Gastric Carcinoma

Blood group A, not O was considered as the risk factor for Gastric carcinoma but blood group A is also not considered as risk factor according to standard books.

 About duodenal ulcers standard books writes “Although once considered a premalignant conditions, it is likely that older literatures was confounded by mistakenly labeling inadequately biopsied ulcers and healing ulcers as ‘benign’ when in fact they were malignant to begin with”.

Gastric cancers can grow to an extent to cause damage to cells producing intrinsic factors and hence vitamin B12 deficiency. Vitamin B12 deficiency may also occur in post gastrectomy patients of gastric carcinoma, autoimmune pernicious anemia predisposing to gastric cancer and atrophic gastritis.

Ans. is ‘a’ i.e. Incidence increasing world-wide 

“For unclear reason, the incidence and mortality rates for gastric cancer have decreased markedly during the past 65 years… Gastric cancer incidence has decreased worldwide but remains high in Japan, China, Chile and Ireland” – Harrison 16/e, p 524

Other options:

• Option b

Schwartz writes – “Several decades ago, the large majority of gastric cancers were in the distal stomach. Recently, there has been a proximal migration of tumors so that currently the distribution is closer to 40% distal, 30% middle and 30% proximal”.

• Option c

Surgery is the only curative treatment for gastric cancer. It is also the best mode of palliation

• Option d

Most important prognostic factors for gastric carcinoma are

1)       lymph node status

2)       depth of tumor invasion

Robbins 7/e, p 824 writes ‑

“The morphologic feature having the greatest impact on clinical outcome is the depth of invasion.”

Answer ‘b’ i.e. Invasion of mucosa and submucosa irrespective to lymph node spread. ; ‘c’ i.e. Radical gastrectomy preferred 

• As already explained before, Early gastric cancer is carcinoma limited to the mucosa and submucosa of the stomach regardless of the lymphnode status
• Radical subtotal gastrectomy is the standard operation for gastric cancers.
• Endoscopic Resection
• It has been demonstrated that some patients with early gastric cancer can be adequately treated by an endoscopic mucosal resection.
• Currently endoscopic mucosal resection is limited to :early gastric cancers, confined to mucosa, < 2 cm in size, with no node involvement

Ans is A (Haemetemesis present in majority of patients)

Option C

There is confusion about option C. It is not a completely true statement, but it’s not totally false either. See the explanation below:

D2 gastrectomy refers to the extent of lymphadenectomy done along with the gastrectomy.

Extended lymph node dissections for the treatment of gastric cancer have best been described by the Japanese, and subsequently the JCGC D categories are used to define the extent of lymphatic dissection performed. In the JCGC (Japanese classification of gastric cancer) system, lymph node basins are numbered and subsequently grouped according to the location of the primary. These are grouped into 3 levels: N1, N2 & N3. The nodal stations defined as level NI, N2, and N3 vary depending on the location of the tumor. In general, N1 nodes are within 3 cm of the tumor, N2 nodes are along the hepatic and splenic arteries, and N3 nodes are the most distant.

A D1 gastrectomy refers to the removal of NI lymph nodes, D2 gastrectomy to dissection of 1\11 and N2, and D3 resection to a D2 resection plus removal of para-aortic lymph nodes.

Ans. is ‘b’ i.e., ‘O’ blood group 

Ans. is ‘d’ i.e., None of the above 

Most appropriate surgery is -3 Radical subtotal gastroectomy

Ans. is ‘a’ i.e., Pernicious anaemia 

Answer is C (Gastric adenocarcinoma confined to mucosa and submucosa):

Early gastric carcinoma is defined as a lesion confined to the mucosa and submucosa regardless of the presence or absence of perigastric lymphnode metastasis

Answer is C (Involvement of mucosa, submucosa and muscularis)

Early gastric cancer:      Cancer limited to the mucosa and submucosa with or without lymph node involvement.

Late gastric cancer :       Cancer involving the muscularis.

Ans. is ‘d’ Activation of RAS

• In the course of multi-step stomach carcinogenesis, various genetic and epigenetic alterations of oncogenes, tumor-suppressor genes, DNA repair genes, cell cycle regulators and cell adhesion molecules are involved. Genetic alteration in gastric cancer include:
• Intestinal type gastric cancer: K-ras mutation, APC mutation, pS2 methylation, HMLH1 methylation, p I ema methylation, p 73 deletion and C-erb B-2 amplification.

1. Diffuse type gastric caner: CDH I gene (E-Cadherin) mutation, K-sam amplification.
2. For both type: Telomerase reduction (telomerase shortening), hTERT expression, genetic instability, overexpression of the cyclin E & CDC25B & E2F I genes,p53 mutations, reduced expression, CD44 aberrabont transcripts, and amplification of the C-met Cyclin E genes.

Coming to question:

• All the given four genetic alterations may be associated with stomach cancer.
• However among the given options K-ras is best answer as it is associated with gastric cancer in minimum percentage (amongst given options):

Source: Textbook of mechanism of carcinogenesis and cancer prevention