1. Gastric Carcinoma

2. Incidence/Prevalence
Adenocarcinoma - 90%
intestinal (decreasing trend)
diffuse (increase trend)
Non-Hodgkin's lymphoma - 6%
GIST
Carcinoid
Squamous cell Ca

3. Incidence/Prevalence
3rd most common GI malignancy (after colorectal and pancreatic)
Second causes of death from cancer
lung (17.8 %), gastric (10.4 %), and liver (8.8 %)
The worldwide incidence of gastric cancer has declined rapidly over the recent few decades
Part of the decline may be due to the recognition of certain risk factors such as H. pylori and other dietary and environmental risks
Despite the decline, the absolute number of new cases per year is increasing

4. GEOGRAPHICAL VARIATION
The incidence of gastric cancer varies with different geographic regions.
Approximately 60 percent of gastric cancers occur in developing countries
The highest incidence rates are in Eastern Asia, the Andean regions of South America, and Eastern Europe
Japan & S. America  75 & 150 / 100,000
US & W.Europe  8 & 15 / 100,000

5. Incidence/Prevalence
Early Gastric Carcinoma
Japan  40 %
United States  %

6. Incidence/Prevalence
Slowly developing
Usually discovered in advanced stages
Men>Women
Occurs between the ages of 50-70

7. ENVIRONMENTAL RISK FACTORS
 Emigrants from high-incidence to low-incidence countries often experience a decreased risk of developing gastric carcinoma.
Diet 
Foods such as pickled vegetables, salted fish and meat, smoked foods and salt
Salt — High salt intake damages stomach mucosa and increases the susceptibility to carcinogenesis in rodents
Dietary nitrates (bacteria in stomach breaks down nitrites to compounds that are carcinogenic in animals)

8. ENVIRONMENTAL RISK FACTORS
People who smoke cigarettes or use alcohol are 1.5 times more likely
Socioeconomic status 
-The risk of distal gastric cancer is increased by approximately twofold in populations with low socioeconomic status
- By contrast, proximal gastric cancers have been associated with higher socioeconomic class

9. ENVIRONMENTAL RISK FACTORS
H. pylori: Important in the etiology of peptic ulcers and gastric cancer
Found in 60 percent of gastric carcinomas
Gastric surgery 
increased risk of gastric cancer after gastric surgery Billroth II procedure , with the risk being greatest 15 to 20 years after surgery

10. RISK FACTORS Gastric polyps Gastric ulcer Genetic factors include:
First degree relatives
Type A blood
Pernicious anemia

11. Anatomy of Stomach
Cardia
Pylorus
Body
Antrum

12. Stomach-normal histology
Parietal cells - in body produce HCl
Chief cells - in body - pepsinogen
Mucous cells - all over - mucus
G cells-in antrum - gastrin

13. Anatomy of the stomach

14. Location 37% in the proximal third of the stomach
30% in the distal stomach
20% in the midsection
Remaining 13% in the entire stomach

15. Gastric Carcinoma Lauren Classification
There are two main histologic variants of gastric adenocarcinoma.
The most frequent is the "intestinal type", so called because of its morphologic similarity to adenocarcinomas arising in the intestinal tract.
The less common diffuse type gastric cancers

16. Gastric Carcinoma Lauren Classification
Intestinal
patients greater than 50, male>female
arises from metaplastic glands in chronic gastritis; associated with H. pylori
incidence decreasing in USA
Diffuse (signet ring cell, linitis plastica)
younger patients, no gender preference
not associate with H. pylori
incidence increasing

17. Intestinal type
One model for the "intestinal type" of gastric cancer describes a progression from chronic gastritis to chronic atrophic gastritis, to intestinal metaplasia, dysplasia, and eventually to adenocarcinoma

18. Morphologic types of Carcinoma Stomach
Fungating
Ulcerating
Diffuse

19. Ulcerated gastric adenocarcinoma

20. Thickened “linitis plastica”
type adenocarcinoma infiltrating gastric wall

21. Physical Assessment Early gastric cancer
Abdominal discomfort initially relieved with antacids
Feeling of fullness
Epigastric, back, or retrosternal pain
NOTE: most people will show no clinical manifestations

22. Symptoms of Gastric Disorders
Heartburn
Epigastric pain
Dyspepsia (upset stomach)
Vomiting
Hematemesis
Frequently “coffee-ground” emesis
Melena

23. Physical Assessment Advanced stage: Nausea/vomiting
Obstructive symptoms
Iron deficiency/anemia
Palpable epigastric mass
Enlarged lymph nodes
Weakness/fatigue
Progressive weight loss

24. DIAGNOSIS Esophagogastroduodenoscopy - Polypoid mass - Ulcer crater
- Thickened fibrotic gastric wall

25. Preoperative evaluation
Abdominopelvic CT scan 
Endoscopic ultrasonography 
Chest CT
For patients with a proximal gastric cancer
PET scan
Sensitivity of PET scans for the detection of peritoneal carcinomatosis is only about 50 percent.
 Staging laparoscopy 
Between 20 and 30 % of patients who have disease that is beyond T1 stage on EUS will be found to have peritoneal metastases despite having a negative CT scan

26. Gastric carcinoma Tumor Node Metastasis
T1 invades lamina propria or submucosa
N0 no mets in LN
M0 no distant mets
T2 invades muscularis propria or subserosa
N1 mets in perigastric LN
1-6 LN
M1 Distant mets
T3 penetrates serosa
N2 mets in perigastric LN
7 – 15 LN
T4 invades adjacent organs
N3 mts to > 15 LN

27. STAGE GROUPING Stage 0 Tis N0 M0 Stage 1A T1 Stage IB N1 T2a/b
Stage II N2 T3
Stage IIIA T4
Stage IIIB
Stage IV
N1–3
T1–3 N3
Any T
Any N M1
From AJCC Cancer Staging Manual, 6th ed. New York, Springer-Verlag, 2001.

28. Spread of Gastric Ca
Spreads through stomach into the gastric wall to the
Lymph nodes
Pancreas
Transverse colon
Omentum
Through portal vein into
Liver
Through systemic circulation into
lungs, and bone
Peritoneum
Ovaries
Pelvic cul-de-sac
Distant Lymph nodes

29. Spread of Gastric Ca

30. Clinical Presentation
Physical signs – advanced or mts
Palpable abdominal mass
Palpable supraclavicular (Virchow’s) LN
Palpable periumbilical (Sister Mary Joseph’s) LN
Peritoneal mets palpable by rectal exam (Blumer’s shelf)
Palpable ovarian mass (Krukenberg’s tumor)
Hepatomegaly

31. Surgical Treatment Absence of distant mts
Patient with distant mts but with complicated tumor
Line of resection at least 6 cm from the tumor mass to decrease recurrence at anastomosis

32. Carcinoma of Stomach Surgical options Total gastrectomy
Proximal tumours
Mid-body tumours
Subtotal gastrectomy
Distal tumours
Omentectomy

33. Distal Tumors Account for ~ 35 % of all gastric cancers
No 5-year survival difference b/n subtotal vs total gastrectomy
Subtotal appropriate if negative margins
Recurrence vs nonrecurrence depends on margin of 3.5 cm vs 6.5 cm
margins 4 – 6 cm  10% involvement
margins 2 cm  30 %

34. Cardia / proximal ~ 35-50% of gastric adenocarcinomas Proximal
Proximal Tumors
Cardia / proximal ~ 35-50% of gastric adenocarcinomas
Proximal
More advanced at presentation
Curative resection is rare
Total gastrectomy

36. Palliation 20 – 30% of gastric cancer presents as stage IV disease
Surgical palliation
Percutaneous, endoscopic, radiotherapuetic techniques
Nonoperative tx
Laser recanalization, endoscopic dilatation (+/- stent)

37. Carcinoma of Stomach Surgical treatment
Overall 5 year survival rate 10 – 21% in western series
Japanese series 50%
Adjuvant therapy (postoperative)
Neoadjuvant therapy (preoperative)
Response rates vary from 21 –31% clinical response rate to complete response rate of 0-15%

38. Adjuvant Therapy Southwest Cancer Oncology Group trial
5-FU, Leucovorin w/ chemorad for R0
3 yr survival 41%
Chem/Rad 3 yr survival 50%
28% benefit in survival

39. Gastric Carcinoma - Natural History
2/3 of patients have locally advanced or metastatic disease at diagnosis
50% recurrence following curative surgery
Adjuvant Chemo + R/T improves survival

40. Recurrence After gastrectomy quite high 40 – 80 %
Most occur w/in first 3 years
Locoregional failure 38 – 45%
Anastomosis, gastric bed and regional nodes
Peritoneal dissemination – 54%
Annual endoscopy for subtotal gastrectomy

41. Gastric Carcinoma Prognosis invasion is most important factor
early: limited to mucosa and submucosa; 90-95% survival at 5 years
late: beyond submucosa; less than % survival at 5 years
Five-year survival
95 % for patients with superficial T1 tumors and negative lymph nodes (stage IA disease)
7 - 8 % for patients with N3 nodes or any distant metastases
LN Dissection