 0.05 cm3 to 15.28 cm3, and the mean marginal dose was 15.8 Gy (range 9.6-30.0 Gy). Ten patients experienced treatment failure at a mean of 28.0 ± 26.7 months. The actuarial 5- and 10-year tumor control rates were 79.0% and 69.8%, respectively. D98% was an independent predictive factor of tumor control (HR 0.846 [95% CI 0.749-0.956], p = 0.007), with a cutoff value of 11.5 Gy for the entire cohort and 10 Gy for the craniopharyngioma group. Visual deterioration occurred in 2 patients with the maximum point dose of 10.1 Gy and 10.6 Gy to the optic apparatus.

CONCLUSIONS

In pediatric patients, D98% was a reliable index of the minimum required dose for long-term control of sellar and parasellar tumors after GKS. The optimal D98% value for each tumor diagnosis needs to be elucidated in the future.

Chondrosarcoma of the spine: a narrative review

Chondrosarcoma is an uncommon primary bone tumor with an estimated incidence of 0.5 per 100,000 patient-years. Primary chondrosarcoma of the mobile spine and sacrum cumulatively account for less than 20% of all cases, most .commonly causing patients to present with focal pain with or without radiculopathy, or myelopathy secondary to neural element compression. Because of the rarity, patients benefit from multidisciplinary care at academic tertiary-care centers. Current standard-of-care consists of en bloc surgical resection with negative margins; for high grade lesions adjuvant focused radiation with ≥60 gray equivalents is taking an increased role in improving local control. Prognosis is dictated by lesion grade at the time of resection. Several groups have put forth survival calculators and epidemiological evidence suggests prognosis is quite good for lesions receiving R0 resection. Future efforts will be focused on identifying potential chemotherapeutic adjuvants and refining radiation treatments as a means of improving local control.

Determinants of Survival in Skull Base Chondrosarcoma: A National Cancer Database Study

OBJECTIVE

Chondrosarcomas of the skull base are rare tumors most commonly treated surgically with or without adjuvant radiation therapy. Using the National Cancer Database (NCDB), we analyzed overall survival (OS), treatment modalities, and prognosticators.

METHODS

The NCDB was queried for all cases of histologically confirmed skull base chondrosarcoma treated between 2004 and 2015, excluding patients with more than 1 malignant tumor, on palliative care, receiving unrelated concurrent treatments, or having less than 1 month of follow-up. The χ² test for categorical variables, Cox proportional hazards models, and Kaplan-Meier log-rank analysis were used to test associations with the use of adjuvant radiation, OS, and survival time.

RESULTS

A total of 498 patients with skull base chondrosarcoma were identified in the NCDB. Of them, 224 (45.0%) and 198 (39.8%) were treated with either surgery alone or surgery with adjuvant radiation therapy, respectively. Patients more likely to undergo surgery with adjuvant radiation had higher tumor grade (P = 0.008), later year of diagnosis (P = 0.002), positive surgical margins (P < 0.001), and treatment at an academic institution (P = 0.02). Patient, tumor, and socioeconomic factors associated with worse OS on multivariate analysis included the Charlson/Deyo Comorbidity Score ≥2 (P = 0.017), as well as clear cell (P = 0.02) and dedifferentiated (P = 0.006) histology. Age, tumor grade, tumor size, treatment modality, insurance status, facility type, and urban/rural population did not show a statistically significant impact on OS.

CONCLUSION

The mainstay of treatment for skull base chondrosarcoma is surgery, with consideration of adjuvant radiation. This study demonstrated worse overall survival associated with more frail patients and aggressive histology types. It is important to consider these factors when planning the clinical management of these patients.

Clinicopathological and Prognostic Characteristics in Dedifferentiated/Poorly Differentiated Chordomas: A Pooled Analysis of Individual Patient Data From 58 Studies and Comparison With Conventional Chordomas

Background

Currently, the clinicopathological and prognostic characteristics of dedifferentiated chordoma (DC) and poorly differentiated chordoma (PDC) remain poorly understood. In this study, we sought to characterize clinicopathological parameters in a large PDC/DC cohort and determine their correlations with progression-free survival (PFS) and overall survival (OS) of patients. We also attempted to compare clinical features between PDC/DC and conventional chordoma (CC).

Methods

Literature searches (from inception to June 01, 2020) using Medline, Embase, Google Scholar and Wanfang databases were conducted to identify eligible studies according to predefined criteria. The local database at our center was also retrospectively reviewed to include CC patients for comparative analysis.

Results

Fifty-eight studies from the literature and 90 CC patients from our local institute were identified; in total, 54 PDC patients and 96 DC patients were analyzed. Overall, PDC or DC had distinct characteristics from CC, while PDC and DC shared similar clinical features. Adjuvant radiotherapy and chemotherapy were associated with both PFS and OS in PDC patients in the univariate and/or multivariate analyses. In the DC cohort, tumor resection type, adjuvant chemotherapy and tumor dedifferentiation components significantly affected PFS, whereas none of them were predictive of outcome in the multivariate analysis. By analyzing OS, we found that surgery, resection type and the time to dedifferentiation predicted the survival of DC patients; however, only surgery remained significant after adjusting for other covariables.

Conclusions

These data may offer useful information to better understand the clinical characteristics of PDC/DC and may be helpful in improving the outcome prediction of patients.

Protons versus photons for the treatment of chordoma

BACKGROUND

Chordoma is a rare primary bone tumour with a high propensity for local recurrence. Surgical resection is the mainstay of treatment, but complete resection is often morbid due to tumour location. Similarly, the dose of radiotherapy (RT) that surrounding healthy organs can tolerate is frequently below that required to provide effective tumour control. Therefore, clinicians have investigated different radiation delivery techniques, often in combination with surgery, aimed to improve the therapeutic ratio.

OBJECTIVES

To assess the effects and toxicity of proton and photon adjuvant radiotherapy (RT) in people with biopsy-confirmed chordoma.

SEARCH METHODS

We searched CENTRAL (2021, Issue 4); MEDLINE Ovid (1946 to April 2021); Embase Ovid (1980 to April 2021) and online registers of clinical trials, and abstracts of scientific meetings up until April 2021.

SELECTION CRITERIA

We included adults with pathologically confirmed primary chordoma, who were irradiated with curative intent, with protons or photons in the form of fractionated RT, SRS (stereotactic radiosurgery), SBRT (stereotactic body radiotherapy), or IMRT (intensity modulated radiation therapy). We limited analysis to studies that included outcomes of participants treated with both protons and photons.

DATA COLLECTION AND ANALYSIS

The primary outcomes were local control, mortality, recurrence, and treatment-related toxicity. We followed current standard Cochrane methodological procedures for data extraction, management, and analysis. We used the ROBINS-I tool to assess risk of bias, and GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included six observational studies with 187 adult participants. We judged all studies to be at high risk of bias. Four studies were included in meta-analysis. We are uncertain if proton compared to photon therapy worsens or has no effect on local control (hazard ratio (HR) 5.34, 95% confidence interval (CI) 0.66 to 43.43; 2 observational studies, 39 participants; very low-certainty evidence). Median survival time ranged between 45.5 months and 66 months. We are uncertain if proton compared to photon therapy reduces or has no effect on mortality (HR 0.44, 95% CI 0.13 to 1.57; 4 observational studies, 65 participants; very low-certainty evidence). Median recurrence-free survival ranged between 3 and 10 years. We are uncertain whether proton compared to photon therapy reduces or has no effect on recurrence (HR 0.34, 95% CI 0.10 to 1.17; 4 observational studies, 94 participants; very low-certainty evidence). One study assessed treatment-related toxicity and reported that four participants on proton therapy developed radiation-induced necrosis in the temporal bone, radiation-induced damage to the brainstem, and chronic mastoiditis; one participant on photon therapy developed hearing loss, worsening of the seventh cranial nerve paresis, and ulcerative keratitis (risk ratio (RR) 1.28, 95% CI 0.17 to 9.86; 1 observational study, 33 participants; very low-certainty evidence). There is no evidence that protons led to reduced toxicity. There is very low-certainty evidence to show an advantage for proton therapy in comparison to photon therapy with respect to local control, mortality, recurrence, and treatment related toxicity.

AUTHORS' CONCLUSIONS

There is a lack of published evidence to confirm a clinical difference in effect with either proton or photon therapy for the treatment of chordoma. As radiation techniques evolve, multi-institutional data should be collected prospectively and published, to help identify persons that would most benefit from the available radiation treatment techniques.

Long-term outcomes of grade I/II skull base chondrosarcoma: an insight into the role of surgery and upfront radiotherapy

PURPOSE

To clarify the need for post-operative radiation treatment in skull base chondrosarcomas (SBCs).

METHODS

A retrospective analysis of patients with grade I or II SBC. Patients were divided according to post-surgical treatment strategies: (A) planned upfront radiotherapy and (B) watchful waiting. Tumor control and survival were compared between the treatment groups. The median follow-up after resection was 105 months (range, 9-376).

RESULTS

Thirty-two patients (Grade 1, n = 16; Grade 2, n = 16) were included. The most frequent location was petroclival (21, 64%). A gross total resection (GTR) was achieved in 11 patients (34%). Fourteen (44%) underwent upfront radiotherapy (group A) whereas 18 (56%) were followed with serial MRI alone (group B). The tumor control rate for the entire group was 77% and 69% at 10- and 15-year, respectively. Upfront radiotherapy (P = 0.25), extent of resection (P = 0.11) or tumor grade (P = 0.83) did not affect tumor control. The majority of Group B patients with recurrent tumors (5/7) obtained tumor control with repeat resection (n = 2), salvage radiotherapy (n = 2), or a combination of both (n = 1). The 10-year disease-specific survival was 95% with no difference between the group A and B (P = 0.50).

CONCLUSION

For patients with grade I/II SBC, a reasonable strategy is deferral of radiotherapy after maximum safe resection until tumor progression or recurrence. At that time, most patients can be successfully managed with salvage radiotherapy or surgery. Late recurrences may occur, and life-long follow-up is advisable.

Cervical chordomas: multicenter case series and meta-analysis

BACKGROUND

En bloc spondylectomy is the gold standard for surgical resection of sacral chordomas (CHO), but the effect of extent of resection on recurrence and survival in patients with CHO of the cervical spine remains elusive.

METHODS

MEDLINE, Embase, Scopus, and Cochrane were systematically reviewed. Patients with cervical CHO treated at three tertiary-care academic institutions were reviewed for inclusion. We performed an individual participant data meta-analysis to assess the overall survival (OS) and progression free survival (PFS) after en bloc-gross total resection (GTR) and intralesional-GTR compared to subtotal resection (STR). We then performed an intention-to-treat analysis including all patients with attempted en bloc resection in the en bloc group, regardless of the surgical margins.

RESULTS

There was a total of 13 series including 161 patients with cervical CHO, including our current series of 22 patients. GTR (en bloc-GTR + intralesional-GTR) was associated with a significant decrease in the risk of local progression (pooled hazard ratio (PHR) = 0.22; 95% CI 0.08-0.59; p = 0.003) and risk of death (PHR 0.31; 95%; CI 0.12-0.83; p = 0.020). A meta-regression analyses determined that intralesional-GTR improved PFS (PHR 0.35; 95% CI 0.16-0.76; p = 0.009) as well as OS (PHR 0.25; 95% CI 0.08-0.79; p = 0.019) when compared to STR. En bloc-GTR was associated with a significant reduction in the risk of local progression (PHR 0.06; 95% CI 0.01-0.77; p = 0.030), but not a decreased OS (PHR 0.50; 95% CI 0.19-1.27; p = 0.145). Our intention-to-treat analyses revealed a near significant improvement in OS for the en bloc group (PHR: 0.15; 95% CI 0.02-1.22; p = 0.054), and nearly identical improvement in PFS. Radiation data was not available for the studies included in the meta-analysis.

CONCLUSION

This is the first and only meta-analysis of patients with cervical CHO. We found that both en bloc-GTR and intralesional-GTR resulted in improved local tumor control when compared to STR.

Radiotherapy of extraosseous nasopharyngeal chordoma: A case report and literature review

Chordomas are slow-growing aggressive tumors that account for 1-4% of all bone tumors. The anatomical distribution of chordomas includes 50-60% in the sacrococcygeal region, 25-30% in the skull base and 15% in the mobile spine. Virchow was the first to describe and term these tumors as ‘ecchordosis physaliphora’ in 1857, and Muller established their notochordal origin in 1895. Extraosseous chordomas of the nasopharynx are very rare, and they exhibit similarities with other lesions of the nasopharynx, presenting as a soft tissue mass. Gross total resection combined with postoperative radiotherapy offers the best chance of long-term control. We herein present the case of a 63-year-old female patient with complaints of left temporal headaches, dizziness, left nasal obstruction, left maxillary area numbness, left ear hearing loss and swallowing difficulty. Computed tomography imaging examination revealed an 8.2x3.2x5.7-cm space-occupying lesion with central necrosis in the nasopharynx and oropharynx, partially occluding the pharyngeal lumen; the mass had infiltrated the left parapharyngeal space, the left medial and lateral pterygoid muscle and the left parotid gland, with bone erosion of the left mandible. The patient was diagnosed with extraosseous chordoma of the nasopharynx, conventional type, stage IIB. The patient underwent surgery and high-dose radiotherapy and local control of the chordoma was achieved. However, the patient succumbed to a lung metastasis. The details of the case are discussed, and a review of the current medical literature is presented to provide an updated discussion on the current status of nasopharyngeal chordoma research.

Clivus chordomas: Heterogeneous tumor extension requires adapted surgical approaches

OBJECTIVE

Clivus chordomas are semi-malignant, but infiltratively growing tumors. Currently, a widely-accepted treatment concept encompasses maximal, but safe, surgical resection and radiotherapy. Caused by the size and the tumor extension, different surgical approaches, especially in recurrent cases, might be necessary.

METHODS

Retrospective review of 50 patients on whom 70 surgeries were performed: 29 in primary and 41 in recurrent cases. Based on MRI images, all cases were asserted according to the size and the extension of the tumor. Used surgical approaches were evaluated. Postoperative complications, neurological function prior to and after the surgery, the extent of tumor resection on postoperative MR images were assessed and progression-free survival was calculated.

RESULTS

Tumor size was estimated as small (< 5 cm³) in 8, as medium (5-20 cm³) in 21, as large (20-100 cm³) in 17, and as giant (> 100 cm³) in 4 patients. Most frequently used surgical approaches in primary cases were the transsphenoidal one and midfacial degloving (51.7 % and 17.2 %, respectively). In recurrent cases, dependent on the tumor extension, transsphenoidal (21.9 %), retrosigmoidal (29.3 %), and pterional (19.5 %) approaches, as well as midfacial degloving (17.1 %) were used. Due to the vast tumor extension and infiltration, gross total or near total resection could be achieved in 12 patients (24 %), only. There was no mortality and no major complications in primary cases. In recurrences, however, postoperative hemorrhages and strokes emerged in 4.9 % and 7.1 %. Minor complications occurred in 17.1 % and were dominated by CSF leaks (12.2 %), both in primary in recurrent cases. While most cranial nerve impairments were caused by tumor infiltration of the cavernous sinus, and hence have not improved by treatment, the sixth nerve palsy as a consequence of tumor mass compression, could significantly be improved by surgery. Following surgery, patients were subjected to radiotherapy (68.9 % for primary cases, and 36.6 % for recurrences) mainly with carbon ions. Overall, 5-year progression-free survival was 44.7 %.

CONCLUSION

Caused by the heterogenous pattern of growth of clivus chordomas, surgical approaches should be chosen individually. Vast and infiltrative tumor extension constitute major limitations of surgical resection, and hence result in poor progression-frees survival.

A multimodal treatment of carbon ions irradiation, miRNA-34 and mTOR inhibitor specifically control high-grade chondrosarcoma cancer stem cells

BACKGROUND AND PURPOSE

High-grade chondrosarcomas are chemo- and radio-resistant cartilage-forming tumors of bone that often relapse and metastase. Thus, new therapeutic strategies are urgently needed.

MATERIAL AND METHODS

Chondrosarcoma cells (CH-2879) were exposed to carbon-ion irradiation, combined with miR-34 mimic and/or rapamycin administration. The effects of treatment on cancer stem cells, stemness-associated phenotype, radioresistance and tumor-initiating properties were evaluated.

RESULTS

We show that high-grade chondrosarcoma cells contain a population of radioresistant cancer stem cells that can be targeted by a combination of carbon-ion therapy, miR-34 mimic administration and/or rapamycin treatment that triggers FOXO3 and miR-34 over-expression. mTOR inhibition by rapamycin triggered FOXO3 and miR-34, leading to KLF4 repression.

CONCLUSION

Our results show that particle therapy combined with molecular treatments effectively controls cancer stem cells and may overcome treatment resistance of high-grade chondrosarcoma.

The Role of Radiotherapy for Chordoma Patients Managed With Surgery: Analysis of the National Cancer Database

STUDY DESIGN

Retrospective review.

OBJECTIVE

To determine if adjuvant radiation therapy (RT) improves overall survival (OS) following surgical resection of chordomas.

SUMMARY OF BACKGROUND DATA

The role of RT for the treatment of chordomas remains incompletely described. Previous studies have not found adjuvant RT to improve OS, but these studies did not group patients based on surgical margin status or radiation dose or modality. We used the National Cancer Database to investigate the role of RT in chordomas following surgical resection.

METHODS

Patients were stratified based on surgical margin status (positive vs. negative). Utilizing the Kaplan-Meier method, OS was compared between treatment modalities (surgical resection alone, therapeutic RT alone, and surgical resection plus therapeutic RT). OS was subsequently compared between patients treated with palliative dose (<40 Gy), low dose (40-65 Gy), and high dose (>65 Gy) RT. Similarly, OS was compared between advanced RT modalities including proton beam therapy (PBT) and intensity-modulated radiation therapy (IMRT), stereotactic radiosurgery (SRS), and external beam radiation therapy (EBRT). A multivariable model was used to determine adjusted variables predictive of mortality.

RESULTS

One thousand four hundred seventy eight chordoma patients were identified; skull base (n = 567), sacral (n = 551), and mobile spine (n = 360). Surgical resection and therapeutic adjuvant RT improved 5-year survival in patients with positive surgical margins (82% vs. 71%, P = 0.03). No clear survival benefit was observed with the addition of adjuvant RT in patients with negative surgical margins. High dose RT was associated with improved OS compared with palliative and low dose RT (P < 0.001). Advanced RT techniques and SRS were associated with improved OS compared with EBRT. In the multivariate analysis high dose advanced RT (>65 Gy) was superior to EBRT.

CONCLUSION

Patients with positive surgical margins benefit from adjuvant RT. Optimal OS is associated with adjuvant RT administered with advanced techniques and cumulative dose more than 65 Gy.

LEVEL OF EVIDENCE

4.

A preoperative risk classifier that predicts tumor progression in patients with cranial base chondrosarcomas

OBJECTIVE

The authors conducted a study to identify clinical features of cranial base chondrosarcomas that will predict tumor progression after resection.

METHODS

The authors performed a retrospective study at a tertiary referral cranial base center. Patients who underwent resection of cranial base chondrosarcomas between January 2004 and December 2018 were followed longitudinally. The main outcome measure was progression-free survival (PFS).

RESULTS

A total of 41 patients were treated for histopathologically proven "conventional" cranial base chondrosarcomas during the study period, and the median PFS was 123 months for the cohort. Univariate analysis was performed on clinical, anatomical, and radiographic parameters collected for each patient. Features that were statistically significant were fed into a multivariate regression model, which revealed two independent predictors of PFS: patient age and encasement of 3-4 major arteries (> 25% of the vessel wall surrounded by tumor). Using these two variables of age and multiple arterial vessel encasement, the authors generated a risk stratification model using a simple point system to predict PFS in patients with cranial base chondrosarcomas. Based on these two factors known preoperatively, this model could stratify patients into high-risk (10% of patients), intermediate-risk (68% of patients), and low-risk (22% of patients) subgroups corresponding to dramatically distinct median PFS (1.8 years, 10.2 years, and no progression, respectively).

CONCLUSIONS

In patients with cranial base chondrosarcomas, age and artery encasement are variables known preoperatively that can powerfully predict tumor progression, define operative goals, and aid in selecting postoperative adjuvant therapy.

The preliminary results of proton and carbon ion therapy for chordoma and chondrosarcoma of the skull base and cervical spine

Purpose

To evaluate the short-term outcomes in terms of tumor control and toxicity of patients with skull base or cervical spine chordoma and chondrosarcoma treated with intensity-modulated proton or carbon-ion radiation therapy.

Methods

Between 6/2014 and 7/2018, a total of 91 patients were treated in our Center. The median age was 38 (range, 4–70) years. Forty-six (50.5%) patients were treated definitively for their conditions as initial diagnosis, 45 (49.5%) patients had recurrent tumors including 14 had prior radiotherapy. The median gross tumor volume was 37.0 (range, 1.6–231.7) cc. Eight patients received proton therapy alone, 28 patients received combined proton and carbon ion therapy, 55 patients received carbon-ion therapy alone.

Results

With a median follow-up time of 28 (range, 8–59) months, the 2-year local control (LC), progression free (PFS) and overall survival (OS) rates was 86.2, 76.8, and 87.2%, respectively. Those rates for patients received definitive proton or carbon-ion therapy were 86.7, 82.8, and 93.8%, respectively. On multivariate analyses, tumor volume of > 60 cc was the only significant factor for predicting PFS (p = 0.045), while re-irradiation (p = 0.012) and tumor volume (> vs < 60 cc) (p = 0.005) were significant prognosticators for OS. Grade 1–2 late toxicities were observed in 11 patients, and one patient developed Grade 3 acute mucositis.

Conclusions

Larger tumor volume and re-irradiation were related to inferior survival for this group of patients. Further follow-up is needed for long-term efficacy and safety.

Radiomic analysis of multiparametric magnetic resonance imaging for differentiating skull base chordoma and chondrosarcoma

PURPOSE

Patients with skull base chordoma and chondrosarcoma have different prognoses and are not readily differentiated preoperatively on imaging. Multiparametric magnetic resonance imaging (MRI) is a routine diagnostic tool that can noninvasively characterize the salient characteristics of tumors. In the present study, we developed and validated a preoperative multiparametric MRI-based radiomic signature for differentiating these tumors.

METHOD

This retrospective study enrolled 210 patients and consecutively divided them into the primary and validation cohorts. A total of 1941 radiomic features were acquired from preoperative T1-weighted imaging, T2-weighted imaging and contrast-enhanced T1-weighted imaging for each patient. The most discriminative features were selected by minimum-redundancy maximum-relevancy and recursive feature elimination algorithms in the primary cohort. The multiparametric and single-sequence MRI signatures were constructed with the selected features using a support vector machine model in the primary cohort. The ability of the novel radiomic signatures to differentiate chordoma from chondrosarcoma were assessed using receiver operating characteristic curve analysis in the validation cohort.

RESULTS

The multiparametric radiomic signature, which consisted of 11 selected features, reached an area under the receiver operating characteristic curve of 0.9745 and 0.8720 in the primary and validation cohorts, respectively. Moreover, compared with each single-sequence MRI signature, the multiparametric radiomic signature exhibited better classification performance with significant improvement (p <  0.05, Delong's test) in the primary cohorts.

CONCLUSION

By combining features from three MRI sequences, the multiparametric radiomics signature can accurately and robustly differentiate skull base chordoma from chondrosarcoma.

Application of nomograms to predict overall and cancer-specific survival in patients with chordoma

Background

The survival prediction of patients with chordoma is difficult to make due to the rarity of this oncologic disease. Our objective was to apply a nomogram to predict survival outcomes in individuals with chordoma of the skull base, vertebral column, and pelvis.

Methods

A total of 558 patients with chordoma between 1973 and 2014 were collected from the Surveillance, Epidemiology, and End Results (SEER) database. Independent prognostic factors in patients with chordoma were identified via univariate and multivariate Cox analysis. Then these prognostic factors were incorporated into a nomogram to predict 3- and 5-year overall survival and cancer-specific survival rates. Internal and external data were used to validate the nomograms. Concordance indices (C-indices) were used to estimate the accuracy of this nomogram system.

Results

A total of 558 patients were randomly assigned into a training cohort (n = 372) and a validation cohort (n = 186). Age, surgical stage, tumor size, histology, primary site, and use of surgery were identified as independent prognostic factors via univariate and multivariate Cox analysis (all p < 0.05) and further included to establish the nomogram. The C-indices for overall survival and cancer-specific survival prediction of the training cohort were 0.775 (95% confidence interval, 0.770-0.779) and 0.756 (95% confidence interval, 0.749 -0.762). The calibration plots both showed an excellent consistency between actual survival and nomogram prediction.

Conclusion

Nomograms were constructed to predict overall survival and cancer-specific survival for patients with chordoma of the skull base, vertebral column, and pelvis. The nomogram could help surgeons to identify high risk of mortality and evaluate prognosis in patients with chordoma.

Proton therapy for brain tumours in the area of evidence-based medicine

ADVANCES IN KNOWLEDGE

This review details the indication of brain tumors for proton therapy and give a list of the open prospective trials for these challenging tumors.