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Does the Mini-Gastric Bypass Cause Cancer?A concern raised by some, is the potential association of the Billroth II (BII) type connection used in the Mini-Gastric Bypass with stomach (gastric) cancer. There are some medical studies that seem to raise concerns about the relation between the Billroth II type connection and gastric cancer. A careful review shows that this is not a reasonable concern. A good and very well-done study looking at this question was published in the New England Journal by Schafer et. al. In this study performed by the Mayo Clinic studied residents of Minnesota, who had surgery for ulcers between 1935 to 1959. These patients were followed for over 5,635 person-years. They found gastric cancer in only two of the patients in the surgical group, as compared with an expected rate of 3 people. That is, they found that the rate of gastric cancer in the surgery patients was actually lower than that seen in unoperated patients. Many other studies of Billroth II patients have found no evidence of an increased incidence of gastric cancer. In a recent study by Bassily the records of 569 patients who had a partial gastrectomy for ulcer disease were analyzed. Five hundred and seven patients (83.5%) had a Billroth II. They showed that "the risk of gastric cancer was not increased after Billroth II partial gastrectomy." In a study from Finland the risk of gastric cancer after gastric surgery for ulcer was reported. Six of the 285 patients developed gastric cancer after the operation. The risk of contracting gastric cancer in the rest of the population (individuals who had no operation) of equal size and age during a similar follow-up period was 8 cases. That is to say, the operated patients had a lower risk of gastric cancer than the nonoperated patients. This study, as well as many others, shows that the risk of gastric cancer does not significantly increase after partial gastrectomy for benign peptic ulcer. It is true that there are some studies that appear to show an increased risk of gastric stump cancer as compared to the general population. But these studies are seriously flawed. All of the studies that show slight increases in the rate of gastric cancer following Billroth II include patients that have had the surgery for ulcer disease. The problem with this kind of study design is the fact that gastric ulcer is associated with an increased risk of gastric cancer. For example, in a study by Molloy and Sonnenberg the association between ulcer and gastric cancer was demonstrated in patients from the US Department of Veterans Affairs. 3,078 subjects with gastric cancer were compared with a 89,082 people without gastric cancer. This study showed that gastric ulcer patients had an increased rate of gastric cancer (relative risk 1.53, note that this increased risk is similar in magnitude to the increased risk reported in the studies showing an increased risk of gastric cancer in Billroth II surgical patients.) Many other studies confirm these findings that ulcer patients have an increased risk of gastric cancer. In a study by Hansson published in the New England Journal of Medicine the risk of stomach cancer in 57,936 patients was analyzed. The rate of gastric cancer among patients with gastric ulcers was increased 1.8 times. Again, this value is very similar to that reported for the increase seen in some studies of post-gastrectomy patients. They concluded that gastric ulcer disease and gastric cancer have causative factors in common. Thus the studies that find small increased rates of gastric cancer in post gastrectomy patients may simply be identifying gastric ulcer patients that are prone to develop gastric cancer regardless of any surgery they may have had. The incidence of gastric cancer in the United States has decreased four-fold since 1930 to approximately 7 cases per 100,000 people. It is important to look at the actual size of the reported possible increased risk of stomach cancer in the series that appear to find an increased risk of stomach cancer in post gastrectomy patients. In other words, how much of an increased risk are we talking about and how does that compare to other factors involved in the development of gastric cancer. As described above the many studies find no increased risk of gastric cancer in Billroth II patients, but in the studies that do find an increase in risk, how much of an increase is seen and how does this compare to other factors involved in the development of gastric cancer? Analysis of these issues can put these studies reporting an increased risk of gastric cancer into proper perspective. What causes cancer of the stomach? No single cause for stomach cancer has been identified but a number of important risk factors are known. Diets rich in salted or smoked foods have been associated with increased cancer risk in many studies. Similarly, some foods contain nitrites and these chemicals can be converted to more harmful compounds (carcinogens) by bacteria in the stomach. Lack of vitamin C, fruit and vegetables may be important. Stomach cancer is more common in smokers and in those with heavy alcohol intake. Helicobacter Pylori In recent years studies have reported that infection with Helicobacter pylori (HP) can increase the risk of gastric cancer three to six fold. This data has come from large population studies comparing the rates of HP infection in patients with gastric cancer compared with patients who do not. It has been estimated that HP infection may actually be responsible for approximately 60% of all cases of stomach cancer. At present, there is no general recommendation that antibiotic therapy should be offered to people with the H. Pylori infection. Studies clearly show that H Pylori not gastrectomy appears to be the risk factor associated with gastric cancer and physicians who feel this is of concern can provide treatment to patients to eradicate H. Pylori. The risk of stomach cancer is also slightly higher in close relatives of patients with the disease. Hundreds of articles have looked at factors that affect the development of gastric cancer. These studies of stomach cancer indicate that salted, smoked, pickled, and preserved foods (rich in salt, nitrite, and preformed N-nitroso compounds) are associated with an increased risk of gastric cancer. There is good evidence that the high eating fresh fruit and raw vegetables and a high intake of antioxidants are associated with reduced risks of gastric cancer. Now with all of these factors know to affect the risk of gastric cancer, where is post-gastrectomy positioned as a risk factor? Extensive research shows that gastric cancer has an environmental cause, of which diet appears to be the most important component. Studies show that there is an approximately a threefold increased risk of gastric cancer for frequent consumption of fresh and processed meats (relative risk 3.1 and 3.2). Gastric cancer risk rises with increasing intake of smoked and pickled foods (relative risk 3.7.) All of these factors that increase the risk of gastric cancer are as much as twice as high as that seen with the studies showing an effect of gastrectomy on gastric cancer risk. Many studies also show a decreasing risk of stomach cancer with increasing frequency of vegetable consumption. Increased intake of citrus fruits (risk 0.47) and raw-green vegetables (risk 0.56) appear to be protective. Consumption of salty snacks more than twice per month has been associated with an 80 percent increased risk. These findings are consistent with many studies around the world that indicate important roles for salt, processed meats, and vegetable consumption in the risk of gastric cancer. There are dozens more articles like these but we can summarize these findings as follows:
It may also be of value to point out that thousands of general surgeons routinely perform the Billroth II anastomoses on a daily basis. Tens of thousands of patients undergo Billroth II type gastrojejunostomy on a yearly basis and there is no ground swell effort being generated against the risk of the Billroth II type anastomoses. The Causes of Stomach CancerFollowing are questions that will help you determine if you're at high risk for developing stomach cancer:
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