Lymphedema is a chronic condition that emerges for many patients after they’ve undergone certain treatments for cancer. That’s because radiation and/or surgical removal of tissues (often including some or all lymph nodes) can have a damaging effect on the lymphatic system in the affected area.
Physical trauma is another potential trigger for lymphedema; perhaps subsequent to an accident, or following surgery for a non-cancer related reason. In certain parts of the developing world, infection with a parasite can trigger lymphedema (filariasis). In any event, these forms of lymphedema are called secondary lymphedema, as it occurs only after a precipitating event damages local lymphatic structures.
Although lymphedema symptoms can be managed, it remains incurable. For most sufferers, the goal is to manage their condition successfully. For some patients that can mean few, if any, symptoms. Unfortunately, lymphedema may strike at any time following a precipitating event. In some instances, it may manifest months or even years after successful treatments for cancer. No one knows for certain why lymphedema occasionally occurs so long after such treatments.
Not all cases of lymphedema are related to an identifiable precipitating cause. In fact, some sufferers are born with defects that immediately — or eventually — lead to lymphedema. This form of the condition, called primary lymphedema, is also known as hereditary lymphedema. People with this relatively rare form of the illness may be born with poorly or incompletely formed lymphatic structures. In some instances, primary lymphedema is related to other “malformative” diseases, such as Klinefelter, Turner or Noonan syndromes.
Although secondary lymphedema is more common, there are at least seven subtypes of primary lymphedema. They run the gamut from congenital hereditary lymphedema to lymphedema-distichiasis, lymphedema praecox (Meige disease), lymphedema tarda, and Nonne-Milroy disease, among others. Some of these hereditary forms may result in edema that develops almost immediately, while other forms may only manifest during puberty, or even later. Lymphedema tarda, for instance, is a form of hereditary lymphedema that typically manifests only after the age of 35.
For reasons that are unclear, females are more likely to suffer from primary lymphedema than males. In the general population, only about one in 6,000 people are born with primary lymphedema. The great majority of cases (about 80%) consist of hereditary lymphedema type II (Meige syndrome). This is a form that manifests during or after puberty. Although it typically affects the legs, other areas such as the arms or face may be involved although this may be another genetic cause for lymphedema.
Predetermined versus Predisposed
As we have seen, there are two main types of lymphedema: primary and secondary. Primary is related to heredity; a person is born with this defect. Secondary develops when otherwise healthy lymphatic structures are harmed by trauma, infection, surgery or radiation. The former is an example of a predetermined condition. Genetics cannot presently be changed; one is born with this condition. But what about predisposition? Can an otherwise healthy person be more predisposed to develop secondary lymphedema?
According to an article published in Lymphatic Research Biology, in 2012, there is some evidence that certain normal individuals possess certain genes that may predispose them to be susceptible to the development of secondary lymphedema following cancer-related treatments. Another article published that year in Clinical Cancer Research appeared to confirm this link between certain mutations and susceptibility to secondary lymphedema following breast cancer treatment. In the latter paper, the authors argued: “genetic susceptibility is an important risk factor for secondary lymphedema.” *
Although experts have not yet incorporated this finding into their approach to the treatment of breast cancer, the authors suggest that this new understanding of the role of genetics in susceptibility to secondary lymphedema indicates new approaches may be required to minimize the risk of the condition.
*Feingold DN, Baty CJ, et al. Connexin 47 mutations increase risk for secondary lymphedema following breast cancer treatment. Clin Cancer Res. 2012 Apr 15;18(8):2382-90.