A new treatment for advanced melanoma can temporarily isolate the flow of blood to and from a limb, facilitating the use of strong localized chemotherapy. Melanoma is a soft tissue skin cancer that typically develops in areas of the body that are frequently exposed to the sun. It develops because of an uncontrolled growth in melanocytes, the pigment-producing cells that give your skin its unique coloring.
How frequently melanoma happens
Melanoma is the leading cause of death from skin cancer but represents fewer than 5% of skin cancer cases.1 According to the American Academy of Dermatology, melanoma is caused by long term exposure to ultraviolet (UV) light and can be largely prevented by taking protective precautions.
Melanoma rates are rising. Sun exposure, tanning beds, and insufficient use of sun protection, including hats, clothing, and sunscreen all contribute to the higher and younger incidence rates.
Some people are diagnosed with melanoma when it has already spread, also called metastatic. This can be a first-time diagnosis or a recurrence from a prior melanoma. Advanced melanoma can be difficult to treat effectively and is often fatal when left untreated. Once the cancer has begun to spread beyond the site of the original tumor, effective treatment outcomes and survival projections are in general significantly worsened.
Catching melanoma early
Melanoma that is caught early can be effectively treated, with a 5-year survival rate around 98%. These rates go down to 64% when the melanoma has spread through lymph nodes to nearby regions, and 23% if it has spread to more distant organs or areas of the body.
Traditional systemic chemotherapy has significant side effects, destroying cancer cells as well as other important cells in the bloodstream.1 Further, chemotherapy drugs have not been as effective in combatting melanoma as they are in fighting some other forms of cancer. In fact, until now, amputation has been the best option for some people with advanced limb melanoma or sarcoma. Available treatment approaches for local melanomas include cryotherapy, laser ablation, T-VEC injections, immunotherapy and surgeries.1
Isolated limb infusion
This new procedure, isolated limb infusion (ILI) was designed to control the flow of chemotherapy treatment directly to the melanoma in an affected arm or leg.1 Infusion is a method of putting fluids, in this case, chemotherapy drugs, into the bloodstream. The technique isolates the limb by cutting off the blood flow to the area allowing for the chemo medications to be infused directly into the limb.
What ILI is like
The medicine is infused, delivered through catheters put into an artery and a vein so it can be circulated near the tumor. Normal circulation is stopped with a tourniquet, a tight band that restricts blood flow into and out of the limb, while heated chemotherapy drugs are infused. The procedure is performed under general anesthesia and lasts around 30 minutes, followed by flushing out with a saline solution to clear the limb of the chemo. Circulation is then restored by releasing the tourniquet.1 The procedure can successfully deliver cancer-fighting medications to an arm or leg while keeping it out of the rest of the body.
ILI is minimally invasive and has the potential to improve effective disease control, thus saving limbs and lives.1,3 It is considered an advanced version of another treatment, isolated limb perfusion (ILP).1
Isolated limb perfusion
Around since the 1950’s, ILP treatment also bypasses blood flow to the limb. ILP directs treatment through a major artery. Perfusion means to bathe a specific area of the body such as an arm or leg with high doses of chemotherapy through a blood vessel. During ILP there are sometimes systemic side effects because the drugs (chemo) can leak into the bloodstream due to high pressure and high-volume flow conditions of the procedure. ILI employs low-flow circulation, so leakage into the body is negligible and systemic side effects are less likely.3
What’s the difference?
ILI and ILP are both considered locoregional treatments and have both been effective in treating advanced cases of melanoma. Both procedures are generally preferable to systemic therapies.3
Research reports show that ILI hospital stays are shorter, but ILP appears to have a higher complete response rate. These evaluations, however, are limited because there is currently no statistically valid comparison of the two procedures. Selected patient populations for each procedure vary.
Choosing one or the other
ILI appears to be well tolerated with side effects generally limited to redness and swelling in the arm or leg that was treated. The response rate to the treatment ranged between 54 and 84 percent with those who responded living nearly 5 years longer than those who did not respond.1 The response rate refers to the percentage of those whose cancer is smaller or eliminated after treatment. At this point, ILI appears to be offered to older people with more advanced disease. This is because ILP is a more invasive and complex procedure, but age and stage are generally factors associated with poorer outcomes.3
Researchers suggest that a future randomized controlled trial or case-control study would permit similar patient populations to be compared, thereby allowing for a closer comparison of the two procedures.3
New Procedure Brings Chemo to Melanoma. Available at: https://www.rush.edu/news/press-releases/new-procedure-brings-chemo-melanoma. Accessed 7.23.19.
Melanoma. Available at: https://www.aad.org/media/stats/conditions. Accessed 7.27.19.
Kroon, H. Thompson, J. Isolated Limb Infusion and Isolated Limb Perfusion for Melanoma: Can the Outcomes of these Procedures be Compared? Available at: https://link.springer.com/article/10.1245/s10434-018-7067-4. Accessed 7.23.19.