What Is Intraoperative Radiotherapy (IORT)?
Intraoperative radiotherapy is a radiotherapy that delivers a concentrated dose of radiation during the time of surgery directly to a tumor site. This cutting-edge medical technique offers several advantages over traditional radiotherapy, which involves implanting radioactive sources near or within the tumor.
The primary aim of IORT is to localize the radiation and the site where the cancer is most likely to recur, thereby maximizing the radiation dose to cancerous cells and minimizing exposure to healthy surrounding tissues and organs. This treatment is a highly effective therapy because of localizing the maximum dose to the cancer site.
Also, the potential side effects associated with radiation therapy can be reduced. The duration of the treatment is about 20-30 minutes. IORT was employed in the multidisciplinary management of locally advanced and recurrent cancer. Still, in recent times, IORT can also be used in earlier-stage cancers such as breast and prostate cancer.
How Is Intraoperative Radiotherapy Performed?
IORT is a complex medical procedure that requires collaboration between radiation oncology and surgical teams.
The following are the steps involved while performing an IORT:
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Intraoperative radiotherapy begins with surgery to remove the cancerous cells or tumor. The surgeons carefully remove the cancerous cells or tumors and ensure no cancerous cells remain in the surrounding tissue.
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After removing the tumor, the tumor bed will be exposed by the surgeons; this is where the tumor was previously located. This area is very important during this procedure because it is the target site for radiation therapy.
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After exposing the tumor bed, the radiation oncology team delivers a precise, concentrated dose of radiation directly to the tumor bed. This is achieved using a special applicator designed for IORT. This applicator will administrate targeted radiation therapy without harming adjacent tissues. The applicator used during the surgery depends on various factors such as the patient's body weight, location, shape and size of the tumor, pathological features, individual preferences, and the ideal applicator for the tumor bed cavity.
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Also, nearby healthy tissues and organs are at high risk of radiation exposure during radiation therapy, so they are carefully shielded or moved out of the radiation field to reduce the exposure.
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After precisely delivering the radiation treatment, the surgical team closes the incision as normal for the specific surgical procedure. Later, the patient is taken to the recovery area.
What Are the Advantages of Intraoperative Radiotherapy?
Intraoperative radiotherapy has various benefits that have made it an increasingly popular option for cancer treatment:
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IORT allows precise radiation delivery directly into the tumor bed during surgery. This method helps to minimize radiation exposure to surrounding healthy cells, reducing the risk of damage to the cells and side effects.
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Tumor cells are often more sensitive to radiation during surgery due to oxygen levels and metabolism changes. This can increase the effectiveness of radiation therapy when administered intra-operatively.
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Conventional radiation therapy mostly requires multiple sittings, whereas IORT is completed in a single session during surgery. This helps reduce the overall treatment duration and less hospital visits for patients.
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Radiation doses will be less when compared to conventional radiation therapy, as IORT is delivered directly to the tumor bed. This is beneficial in cases where sensitive structures are nearby, such as the heart or spinal cord.
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The immediate application of radiation therapy after tumor removal helps reduce cancer recurrence at the surgical site.
What Are the Applications of Intraoperative Radiotherapy?
IORT has been effective and versatile in treating various types of cancer. Some of its notable applications are:
1. Breast Cancer: Most breast cancer recur even after removing tumors from the breast (breast-conserving surgery) and using high-powered X-rays of the whole breast. IORT, along with breast-conserving surgery or lumpectomy, is proven effective, as it delivers targeted radiation to the tumor bed after tumor removal, reducing the risk of recurrence.
2. Colorectal Cancer - IORT has been used for recurrent or advanced primary colorectal cancer. Using IORT during colorectal cancer surgery reduces the risk of cancer cells remaining in the surgical site. The complication rate is also fairly reduced after using IORT.
3. Gynecological Cancers - IORT is increasingly used to treat gynecological cancers, such as endometrial and cervical cancer. Treating a metastatic para-aortic nodal disease from cervical cancers with external irradiation of dose 55 to 60 Gy creates severe complications. In such cases, IORT helps in reducing complications and providing effective treatment. Relapse of cancer in the para-aortic nodes or pelvic side wall can also be treated with IORT along with salvage therapy, as it allows for precise radiation delivery while sparing nearby critical structures.
4. Gastrointestinal Tumors - Curative resection is the cornerstone for gastric cancer. However, this has a high incidence of systemic failures, and recurrence in the primary site is noted. The use of IORT after curative resection is effective, and recurrence in the primary site has been greatly reduced.
5. Pancreatic Cancer - In cases of pancreatic cancer, survival rates were less even after complete resection because of recurrence in the primary site and systemic metastasis. IORT can administer radiation directly to the tumor bed during surgery, offering a better survival rate and local control of the disease.
6. Soft Tissue Sarcomas - Soft tissue sarcoma is a cancer that develops in muscles, tendons, and other soft tissues. Surgery is the mainstay treatment for soft-tissue sarcomas; however, in the case of large or high-grade sarcomas, surgery may hamper the functionality of the limb or the organ. Therefore, radiation therapy plays an important role in preserving the function of the limb or organs. IORT has been used in advanced tumors to increase doses beyond conventional EBRT and improve local control rates. In extremity sarcomas, using IORT helps in reducing the dose and volumes of radiation so it can be tolerated by normal structures like bone, joint space, and skin.
7. Brain Tumors - Intraoperative radiotherapy has also been employed in brain tumor surgeries, where it helps target remaining cancer cells while minimizing damage to healthy brain tissue.
Conclusion
Intraoperative radiotherapy (IORT) is a great innovation in cancer treatment. It delivers precise radiation directly to the tumor bed during surgery, thereby minimizing the radiation exposure to healthy tissues, reducing treatment time, and enhancing treatment outcomes. It can be applied to a wide range of cancers and enhance the survival rate of the patients.
