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Gastric Cancer
Matt White
AM Report
April 19, 2010
Objectives
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Epidemiology
Clinical Presentation
Diagnosis
Staging
Treatment
Screening
Objectives
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Epidemiology
Clinical Presentation
Diagnosis
Staging
Treatment
Screening
Epidemiology
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Incidence: 21,260 cases in 2007
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~7 per 100,000
11,210 cancer deaths in 2007
Mortality significantly decreased in past 75
years (unknown reasons)
Gastric tumors
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85% adenoocarcinomas
15% lymphomas and gastrointestinal stromal
tumors (GIST)
Adenocarcinoma Cancer types
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“Intestinal type” (more common)
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Morphologically similar to intestinal
adenocarcinomas.
Diffuse-type
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Lack of intercellular adhesions (germline mutation
in protein E-cadherin)
Spectrum of gastric cancer
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Proposed progression:
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chronic gastritis -->
– chronic atrophic gastritis -->
 intestinal metaplasia -->
– dysplasia -->
 adenocarcinoma
Risk Factors for gastric cancer
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Diet
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Obesity
Smoking (HR 2-3)
? Alcohol
H. Pylori
Low socioeconomic status
Hereditary diffuse gastric cancer
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nitroso compounds
low fruit/vegetable, high fried foods/processed meat
High salt intake
40-67% lifetime risk for men, 60-83% for women
Immigrants from endemic areas
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maintain native country risk, risk to offspring similar to new homeland
Objectives
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Epidemiology
Clinical Presentation
Diagnosis
Staging
Treatment
Screening
Presentation
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Approximately 50% of cases present with
symptoms and have disease extending
beyond locoregional confines
Of locoregional cases, only ½ can undergo a
potentially curative resection
Symptoms at presentation
Symptoms (cont’d)
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Dysphagia: more common with proximal
gastric tumors
Occult GI bleeding very common, overt
bleeding <20%.
Less Common Symptoms
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Pseudoachalasia: if Auerbach’s plexus
involved
Colonic obstruction: if cancer spreads (direct
extension) to colonic wall
Signs
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Palpable abdominal mass: most common
physical finding
If cancer spreads via lymphatics…
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Left supraclavicular node (Virchow’s)
Periumbilical node (Sister Mary Joseph)
Left axillary node (Irish)
Enlarged ovary (Krukenberg's tumor)
Ascites
Objectives
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Epidemiology
Clinical Presentation
Diagnosis
Staging
Treatment
Screening
Diagnosis
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EGD
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Gold standard
Single biopsy from ulcer -> sensitivity ~ 70%
Seven biopsies from ulcer -> sensitivity >98%
Brush cytology increases sensitivity of single
biopsies, aid in multiple biopsies unclear
Barium studies
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False negative in as many as 50% of cases
Sensitivity as low as 14% in early cases
May be superior to EGD for linitis plastica
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EGD may be normal while “leather-bottle” will be
apparent on radiograph
Linitis Plastica
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Diffuse-type gastric cancer
Tumor often infiltrates the submucosa and
muscularis propria
Superficial biopsies may be falsely negative
Combination of strip and bite biopsy needed
if suspicious for linitis plastica
Linitis Plastica, “leather bottle stomach”
Objectives
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Epidemiology
Clinical Presentation
Diagnosis
Staging
Treatment
Screening
Staging of Gastric Cancer
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Two systems:
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Japanese classification (more elaborate and
anatomic based)
Western: developed by American Joint Committee
on Cancer (AJCC) and International Union Against
Cancer (UICC) -- more widely used
Tumors at GE junction of in cardia of stomach
within 5cm of GE junction
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Classified using esophageal staging
Other caveats
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T stage: dependent on depth of tumor
invasion NOT size of lesion
Nodal stage: based on # of positive LN rather
than location of LNs (proximity to tumor)
Staging workup
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Biopsy
Imaging
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CT: evaluates for metastases (M stage)
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20-30% with negative CT have intraperitoneal disease at
laparatomy
Accuracy of 50-70% for T stage
Slightly worse accuracy for N stage compared to EUS
EUS: most reliable nonsurgical method to evaluate
depth of invasion
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More accurate than CT for T stage
65-90% accurate for N stage
Staging workup
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PET
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More sensitive than CT for detection of distant
metastases.
Also useful for detecting LNs
Negative PET not helpful- even large tumors can
be falsely negative if metabolic activity low.
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Most diffuse gastric cancers (signet ring) are not FDG
avid
Staging workup
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Serologic markers
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CEA, CA-125, CA 19-9, CA 72-4 may be elevated
but have low sensitivity/specificity
None are diagnostic
Preoperative elevation in markers usually
pretends high risk of adverse outcome
No serologic finding should exclude surgical
consideration
AJCC Staging System
AJCC Staging System
Objectives
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Epidemiology
Clinical Presentation
Diagnosis
Staging
Treatment
Screening
Treatment
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Locoregional (stage I-III) disease
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Potentially curable
Refer for multidisciplinary evaluation and
consideration of surgery
Advanced (stage IV) disease
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Palliative therapy
Studies indicate longer survival and better quality
of life with systemic treatment
Treatment
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Complete surgical resection with removal of
LNs (only chance of cure)
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Possible in < 1/3 of cases
Subtotal gastrectomy for distal carcinomas,
total or near-total for proximal masses
Reduction of tumor bulk (palliative)
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Chemotherapy (cisplatin + 5-FU or irinotecan)
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Partial response in 30-50% of patients
Radiation (for pain control, no mortality benefit with
XRT alone)
Data from SEER. Patients diagnosed from 1991-2000 (n=14,097). Stage IA
(n=1194), stage IB (n=655), stage IIA (n=1161) stage IIB (n=1195), stage IIIA
(n=1031), stage IIIB (n=1660), stage IIIC (n=1053), stage IV (n=6148).
Prognosis
Stage
0
IA
IB
TNM
IIIA
IIIB
IV
Features
% 5-year
survival*
TisN0M0
Node negative; limited to mucosa
1
90
T1N0M0
Node negative; invasion of lamina propria or
submucosa
7
59
T2N0M0
Node negative; invasion of muscularis
propria
10
44
T2N1M0
Node positive; invasion beyond mucosa but
within wall
17
29
T3N0M0
Node negative; extension through wall
T2N2M0
T3N1-2M0
Node positive; invasion of muscularis propria
or through wall
21
15
T4N0-1M0
Node negative; adherence to surrounding
tissue
14
9
T4N2M0
Node negative; adherence to surrounding
tissue
30
3
Any M1
Distant Metastases
T1N2M0
II
% of
Cases*
** Data from American Cancer Society
Objectives
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Epidemiology
Clinical Presentation
Diagnosis
Staging
Treatment
Screening/Follow-up
Screening
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Currently screening programs in Japan, Venezuela,
Chile due to high incidence
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Mostly barium studies, EGD is concerning findings
Some use serum pepsinogen testing for high risk with EGD
confirmation
H. pylori: sensitivity 88%, specificity 41% (Japan)
Japan study: 5-year survival 74-80 in screened group, 4656% for non-screened group.
Not cost effective in US due to relatively low
incidence (<10 per 100,000)
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Preventing incidence of 1 gastric cancer death estimated to
cost $247,600
Gastric Ulcers
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25% of patient with gastric cancer have history of a
gastric ulcer
American Society of Gastrointestinal Endoscopy
recommendations:
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Follow-up EGD in 8-12 weeks to verify healing.
Non-healing ulcers need repeat biopsies
Question of cost-effectiveness of repeat
endoscopies; however, small (curable) lesions may
be missed without follow-up.
Take Home Points
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Most cases present in advanced stage
Staging workup (CT vs PET vs EUS) to
evaluate extent of disease
Staging laparoscopy indicated for medically
fit patients with >T1 lesion and without stage
IV disease
Ensure follow-up of ulcers seen on EGD
No effective screening in US patients
References
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Harrison’s Principles of Internal Medicine
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