Gastric Cancer Presentation

8/6/2019 Gastric Cancer Presentation

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Gastric Cancer


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Presentation 62 year old male who presented with epigastric pain

and weight loss.

EGD: 1.1cm ulcerative lesion in the distal stomach. EUS: Invasion to the muscularis.

Bx: adenocarcinoma.

CT A & P: primary not visualized; no evidence ofmets


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Presentation Patient underwent robotic assisted laparascopic distal

gastrectomy with gastrojejunostomy (billroth II) and

D2 lymph node dissection. Path: 0.7 cm focus of invasive adenocarcinoma with

minor component of signet ring extending throughthe muscularis (pT3). 0/19 LN positive (pN0).Margins negative. (gross resection margins 4/2cmproximal and distal respectively).

Final stage: pT3N0M0.


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Treatment Recommendations Postoperative chemoradiation

45Gy in 25 fractions to high risk areasgiven concurrently with 5-FU basedchemotherapy.


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Treatment Why postoperative chemoradiation?

Intergroup 0116

Randomized phase III trial enrolled patientswith T2+ or N+ disease observation vs.postoperative chemoradiation.

Results: Decreased LRF and increased survival

(MS= 35 vs. 26 months).


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Why not Magic Trial?

Technically, patient was eligible.

Favorable risk T2s may be treated with surgeryonly followed by observation (?).


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Radiation Technique Targets: gastric bed, anastamoses, residual

stomach, pancreatic head and 1stand 2nd

parts of duodenum. Not covering: lymph nodes.


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Background Epidemiology: 22710 new cases and 11780 deaths from gastric

cancer each year in the U.S.

Median age at diagnosis is 65.

Tumor location:

GE junction, cardia, and fundus-35% of cases (incidencerising)

Body-25%

Antrum and distal stomach-40% (incidence falling) Histology: 90% are adenocarcinoma.

Subtypes: Intestinal (older pts, less aggressive) and diffuse(yonger pts, more aggressive)


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Workup H&P

EGD with biopsy EUS

CT abdomen and pelvis

CXR (CT chest for GEJ tumor to rule outmediastinal LNs).

PET/CT: Being evaluated, but role stilluncertain.


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Staging T stage

T1a: lamina propria or muscularis mucosa

T1b: submucosa T2: muscularis propria T3: subserosa without involving visceral

peritoneum or adjacent structures T4a: Visceral peritoneum

T4b: adjacent structures N stage

N1: 1-2 regional nodes N2: 3-6 N3: 7 or more


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Surgery NCCN recommendation for surgery is a

sub-total gastrectomy with D2 lymphnode dissection.

Goals of surgery:

1. >-5 cm proximal/distal margin

2. >=15 LN sampled.


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Surgery Why >5cm gross surgical margins?

Annals 1980:

2 cm gross (-) margin30% microscopically

positive margin.

4-6 cm gross (-) margin10% microscopicallypositive margin.

6cm gross (-) margin0% microscopicallypositive

margin.


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Surgery Why 15 LN?

5-year Survival as a Function of Stage and #LNs

Examined. (Hundahl et al. Cancer 2000)LNsexam

1A 1B II

1 78% 58% 34%

2-6 75% 48% 26%

7-15 81% 60% 34%

>15 79% 68% 44%

>24 79% 68% 44%


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SurgeryD1:

1/2: paracardiac 3/4:

Lesser/Greater Curvature 5/6:

supra/infrapyloric

D2:

7: Left Gastric; 8: Common

Hepatic 9: Celiac 10: Splenic

hilus 11: Splenic

D3: 12: hepatoduodenal

ligament 13: 14: root of

mesentery


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Surgery D1 or D2 LND?

Controversial, but D2 dissection standardin Asia and recommended by NCCN.

At least one of the major path studies thatformed the basis for radiotherapy guidelineswas based on patterns of failure in patients

who had undergone D2 dissections.


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Radiation-Why? Intergroup 0116 demonstrated a survival benefit to

postoperative chemo-RT. Impetus for this trial were retrospective studies which

demonstrated a significant locoregional component to failure after

surgery.

Of note, approximately 20% of recurrences occurred inthe local regional area as the only site of initial failure.


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Risk of Local vs. Regional Failure as a function ofT and N stage. (Landry et al. 1990).

Increased risk of local failure with disease extendingbeyond the mucosa--20% overall (T3 and T4 disease>35%)

Increased risk of regional failure with nodal positivity.

Low rate of regional failure in node-negative patients evenwith advanced T-stage. ( 2/37 patients in Mass General

Series with T3 or T4 disease)


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Which Lymph Nodes?


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Putting it all together Classic guidelines consider 3 areas:

gastric bed, residual stomach, andlymph nodes.

For present case, plan was to treat gastricbed (including pancreatic head and 1stand

2nd

portion of duodenum) and residualstomach, but not the lymph nodes.


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Gastric Bed Why Gastric Bed?

Significant increase in local failure (>20%)

when disease has extended beyond themucosal layers.


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Gastric Bed Gastric bed usually refers to preop location of stomach + any

anastamoses. Guidelines will additionally specify a portion ofpancreas and/or duodenum to include in the gastric bed

based on location of primary.

Prox 1/3: tail of pancreas

Middle 1/3: body of pancreas

Distal 1/3: head of pancreas

and 1st and 2nd portion of

duodenum.


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Residual Stomach Included in present case. Why?

Surgical Margins


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Lymph Nodes Not covered. Why?

>15 LN sampled. All negative.

Operative series demonstrated low risk ofregional failure in node-negative patients whounderwent D2 dissection even with advancedT-stage disease.

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Gastric Cancer Presentation

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