What types of brachytherapy can be used to treat this cancer type?

Brachytherapy is a minimally invasive procedure that involves placing a source of radiation directly into the rectum to kill cancer cells.

Endorectal brachytherapy

Brachytherapy for rectal cancer is typically performed using endorectal brachytherapy. "Endorectal" refers to inside the rectum. This treatment involves placing a small balloon-like device (a rectal applicator) into the rectum to deliver high-intensity radiation for a few minutes. This is typically done in 4 treatments (or less), with about 2 weeks between each treatment. This can let some patients, particularly elderly patients, avoid major surgery and a colostomy. This type of treatment is used for some small rectal cancers or in cases where radiation was already given in the pelvic area, and the rectal cancer has come back. Sometimes, external-beam radiation therapy is also given.

High-dose-rate endorectal brachytherapy (HDREBT)

For rectal cancer, the most common type of brachytherapy is typically high-dose-rate (HDR) brachytherapy. During the procedure, a high dose of radiation is delivered to the tumor over a short period, often in multiple sessions. HDR brachytherapy allows for precise targeting of the cancerous cells while minimizing radiation exposure to healthy surrounding tissue and organs at risk. It is often part of a comprehensive treatment plan, including surgery, chemotherapy, and/or external beam radiation therapy. However, the specific treatment approach may vary depending on the individual patient's condition and the recommendations of their healthcare team.

Image-Guided Brachytherapy for Rectal Cancer

Image-guided high-dose-rate (HDR) endorectal brachytherapy has advanced significantly in recent years. This technique utilizes advanced imaging technologies such as MRI or CT scans to visualize the tumor and surrounding structures precisely. By integrating these images into the treatment planning process, oncologists can accurately position the radiation source in respect to the tumor, ensuring optimal radiation delivery while minimizing damage to nearby healthy tissues. This level of precision allows higher radiation doses to be delivered directly to the tumor, improving treatment outcomes and reducing side effects for patients. Brachytherapy therapy irradiates from the inside of the body compared to EBRT, where radiation comes from outside the patient and goes through healthy tissue during treatment delivery.

How brachytherapy for this cancer type is performed.

Brachytherapy for rectal cancer is typically performed using a technique called endorectal brachytherapy. Here's how it's done:

  • Preparation: The patient is positioned comfortably, usually lying on their back with their legs elevated. Anesthesia or sedation may be administered to ensure comfort during the procedure.
  • Insertion of the applicator: A rectal applicator is inserted into the rectum. The applicator contains channels that can be connected to a machine holding the radiation source (afterloader). During treatment delivery, the source can be precisely positioned inside the applicator channels to deliver the dose to the tumor.
  • Imaging: Before the applicator is inserted, imaging techniques such as ultrasound or CT and MR scans are used to locate the tumor and plan the treatment precisely.
  • Radiation delivery: Once the applicator is in place and the treatment plan is finalized, the connectors between the applicator and the source machine (afterload) are done, and the radiation can be delivered. The actual radiation delivery usually takes a couple of minutes only.
  • Monitoring: The medical team monitors the patient's vital signs throughout the procedure and may use imaging techniques to ensure proper applicator positioning and accurate radiation delivery.
  • Removal of the applicator: After the prescribed radiation dose has been delivered, the applicator is carefully removed from the rectum.
  • Post-Treatment care: Patients may experience discomfort or side effects following the procedure, such as rectal irritation or bowel changes. However, these are typically temporary and can be managed with medications or other supportive measures.
  • Follow-up: Patients will have regular follow-up appointments with their healthcare team to monitor their response to treatment and assess for any long-term side effects or cancer recurrence.

For most patients with rectal cancer, HDR brachytherapy is a well-tolerated procedure.

How effective is brachytherapy?

Clinical findings have consistently demonstrated the effectiveness of brachytherapy in treating rectal cancer, especially HDR brachytherapy. Studies have shown high tumor control rates and favorable outcomes, particularly when combined with other treatment modalities such as surgery and chemotherapy. Brachytherapy offers the advantage of delivering targeted radiation directly to the tumor site, resulting in effective local tumor control while minimizing radiation exposure to surrounding healthy tissues.

The study titled "Clinical applications of high-dose-rate endorectal brachytherapy for patients with rectal cancer," published in ELSEVIER's Cancer/Radiothérapie journal1, explores the effectiveness of high-dose-rate endorectal brachytherapy (HDREBT) in treating rectal cancer. Through improved imaging techniques, HDREBT offers targeted radiation treatment, showing promise in achieving high tumor regression rates and improved tumor control without surgery. The study, conducted through phase I and II trials, indicates that HDREBT is safe, well-tolerated, and effective in preoperative and postoperative settings. Presently, ongoing phase III studies are investigating its potential role in non-operative management for operable rectal cancer patients.

Additionally, advancements in brachytherapy techniques, including image-guided procedures, have further improved treatment outcomes by allowing for more precise targeting of cancerous tissue. Overall, clinical evidence supports the use of rectal brachytherapy as a valuable component of multimodal treatment approaches for rectal cancer, offering patients a promising option for disease management.

The article titled "Image-Guided Brachytherapy for Rectal Cancer: Reviewing the Past Two Decades of Clinical Investigation," by Dr. Te Vuong2, underscores the substantial progress made in image-guided brachytherapy for rectal cancer over the last twenty years. These advancements have paved the way for the adoption of high-dose-rate endorectal brachytherapy (HDREBT), heralding improved tumor precision, minimized side effects, and enhanced treatment efficacy, notably in non-operative management (NOM) strategies for rectal cancer patients deemed curable.

Contact X-Ray brachytherapy as a boost treatment is also showing promising outcomes for organ preservation. The OPERA3 study found that using contact x-ray brachytherapy boost, following or preceding neoadjuvant chemoradiotherapy, increases the probability of 3-year organ preservation for patients with early rectal cancers. This means that more patients were able to keep their organs intact after treatment when they received the contact x-ray brachytherapy.

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  1. Elsevier Cancer/Radiothérapie Volume 26, Issues 6–7, October 2022, Pages 879-883. Clinical applications of high dose rate endorectal brachytherapy for patients with rectal cancer by T. Vuong et al. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S1278321822001536?via%3Dihub
  2. Cancers 2022, 14(19), 4846. Image-Guided Brachytherapy for Rectal Cancer: Reviewing the Past Two Decades of Clinical Investigation, by Te Vuong et al. Retrieved from https://www.mdpi.com/2072-6694/14/19/4846
  3. Elsevier The Lancet Gastroenterology & Hepatology, Volume 8, Issue 4, April 2023, Pages 356-367.
    Neoadjuvant chemoradiotherapy with radiation dose escalation with contact x-ray brachytherapy boost or external beam radiotherapy boost for organ preservation in early cT2–cT3 rectal adenocarcinoma (OPERA): a phase 3, randomised controlled trial. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S2468125322003922?via%3Dihub