Background: As the population survives to older ages and with the growing success of early detection and treatment of cancer, many survivors tend to develop second primary cancers. Most occur at random, reflecting general population cancer incidence rates; oftentimes, two specific cancers may cooccur with increased probability. Hypothesis: Gastrointestinal cancers tend to co-occur at increased rates. Results: Esophageal cancer tends to co-occur with other tobacco-related cancers. Radiation therapy (RT) for breast cancer may increase the risk of esophageal cancer. Small and large bowel adenocarcinomas tend to co-occur at increased rates, suggesting that they share similar risk factors. Pancreatic cancer is difficult to assess, but has been linked to other tobacco-related cancers. There are no obvious patterns involving gastric cancer. Conclusions: Aside from etiologic clues provided by these sorts of analyses, the study of second malignancies can also be of clinical significance, suggesting the appropriate surveillance and screening strategies to use in cancer survivors.
- Gastrointestinal tract
- Secondary malignancies