Lymphedema is a chronic swelling condition that can arise from the damage or removal of lymph vessels and lymph nodes during cancer therapy. Being one of the most common and significant side-effects of breast cancer treatment, awareness of breast cancer related lymphedema is growing amongst health care practitioners and cancer patients alike. With expanding awareness, there is a growing need to better define and describe patient risk.
The incidence of developing breast cancer related lymphedema is commonly reported at around 30-40%, but the various clinical studies on the topic actually report a wide range of rates, from less than 5% to as high as 65%. So why the disparity in incident rates, and how can you get a measure of your own personal risk?
Defining the risk of lymphedema on a patient-by-patient basis is obviously very difficulty. There are a myriad of factors that will influence your personal risk, including general health and fitness, weight, and preventative behaviours. However, something can be learned about your own risk of lymphedema by examining the risk of breast cancer related lymphedema broken down by medical procedure:
Table 1 summarizes the reported rates of breast cancer related lymphedema for common cancer treatments, according to the various studies published on the topic to date (Shah, C., Arthur, D., et al. Breast-cancer related lymphedema: a review of procedure-specific incidence rates, clinical assessment AIDS, treatment paradigms, and risk reduction. Breast J. 2012 Jul-Aug;18(4):357-61.). As can be seen in the table, the incidence of lymphedema can vary greatly by procedure. Not surprisingly, risk generally increases with the aggressiveness of the cancer therapy received. (Additional abbreviations in the table: BCRL: Breast Cancer Related Lymphedema; PMRT: Post Mastectomy Radiation Therapy.)
The large variability in rates reported for an individual procedure is likely the result of differences in study design, such as length of follow-up and method of detection of lymphedema. Variables including the presence of tumour positive nodes, the use of chemotherapy, and other patient characteristics (such as increased body mass index) can have a significant effect on incidence rate as well.
There is an important message to take away from this. While you may fall into a category of lesser or greater risk, your personal chance of developing lymphedema is determined by a wide range of factors. These include not only the details of your particular treatment (the quality of which continues to improve as medical knowledge advances), but also modifiable factors such as body weight, general health and fitness, and preventative measures.
Indeed, since first writing this post we have see a blossom of research on lymphedema risk factors. While the significance of these risk factors to your personal risk of lymphedema remains to be clarified, understanding these risks are instructive for patients and health practitioners estimating relative risk, and exploring ways to reduce it. Please check out our more recent posts on genetic predisposition to secondary lymphedema, chemotherapy as a risk factor for lymphedema, and lymphedema caused by obesity.