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From Wikipedia, the free encyclopedia

Oncologist
Occupation
Names Doctor, Medical Specialist
Type Specialty
Activity sectors Medicine
Description
Education required Doctor of Medicine
Fields of employment Hospitals, Clinics

Oncology (from the Ancient Greek onkos (ὄγκος), meaning bulk, mass, or tumor, and the suffix -logy (-λογία), meaning "study of") is a branch of medicine that deals with tumors (cancer). A medical professional who practices oncology is an oncologist.

Oncology is concerned with:

Contents

Diagnosis

The most important diagnostic tool remains the medical history: the character of the complaints and any specific symptoms (fatigue, weight loss, unexplained anemia, fever of unknown origin, paraneoplastic phenomena and other signs). Often a physical examination will reveal the location of a malignancy.

Diagnostic methods include:

Apart from in diagnosis, these modalities (especially imaging by CT scanning) are often used to determine operability, i.e. whether it is surgically possible to remove a tumor in its entirety.

Generally, a "tissue diagnosis" (from a biopsy) is considered essential for the proper identification of cancer. When this is not possible, "empirical therapy" (without an exact diagnosis) may be given, based on the available evidence (e.g. history, x-rays and scans.)

Occasionally, a metastatic lump or pathological lymph node is found (typically in the neck) for which a primary tumor cannot be found. This situation is referred to as "carcinoma of unknown primary", and again, treatment is empirical based on past experience of the most likely origin.

Therapy

It depends completely on the nature of the tumor identified what kind of therapeutical intervention will be necessary. Certain disorders will require immediate admission and chemotherapy (such as ALL or AML), while others will be followed up with regular physical examination and blood tests. A detailed discussion of treatment options according to the type of cancer is at the National Cancer Institute website with sections on adult cancers, pediatric cancers, and supportive care. There is also a section on complementary and alternative methods of treatment.

Often, surgery is attempted to remove a tumor entirely. This is only feasible when there is some degree of certainty that the tumor can in fact be removed. When it is certain that parts will remain, curative surgery is often impossible, e.g. when there are metastases elsewhere, or when the tumor has invaded a structure that cannot be operated upon without risking the patient's life. Occasionally surgery can improve survival even if not all tumour tissue has been removed; the procedure is referred to as "debulking" (i.e. reducing the overall amount of tumour tissue). Surgery is also used for the palliative treatment of some of cancers, e.g. to relieve biliary obstruction, or to relieve the problems associated with some cerebral tumors. The risks of surgery must be weighed up against the benefits.

Chemotherapy and radiotherapy are used as a first-line radical therapy in a number of malignancies. They are also used for adjuvant therapy, i.e. when the macroscopic tumor has already been completely removed surgically but there is a reasonable statistical risk that it will recur. Chemotherapy and radiotherapy are commonly used for palliation, where disease is clearly incurable: in this situation the aim is to improve the quality of and prolong life.

Hormone manipulation is well established, particularly in the treatment of breast and prostate cancer.

There is currently a rapid expansion in the use of monoclonal antibody treatments, notably for lymphoma (Rituximab), and breast cancer (Trastuzumab).

Vaccine and other immunotherapies are the subject of intensive research.

Palliative care

Approximately 50% of all cancer cases in the Western world can be cured with radical treatment. For pediatric patients, that number is much higher. A large number of cancer patients will die from the disease, and a significant proportion of patients with incurable cancer will die of other causes. There may be ongoing issues with symptom control associated with progressive cancer, and also with the treatment of the disease. These problems may include pain, nausea, anorexia, fatigue, immobility, and depression. Not all issues are strictly physical: personal dignity may be affected. Moral and spiritual issues are also important.

While many of these problems fall within the remit of the oncologist, palliative care has matured into a separate, closely allied specialty to address the problems associated with advanced disease. Palliative care is an essential part of the multidisciplinary cancer care team. Palliative care services may be less hospital-based than oncology, with nurses and doctors who are able to visit the patient at home.

Ethical issues

There are a number of recurring ethical questions and dilemmas in oncological practice. These include:

These issues are closely related to the patients' personality, religion, culture, personal, and family life. The answers are rarely black and white. It requires a degree of sensitivity and very good communication on the part of the oncology team to address these problems properly.

Progress and research in oncology

There is a tremendous amount of research being conducted on all frontiers of oncology, ranging from cancer cell biology to chemotherapy treatment regimens and optimal palliative care and pain relief. This makes oncology a continuously changing field.

Therapeutic trials often involve patients from many different hospitals in a particular region. In the UK, patients are often enrolled in large studies coordinated by Cancer Research UK (CRUK)[1], Medical Research Council (MRC)[2], the European Organisation for Research and Treatment of Cancer (EORTC)[3] or the National Cancer Research Network (NCRN).[4]

Specialties

There are several sub-specialties within oncology. Moreover, oncologists often develop an interest and expertise in the management of particular types of cancer.

Oncologists may be divided on the basis of the type of treatment provided.[5]

In the United Kingdom and several other countries, oncologists may be either clinical or medical oncologists. The main difference is that clinical oncologists deliver radiotherapy, while medical oncologists do not. (This difference does not apply in North America: the terms, clinical oncologist and medical oncologist are used interchangeably.)

In most countries it is now common that patients are treated by a multidisciplinary team. These teams will meet on regular basis and discuss the patients under their care. These teams consist of the medical oncologist , a clinical oncologist or radiotherapist, a surgeon (sometimes there is a second reconstructive surgeon), a radiologist, a pathologist, an organ specific specialist such as a gynaecologist or dermatologist, and sometimes the general practitioner is also involved. These disease oriented teams are sometimes in conflict with the general organisation and operation in hospitals. Historically hospitals are organised in an organ or technique specific manner. Multidisciplinary teams operate over these borders and it is sometimes difficult to define who is in charge.

In veterinary medicine, veterinary oncology is the sub-specialty that deals with cancer diagnosis and treatment in animals.

See also

References

Further reading

  • Vickers, A., Banks, J., et al. Alternative Cancer Cures: "Unproven" or "Disproven"? CA Cancer J Clin 2004 54: 110-118. Full text online

External links

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Study guide

Up to date as of January 14, 2010

From Wikiversity

Oncology is the medical subspecialty dealing with the study and treatment of cancer. A physician who practices oncology is an oncologist. The term originates from the Greek onkos (ογκος), meaning bulk, mass, or tumor and the suffix -ology, meaning "study of."

Oncologists may be divided on the basis of the type of treatment provided.

  • Surgical oncologists. These clinicians are surgeons who specialize in tumor removal.
  • Radiation oncologists: people who specialize in the treatment of cancer with radiation, a process called radiotherapy
  • Medical oncologists: who deal with using medication or chemotherapy to treat cancer.

In the UK, the majority of oncologists are known as Clinical Oncologists, and are fully qualified to practice both chemotherapy and radiotherapy. In most other countries these disciplines are more clearly segregated.

Oncologists may also be categorized on the basis of the patient type.

  • Gynecologic oncologists specialize in the treatment of cancer in women. Gynecologic oncologists can perform and give chemotherapy and assist in radiation therapy for these cancers in women.
  • Pediatric oncologists specialize in the care of children with cancer.

Oncology is concerned with:The diagnosis of cancer therapy (e.g. surgery, chemotherapy, radiotherapy and other modalities).

Follow-up of cancer patients after successful treatment palliative care of patients with terminal malignancies are also important topics within oncology.

Ethical questions surrounding cancer care can also arise.

Screening efforts of vulnerable populations, or of the relatives of patients (in types of cancer that are thought to have a heritable basis, such as breast cancer exist and are helpful in combating cancer.

The oncologist often coordinates the multidisciplinary care of cancer patients, which may involve physiotherapy, counseling, and clincal genetics, to name but a few. On the other hand, the oncologist often has to liaise with pathologists on the exact biological nature of the tumor that is being treated.

Lessons

  1. Molecular and cell biology of cancer
  2. Aetiology, epidemiology, and prevention of cancer
  3. Diagnosis and investigative procedures
  4. Scientific basis of cancer treatment
  5. Complications of cancer
  6. Quality of life and psychosocial issues
  7. Assessment of the results of cancer treatment

See also

Related news


Wikibooks

Up to date as of January 23, 2010

From Wikibooks, the open-content textbooks collection

  • Diagnosis
  • Therapy
  • Follow-up
  • Palliative care
  • Ethical issues
  • Progress and research in oncology

Contents

DNA methylation dissorders and cancer

DNA methylation system controls genes exprexssion. This system depends on ONE CARBON UNITS (OCU) metabolism - Folate system, Methionine cycle... Any disturb of OCU metabolism sytem disregulates normal DNA methylation and could couse abnormal DNA methylation pattern. DNA methylation closely depends aproximately on 170 substrates, metabolites, enzymes, the other SAM acceptors...

http://www.protocol-online.org/forums/index.php?showtopic=5897&st=45

About DNA Methylation

Methylation is a natural epigenetic process that occurs when a methyl group binds to one of DNA’s four bases, cytosine. Methylation exerts control over the activity of genes by turning them off when not needed. Measuring the differences in the methylation patterns between healthy and diseased tissue can be used to detect a change in gene activity that could trigger diseases such as cancer. Similarly, DNA methylation patterns can be used to predict a patient’s response to a drug. Epigenomics has developed an industrial process that is able to read and interpret these methylation patterns and uses them as biomarkers for developing molecular diagnostic and pharmacodiagnostic tests.

S-Adenosylmethionine (SAM) is the universal methyl donor for a broad range of methyltransferase reactions. Among the most important of these is the methyltransferase reaction in which cytosines at CpG sites on DNA become methylated. DNA methylation is a critical factor in the control of gene expression and both hyper- and hypo-methylation have been implicated in the inappropriate regulation of proto-oncogenes and tumor-suppressor genes, and have been associated with the development of various cancers.1,2 Therefore, understanding the regulatory mechanisms that control DNA methylation is important for understanding normal cell function, gene expression, and neoplastic transformation. DNA methylation depends on the availability of methyl groups provided by the folate and methionine cycles, the control of the DNA methyltransferase (DNMT) reaction, and the availability of cytosine substrates that is controlled by histones and other DNA-binding proteins. In the present paper we are solely concerned with the first two mechanisms, and so assume that the availability of methylation sites is constant. The level of SAM and the velocity of the DNA methyltransferase reaction depend on the properties of both the methionine and folate cycles. These metabolic cycles in turn depend on the dietary intake of certain nutrients (methionine, choline, betaine) and vitamins (B12, folate, B6) and are affected by polymorphisms in the genes for enzymes of the methionine and folate cycles.3-6 Because defects in folate and methionine metabolism are associated with a large number of serious disorders (several types of cancer,7-10 cardiovascular disease,11-13 neural tube defects14 and neurodegenerative diseases15,16), the genes and enzymes of these cycles have been well studied.

from Long-Range Allosteric Interactions between the Folate and Methionine Cycles Stabilize DNA Methylation Reaction Rate H. Frederik Nijhout, Michael C. Reed, David F. Anderson, Jonathan C. Mattingly, S. Jill James and Cornelia M. Ulrich


volume 1 | issue 2 april/may/june 2006 Pages: 81 - 87

About DMH

Differential Methylation Hybridization (DMH) is the most recent addition to Epigenomics’ proprietary DNA methylation technology portfolio. With Epigenomics’ DMH microarrays more than 50,000 human genomic fragments can be profiled for their methylation status in a single experiment. DMH is robust and delivers highly reproducible results. This makes DMH a fast and cost-effective tool to discover novel DNA methylation biomarkers for diagnostic and pharmacodiagnostic applications.

Epigenomics AG (Frankfurt, Prime Standard: ECX), a cancer molecular diagnostics company developing products based on DNA methylation, has entered into an R&D collaboration with Myriad Genetics, Inc. (NASDAQ: MYGN) to identify and analyze DNA methylation biomarkers that may predict patients’ response to an undisclosed marketed oncology drug.

Under the agreement, Epigenomics will use its proprietary Differential Methylation Hybridization (DMH) microarray platform to perform genome-wide DNA methylation profiling on samples provided by Myriad and compare these profiles to identify DNA methylation biomarkers associated with sensitivity and resistance to the drug.

Date: Wednesday, 09.05.2007

Genome Wide DNA Methylation in Cancer

Christoph Plass, Ph.D., Associate Professor, Department of Medical Microbiology and Immunology, Division of Human Cancer Genetics, James Cancer Hospital and Solove Research Institute, Ohio State University

Numerous genetic defects have been reported that contribute to human malignancies. Equally effective are interconnected epigenetic modifications including DNA methylation, histone tail modifications and microRNA expression changes, that interfere with the expression profiles of hundreds of genes. DNA methylation of promoter sequences or loss of DNA methylation at repetitive sequences results in gene silencing or affects the integrity of chromosomes and consequently impacts on the stability of the genome. DNA methylation is tightly linked to histone tail modifications that alter the chromatin condensation status. More recently, the alterations of microRNAs expression patterns emerged as an additional epigenetic modifications of the malignant cell targeting and modifying the expression of multiple cancer genes. Epigenetic modifications of the DNA do not change the DNA sequence and are therefore potentially reversible by either removing methyl groups or by interference with the enzymes that mediate histone tail modifications, both of these interferences can potentially reactivate silenced genes. The presentation will review current concepts and strategies to study genome wide alterations in epigenetic modifications in human malignancies.

Date: 01.03.2007

Regulation of RASSFS1A gene by methylation

http://sundoc.bibliothek.uni-halle.de/diss-online/05/05H171/t5.pdf

Clinical Research

DNA Methylation of Tumor Suppressor Genes in Clinical Remission Predicts the Relapse Risk in Acute Myeloid Leukemia

Shuchi Agrawal1, Matthias Unterberg1, Steffen Koschmieder1, Udo zur Stadt2, Uta Brunnberg1, Walter Verbeek3, Thomas Büchner1, Wolfgang E. Berdel1, Hubert Serve1 and Carsten Müller-Tidow1 1 Department of Medicine, Hematology and Oncology, University of Münster, Münster, Germany; 2 Department of Pediatric Hematology and Oncology, University Medical Center Hamburg Eppendorf, Hamburg, Germany; and 3 Department of Medicine, Maria-Hilf Kliniken, Mönchengladbach, Germany

Requests for reprints: Carsten Müller-Tidow and Hubert Serve, Department of Medicine A, Hematology and Oncology, University of Münster, Domagkstr. 3, 48129 Münster, Germany. Phone: 49-251-835-2995; Fax: 49-251-835-2673; E-mail: muellerc@uni-muenster.de.


Epigenetic changes play an important role in leukemia pathogenesis. DNA methylation is among the most common alterations in leukemia. The potential role of DNA methylation as a biomarker in leukemia is unknown. In addition, the lack of molecular markers precludes minimal residual disease (MRD) estimation for most patients with hematologic malignancies. We analyzed the potential of aberrant DNA promoter methylation as a biomarker for MRD in acute leukemias. Quantitative real-time PCR methods with bisulfite-modified DNA were established to quantify MRD based on estrogen receptor (ER) and/or p15INK4B methylation. Methylation analyses were done in >370 DNA specimens from 180 acute leukemia patients and controls. Methylation of ER and/or p15INK4B occurred frequently and specifically in acute leukemia but not in healthy controls or in nonmalignant hematologic diseases. Aberrant DNA methylation was detectable in >20% of leukemia patients during clinical remission. In pediatric acute lymphoblastic leukemia, methylation levels during clinical remission correlated closely with T-cell receptor/immunoglobulin MRD levels (r = +0.7, P < 0.01) and were associated with subsequent relapse. In acute myelogenous leukemia patients in clinical remission, increased methylation levels were associated with a high relapse risk and significantly reduced relapse-free survival (P = 0.003). Many patients with acute leukemia in clinical remission harbor increased levels of aberrant DNA methylation. Analysis of methylation MRD might be used as a novel biomarker for leukemia patients' relapse risk.

Data: Cancer Research 67, 1370-1377, February 1, 2007. doi: 10.1158/0008-5472.CAN-06-1681

The other mechanism of genes expression regulation

http://nobelprize.org/nobel_prizes/medicine/laureates/2006/press.html

Several other important findings were reported by plant researchers in the 1990s. Towards the end of the decade Fire and Mello shed light on the mechanism underlying this mysterious gene shut-down. The pair injected single-stranded sense RNA from a muscle gene into worms. Nothing happened, nor did anything happen when they instead injected antisense RNA from the same gene. But both sense and antisense RNA, administered together, made the worms begin to twitch. Antisense and sense RNA were forming double-stranded RNA (dsRNA) that intercepted translation of the muscle gene into protein.


Both in plants and animals, RNAi is a natural defence against invading genetic material, whether artificially introduced, as in the above experiments, or by nature in the form of viruses. In addition, this process is one of three key ways of silencing genes throughout development. Beyond the natural role of RNAi the technology has huge implications for medicine. Being able to target and silence faulty genes holds great promise for treating diseases with a genetic component. And without the worms and the petunia, we’d be none the wiser.

from http://epigenome.eu/en/1,38,0

General remarks on Epigenetics

http://www.sciencemag.org/feature/plus/sfg/resources/res_epigenetics.dtl

  • Complementary and alternative therapies
  • Specialties within oncology

Simple English

Oncology is the medical sub-speciality that deals with the study and treatment of cancer. A doctor that practices oncology is called an oncologist. The term originates from the Greek onkos (ονκος), meaning bulk, mass, or tumour; and the suffix -ology, meaning "study of."


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