Ependymomas: Types & Treatments
Ependymomas: Types & Treatments Ependymomas are a type of brain tumor that can also occur in the spinal cord. Although they are considered rare, they play a significant role in pediatric cancer. It is crucial to understand these tumors to ensure timely diagnosis and optimal treatment.
Identifying the specific type of ependymoma is essential for accurate diagnosis and treatment planning. Different types of ependymomas are located within different areas of the brain and spinal cord, necessitating tailored approaches to effectively manage them.
Diagnosing ependymomas involves various imaging techniques, such as MRI and CT scans, along with biopsy procedures for definitive diagnosis. Early and accurate diagnosis helps in designing appropriate treatment strategies.
Treatment options for ependymomas include surgical resection, radiation therapy, and chemotherapy. Each treatment modality is tailored to the individual patient’s needs, ensuring the best possible outcomes.
Surgical resection is a common approach to remove ependymomas, but it requires surgical expertise due to the tumors’ critical location. Radiation therapy and chemotherapy are also employed to target and control ependymomas, reducing the risk of recurrence.
Prognosis and survival rates for ependymomas vary depending on several factors such as tumor location, grade, and patient age. Ongoing research aims to improve overall outcomes and prognosis for patients.
Recent advancements in ependymoma research have paved the way for novel treatment approaches and clinical trials. These developments are a result of collaborative efforts, aiming to enhance our understanding of this rare tumor.
Acibadem Healthcare Group has made significant contributions in the treatment, research, and awareness of ependymomas. With their expertise and innovative approaches, they are at the forefront of providing comprehensive care and improving outcomes for patients.
Finally, raising awareness about ependymomas and rare tumors is crucial for early detection and optimal treatment. By educating the public and supporting patients and families, we can make a difference in the lives of those affected by these tumors.
Understanding Ependymomas
Ependymomas are rare tumors that occur in the brain and spinal cord, predominantly affecting pediatric cancer patients. These tumors arise from ependymal cells, which line the ventricles of the brain and the central canal of the spinal cord.
Ependymomas are considered rare tumors, accounting for only 2-3% of all brain tumors in children and around 6% in adults. Their rarity makes them challenging to diagnose and treat, requiring specialized expertise and a multidisciplinary approach.
These tumors can occur at any age, but they are most commonly diagnosed in children between the ages of 5 and 10. Ependymomas can manifest in various regions of the brain, including the cerebrum, brainstem, and cerebellum, as well as in different segments of the spinal cord.
The impact of ependymomas on pediatric cancer patients is significant. These tumors can cause neurological symptoms, such as headaches, seizures, difficulty walking, and changes in behavior. The location of the tumor within the brain or spinal cord determines the specific symptoms experienced by the patient.
Symptoms of Ependymomas
The symptoms of ependymomas can vary depending on the location and size of the tumor. Common symptoms include:
- Headaches
- Nausea and vomiting
- Seizures
- Weakness or numbness in the limbs
- Difficulty walking or balancing
- Changes in behavior or personality
It is important to note that these symptoms are not exclusive to ependymomas and may be indicative of other medical conditions. A comprehensive medical evaluation, including imaging and diagnostic tests, is necessary for an accurate diagnosis.
Ependymoma Survival Rates
The prognosis for patients with ependymomas varies depending on several factors, including the tumor location, grade, and extent of surgical resection. The five-year survival rate for pediatric ependymoma patients ranges from 45% to 75%, with higher survival rates observed in patients with completely resected tumors.
Ependymoma Grade | Five-Year Survival Rate |
---|---|
Grade I | Approximately 75% |
Grade II | Approximately 55% |
Grade III | Approximately 45% |
Treatment options for ependymomas include surgical resection, radiation therapy, and chemotherapy. The specific treatment plan is tailored to the individual patient’s needs and is determined by factors such as tumor location, size, and grade.
In the following sections, we will explore in detail the different types of ependymomas, the diagnostic procedures used to identify them, and the various treatment options available to patients. We will also discuss the latest advancements in ependymoma research and the contributions made by Acibadem Healthcare Group in the field of tumor treatment.
Types of Ependymomas
In this section, we will explore the different types of ependymomas, discussing their specific locations within the brain and spinal cord. Identifying the precise type of ependymoma is crucial for accurate diagnosis and effective treatment planning.
Ependymomas are a diverse group of brain and spinal cord tumors that originate from the ependymal cells lining the ventricles or the central canal of the spinal cord. These tumors can occur in various regions, leading to distinct types of ependymomas.
To better understand the different types of ependymomas, let’s take a closer look at their specific location:
Intracranial Ependymomas
Intracranial ependymomas develop within the brain and are further classified based on their location:
- Supratentorial ependymomas: These tumors occur in the cerebral hemispheres, above the tentorium (a membrane that separates the cerebellum from the cerebrum).
- Infratentorial ependymomas: These tumors form in the posterior fossa, which includes the cerebellum, brainstem, and fourth ventricle.
Type of Ependymoma | Location |
---|---|
Supratentorial Ependymoma | Cerebral hemispheres, above the tentorium |
Infratentorial Ependymoma | Posterior fossa, including the cerebellum, brainstem, and fourth ventricle |
Spinal Ependymomas
Spinal ependymomas develop within the spinal cord and are classified based on their location along the spinal column:
- Intramedullary ependymomas: These tumors grow within the substance of the spinal cord itself.
- Extramedullary ependymomas: These tumors form outside the spinal cord, typically within the spinal canal.
Type of Ependymoma | Location |
---|---|
Intramedullary Ependymoma | Within the substance of the spinal cord |
Extramedullary Ependymoma | Outside the spinal cord, within the spinal canal |
Each type of ependymoma may exhibit unique characteristics and require a tailored treatment approach. Understanding the specific type and location of the tumor plays a critical role in enabling healthcare professionals to develop a comprehensive treatment plan.
In the following sections, we will delve into diagnostic procedures, treatment options, and the latest advancements in ependymoma research to further enhance our understanding of these rare and complex tumors.
Diagnosing Ependymomas
In order to accurately diagnose ependymomas, a comprehensive diagnostic approach is essential. This involves the use of advanced imaging techniques, such as magnetic resonance imaging (MRI) and computed tomography (CT) scans, as well as biopsy for definitive diagnosis.
Imaging Techniques
MRI and CT scans are invaluable tools in the diagnosis of ependymomas. These imaging techniques allow healthcare providers to visualize the brain and spinal cord, helping to identify the location, size, and characteristics of the tumor. Brain tumor diagnosis and spinal cord tumor diagnosis can be effectively facilitated through these non-invasive imaging procedures.
MRI uses powerful magnets and radio waves to create detailed images of the brain and spinal cord, providing valuable information about the structure and integrity of these vital organs. CT scans, on the other hand, use X-rays to create cross-sectional images, allowing healthcare providers to assess the presence and extent of tumor growth.
Both MRI and CT scans play a crucial role in the initial assessment and tumor diagnosis of ependymomas. These diagnostic tools enable healthcare providers to determine the appropriate course of treatment for each individual patient.
Biopsy
A biopsy is often necessary to confirm the presence of ependymomas and to determine their specific characteristics. During a biopsy, a small sample of tissue is extracted from the tumor and examined under a microscope by a pathologist. This procedure provides crucial information about the tumor’s cellular makeup, grade, and genetic profile, which helps guide treatment decisions.
A brain or spinal cord tumor biopsy can be performed using various techniques, including stereotactic biopsy or open surgery. The choice of biopsy method depends on factors such as the tumor’s location, size, and accessibility. Regardless of the approach, biopsy provides valuable insights that aid in accurate diagnosis and treatment planning.
Diagnostic Procedures for Ependymomas | Advantages |
---|---|
MRI | – Provides detailed images of the brain and spinal cord |
CT scan | – Assesses tumor presence and extent |
Biopsy | – Confirms tumor presence and provides crucial information about cellular makeup and grade |
Ependymoma Treatment Options
When it comes to treating ependymomas, there are several options available for patients. The treatment plan is tailored to each individual’s specific needs, taking into consideration factors such as tumor location, size, and the patient’s overall health. The goal of treatment is to remove or shrink the tumor, alleviate symptoms, and improve the patient’s quality of life.
Surgical Resection
One of the primary treatment options for ependymomas is surgical resection. This involves the removal of the tumor through a surgical procedure. The extent of the surgery will depend on the size and location of the tumor. In some cases, complete resection may be possible, while in others, partial resection may be necessary. Surgical resection is often combined with other treatments such as radiation therapy or chemotherapy to improve outcomes.
Radiation Therapy
Radiation therapy is another important treatment modality for ependymomas. It uses high-energy beams to target and destroy cancer cells. Radiation therapy can be administered externally or internally, depending on the tumor location and stage. This treatment option is commonly used after surgical resection to eliminate any remaining cancer cells and prevent recurrence. It is also effective in treating tumors that cannot be surgically removed.
Chemotherapy
Chemotherapy may be recommended for patients with ependymomas, especially in cases where the tumor is difficult to reach through surgery or radiation therapy. Chemotherapy involves the use of drugs that kill or slow down the growth of cancer cells. These drugs are typically administered intravenously or orally. Chemotherapy can be used as a primary treatment option for some ependymomas or in combination with surgery and radiation therapy.
It’s important to note that the treatment approach for ependymomas may vary depending on the specific case and the expertise of the healthcare team. The decision on which treatment option to pursue will be made by a multidisciplinary team of specialists, including neurosurgeons, oncologists, and radiation therapists, among others. The goal is to develop a comprehensive treatment plan that maximizes the chances of successful tumor treatment while minimizing potential side effects.
Treatment Option | Description |
---|---|
Surgical resection | Removal of the tumor through a surgical procedure |
Radiation therapy | Use of high-energy beams to destroy cancer cells |
Chemotherapy | Use of drugs to kill or slow down the growth of cancer cells |
Ependymomas: Types & Treatments: Surgical Approaches for Ependymomas
The successful management of ependymomas often involves surgical intervention. Brain tumor surgery and spinal cord tumor surgery play crucial roles in achieving tumor resection and optimal patient outcomes. Highly skilled surgeons with expertise in neurosurgery are essential for these delicate procedures.
Brain Tumor Surgery
In brain tumor surgery, the neurosurgeon meticulously removes the ependymoma from the brain tissue, aiming for a complete resection while preserving surrounding healthy tissue. The surgeon carefully navigates the intricate network of structures within the brain to ensure that the tumor is fully excised.
During the procedure, advanced imaging techniques and intraoperative monitoring may be employed to guide the surgeon and minimize risks. This comprehensive approach ensures a thorough and precise surgical intervention.
Spinal Cord Tumor Surgery
Spinal cord tumor surgery involves the removal of ependymomas from the spinal cord region. The surgeon carefully accesses the tumor, considering the delicate nature of the spinal cord and the surrounding nerve roots.
The goal of spinal cord tumor surgery is to achieve complete tumor resection without causing significant damage to the spinal cord or nerve structures. This requires intricate surgical techniques, meticulous planning, and the utmost precision to optimize patient outcomes.
Risks and Limitations
While surgical resection is a critical component of ependymoma treatment, it does carry certain risks and limitations. The location, size, and aggressiveness of the tumor can influence the surgical approach and the potential for complete resection.
Additionally, due to the intricate nature of the brain and spinal cord, there is always a level of inherent risk associated with these procedures. Surgeons must carefully weigh the potential benefits against potential risks when considering surgery as part of the treatment plan.
Post-surgery, patients may also experience short-term or long-term complications, such as neurological deficits or infection. Close monitoring and appropriate post-operative care are essential to manage and minimize these risks.
All surgical decisions are made on an individual basis, considering factors such as tumor characteristics, patient age, overall health, and the tumor’s proximity to critical structures. The surgeon will collaborate closely with the healthcare team to determine the most suitable approach for each patient.
Radiation Therapy for Ependymomas
In the treatment of ependymomas, radiation therapy plays a crucial role. It is an essential component of the multidisciplinary approach in targeting ependymoma cells and improving patient outcomes. Radiation therapy utilizes high-energy beams to destroy cancerous cells, preventing their growth and spread throughout the brain or spinal cord.Ependymomas: Types & Treatments
Various techniques and technologies are employed in radiation therapy for ependymomas, ensuring precise targeting while minimizing damage to healthy tissues. The specific approach depends on the tumor’s location, size, and the individual patient’s condition. The goal is to maximize the therapeutic effect while minimizing potential side effects.
Brain tumor radiation therapy:
- External beam radiation therapy (EBRT): This is the most common radiation technique used for ependymomas. It involves delivering radiation from an external machine directly to the tumor site, carefully controlling the radiation dose and targeting only the affected area.
- Intensity-modulated radiation therapy (IMRT): This advanced technique uses computer-controlled x-ray beams with varying intensities to conform to the shape of the tumor, allowing for precise radiation delivery and sparing nearby healthy tissues from unnecessary exposure.
- Proton therapy: Proton therapy is a form of radiation therapy that uses protons instead of x-rays. This technology allows for highly targeted radiation delivery, minimizing the radiation dose to healthy tissues surrounding the tumor.
Spinal cord tumor radiation therapy:
- Spinal irradiation: For ependymomas located in the spinal cord, radiation therapy may involve delivering radiation to the entire spinal cord and surrounding areas. This helps to target any microscopic cancer cells that may have spread beyond the visible tumor.
- Spinal stereotactic body radiation therapy (SBRT): This approach uses highly focused radiation beams to deliver a precise, high dose of radiation to the tumor, while sparing normal tissues. It is particularly effective for small spinal cord tumors.
During radiation therapy for ependymomas, patients will undergo a series of treatment sessions to gradually and effectively deliver the prescribed dose of radiation. The treatment schedule and duration will depend on various factors, including the tumor type, location, and the individual’s overall health.
While radiation therapy for ependymomas has proven to be an effective treatment modality, it may also carry certain risks and potential side effects. The radiation oncology team carefully monitors patients throughout the treatment process, ensuring that any side effects are promptly addressed and managed.
Radiation Therapy Techniques | Advantages | Disadvantages |
---|---|---|
EBRT | – Widely available and commonly used – Precise targeting of tumor site |
– Potential damage to nearby healthy tissues |
IMRT | – Highly precise radiation delivery – Minimizes damage to surrounding tissues |
– Longer treatment duration |
Proton therapy | – Highly targeted radiation delivery – Spares normal tissues from unnecessary exposure |
– Limited availability – High cost |
Spinal irradiation | – Targets entire spinal cord and surrounding areas – Addresses potential spread of microscopic cancer cells |
– Increased risk of radiation-induced side effects |
SBRT | – Highly focused radiation beams – Precise and effective for small tumors |
– Limited to eligible patients and tumor sizes |
Chemotherapy for Ependymomas
Chemotherapy plays a significant role in the management of ependymomas, rare brain and spinal cord tumors. This treatment approach involves the use of powerful drugs to target and kill cancer cells. While chemotherapy may not always be the primary treatment option for ependymomas, it can be effective in combination with other therapies.
There are different types of chemotherapy drugs used in the treatment of ependymomas. These medications are designed to disrupt the growth and division of cancer cells, helping to slow down tumor progression and reduce the risk of recurrence. Specific chemotherapy drugs used for ependymomas may include:
- Cisplatin: This drug is commonly used in combination with other chemotherapy agents to treat ependymomas. It works by interfering with the DNA in cancer cells, ultimately disrupting their ability to replicate.
- Vincristine: Vincristine is another chemotherapy drug that may be used in the treatment of ependymomas. It inhibits tumor growth by targeting microtubules, which are essential for cell division.
- Carboplatin: Carboplatin is a platinum-based chemotherapy drug that is often used to treat ependymomas. It works similarly to cisplatin by damaging the DNA in cancer cells.
Ependymomas: Types & Treatments While chemotherapy can be an effective treatment option for ependymomas, it is important to note that it may also have side effects. These side effects vary depending on the specific drugs used and the individual patient’s response. Common side effects of chemotherapy for ependymomas may include nausea, vomiting, hair loss, fatigue, and increased susceptibility to infections.
Research and advancements in chemotherapy continue to improve outcomes for patients with ependymomas. Clinical trials are exploring new chemotherapy drugs, delivery methods, and treatment combinations to enhance effectiveness and reduce side effects. As scientists and healthcare professionals gain a deeper understanding of the biology of ependymomas, personalized and targeted chemotherapy approaches are being developed to optimize treatment outcomes.
Advantages of Chemotherapy for Ependymomas | Disadvantages of Chemotherapy for Ependymomas |
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Prognosis and Survival Rates for Ependymomas
Understanding the prognosis and survival rates associated with ependymomas is crucial for patients and their loved ones. Several factors influence the outcome and long-term survival of individuals with ependymomas, including the location of the tumor, its grade, and the effectiveness of treatment.
According to research studies, the overall survival rates for ependymomas vary depending on the specific type and location of the tumor. Patients diagnosed with ependymomas have a five-year survival rate ranging from 50% to 95%, depending on the grade of the tumor and the extent of surgical resection.
Brain tumor prognosis and spinal cord tumor prognosis can be influenced by factors such as tumor size, tumor grade, age at diagnosis, and the presence of genetic abnormalities. High-grade ependymomas generally have a less favorable prognosis compared to low-grade tumors, highlighting the importance of timely diagnosis and appropriate treatment.
Advancements in tumor research and treatment have significantly improved the prognosis for ependymoma patients in recent years. Radiation therapy, chemotherapy, and targeted therapies have shown promising results in increasing survival rates and improving overall outcomes.
Factors Affecting Prognosis:
- Tumor grade: Higher-grade tumors tend to have a more aggressive course and may have a less favorable prognosis.
- Tumor location: The location of the ependymoma within the brain or spinal cord can influence the prognosis and treatment options.
- Extent of surgical resection: A complete or near-complete removal of the tumor during surgery can significantly improve the prognosis.
- Age at diagnosis: Younger patients typically have better outcomes compared to older individuals with ependymomas.
Improving Prognosis and Survival Rates:
Researchers and healthcare professionals are continually working towards improving prognosis and survival rates for ependymoma patients. Ongoing clinical trials and studies are exploring new treatment approaches, targeted therapies, and innovative methods to deliver radiation therapy.Ependymomas: Types & Treatments
Collaborative efforts among medical institutions, such as Acibadem Healthcare Group, contribute to advancements in tumor research and treatment. By combining expertise, sharing knowledge, and leveraging the latest technologies, healthcare providers strive to enhance patient outcomes and survivorship.
Ependymoma Type | Five-Year Survival Rate |
---|---|
Grade I – Subependymoma | 85-95% |
Grade II – Myxopapillary ependymoma | 70-95% |
Grade II-III – Classic ependymoma | 70-80% |
Grade III – Anaplastic ependymoma | 50-75% |
It is important to note that these survival rates are approximate, and individual prognosis may vary. Consultation with a healthcare specialist is essential for accurate prognosis assessment and personalized treatment planning.
Latest Advancements in Ependymoma Research
Ependymomas, a rare type of brain and spinal cord tumor, have been the focus of extensive research to improve treatment outcomes and patient prognosis. In recent years, significant advancements have been made in understanding and managing ependymomas, paving the way for more effective therapies and better patient care.
Advances in Tumor Research
Tumor research plays a crucial role in deepening our understanding of ependymomas and identifying potential targets for therapy. Ongoing studies have focused on the genetic and molecular characteristics of ependymomas, allowing researchers to classify these tumors into more refined subtypes. This classification aids in tailoring treatment approaches to individual patients, leading to more personalized and effective therapy.
Additionally, advancements in imaging techniques, such as high-resolution MRI and molecular imaging, have enabled better visualization of ependymomas. This improved imaging accuracy allows for more precise surgical planning and targeted treatment delivery.
Clinical Trials
Clinical trials are vitally important in advancing ependymoma research. These trials evaluate the safety and efficacy of new therapies, including targeted drugs and immunotherapies, in treating ependymomas. By participating in clinical trials, patients gain access to promising treatments that may not be available through conventional methods.
Furthermore, clinical trials facilitate collaboration between researchers, medical professionals, and patients, fostering a multidisciplinary approach to ependymoma research. This collective effort maximizes knowledge-sharing and accelerates the development of innovative therapeutic strategies.
Collaborative Efforts
The advancement of ependymoma research heavily relies on collaborative efforts among institutions, researchers, and healthcare providers. Collaborative research networks bring together experts from various fields, including neurosurgery, oncology, radiology, and pathology, to tackle the complexities of ependymomas collectively.
Through shared resources, data, and expertise, collaborative efforts enable faster progress in the development of targeted therapies and improved diagnostic methods. These partnerships also enhance the exchange of ideas, leading to breakthroughs in ependymoma research.
Advancements in Ependymoma Research | Key Findings |
---|---|
Genetic and Molecular Characterization | Refined tumor classification for personalized treatment approaches. |
Improved Imaging Techniques | Precise visualization for more accurate surgical planning and treatment delivery. |
Clinical Trials | Evaluation of new therapies, including targeted drugs and immunotherapies. |
Collaborative Efforts | Partnerships between institutions and experts leading to faster progress in ependymoma research. |
As research continues to advance, new discoveries in ependymoma biology and treatment are on the horizon. These advancements offer hope for improved outcomes and better quality of life for patients diagnosed with ependymomas.
Acibadem Healthcare Group’s Contribution to Ependymoma Treatment
Ependymomas: Types & Treatments Acibadem Healthcare Group has emerged as a driving force in tumor research and treatment, specifically in the field of ependymomas. Through their expertise and innovative approaches, they are making significant contributions to pediatric cancer treatment and improving outcomes for patients.
Advanced Treatment Modalities
Acibadem Healthcare Group utilizes state-of-the-art technology and cutting-edge techniques to provide comprehensive and personalized ependymoma treatment. Their multidisciplinary team of experts collaborates to develop individualized treatment plans, ensuring the most effective approach for each patient.
Treatment Modalities | Description |
---|---|
Surgical Intervention | Acibadem’s highly skilled surgeons employ meticulous techniques to remove ependymomas, minimizing damage to surrounding healthy tissue. |
Radiation Therapy | Using advanced radiation techniques, such as stereotactic radiosurgery, Acibadem’s radiation oncologists precisely target ependymoma cells while sparing healthy tissues. |
Chemotherapy | Acibadem Healthcare Group stays at the forefront of chemotherapy research, offering tailored drug regimens to effectively combat ependymomas. |
Research and Collaborative Efforts
Recognizing the importance of tumor research, Acibadem Healthcare Group actively contributes to the scientific community’s knowledge base on ependymomas. They participate in clinical trials, exploring novel treatment options and continuously seeking ways to improve patient outcomes.
Furthermore, Acibadem’s collaboration with leading research institutions and healthcare organizations enhances their understanding of ependymomas and drives innovation in tumor treatment.
Patient-Centric Care
Acibadem Healthcare Group prioritizes patient-centric care, ensuring that individuals and their families receive the support they need throughout their ependymoma journey. Their compassionate healthcare professionals provide comprehensive information, addressing concerns and guiding patients throughout the treatment process.
By combining expertise, innovation, research, and patient-centered care, Acibadem Healthcare Group is revolutionizing ependymoma treatment and offering hope to patients facing this rare tumor.
Raising Cancer Awareness for Ependymomas
Increasing cancer awareness is crucial, especially when it comes to rare tumors like ependymomas. By spreading knowledge and understanding, we can make a significant impact on early detection, treatment, and support for pediatric cancer patients and their families.
Educating the public about ependymomas and their symptoms is essential for early diagnosis. Awareness campaigns can empower individuals to recognize warning signs, such as headaches, nausea, and impaired motor skills, prompting them to seek medical attention promptly. Additionally, by advocating for routine check-ups and regular screenings, we can enhance the chances of detecting ependymomas earlier, leading to more effective treatments.
Supporting patients and their families is another vital aspect of cancer awareness. By providing resources, information, and emotional assistance, we can help ease the burden of managing a rare tumor diagnosis. Support groups, counseling services, and online communities can create safe spaces where individuals facing ependymomas can find comfort, inspiration, and practical advice.
Advocacy plays a pivotal role in fostering advancements in ependymoma research and treatment. By supporting research institutions, nonprofit organizations, and healthcare providers like Acibadem Healthcare Group, we can contribute to groundbreaking discoveries and innovations. Collaborative efforts between medical professionals, researchers, and advocacy groups can drive progress and improve outcomes for those affected by ependymomas.Ependymomas: Types & Treatments
FAQ
What are ependymomas?
Ependymomas are rare brain and spinal cord tumors that primarily affect pediatric patients. They originate from the ependymal cells, which line the ventricles of the brain and the central canal of the spinal cord.
What are the types of ependymomas?
Ependymomas can be classified into different types based on their location within the brain and spinal cord. These include supratentorial ependymomas, infratentorial ependymomas, and spinal ependymomas.
How are ependymomas diagnosed?
Ependymomas are diagnosed through a combination of imaging techniques, such as MRI and CT scans, and a biopsy to confirm the presence of tumor cells. These diagnostic procedures help determine the location, size, and grade of the tumor.