Study: Multiple sclerosis may affect breast and colorectal cancer survival
People with multiple sclerosis (MS) have lower overall survival after a breast or colorectal cancer diagnosis compared to people diagnosed with these cancers who do not have multiple sclerosis. Survival differed by cancer type. (posted 12/10/21)
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Contents
At a glance | What does this mean for me? |
Study findings | In-depth |
Strengths and limitations | Questions for your doctor |
STUDIES AT A GLANCE
What are these studies about?
These studies are about whether overall survival and cancer-specific survival after a breast or colorectal cancer diagnosis are different in people with multiple sclerosis (MS) than in those without MS.
Why are these studies important?
Life expectancy for people living with MS has improved over time. However, on average, people with MS live 6-7 years less than the general population. Their most common cause of death is related to MS. However, depending on the study, cancer has been reported as the second or third most common cause of death in adults with MS. Does MS affect cancer outcomes? A better understanding of the impact of MS on cancer is needed to help patients and their healthcare providers make informed decisions about their treatment.
Breast Cancer Survival in Multiple Sclerosis
- Women with MS were more likely to die from any cause (other than cancer) after a breast cancer diagnosis compared to women without MS.
- The reason for this difference is unknown. Possible reasons may include disability in women with MS. For example, women who have more disability due to MS may face barriers to treatment, may receive less aggressive treatment or may be more susceptible to complications from treatment or other factors that decreased their overall survival. Another possibility is that breast cancer or treatment for it worsened MS.
- Women with MS were no more likely to die from breast cancer compared to women without MS.
Colorectal Cancer Survival in Multiple Sclerosis
- People with MS were more likely to die from any cause after a colorectal cancer diagnosis compared to people without MS but only in the first 6-12 months after that diagnosis.
- People with MS were more likely to die from colorectal cancer in the first 6 months after their cancer diagnosis.
- The reason for these differences is unknown. Possible reasons may include disability in people with MS. For example, people who have more MS-related disabilities may face barriers to treatment, may have received less aggressive treatment or may be more susceptible to complications from treatment or other factors that decreased their overall survival. Another possibility is that colon cancer or treatment for colon cancer worsened MS.
Strengths and limitations
Both studies were conducted by the same group of researchers. The study designs were identical.
Strengths
- The design of the studies was a strength. Cancer patients without MS were matched to cancer patients with MS by birth year, year of cancer diagnosis and where they lived. Four patients without MS were matched to each patient with MS. This ratio (four patients without MS compared to each patient with MS) strengthened results.
- The studies were done in Canada, a country with universal health care. This likely resulted in most patients being treated similarly.
Limitations
- The data that the researchers analyzed did not have information on race or ethnicity, factors that are known to be associated with breast and colon cancer outcomes. It is not known whether the impact of MS on cancer survival would be different in people of different racial or ethnic groups.
- On death certificates, the cause of death due to cancer did not show the type of cancer. The primary site of the cancer was not reported. Therefore, researchers may have underestimated the number of deaths that were specifically due to breast or colon cancer.
- The study did not include information about genetic testing results. It is not known whether the impact of MS on survival would be different in people with inherited mutations.
What does this mean for me?
Because people with MS who are diagnosed with either breast or colon cancer have lower overall survival than people with the same diagnoses who do not have MS. Patients with MS should have a clear understanding of their prognosis to guide their clinical decision-making. This will help them and their healthcare providers to not only determine the best treatments and timing, but to also balance the benefits of cancer treatment and related side effects relative to their life expectancy, quality of life and current health status.
If you have MS and have been diagnosed with breast or colon cancer, you should talk to your healthcare providers to develop a treatment plan that best meets your current health needs.
If you have MS, it’s important for you to know about and follow guidelines for cancer screening and prevention. If you are taking the drug ocrelizumab (Ocrevus) for MS, you should be aware that it carries a warning because it has been shown to slightly increase the risk of breast cancer.
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posted 12/10/21
References
Breast Cancer Survival in Multiple Sclerosis: A Matched Cohort Study. Neurology. 2021; 97(1). Published online May 19, 2021.
Marrie RA, Maxwell C, Mahar A, et, al. Colorectal Cancer Survival in Multiple Sclerosis: A Matched Cohort Study. Neurology. 2021; 97(14). Published online September 15, 2021.
Marrie RA, Maxwell C, Mahar A, et, al. Cancer Incidence and Mortality Rates in Multiple Sclerosis: A Matched Cohort Study. Neurology. 2021; 96(4). Published online November 5, 2020.
Disclosure
FORCE receives funding from industry sponsors, including companies that manufacture cancer drugs, tests and devices. All XRAYS articles are written independently of any sponsor and are reviewed by members of our Scientific Advisory Board prior to publication to assure scientific integrity.
Questions to ask your health care provider
- How will my cancer diagnosis impact my MS?
- How will my MS impact my cancer treatment?
- Should the treatment plan for my cancer be modified because I have MS?
- Do any of the medication(s) I take to treat MS increase my risk of cancer?
- How can I reduce my risk of cancer?
Who covered this study?
Everyday Health
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