Editing Sarcoma (section)

==Diagnosis==
===Bone sarcomas===
{{Main|Bone sarcoma}}
Diagnosis of [[bone sarcoma]]s begins with a thorough history and physical examination which may reveal characteristic signs and symptoms (see Signs and Symptoms above).<ref name=":2" /> Laboratory studies are not particularly useful in diagnosis, although some bone sarcomas (such as osteosarcoma) may be associated with elevated [[alkaline phosphatase]] levels, while others (such as Ewing sarcoma) can be associated with elevated [[erythrocyte sedimentation rate]].<ref name=":3">{{Cite book|title=Dahlin's Bone Tumors| vauthors = Unni K |publisher=Lippincott Williams & Wilkins|year=2010|isbn=978-0-7817-6242-7|location=Philadelphia, PA|pages=1–8}}</ref> Importantly, however, none of these laboratory findings are specific to bone sarcomas, meaning that elevations in these lab values are associated with many other conditions as well as sarcoma, and thus cannot be relied upon to conclusively diagnose sarcoma.<ref name=":2" /> 

Imaging studies are critically important in diagnosis, and most clinicians will order a plain [[Radiography|radiograph]] (X-ray) initially.<ref name=":2" /> Other imaging studies commonly used in diagnosis include [[magnetic resonance imaging]] (MRI) studies and [[Bone scintigraphy|radioisotope bone scans]].<ref name=":3" /><ref name=":2" /> A [[CT scan]] is typically  not used in diagnosis of most types of bone sarcoma, although it is an important tool for staging (see below).<ref name=":2" /> Definitive diagnosis requires biopsy of the tumor and careful review of the biopsy specimen by an experienced pathologist.<ref name=":2" />

===Soft-tissue sarcomas===
{{Main|Soft-tissue sarcoma}}
Diagnosis of [[soft-tissue sarcoma]]s also begins with a thorough history and physical examination.<ref name=":2" /> Imaging studies can include either CT or MRI, although CT tends to be preferred for soft-tissue sarcomas located in the [[thorax]], [[abdomen]], or [[Retroperitoneal space|retroperitoneum]].<ref name=":2" /> [[Positron emission tomography]] (PET) also may be useful in diagnosis, although its most common use is for staging (see below).<ref name=":2" /> As with bone sarcomas, definitive diagnosis requires biopsy of the tumor with evaluation of histology by a trained pathologist.<ref name=":2" /><ref>{{Cite journal| vauthors = Rastogi S, Aggarwal A, Shishak S, Barwad A, Dhamija E, Pandey R, Mridha AR, Khan SA, Deo SS, Sharma MC |date=2019-08-09|title=Discordance of Histo-pathological Diagnosis of Patients with Soft Tissue Sarcoma Referred to Tertiary Care Center |url= http://waocp.com/journal/index.php/apjcc/article/view/274 |journal=  Asian Pacific Journal of Cancer Care|volume=4 |issue=4 |pages=119–123 |doi=10.31557/apjcc.2019.4.4.119-123 |doi-access=free }}</ref>

=== Staging ===
In general, [[cancer staging]] refers to how advanced a cancer is, and usually it is based upon factors such as tumor size and whether it has spread to other parts of the body.<ref name=":2" /><ref>{{Cite web|url=https://www.cancer.gov/about-cancer/diagnosis-staging/staging|title=Staging|date=2015-03-09|website=National Cancer Institute|language=en|access-date=2019-03-21}}</ref> Staging is important because the stage affects the [[prognosis]] (likely outcome), as well as the types of treatments that are likely to be effective against the cancer.<ref name=":1" /><ref name=":0" /> With sarcomas, staging requires a determination of whether the tumor has grown into surrounding tissues ("local invasion"), as well as imaging to determine whether it has spread (a process known as "[[metastasis]]") to lymph nodes (forming "nodal metastases") or to other tissues or organs in the body (forming "distant metastases").<ref name=":0" />

The most common imaging tools used for staging '''bone sarcomas''' are MRI or CT to evaluate the primary tumor, contrast-enhanced CT of the chest to evaluate whether the cancer has spread (i.e., metastasized) to the lungs, and radioisotope bone scan to evaluate whether the cancer has spread to other bones.<ref name=":0" /> Staging for '''soft-tissue sarcomas''' typically includes imaging of the primary tumor by MRI or CT to determine tumor size, as well as contrast-enhanced CT of the chest to evaluate for metastatic tumors in the lungs.<ref name=":0" />

===Grade===
Like some other cancers, sarcomas are assigned a [[Grading (tumors)|grade]] (low, intermediate, or high) based on the appearance of the tumor cells under a microscope.<ref name=":6">{{Cite web|url=https://www.cancer.gov/about-cancer/diagnosis-staging/prognosis/tumor-grade-fact-sheet|title=Tumor Grade|date=2013-05-09|website=National Cancer Institute|language=en|access-date=2019-03-21}}</ref> In general, grade refers to how aggressive the cancer is and how likely it is to spread to other parts of the body ("metastasize").<ref name=":6" /> Low-grade sarcomas have a better prognosis than higher-grade sarcomas, and are usually treated surgically, although sometimes radiation therapy or chemotherapy are used.<ref name=":2" /><ref name=":0" /> Intermediate- and high-grade sarcomas are more frequently treated with a combination of surgery, chemotherapy, or radiation therapy.<ref name=Buecker05>{{cite journal |vauthors=Buecker P |title=Sarcoma: A Diagnosis of Patience |journal=ESUN |volume=2 |issue=5 |year=2005 |url=http://sarcomahelp.org/articles/patience.html |access-date=2009-04-15 |archive-date=4 December 2020 |archive-url=https://web.archive.org/web/20201204224156/http://sarcomahelp.org/articles/patience.html |url-status=dead }}</ref> Since high-grade tumors are more likely to undergo metastasis (invasion and spread to locoregional and distant sites), they are treated more aggressively. The recognition that many sarcomas are sensitive to chemotherapy has dramatically improved the survival of patients. For example, in the era before chemotherapy, long-term survival for pediatric patients with localized osteosarcoma was only about 20%, but now has risen to 60–70%.<ref>{{cite journal | vauthors = Longhi A, Errani C, De Paolis M, Mercuri M, Bacci G | title = Primary bone osteosarcoma in the pediatric age: state of the art | journal = Cancer Treatment Reviews | volume = 32 | issue = 6 | pages = 423–436 | date = October 2006 | pmid = 16860938 | doi = 10.1016/j.ctrv.2006.05.005 }}</ref>