Radiation therapy in the management of gynaecological cancer

Therapeutic applications for radiation therapy followed quickly from the discovery of X-rays by Roentgen in 1895. The first radiation treatment is credited to Grubbe, who reported the external beam treatment of breast cancer in 1896. Application to gynaecological cancers was almost immediate. However, the limited penetrating ability of the low-energy radiation of early X-ray tubes and isotopes was a major limitation. Consequently, brachytherapy and near-contact external beam therapy were preferred for gynaecological cancer until the advent of cobalt-60—the first source of a penetrating beam of megavoltage photons with a high dose rate, long half-life, and reasonable cost. This led to cobalt-60 machines becoming the most widely utilized treatment machine from the 1950s to 1970s. Radar research during World War II dramatically improved microwave technology. Linear accelerator-based machines (linacs) applied these advances to use microwaves to accelerate electrons onto a tungsten target and emit a fraction of their kinetic energy as mega-electron volt energy X-rays. The emitted X-rays are collimated into a beam and directed towards the patient. Advantages of linacs over cobalt-60 include higher dose rates, sharper beam edges, higher energies, and simplified radiation protection. This chapter describes the basic principles of radiotherapy and the role of radiotherapy in the management of gynaecological cancers, including cervix cancer, uterine cancer, and rarer tumours such as those arising from vaginal, vulvar, and ovarian cancers.