C-reactive protein (CRP) is a protein in the blood. CRP levels are a marker for inflammation; your body makes more CRP when there is inflammation or infection. Many doctors use CRP levels to estimate overall heart health and help figure out if you have atherosclerosis, a build-up of plaque on the walls of the arteries, which causes inflammation.
People diagnosed with early-stage breast cancer who have lumpectomy to remove the cancer usually have radiation therapy after surgery. Radiation therapy after lumpectomy lowers the risk of the cancer coming back (recurrence) and makes lumpectomy as effective as mastectomy. Radiation is also sometimes given after mastectomy, depending on the characteristics of the cancer.
A small study suggests that women with high CRP levels have a higher risk of severe skin side effects from radiation treatment for breast cancer.
The research was published online on July 10, 2018 by the Journal of Clinical Oncology. Read the abstract of “Association Between Inflammatory Biomarker C-Reactive Protein and Radiotherapy-Induced Early Adverse Skin Reactions in a Multiracial/Ethnic Breast Cancer Population.”
Known risk factors
Ongoing inflammation in the body can be caused by a number of things, including being overweight, smoking, allergies, and insulin resistance caused by diabetes. Based on an earlier pilot study, the researchers that did this study believe that inflammation may play a major role in the severity of skin side effects caused by radiation.
Skin reactions to radiation therapy vary. If you’re undergoing radiation, the first thing you’ll likely notice is a change in the color of your skin. If you have a light complexion, your skin will change from pinkish to red. If you have a dark complexion, the redness may be harder to see. But most women will have some skin soreness or dry skin. In some cases, it may look and feel like a sunburn. You’re more likely to have a more severe reaction if:
- you have a fair complexion and are susceptible to sunburn
- you have large breasts
- you’re overweight
- you’ve recently had chemotherapy
- you’re receiving radiation after mastectomy and the treatment is designed to give a high dose to the skin
How they did the study
This study included 1,000 women who had been diagnosed with stage 0 to stage IIIA breast cancer between October 2011 and June 2013. The women had already had surgery to remove the cancer and were scheduled to have radiation therapy.
The women completed a questionnaire that asked about their age and other demographic information, as well as their race, ethnicity, and smoking history. The researchers took a blood sample from each woman before she started radiation therapy and immediately after radiation therapy was completed.
The researchers used high-sensitivity CRP testing on the blood samples to determine the women’s CRP levels. High-sensitivity CRP testing is more accurate at measuring lower levels of CRP than traditional testing.
CRP tests, both traditional and high-sensitivity, are commonly available at most labs and can be ordered by your doctor.
The researchers also reviewed the women’s medical records to collect information on their weight, history of high blood pressure/diabetes, and breast cancer diagnosis.
The characteristics of the women:
- 623 were white
- 280 were black
- 64 were Asian/Pacific Islander
- 33 were of other races
- 241 were of Hispanic ethnicity
- 759 were not Hispanic
- 78% of the women were overweight or obese
- 47% had a history of high blood pressure
- 19% had a history of diabetes
Most of the women -- 91% -- had whole-breast radiation and 40% of the women had already been treated with chemotherapy:
- 86% of the women received radiation treatment on a traditional 6-week schedule
- 14% of the women received radiation on an accelerated 3-week schedule, which means they received a higher dose of radiation at each treatment, but had the same overall dose as women on the 6-week schedule
After radiation therapy was completed, the researchers also collected information on any severe skin effects (grade 3 or grade 4) the women had:
- 48% of the women on a traditional radiation schedule and 10% of the women on an accelerated schedule had grade 3 skin side effects
- 17% of women on a traditional schedule and 5% of women on an accelerated schedule had grade 4 skin side effects
The researchers found that CRP levels before and after radiation therapy varied by race, weight, history of diabetes, and history of high blood pressure:
- black women had the highest CRP levels and Asian/Pacific Islander women had the lowest
- women who were obese had CRP levels that were almost 4 times as high as women at a normal weight
- women who were overweight had CRP levels that were nearly twice as high as women at a normal rate
- women with a history of diabetes and/or high blood pressure had CRP levels that were higher than women who didn’t have a history of these conditions
All these differences were statistically significant, which means they were likely due to the differences in the women’s race, weight, and history of diabetes/high blood pressure rather than just because of chance.
The researchers then compared CRP levels and severe skin reactions in the women.
Main findings and take-away
Women with the highest CRP levels before radiation therapy had more than double the risk of severe skin side effects compared to women with the lowest CRP levels.
Because being overweight or obese also increases the risk of severe skin side effects from radiation therapy, the researchers adjusted for any influence weight may have had on the skin side effects and analyzed the data again. The found that women with higher than average CRP levels after radiation therapy continued to have a higher risk of severe skin side effects.
“While this study was small, it is interesting,” said Marisa Weiss, M.D., Breastcancer.org founder and chief medical officer. “The biggest risk for skin side effects is having skin rubbing on skin. Women who are overweight or obese have bigger skin folds. The best thing to do is to keep skin away from skin so there is no rubbing or friction. Especially where your arm presses against your armpit and the other portion of your breast, along the bottom crease of your breast, and along your cleavage.”
To avoid skin-on-skin contact:
- Try to keep your arm away from your body as much as you can. When you’re sitting or driving, keep a box with a pillow on it next to you so you can prop your arm up on it. When you’re walking or standing, keep your hand on your hip with your elbow out to the side. You can also wear a belt around your natural waist as a reminder -- when you’re walking or standing, keep your hand tucked in the belt.
- Instead of a bra, wear a t-shirt and tie the front of it into a ponytail and tuck the tail under your breast. If you’re not comfortable going braless, wear a supportive bra without an underwire or lace to keep your breasts separated and lifted. For more support and padding, you can roll up a sock and put that between your breast and the bra. Another option is to wear a tube top, but roll it up and wear it just under your breasts for support.
Some other tips to help prevent and manage radiation skin side effects are:
- Avoid using soaps, deodorants, lotions, or any product with fragrance or alcohol.
- Instead of deodorant, use cornstarch to keep your skin dry and reduce friction. Don’t use talc. You can put powder made from cornstarch into a single knee-high nylon or a thin sock and knot the top. Then gently tap the sock again your skin.
- At the beginning of treatment, moisturize your skin after each treatment with A&D, Eucerin, Aquaphor, Biafene, or Radiacare. You also can put it on at night. It’s a good idea to wear an old T-shirt to bed so the ointment doesn't get on your sheets.
For much, much more information on radiation and any side effects it may cause, visit the Breastcancer.org Radiation Therapy section.
To discuss the side effects of radiation treatment with others, join the Breastcancer.org Discussion Board forum Radiation Therapy - Before, During, and After.