Use of the Accuray TomoTherapy System for Advanced Rectal Cancer to Improve Treatment Efficacy and Reduce Side Effects

Accuray Incorporated announced today that two new studies demonstrate the benefits of the TomoTherapy System in the treatment of advanced rectal cancer. Radiotherapy, with or without chemotherapy, followed by surgery is the standard of care in the treatment of locally, advanced rectal cancer. However, radiation delivered to surrounding organs, such as the bowel and bladder, may lead to life-changing side effects, making it critically important for the radiation to be delivered with extreme accuracy and precision. The TomoTherapy platform, including the next-generation Radixact^® System, is the only system available that is capable of helical radiation delivery continuously delivering image-guided, intensity-modulated radiation therapy (IG-IMRT) from a full 360 degrees around the patient as the treatment table also moves — providing greater control of the radiation dose so it conforms precisely to the tumor and minimizes dose to healthy tissue.

Patients enrolled in the two studies received simultaneous daily radiation and a targeted radiation boost over a 25-day time period. The study investigators found that the TomoTherapy platform’s unique architecture enabled the delivery of a high dose of radiation, directly to the tumor, through the integrated boost of radiation, while minimizing radiation to organs in close proximity to the targeted tumor. As a result, patients in the studies experienced improved treatment results and reduced side effects. These study outcomes compare favorably to conventional radiotherapy, based on results from other studies.

Novel treatment approach shows promising results
The clinical teams at Centre Hospitalier Universitaire Vaudois (CHUV) in Lausanne, Switzerland and the Clinica Luganese in Lugano, Switzerland, reported on their retrospective analysis of patients with advanced rectal cancer treated with TomoHelical™. The study titled, “Neoadjuvant chemoradiotherapy delivered with helical tomotherapy under daily image guidance for rectal cancer patients: efficacy and safety in a large, multi-institutional series,” was published in the Journal of Cancer Research and Clinical Oncology, and found:

• Treatment with TomoHelical is safe, with low rates of severe toxicity
  • Radiation delivered with helical TomoTherapy following daily imaging with the platform’s integrated imaging capabilities allowed for the reduction of treatment margins around the tumor, so less normal tissue was irradiated. The authors highlight a “clear reduction in the rates of acute and late non-hematological toxicities” when compared to a randomized trial evaluating the use of 2D- or conformal 3D-RT techniques, published in the New England Journal of Medicine (NEJM)[1]
• The four-year outcomes showed excellent local tumor control and disease-free survival rates of 88.4 percent and 74.6 percent, respectively
• A significantly higher rate of pathological complete response (pCR) was reported in the group of patients who received a simultaneous integrated boost compared to those who did not receive the boost. pCR is an indication of how well the treatment is working, with those patients achieving a pCR experiencing reduced rates of local recurrence and better overall survival

“The results of our analysis are encouraging because they indicate that patients with advanced rectal cancer may have a better option for effectively treating their disease. Further studies are needed, however, we believe that highly conformal radiation doses delivered with TomoHelical in combination with daily image guidance may become the new standard of care for pre-surgical treatment in patients with advanced rectal cancer,” said Dr. Berardino De Bari, assistant professor and radiation oncologist in the radiation oncology department, CHUV.

Listen to Dr. De Bari share his experience using the TomoTherapy System at this link.

Targeted radiation boost helps maintain patient quality of life
In another study, clinicians at Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College in Beijing, People’s Republic of China, published results of their advanced rectal cancer study titled, “Concomitant dose escalation with image-guided TomoTherapy^® in locally advanced mid-low rectal cancer: a single-center study,” in Cancer Management and Research. Highlights of the study include:

• The clinical team used TomoHelical™ to simultaneously deliver daily radiation treatments and a targeted radiation dose boost to the primary tumor, to improve outcomes and quality of life in patients with advanced rectal cancer
• TomoHelical treatment was able to significantly reduce the volume of the tumor, while minimizing dose to surrounding organs-at-risk. This enabled surgeons to perform sphincter-preserving surgery while removing the remaining tumor in 80.1 percent of patients in the study, thereby increasing the chance of maintaining normal bowel function and preserving quality of life
• Treatment resulted in positive outcomes with 95.5 percent of patients showing local tumor control and 70.9 percent exhibiting no signs of cancer five years after the radiation therapy procedure
• At the study authors’ institution, the outcomes associated with TomoHelical treatment were superior to that with their non-dose-escalated conventional approach

“Surgical treatment of mid-low rectal cancer offers the best option for long-term management of the disease, though can be challenging because of the risk of damaging surrounding organs and the resulting side effects, including bleeding, fecal incontinence, sexual and urinary dysfunction, and pelvic pain,” said Fuquan Zhang [professor and chairman of the radiation oncology department]. “With the simultaneous use of daily radiation and a targeted boost, delivered with TomoHelical, we were able to effectively reduce the tumor volume while preserving the sphincter and its functionality for the majority of patients in the study,” continued Ke Hu [professor and vice chairman of the radiation oncology department].

Listen to Prof. Zhang share his experience using the TomoTherapy System here.

“These most recent studies are a valuable addition to the available literature on the use of chemoradiation prior to surgery in the treatment of advanced rectal cancer. The treatment outcomes are extremely promising and may offer new hope to patients whose previous options were limited,” said Fabienne Hirigoyenberry-Lanson, Ph.D., vice president global medical and scientific affairs, at Accuray. “The treatment regimens described in the studies reinforce the benefits of the unique capabilities of the TomoTherapy platform and what we would also expect to see with the Radixact^® System. With TomoHelical mode, clinical teams were able to effectively and efficiently treat the rectal tumors while minimizing side effects and importantly, their potential impact on the quality of life.”