If Cancer Cells Are Found Biology Essay

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If cancer cells are found in the tissue sample, the next step is to stage, or find out the extent of the disease. Various tests determine whether the cancer has spread and, if so, what parts of the body are affected. Because stomach cancer can spread to the liver, the pancreas, and other organs near the stomach as well as to the lungs, the doctor may order a CT scan, a PET scan, an endoscopic ultrasound exam, or other tests to check these areas. Blood tests for tumor markers, such as carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) may be ordered, as their levels correlate to extent of metastasis, especially to the liver, and the cure rate.

Staging may not be complete until after surgery. The surgeon removes nearby lymph nodes and possibly samples of tissue from other areas in the abdomen for examination by a pathologist.

The clinical stages of stomach cancer are:[19][20]

Stage 0. Limited to the inner lining of the stomach. Treatable by endoscopic mucosal resection when found very early (in routine screenings); otherwise by gastrectomy and lymphadenectomy without need for chemotherapy or radiation.

Stage I. Penetration to the second or third layers of the stomach (Stage 1A) or to the second layer and nearby lymph nodes (Stage 1B). Stage 1A is treated by surgery, including removal of the omentum. Stage 1B may be treated with chemotherapy (5-fluorouracil) and radiation therapy.

Stage II. Penetration to the second layer and more distant lymph nodes, or the third layer and only nearby lymph nodes, or all four layers but not the lymph nodes. Treated as for Stage I, sometimes with additional neoadjuvant chemotherapy.

Stage III. Penetration to the third layer and more distant lymph nodes, or penetration to the fourth layer and either nearby tissues or nearby or more distant lymph nodes. Treated as for Stage II; a cure is still possible in some cases.

Stage IV. Cancer has spread to nearby tissues and more distant lymph nodes, or has metastatized to other organs. A cure is very rarely possible at this stage. Some other techniques to prolong life or improve symptoms are used, including laser treatment, surgery, and/or stents to keep the digestive tract open, and chemotherapy by drugs such as 5-fluorouracil, cisplatin, epirubicin, etoposide,docetaxel, oxaliplatin,

CHAPTER THREE

IMAGING MODALITIES

3.1 Upper GI Series

Radiography has limited diagnostic value in the diagnosis of gastric cancer. Although it suggests a high sensitivity of x-rays (80-95%), there are limitations. Upper gastrointestinal series may show thickened or enlarged gastric folds, filling defects that correspond to a mass or ulcer, or may demonstrate a failure of the stomach to distend normally to air and instilled barium but do not aid in accurate disease staging and do not allow differentiation of benign from malignant lesions

3.2 Endoscopy

It provides the most specific and sensitive means of diagnosis of gastric cancers. Gastrointestinal endoscopy allows the physician to visualize and biopsy the mucosa of the esophagus, stomach, duodenum, and most of the jejunum.

During these procedures, the patient is situated in the left lateral position and may be administered a topical anesthetic to help prevent gagging. Pain medication and a sedative may also be administered prior to the procedure.

The endoscope (a thin, flexible, lighted tube) is passed through the mouth and pharynx and into the esophagus. It transmits an image of the esophagus, stomach, and duodenum to a monitor visible to the physician. Air may be introduced into the stomach through the scope to expand the folds of tissue and enhance examination (Figure 14).

More than 90% of gastric cancers are detected by upper endoscopy and biopsy. Endoscopy facilitates accurate visualization, histological confirmation and typing. Tumor staging, localization and extent of tumor, and associated local complications may also be established during the procedure (Figure 15).   

In cases of known gastric cancer, endoscopy is helpful to establish treatment goals (cure or palliation), TNM stage, and assessment of response to previous therapeutic approaches. Biopsy leads to correct diagnosis in virtually 100% of cases when at least 7 specimens are obtained. The increasing use of endoscopy has resulted in detection of "early gastric cancer", which is amenable to endoscopic therapy.

3.3 Computed Tomography(CT)

CT is used preoperatively primarily to determine the stage and extragastric spread of a gastric carcinoma. This information is vital in deciding between palliative surgery and curative radical surgery Additionally, CT is used to monitor a patient's response to treatment.

CT scans may show polypoidal mass with or without ulceration, focal wall thickening with mucosal irregularity or ulceration or infiltrative lesions, marked contrast enhancement, mucinous carcinomas, which have low attenuation due to their high mucin content and which may contain calcification.

CT scanning has several pitfalls: A pseudomass as a result of a normal gastroesophageal junction may be seen, underdistension of the stomach may simulate wall thickening, and T2 and T3 lesions may be difficult to distinguish. CT may fail to depict tiny omental and peritoneal deposits; small pelvic deposits may be overlooked as well.

3.4 Magnetic Resonance Imaging

MRI studies in which a breath-hold, fast-imaging technique and water were used showed accuracy rates comparable to those of helical, biphasic CT scanning. The fast-imaging technique was superior to CT in detecting serosal invasion.

In T staging, the accuracy of MRI is 73%, compared with 67% for CT. In N staging, the accuracy of MRI is 55%, compared with 59% for CT.

MRI is limited by the presence of respiratory and peristaltic artifacts, the lack of suitable oral contrast media, and a higher cost than that of CT scanning.

3.5 Ultrasonography

The primary role of transabdominal ultrasonography (US) is to detect liver metastases. CT scanning is used first to stage the gastric carcinoma; if no metastases and no invasion of local organs are found, US is used to refine the local stage. The depth of tumor invasion is not accurately assessed with CT, and the investigation of choice for this indication is EUS.[2]

Gastric carcinomas are occasionally identified during US of the upper abdomen.US has improved the accuracy of local staging of gastric carcinomas. Its role is to assess the depth of local invasion and the presence or absence of perigastric nodes. Unlike CT and MRI, US can depict individual layers of the gastric wall. Diagnostic accuracy, In the detection of liver metastases, sensitivities as high as 85% have been reported.

Overstaging is due to the peritumoral inflammatory response.

In T staging, EUS is 89-92% accurate, and CT is 43-65% accurate; however, the accuracy of CT increases with the use of the helical biphasic technique. In N staging, EUS is 60-85% accurate, and CT is 48-70% accurate. Inflammation may cause enlarged nodes. EUS has a high specificity (90%) but low sensitivity (53-80%) because it has a range of 5 cm from the gastric wall for nodes of normal size; thus, it does not permit assessment of the full extent of lymphadenopathy. Involved small nodes are not detected.

Intraoperative US and laparoscopy have an accuracy of 81% in T staging and an accuracy of 93% in N staging; however, the necessary equipment and expertise are not widely available.

3.6 Nuclear Imaging

Fluorodeoxyglucose (FDG) positron-emission tomography (PET) scanning may be useful in the staging and postoperative assessment of gastric carcinomas. FDG-PET depicts the primary tumor, but involved perigastric lymph nodes are not identified separately from the primary tumor. Thus, the role of PET scanning is limited in staging. The use of combined PET-CT scanning may improve diagnostic accuracy.

Indium-111 (111 In) - labeled monoclonal antibody has been used for intraoperative imaging to detect nodes, with an accuracy of 72%.

FDG-PET may be useful in evaluating patients with recurrent gastric cancer; findings can help to localize the disease when CT findings are not diagnostic. Imaging evaluation with PET may also impact the clinical management of patients with recurrent gastric cancer.

CHAPTER FOUR

IMAGE FEATURES OF PATHOLOGY

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Figure :This is a case of diffuse gastric adenocarcinoma (Lauren classification) presenting surgically as 'linitis plastica' (leather bottle stomach). Microscopic regional lymph node metastases were present.

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Figure :Endoscopic view of an ulcerating adenocarcinoma

irregular stenosis with rigidity of the greater curvature of the stomach at prepyloric gastric antrum

Figure Barium irregular stenosis with rigidity of the greater curvature of the stomach at prepyloric gastric antrum

C:\Users\User\Desktop\internet\Gastric carcinoma Radiology Case Radiopaedia.org_files\5cc80d5d4fbcd283844c8784f3912e_big_gallery.jpg

Figure Double contrast images from a barium meal study showing an advanced gastric malignancy involving the body of stomach.

C:\Users\User\Desktop\internet\Gastric adenocarcinoma Radiology Case Radiopaedia.org image_files\3db086d7a30cdca2b17b441c89a97a_big_gallery.jpg

Figure Large stomach adenocarcinoma, with heaped up edges and central ulceration, which is a feature of up to 70% of gastric adenocarcinomas.

http://www.hopkins-gi.org/Upload/200802291431_17542_000.jpg

Figure CT image showing gastric cancer

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Figure : Stomach wall thickening with loss of gut signature sign is noted along lesser curvature. Stomach wall thickening with loss of gut signature sign is noted along lesser curvature.

C:\Users\User\Desktop\internet\Gastric cancer Radiology Case Radiopaedia.org image_files\77015a432f84ff9f9afb9d3b348501_big_gallery.jpg

Figure : Abdomen CT demonstrates a subtle circumferential wall thickening involving the gastric cardia and gastroesophageal junction. High FDG uptake is noted at the gastric cardia confirm the presence of the tumour.

CHAPTER FIVE

DISCUSSION

CHAPTER SIX

TREATMENT/PROGNOSIS/CONCLUSION

6.1 Treatments

6.1.1 Surgery

Endoscopic mucosal resection is a treatment for early gastric cancer removing tumor in the mucosa together with the inner lining of stomach from the wall of stomach using an electrical wire loop through the endoscope. It is a much smaller operation than removing the stomach thus advantageous, pioneered in Japan and also available in the United States.

Endoscopic submucosal dissection is also pioneered in Japan by using similar technique, resecting a large area of mucosa in one piece. The patient would need a formal stomach resection if the pathologic examination of the resected specimen shows incomplete resection or deep invasion by tumor.( Internet ca 1)

Other than that, a radical subtotal gastrectomy is usually the initial treatment of choice. This procedure involves the surgical removal of a large part of the stomach. It is indicated for gastric ulcers, which have a significant predisposition for eventually developing into cancer. At the same time, the surgeon may remove the spleen and resect the associated lymph nodes. Reconstruction is accomplished by a gastrojejunostomy or gastroduodenostomy. The remaining part of the stomach is anastomosed onto that of the jejunum. One of the more common procedures is the Billroth I or Billroth II gastrojejunostomy. Surgical interventions are currently curative in less than 40% of cases, and, may be palliative in cases of metastasis. (PATHO FOR JXR,89

6.1.2 Chemotherapy

Chemotherapy has no firmly established standard of care in treating stomach cancer. Stomach cancer has not been particularly sensitive to chemotherapy drugs and usually it serves to palliatively decrease the tumor size, relieve symptoms of the disease and increase survival rate. Clinical researchers have discovered the advantages of undergoing chemotherapy prior surgery to shrink the tumor, or as adjuvant therapy post surgery to destroy remaining cancer cells. .( Internet ca 1) thus far, chemotherapy has been somewhat successful when administered postoperatively or in cases that are inoperable. (PATHO FOR JXR,89)

6.1.3 Radiation Therapy

The usage of high-energy rays to destroy cancerous cells and stop their growth is how radiation therapy works. It is generally in combination with surgery and chemotherapy or only being used with chemotherapy in cases where the individual is unable to undergo surgery. Radiation therapy may be used to relieve pain or blockage by shrinking the tumor for palliation of incurable disease. .( Internet ca 1) relieve pain As a rule, radiation therapy is not effective in the treatment of gastric carcinoma. The therapeutic radiation dose is quite high, the tolerance level would be reached very fast and the side effects would be significant. Carcinoma of the stomach recurs in 50% to 80% of persons who have had a previous gastrectomy. Radiation therapy is usually administered after the second resection. (PATHO FOR JXR,89)

Prognosis

Most stomach cancers are advanced when they are diagnosed. Only about 20 out of 100 people are able to have surgery to try to cure their cancer. In the UK, overall about 15 out of every 100 people diagnosed (15%) live for at least 5 years. About 11 out of every 100 people diagnosed (11%) live for at least 10 years. Younger people tend to have longer survival compared to older people. In people aged under 50, between 16 to 22 out of 100 (16 to 22%) will live for more than 5 years compared to 5 to 12 out of 100 (5 to 12%) in people over 70. Some American studies have also shown that Asian people have better survival after stomach cancer treatment than people from other ethnic groups.

Prognosis for the different stages of stomach cancer:

Stage one

For stage one stomach cancers, about 8 out of 10 people (80%) live for at least 5 years after they are diagnosed. Unfortunately, very few people are diagnosed this early - probably only about 1 in 100 cases of stomach cancer are stage 1.

Stage two

About 6 out of every 100 stomach cancers are stage two when they are diagnosed. With a stage 2 cancer, more than 5 out of 10 people diagnosed (56%) will live at least 5 years.

Stage three

Stage three stomach cancers are slightly more common still. About 1 in 7 people are stage 3 at diagnosis. As you might expect, the survival statistics fall with this more advanced stage of cancer. With stage 3A stomach cancer about a third of people (38%) live at least 5 years. With stage 3B about 1 in 6 people (15%) live for more than 5 years.

Stage four

Unfortunately, about 8 out of 10 (80%) people diagnosed with stomach cancer are stage four, meaning the cancer has already spread when they are diagnosed. Understandably, the survival statistics are lower than for stage 3 stomach cancers. Doctors generally think a patient is doing very well if they are still alive two years after being diagnosed with stomach cancer that has spread. Fewer than 1 in 20 people (5%) live for at least 5 years if they have stage 4 stomach cancer when they are diagnosed.

The prognosis of gastric carcinoma is related to the stage of the disease at the time of diagnosis and to the histologic grade of the carcinoma.[1]

Pathologic staging of these neoplasms is based on tumor stage, nodal stage, and metastasis stage (TNM). The stages are as follows:

The T stage, representing the extent of penetration through the gastric wall, is categorized as follows:

Tis - Carcinoma in situ, intraepithelial tumor

T1 - Tumor extension to submucosa

T2 - Tumor extension to the muscularis propria or subserosa

T3 - Tumor penetration of the serosa

T4 - Tumor invasion of the adjacent organs

The N stage, representing the number and site of draining lymph nodes involved, is categorized as follows:

N0 - No lymph nodes involved

N1 - Metastases in 1-6 regional lymph nodes

N2 - Metastases in 7-15 regional lymph nodes

N3 - Metastases in >15 regional lymph nodes

The M stage, representing the presence of metastases, is categorized as follows:

M0 - No distant metastases

M1 - Distant metastases

Table : Staging and 5-Year survival rates

Stage

TNM Stage

5-Year Survival

1

T1N0M0, T1N1M0, or T2N0M0

88%

2

T1N2M0, T2N1M0, or T3N0M0

65%

3a

T2N2M0, T3N1M0, or T4N0M0

35%

3b

T3N2M0

35%

4

T4N1-3M0, TxN3M0, or TxNxM1*

5%

*Tx indicates any T stage; Nx, any N stage.

 

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