What does brachytherapy for skin cancer involve?
Brachytherapy delivers the radiation with a high degree of precision. Due to this accurate positioning and the possibility to exactly determine to which depth irradiation is required healthy tissue is spared whilst the tumor gets a high dose of radiation1. This increases efficacy and minimizes damage to healthy surrounding tissues. Read more about the principles of brachytherapy.
Two types of brachytherapy are currently available, isotope based brachytherapy and electronic brachytherapy. The difference between both therapies lies in the source of radiation, either a radioactive isotope, or an X-ray tube which uses electricity to induce radiation. Which type of brachytherapy is prescribed depends mainly on which type of brachytherapy is present in your hospital, on the type and size of the lesion and on a prescriber’s preference.
Brachytherapy not only provides good cosmetic results but has also been shown to be highly effective in preventing the skin cancer from returning 2-3. When compared to external beam radiation therapy, with the source placed at a distance, brachytherapy reduces the amount of radiation to healthy tissues and can be delivered in a much shorter treatment time 4-5.
Both basal cell and squamous cell cancers that have not spread to other parts of the body can be treated effectively with brachytherapy.
Picture: Graphical representation of electronic brachytherapy delivered to a skin cancer lesion
Brachytherapy is typically delivered in a series of treatments (also known as 'fractions') – most people will receive 6–8 fractions. Brachytherapy treatment can be completed in a relatively short space of time, usually over the course of 2-4 weeks 6-8. Treatment is given on an outpatient basis. This means you will not need an overnight stay in hospital. Brachytherapy is therefore a very convenient form of skin cancer treatment.
There are three main stages to the brachytherapy procedure: a) planning, b) treatment delivery and c) post-procedure monitoring.
The planning stage involves a thorough examination of the skin cancer and surrounding area. Ultrasound and/or biopsy may be used to gain an accurate picture of the layers of the skin and the precise position and thickness of the tumor.
The doctor calculates how much radiation is needed to treat the cancer and where the radiation should be placed over the skin.
In some cases, especially with larger lesions or lesions on a very irregular surface a mould of the skin may be taken. This enables the brachytherapy team to create a custom-made device to accurately place the radiation on the skin.
Usually a patient is positioned on a bed or treatment chair. The doctor may use a special pillow to help the patient to maintain a stable position. Then the doctor will precisely position the treatment applicator on the area of skin to be treated.
The role of the skin applicator is to hold the source of radiation in the correct place over the skin during the ‘radiation delivery’ stage and to reduce the radiation to other nearby areas.
There are many different types of applicator available and the exact type will depend on which type of brachytherapy is applied and on the size and shape of the lesion.
The applicators are designed to provide a close and reproducible fit to the surface of the skin.
In some cases a custom-made applicator will be used from a plaster mould of the skin.
Picture left: Electronic brachytherapy skin applicator positioned on a nose lesion. Picture right: Valencia applicator, which is used with isotope based brachytherapy, positioned on a hand.
The applicators are connected to a computer controlled machine which controls the duration of exposure to the source of radiation. This source of radiation may either be a small X-ray source (in case of electronic brachytherapy), or a radioactive isotope (isotope based brachytherapy).
When treatment is ready to start, your doctor will press a start button and the treatment unit will automatically apply the correct dose of radiation exactly to the skin cancer lesion. The accurate positioning of the shielded applicator reduces the risk of healthy surrounding tissues or organs being damaged by the radiation.
Radiotherapy with a brachytherapy treatment system is a painless procedure and can be carried out without an anesthetic. Treatment delivery usually lasts only a couple of minutes per session after which a patient can return immediately to his or her daily life.
A follow-up appointment will be scheduled a few weeks after the last fraction has been delivered.
This appointment is to check that the treatment is going well and to monitor for any possible side effects. Typically follow up visits are scheduled every 3-6 months for the first year and thereafter once per year 9. This schedule of follow up does not depend on the type of therapy for skin cancer but is a general procedure when patients have had skin cancer. Also patients are recommended to regularly screen their skin for new lesions since the risk of developing new skin cancers is significantly higher after having had a first skin cancer lesion.
1. Alam, M., Nanda, S., Mittal, B. B., Kim, N. A., & Yoo, S. (2011, August). The use of brachytherapy in the treatment of nonmelanoma skin cancer: A review. Journal of the American Academy of Dermatology, 377-388
2. Tormo, A., Perez Calatayud, J., Roldan, S., Lliso, F., Miranda, S., Carmona, V., et al. (2011). Preliminary Clinical results Using Valencia Applicator and a New Fracitonation in Non Melanoma Skin Cancer Treatments. Brachytherapy, 10, S14-S101
3. Rio, E., Bardet, E., Ferron, C., Peuvrel, P., Supiot, S., Campion, L., et al. (2005, November 1). Interstitial brachytherapy of periorificial skin carcinomas of the face: a retrospective study of 97 cases. International Journal of Radiation Oncology*Biology*physics, 63(3), 753-757
4. Patel, R. R., & Arthur, D. W. (2006, February). The Emergence of Advanced Brachytherapy Techniques for Common Malignancies. Hematology/Oncology Clinics of North America, 20(1), 97-118
5. National Cancer Insitute. (2010, June). Radiation Therapy for Cancer. Retrieved April 22, 2014, from National Cancer Institute: http://www.cancer.gov/cancertopics/factsheet/Therapy/radiation
6. Tormo, A., Perez Calatayud, J., Roldan, S., Lliso, F., Miranda, S., Carmona, V., et al. (2011). Preliminary Clinical results Using Valencia Applicator and a New Fracitonation in Non Melanoma Skin Cancer Treatments. Brachytherapy, 10, S14-S101
7. Kasper, M. E., Richter, S., Warren, N., Benda, R., Shang, C., & Ouhib, Z. (2013). Complete response of endemic Kaposi Sarcoma lesions with high-dose-rate brachytherapy: Treatment method, results, and toxicity using skin surface applicators. Brachytherapy, 12(5), 495-499
8. Bhatnagar, A., & Loper, A. (2010). The initial experience of electronic brachytherapy for the treatment of non melanoma skin cancer. Radiat oncol, 28(5), 87.
9. American Cancer Society. (2013, October 21). Skin Cancer: Basal and Squamous Cell . Retrieved April 22, 2014, from www.cancer.org: www.cancer.org/cancer/skincancer-basalandsquamouscell/detailedguide/skin-cancer-basal-and-squamous-cell-after-follow-up