This excludes recurrence of, or spread (metastasis) from, the original tumor.
The research team searched the Thames Cancer Registry database. This is one of the world's largest registries, covering a population of 14 million people in the South East of England and containing over 1.5 million cases of cancer.
Around 5% of the patients on the registry had been diagnosed with more than one cancer.
The researchers found over 127,000 patients who had been diagnosed with bowel cancer between 1961 and 1995, almost 66,000 of whom were women.
They then compared the numbers of new cancers developing after the original diagnosis with expected rates in the general population.
The results showed that the risk of developing cancer of the small intestine was higher in men diagnosed with bowel cancer before the age of 60, and more than twice as high in women after the age of 65.
Conversely, bowel cancer was more likely to develop in those whose first cancer had arisen in the small intestine.
Cancer of the eye was also significantly more common in men diagnosed with bowel cancer before the age of 60.
| Over 127,000 bowel cancer sufferers were studied.
Women whose first bowel cancer was diagnosed when they were under 65 were also significantly more likely to develop a new bowel cancer.
They were also at significantly increased risk of developing cervical, womb, and ovarian cancers.
However, the increased risk of ovarian cancer was confined to the first 5 years after a diagnosis of bowel cancer, raising the possibility of spread from the original tumor.
The authors suggest that hormonal factors may have a role, as previous research has indicated a tripling of risk in childless women with a family history of bowel cancer.
The authors conclude that genetic factors might partly explain the relatively high rates of cancers in those affected.