The Role of Brachytherapy in Cervical Cancer Management

Medically reviewed by Dr Johann Tang, Senior Consultant Radiation Oncologist

Overview

Cervical cancer is the 2nd most common cancer among women across the world, diagnosed in an estimated 528,000 women each year and causing approximately 250,000 deaths annually. It is the 10th most common cancer among women in Singapore.

For women who develop locally advanced cervical cancer, the standard of care has evolved from external beam radiation therapy (EBRT) alone to EBRT with brachytherapy and eventually to a combination of EBRT, brachytherapy, and chemotherapy.

The EBRT portion of treatment comprises treatment to the pelvic lymph nodes, parametria, and the primary tumour with a dose adequate to control the microscopic disease. The addition of brachytherapy serves to boost the gross tumour, i.e. increase the extent of tumour that will undergo treatment, and also improves disease control and survival. Finally, the inclusion of chemotherapy serves predominantly as a radiosensitizer, i.e. an agent that makes tumour cells more sensitive to radiation therapy, resulting in improvements of about 5% in overall survival.

Despite brachytherapy’s long-standing role in cervical cancer management, its usage has declined noticeably over the years due to its high costs as well as the greater amount of resources required for it.

This decline in brachytherapy for locally advanced cervical cancer has been accompanied by a decline in the survival of these patients. Therefore, all women with locally advanced cervical cancer should more often than not have access to brachytherapy as part of their treatment management to improve overall survival rates.

What is Brachytherapy?

Brachytherapy is a critical part of the treatment of cervical cancer in which radiation therapy is the primary choice of curative treatment.

The goal of radiation therapy is to deliver a curative dose of radiation to the tumour while limiting the dose, thereby reducing the risk of complications to surrounding organs such as the rectum, bowel and bladder.

Brachytherapy, or internal radiation therapy, involves the application of a radioactive source in close proximity to the tumour e.g. in the vagina or the cervix.

A high dose of radiation is directed at the tumour with the surrounding organs receiving a much lower dose. This increases the chances of a cure while reducing the risk of injuries to normal tissues that are in close proximity to the tumour.

The most common type of brachytherapy used in cervical cancer treatment is intracavitary brachytherapy. A device containing radioactive material is inserted into the vagina, the cervix, and sometimes into the tissues surrounding the cervix.

It is often used in addition to EBRT as part of the management of cervical cancer. It may be used alone in very specific cases of early-stage cervical cancers, although rare.

Types of Brachytherapy

The two types of intracavitary brachytherapy are low-dose rate (LDR) brachytherapy and high-dose rate (HDR) brachytherapy.

Low-Dose Rate Brachytherapy

LDR brachytherapy is performed in a hospital setting and requires the person to stay overnight for several days. It is usually performed under general anaesthesia.

During the procedure, the doctor will position the delivery devices and insert radioactive material into them. Once this is done, the patient is moved to a shielded hospital room where radiation is delivered over a period of 2-3 days. During this time, the patient will be given medication to remain comfortable.

Trained nurses and physicians will care for the patient over the course of the treatment but will take necessary precautions to avoid being exposed to radiation themselves.

High-Dose Rate Brachytherapy

HDR brachytherapy can be delivered on an outpatient basis over several treatments that take place up to a week apart. The treatment can be performed under general anaesthesia or moderate sedation.

During each HDR treatment, radioactive material is inserted for several minutes into the delivery devices and then removed. A few treatments will be delivered, spaced over a period of a day or two.

The advantage of HDR brachytherapy is that you would usually not have to stay in the hospital or still for long periods of time.

Support for Brachytherapy

The Society of Gynaecological Oncology (SGO) and the American Brachytherapy Society (ABS) recently released a statement emphasizing brachytherapy’s continued, critical role as a primary component of radiation therapy for women with cervical cancer.

“[E]xternal beam radiation therapy combined with high-quality brachytherapy has been an established treatment course for women with locoregional cervical cancer for nearly 100 years. Advances in the use of chemotherapy and image-guided brachytherapy have shown promise to increase the number of women cured and decrease the number of women harmed. Despite this, recent data has suggested that other modalities unproven to be equivalent to these tried-and-true techniques are being increasingly utilized in some centers,” they wrote.

As mentioned, while it is important to continue administering brachytherapy and making it accessible to patients, careful coordination of care is also crucial in ensuring optimal delivery of EBRT and brachytherapy. It requires multidisciplinary cooperation between gynaecological, radiation and medical oncology teams as well as support staff.

Possible Short-Term Side Effects of Brachytherapy

Since the radiation administered during brachytherapy only travels a short distance, the main effects of the radiation are on the cervix and the walls of the vagina.

The most common side effect is the irritation of the vagina. It may become red and sore, and there may also be a discharge. The vulva may become irritated as well.

Brachytherapy can also cause many of the same side effects as EBRT such as fatigue, diarrhoea, nausea, irritation of the bladder and low blood counts. However, since brachytherapy is often given right after EBRT, i.e. before the side effects of EBRT go away, it can be hard to know which treatment is causing the side effect.

Conclusion

Brachytherapy is a critical component in the management of cervical cancer in which radiation therapy is the primary treatment.

The benefits of brachytherapy vary depending on the patient, their priorities, and their preferences – though as a minimally invasive treatment method, the benefits of avoiding surgery are universal. These benefits include quicker recovery time, less time spent in a hospital as well as a reduced risk of postoperative infections.

Overall, by enabling the delivery of a targeted dose of radiation at the tumour, brachytherapy improves the rate of cure of cervical cancer.