NOTES by dr Claudio Italiano
If you read this page because your occult blood test is positive, you should know that the injuries of the digestive tube are mainly due to ulcers and gastritis or diverticula which can bleed. However, it is necessary to proceed with further investigations and to exclude more serious injuries such as colon and stomach cancer, especially if the family of any close relative has been affected by these neoplasms.
It
is the most common neoplasm of developed countries and is responsible for about
10% of deaths due to malignancy. It manifests itself at all ages, but the sixth
and the seventh decade are more affected. It affects the two sexes almost with
the same frequency, but is more common in the male. In Italy in Italy 37,733 new
cases including 20,457 males and 17,276 women. He was responsible for 16,646
deaths; for 73% of cases the cancer occurred in the colon and 27% in the rectum.
With regard to age, in 3% of cases they were subjects with <49 aa; 50-29 aa 9%,
60-69 yy. 20%, 70-79 34%, 80 and + 33%.
No single cause has been identified but the research has led to important
acquisitions. The genetics of familial adenomatous polyposis (FAP) and
the knowledge of oncogeni and tumor suppression genes have made it possible to
understand that the p53 locus on chromosome 17 is abnormal in 70%
of cases. At least two chromosomal changes are present in most tumors.
Other conditions associated with the risk of colorectal neoplasia are:
Peutz-Jeghers syndrome, juvenile polyposis. Furthermore, the ambental
factors play their role; physical activity is important and causes cancer risk
reduction; nutrition is important in the prevention of rectum-colon cancer, and
must contain fibers, as confirmed by a European study (EPIC) where RR = 0.75; (diet).
For alcohol, only in large drinkers there is an incidence of cancer increased
from 1.41 to 1, but alcohol intake is> 30 g / day. Smoking is associated with
cancer risk increased at least twice (Giovannucci et al).
Regarding sex and hormones, it seems that women have a lower incidence of cancer, on the other hand, but it does not seem that hormonal therapies in the woman in menopause can play a role in this sense. On the other hand, an important role in the prevention of the case is given by the therapy with non-steroidal anti-inflammatory drugs, for example aspirin. According to a study by the American Cancer Society there is a 40% reduction in risk, and in a Swedish study of 37%; Crohn and RCU are pathologies with a high risk of cancer. Subjects with primary sclerosing cholangitis and familial rectal cancer may have a great risk of developing the tumor if they have an inflammatory bowel disease. The same applies to Acromegaly, which is associated with risk of carcinoma, RR = 2.04. Infection with papilloma virus in anal sexual intercourse is at risk of cancer. Approximately 2/3 of the neoplasms in western populations are located in the sigmo-rectum, the rest uniformly in the rest of the colon. The tumors propagate by local invasion, by remote dissemination through the blood and lymphatic vessels and / or directly into the peritoneal cavity. The organ struck par excellence by metastasis is the liver. The classification of Dukes, already proposed in 1932, has been modified and updated, but it is the most used system. The classification includes the division into moments A, B C1 and C2. In A the tumor is confined to the intestinal wall, in B it extends through the muscular, but does not involve the lymph nodes, in C1 it affects the proximal lymph nodes, in C2 also the distal ones.
The classic symptoms are given by the alteration of the alvo, on the left
constipation is prevalent, while the rectorrhagia or other forms of bleeding
with the emission of live blood, occur in the most distal ones; the proximal
ones have a late onset, sometimes even with anemia. Therefore, only looking for
occult blood in the stool can represent a valid screening of the population.
The diagnosis makes use of the physical examination that is usually normal,
except for the presence of anemia or a palpable abdominal mass; rectal
exploration and sigmoidoscopy are the examinations of choice, sometimes preceded
by the opaque dual-contrast enema, now less employed. In this case it is clear
from the plate reading the apple-like appearance, or the polypoid or plaque or
saddle lesion. At the time of diagnosis, the tumors are small, with margins
detected and rounded, or if they are large in the lumen (in the blind) and / or
can give stenosis to the sleeve.
The evidence that in the colon, flat lesions, or flat lesions of the mucosa are
much more frequent and fearful than previously thought because they represent
adenomas and depressed ones are advanced lesions, the fact that today it is
possible to evaluate the "pit pattern" ", ie it is possible to discern between
hyperplastic and adenomatous lesions that can degenerate into malignant, all
this has allowed the development of chromoendoscopy. Until now with traditional
endoscopy it has been possible to visualize only the mucosal surface of the
colon, and at low resolution, not being able to obtain information on the fine
structure or on the histological characteristics of the mucous layer and the
submucosa. The development of the magnification endoscope has made accurate the
evaluation of the mucosal surface. The fact is, however, that this technique
is
currently more widespread in the East, although it is rapidly spreading in
Western countries. With the recent introduction of these new technologies that
mainly exploit high resolution, "magnification" (ie the enlargement of new
endoscopes with more resolutive pixels, up to 850,000 against the 200,000 of old
endoscopes) and the interaction between some chemicals (or light) and tissues
will soon be able to make more targeted biopsies, increasing the diagnostic
efficiency of endoscopy. The term "chromoendoscopy" indicates the use of a
foreign substance to the surface of the gastrointestinal tract to improve the
visualization of one or more characteristics of the mucosa. The substances used
are chemical dyes that react with the elements present in the mucosa (vital dyes)
or that remain within small structures on the surface of the mucosa (contrast
dyes). The most commonly used vital dye in the colon is methylene blue, which is
absorbed by the cytosol of tissues such as the small intestine, the colonic
mucosa and the epithelia involved in intestinal metaplasia.
The vital staining technique is based on the principle that dysplasia and
cancer absorb lower methylene blue.
Indigo carmine is instead an example of contrast dye. The dye should be sprayed
onto the mucosa with a special catheter. At present the maximum magnification
capacity reached is 170x. With contrast coloring and magnification, the colonic
mucosa appears as a set of numerous dimples (pits) that actually correspond to
the openings of the Lieberkuhn crypts. These can be observed endoscopically only
with a magnifying instrument. The tiny grooves on the mucosal surface, the
smallest details that can be observed with a standard endoscope, circumscribe
areas containing 40 to 60 dimples. Numerous systems have been proposed for the
classification of the pit pattern. The best known classification recognizes six
types and was developed by Kudo. This classification is based on a close
correlation between the pit pattern, other endoscopic characteristics and the
histology of lesions. The same author, in a study published in 2001, obtained a
sensitivity of 93.8% and a specificity of 64.6% in differentiating lesions
containing or not adenocarcinoma.
This is the development of colorectal cancer without the adenoma-carcinoma sequence (type IIc lesion). Types of depressed colorectal cancer are often referred to Kudo's disease 15 years ago. They represent 2.3% of all colorectal carcinomas, and in any case among tumors with submucosal invasion, the percentage of the depressed type is 33%. If you then consider very small injuries, ie under 10 mm, then you can say that they are 66%. For the type III, IV and Vi pattners, endoscopic polypectomy is indicated as the first treatment and the histological investigation, which demonstrates invasion of the submucosa and of the muscular wall, lymph nodes and vessels, and is therefore an absolute indication to surgery (sm1-a, ly + or v + sm1c, sm3); if instead the lesion is simply limited to the mucosa or just extended to the submucosa, with lymph nodes and negative vessels, follow-up can be performed (sm1a-b, ly - and v-). The conventional endoscopy does not allow the identification of small polyps and, indeed, of depressed or flat cancer, but today we see more, thanks to chromoendoscopy, so that in 59-62% of cases vs 41-43% of traditional endoscopy we find depressed cancer, which accounts for as much as 23 and 30% of the total cases of cancerous lesions, as appears from a recent Swedish case study. The flat lesions are on average 16 mm but we are already talking about invasive cancer or lesions with a high degree of dysplasia, especially in the right colon (56% of cases vs 42% of polypoid lesions)
Other techniques under development.
CTC or TC colongrafia, that is a reconstruction of the virtual colonoscopy
elaborated by the PC after tac. It shows polyps of <6 mm with sensitivity of
88.7%, and specificity of 79.6%.
Already established technique that allows visualization of the 5 layers of the
colon wall, with visualization of the mucosal and submucosal invasion (T1), of
the musculated layer (T2), perirectal T3, and parenchymal T4. In addition, it
allows to visualize or not the lymph nodes (N1 or N0). If the lymph nodes are
not evident, that is they are isoecoic with the tissue context, there is no
evidence of their metastatisation.
Colon polyps can be neoplastic, inflammatory or hyperplastic, but also lipomas.
Amartomatous polyps are characteristic of juvenile polyposis and Peutz-Jeghers
syndrome. Inflammatory and hyperplastic polyps are found in inflammatory bowel
diseases.
Adenomatous polyps: they can cause haemorrhages and have neoplastic potential,
especially if they are teared to the villous aspect (frayed) or they are larger
than 2 cm. They must be removed as soon as they are identified during the
endoscopy. The tubular adenoma has dimensions of 15 mm and is pedunculated, the
villous adenoma is broad and sessile, ie without peduncle.
Adenomas have no
metaplastic potential until the dysplastic epithelium passes through the
muscularis mucosae towards the submucosa. In this case the terms of malign polyp
or carcinoma in the initial phase are used.
Hyperplastic or metaplastic polyps are often found, even multiple and even if
they are harmless, sometimes they hide the risk of adenomas in other sites.
The neoplasms of the stomach are in most cases malignant and represent 15% of all deaths from neoplasms; it is mostly about adenocarcinomas, while lymphomas, liposarcomas are a minority. Benign neoplasms are represented by polyps (adenomatosis, hyperplastic and hamartomas), leiomyomas and lipomas.
An endoscopic examination can save the life of the patient who complains of
dyspepsia: in fact in Japan the early gastric cancer, which represents an
initial neoplasm of ulcerated appearance (differential diagnosis with gastric
ulcer !!), is diagnosed in time; from us the diagnosis is unfortunately more
late.
The endoscopic picture of gastric cancer - we said - is that of a neoplastic
ulcer with detected margins, or of a benign ulcer or of a vegetative or nodular
tumor. Less common is the infiltrative type, known as plastic linite, in which
the neoplasm extends to the entire gastric wall.
Therefore gastric carcinoma is divided into:
-
the polypoid type
-
the diffused infiltrant type
-
The ulcerated type
From the histological point of view (of the tissues):
-gastric cancer may present an intestinal glandular pattern and the tumor has the
appearance of a vegetative and expansive mass in the lumen, this being the most
common form.
Gastric polyps can be considered precancerous high-risk lesions! The other
precancerous conditions are pernicious anemia, adenomatous polyps and intestinal
metaplasia and previous gastric surgery. Chronic gastritis associated with
H.pylori was also called into question. The importance of Barrett's esophagus in
the pathogenesis of adenocarcinoma of the gastroesophageal junction is
indisputable.
Gastric polyps are classified into the types:
-
hamartomatous
-
regenerative
-
hyperplastic
-
adenomas (the latter have malignant potential, with high risk when they are
multiple or when the diameter exceeds 2 cm).
Leiomyomas are the most common benign tumors of the stomach and autopsy studies
show that they are the most frequent tumors of the gastrointestinal tract. They
originate from the smooth musculature of the stomach; they are large,
pedunculated, with a polypoid appearance, ulcerated and bleeding; the problem is
to establish if there is any possible potential malignancy, which is sometimes
confirmed by the presence of metastases.
Gastric lymphomas that can be isolated or part of a disseminated process; has
been associated with AIDS and biopsy is essential for diagnosis.
Other gastric neoplasms, in metastatic lesions to pancreatic, ovarian or mammary
adenocarcinoma. Kaposi's sarcoma can rarely occur in patients with
gastric-related AIDS. In this case the appearance is pseudopolipoid, sessile,
detected, of an intense red color, which stands out on the salmon colored
mucosa.