Depending on their age, women diagnosed with uterine cancer may have a higher risk of developing colon cancer later on, according to a new study from Canada.
“As the survival has increased among cancer survivors, it’s important to know what the other problems they’re facing,” said Dr. Harminder Singh, the study’s lead author from the University of Manitoba in Winnipeg.
Cancer of the endometrium - the lining of the uterus - is the most common cancer of the female reproductive tract. The American Cancer Society estimates about 50,000 women will be diagnosed with the cancer in 2013 and about 8,000 will die from it.
Previous research looking at women’s risk for colon cancer following endometrial cancer produced mixed results. Also, no study looked at where in the colon those cancers showed up, which can help pick screening techniques.
For the new study, published in the Journal of Clinical Oncology, the researchers used data on 3,115 women diagnosed with endometrial cancer between 1987 and 2008 in the Canadian province of Manitoba.
The researchers then compared those participants to 15,084 women who were never diagnosed with cancer.
Using the women’s medical records, the researchers then saw how many were diagnosed with colon cancer by 2009.
Overall, about 1.9 percent of women with endometrial cancer went on to get colorectal cancer. That compared to 1.6 percent of women who never had endometrial cancer.
While that’s a small increase among women who already had cancer, it could have been due to chance, according to the researchers.
They did find, however, that seven women diagnosed with endometrial cancer before age 50 ended up with colon cancer during the study. Although a very small number, it works out to be about a four-fold increase over those who never had cancer.
The researchers also found those women and women diagnosed with endometrial cancer between age 50 and 65 years old were more likely to have cancer on the right side of their colons.
That finding, says Singh, suggests colonoscopy would be the preferred screening method in those women.
Dr. Noah Kauff, from the Memorial Sloan-Kettering Cancer Center in New York, told Reuters Health that the findings are consistent with previous research, but the increased risk may be - at least partially - due to women with a hereditary condition known as Lynch Syndrome.
Lynch Syndrome, according to Kauff, who was not involved in the new study, affects between one in 800 or 1,000 people and is known to put people at a higher risk for a number of cancers.
Previous research had found that women diagnosed with endometrial cancer and Lynch Syndrome were at an increased risk for colon cancer.
The new study’s researchers didn’t have data on how many women in their study had Lynch Syndrome, and can’t rule out the possibility that it explains the increase.
Another possible explanation, said Singh, is that estrogen affects the risk for both endometrial and colon cancers.
Singh and his colleagues suggest women diagnosed with endometrial cancer should consider getting a colonoscopy and being screened for Lynch Syndrome - especially younger women.
The National Comprehensive Cancer Network, which represents leading cancer treatment centers, suggests people with Lynch Syndrome get a colonoscopy every one to two years starting between ages 20 and 25 years old.
SOURCE: Journal of Clinical Oncology, online April 8, 2013
Risk of Colorectal Cancer After Diagnosis of Endometrial Cancer: A Population-Based Study
Methods A historical cohort study was performed by linking the Manitoba Cancer Registry and the Manitoba Health administrative databases. Each subject diagnosed with EC as her first cancer between 1987 and 2008 was age matched with up to five women with no history of invasive cancer on the index date (date of EC diagnosis). All subjects were followed up to the date of diagnosis of CRC or another cancer, death, migration, or study end point (December 31, 2009). Competing-risk proportional hazards models were used to compare the CRC incidence rates with adjustment for age, history of lower gastrointestinal endoscopy, and socioeconomic status. There were three mutually exclusive (and competing) outcomes: CRC, another primary cancer, and death.
Results A total of 3,115 women with EC and 15,084 without EC were followed up for a total of 145,502 person-years. Women diagnosed with EC at age ≤ 50 years had an increased risk of being diagnosed with CRC (all CRC: hazard ratio [HR] = 4.41; 95% CI, 1.47 to 13.26; right-sided CRC: HR = 7.48; 95% CI, 1.29 to 43.28). There was no increased risk of all CRC among women 51 to 65 years of age or those older than 65 years at the time of EC diagnosis. However, women 51 to 65 years of age at EC diagnosis had an increased risk of right-sided CRC (HR = 2.30; 95% CI, 1.05 to 5.01).
Conclusion This study suggests young women (age ≤ 50 years) with EC are at increased risk of CRC; risk of right-sided CRC is also increased in women 51 to 65 years old at EC diagnosis.
Piotr M. Czaykowski and
Salaheddin M. Mahmud