CARCINOMA OF THE STOMACH OR GASTRIC CANCER
most of gastric cancer detected in the UK are advanced adenocarcinoma with an appalling overall 5- year survival rate 5-10%. in comparison , in japan , where the disease is commonest over 30%of all gastric cancers are detected early and overall 5- year survival rates exceed 50%.
Types of gastric cancer
It can be divided into intestinal and diffuse type these are recent classification . the intestinal type matches geographical area of increased incidence and is usually accompanied by an area of chronic gastritis . the diffuse type bears no such relationship
These included chronic gastritis , gastric ulcers and gastric polyps are lesions often considered precancerous
the gastric remnant following a partial gastroectomy for benign disease has an increased risk of developing gastric carcinoma .
auto immune gastritis (prenicious anaemia) is subject to dysplatic change which may then become neoplastic ,populations where gastric cancer is common has a high incidence of chronic gastritis , mucosal atrophy (atrophic gastritis )and subsequent intestinal metaplasia all of which are associated with HELICOBACTER PYLORI over 90%of carcinoma are found in areas of gastritis and 10%of patients with chronic gastritis develop a carcinoma .
gastric adenomatous polyps are considered premalignant and the larger the polyp the higher the incidence of malignancy change but any gastric ulcer should be biopsied
Presentation of gastric cancer
depend upon lesion site and disease advancement the disease is difficult to diagnosis early not only because of the diversity of its presentation but also because of time - lag between the commencement of the growth and the appearance of symptoms so presentation can be divided into
the new dyspepsia after 40 malignant dyspepsia is the main and commonest presentation of cancer stomach of old age more in males characterized by pain vomiting but not by periodicity pain and vomiting are continuous to be differentiated from peptic ulcer dyspepsia the pain is unrelieved by any drugs or vomiting the pain is unrelated to meals due to the fact that it is caused by actual infiltration of the nerve endings by tumour vomiting is always spontaneous and blood stained due to ulceration of the tumour and anorexia and loss of weight
incidious onset characterized by three A ,S Anaemia,Anorexia &Asthenia
The obstructive types
carcinoma of the cardia present with dysphagia carcinoma of the pylours with fullness belching and the vomiting and succussion splash or fistula into the colon
May be silent but give rise to features in other organs as obstructive jaundice due to liver metastases ascites peritoneal seedind or nodes at porta hepatis compressing the portal vein krukenberg,s tumour trousseau,s sign (phlebo- thrombosis of superficial veins of the leg ) or troisier sign (left supraclavicular lymph node enlargement virchow,s node)
The mainstay of diagnosis for early lesions is to perform an upper gastrointestinal endoscopy on all patients with a recent onset of dyspepsia or indigestion like pains all suspicious lesions and unusual areas of gastritis should be biopsied or undergo bruch cytology linitis plastica (leather bottle stomach )is suggested if the stomach fails to distend on insufflation. repeat biopsies at the same site (trench biopsy)may be required to reach the areas of submucosal infiltration that are typical for these carcinoma
Double contrast barium radiology
Is complementary to diagnosis a filling defect mucosal irregularity or stricture may be visualized and carman,s mensicus sign :cresenteric barium shadow around the elevated edge of the ulcer linitis plastica ;crumbled narrorwed rigid distorted stomach or large ulcer niche outside the ulcer bearing area
Should be done as 1- stool analysis where occult blood is always positive 2- blood examination for anaemia and it is type as prencious anaemia 3- gastric function test the majority have achlorhydria or hypoclorhydria other as adominal ultrasounf and CT scan
Staging ultrasound and CT scan
Allow visualization of distnat metastese in the liver and lungs which normally precludes surgery . endoscopic ultrasound should be perforemed for all patients in whom surgery is considered . the ultrasound probe is located of an end viewing endoscope and is passed like a normal gastroscope to the level of the tumour it generates a radial ultrosonic image thus allowing T and N staging permitting a much more accurate assessment of local operability .
allows exclusion of small peritoneal deposits or
mall metastases and allow cytology and biopsy of any suspicious lesions . enlarged lymph nodes can also be seen the lesser sac can sometimes be entered safely and any posterior extension into pancreas can be visualized . accurate staging of the disease helps prevent unnecessary laparotomy although the presence of involved nodes does not always preclude surgery
many patient who present with gastric cancer are malnourished if oral feeds can be tolerated and there is no obstruction the high calorie and protein supplemented liquid feeds can be given if oral feeding is not possible then a radiologically placed naso- jejunal tube may be useful in obstructed lesion TPN (total parenteral nutrition) can be used prior to surgery but this should be replaced by a jejunal feeding route created at surgery . in severely cachectic patients operation may need to be delayed to allow correction of profound nutritional disability
The D2 gastrectomy it is has been shown to increase survival in gastric patients . all the lymph node groups which drain the stomach are classified according to their site (supra ,infra pyloric, right ,left ,cardiac ,greater, lesser curve, and those groups along and at the origins of the arterial supply to the stomach . the primary tumour is documented in the upper middle or lower third of the stomach N1 nodes are situated within 3 cm of the primary N 2 nodes are all those mentioned above greater than 3 cm from the primary N2 nodes could all become N1 nodes if the tumour was sited in a different region D2 resection involves removing all the N1 and N1 and N2 nodes with a 5 cm clearance of the tumour the operative
mortality for D2 gastroectomy should not exceed 5%
anastmosis gastrointestinal continuity is restored after radical lower partial gastroectomy with a Roux- en - Y anastomosis . Bilroth1 gastroectomy is considered all advised because the anastomosis will be sited on the original tumour bed . continuity after total gastroectomy is established by Roux-en-Y loop . a naso-jejunal tube is placed allowing aspiration of the gastric remnant or oesophagus and enteral feeding by the jejunum . once contrast swallow shows integrity at 7 days oral feeding can be started
with better preoperative staging less palliative resection are now performed most patients particularly the elderly will not benefit from surgery if there is no chance of complete resection in younger patients with longer life expectancy resection may still be appropriate to debulk the disease prior to other palliative treatment if patients have gastric obstruction however a gastrojejjunostomy is indicated to divert the gastric contents directly into the jejunum