UT Southwest Medical Center
By Kevin Albuquerque, MD Director of Gynecologic Radiation Oncology Service Radiation Oncology and Chika Nwachukwu, MD, Ph.D. Radiation Oncology
Adaptive radiation therapy (ART) – a new patient-specific tumor technology – is now available to treat and cure women with cervical cancer and other gynecological tumors.
Conventional radiation therapy bases the treatment area primarily on the shape of the patient’s pelvic bones, assuming that the tumor is confined within these boundaries. In contrast, ART uses advanced CT and MRI-guided technology to fit around the actual tumor and lymph nodes that may be involved, and adjusts to a much narrower treatment zone with each session.
It is a highly personalized approach, and UT Southwestern’s Center for Adaptive Radiation Oncology is the only location in North Texas that has the advanced technology to treat gynecologic cancer in this way.
ART allows us to adjust the treatment zone based on the following factors:
- Serial and real-time changes in the size, shape and location of the patient’s tumor
- Fluctuations in the positioning of organs in the pelvis, such as the bladder, bowel, and rectum.
By redesigning the treatment area to accommodate these physical changes, we irradiate significantly less healthy tissue and avoid or reduce radiation therapy side effects such as diarrhea or urinary problems.
ART is a significant advance in gynecologic cancer treatment. In 2022, we are starting two clinical trials as part of a larger effort to find out which patients will benefit most from gynecologic ART and to determine the smallest but safest margins we can make around the tumor to minimize the side effects of the treatment to further reduce.
Who is a candidate for ART?
Women with advanced cervical, uterine, vaginal, and vulvar tumors that are changing in size or shape are the best candidates for ART. This technology may also benefit patients with gynecologic cancers such as vaginal and endometrial cancer who are too ill to undergo surgery and patients who cannot receive anesthesia.
Due to their cellular composition, gynecological tumors are usually very sensitive to radiation. Radiation therapy has been used successfully to completely shrink large gynecologic tumors – relieving pelvic pressure, bloating, pain and curing the cancer altogether.
Gynecologic tumors are often in close contact with critical tissues, including the bladder, rectum, ovaries, and reproductive/sexual tissues. Because of the proximity of the tumor and these normal healthy tissues, treatment with conventional radiation can cause side effects that affect these normal tissues. With ART, we can further reduce discomfort by redrawing the border around the actual tumor in each session to avoid treating more of the surrounding healthy tissue and reduce the side effects associated with traditional radiation.
How ART shrinks and heals gyn tumors
ART is a new type of radiation therapy that captures high-quality images immediately before a treatment, adjusts targets for that day to treat only tissues that are affected or at risk, and very quickly reschedule the entire treatment for that day.
Unlike traditional radiation treatment, where a plan is created before therapy begins and used for each subsequent treatment, ART offers an added level of precision and personalization—everything is performed while the patient is comfortably resting on the treatment table.
ART acquires a new CT or MRI that is acquired at the beginning of each subsequent treatment session. The updated image allows us to make day-specific changes. In the days between treatments, the tumors ideally shrink, allowing for a smaller treatment area. MRI-based radiation therapy is a new technology unique to UT Southwestern in North Texas. The machines create images so sharp and detailed that we can see the millimeter distance between a tumor and a nearby organ, or distinguish a tiny, hidden tumor from its surroundings.
We use the real-time MRI information to revise the treatment plan and tighten the original border around the tumor to account for changes such as:
- Bladder fullness or positioning
- bowel fullness or positioning
- patient posture
- tumor shrinkage
Then one of our medical physicists adapts the radiation plan to the new, personalized specifications.
Longer treatment time, fewer side effects
ART sessions last 45-60 minutes, while conventional radiation takes around half an hour. But the extra time to adjust therapy is well worth it. As the tumor shrinks, some women experience immediate relief from cancer-related symptoms such as gas, bloating, bleeding, and/or pain.
A concern of some women is that ART requires additional imaging compared to traditional radiation therapy – which involves a slightly higher but still very low level of imaging-related exposure, particularly with CT imaging. There is no additional ionizing radiation in MRI scans used on some ART platforms.
Most patients say that the small increase in radiation from CT imaging is a welcome trade-off for less unnecessary radiation to tissues around their tumor. Through the potential use of ART, we could avoid or reduce side effects of pelvic radiotherapy, such as:
- urinary incontinence
- diarrhea or bowel changes
- rectal bleeding
ART is approved by Medicare for most cancer treatments, and the ultimate benefits of these new technologies are being determined. Your doctor will explain the risks and benefits of this treatment to your personal condition.