Non-Invasive Radiation Shows Promising Results for Inoperable Kidney Tumors, Study Reveals
A recent study conducted by Australian and Dutch experts has found that targeted, high-dose radiation may benefit older patients with kidney tumors who are not suitable candidates for surgery. The study, known as TransTasman Radiation Oncology Group (TROG) FASTRACK II, is a multi-institutional phase II study that discovered patients treated non-invasively for inoperable kidney cancer with stereotactic ablative body radiotherapy (SABR) experienced 100% local control and cancer-specific survival for more than three years. These findings were presented at the Annual Meeting of the American Society of Radiation Oncology (ASTRO).
While smaller, single institution studies have shown promise for stereotactic radiation treatments in patients with inoperable kidney tumors, FASTRACK II is the first large, multi-institutional clinical trial to test the efficacy of SABR. Lead study author Shankar Siva, a radiation oncologist at the Peter MacCallum Cancer Centre and a professor at the University of Melbourne in Australia, stated, Our study demonstrated that a novel treatment delivered in an outpatient setting is able to achieve unprecedented efficacy for patients with inoperable kidney cancer. There’s an unmet need for curing this type of cancer, and our findings point to the potential of radiation therapy to address that need.
As the global population ages, there is an increasing incidence of kidney cancer in older adults, particularly in those over 70 years old with lower rates of survival. Kidney cancer is currently the sixth most diagnosed cancer in men and the 10th in women worldwide. Surgery has typically been the standard of care for removing kidney tumors, either by removing the tumor and surrounding margins or by removing the entire kidney and surrounding tissue. However, many older individuals with renal cell carcinoma face unique challenges that make surgical treatment difficult. Siva explains, People might have other medical issues such as high blood pressure or diabetes, things that place them at higher risk for complications from surgery. They may have tumors in areas that are difficult to operate on, or where surgery may lead to dialysis.
The research conducted in this study clearly identifies a new population of patients who can benefit from stereotactic radiation. SABR, also known as stereotactic body radiation (SBRT), is a treatment that can shrink or destroy tumors by directly targeting them with high doses of radiation in a small number of outpatient sessions.
The study included 70 patients diagnosed with inoperable, high-risk kidney tumors or who declined surgery for their renal cell cancer. The average age of the patients was 77 years, and they had a single lesion. The patients were treated with SABR in one or three sessions at seven Australian centers and one center in the Netherlands. The treated tumors were relatively large, with an average size of 4.7 centimeters. Patients with tumors smaller than 4 cm received a single fraction of radiation, while those with larger tumors received three fractions.
During the trial’s lifespan (median follow-up of 43 months), none of the patients experienced local progression of their kidney cancer, and no patient died from cancer. The overall survival rate was 99% after one year of SBRT and 82% at three years. Only one patient experienced a distant recurrence of their cancer. Side effects were relatively modest, with no severe toxicities observed. Some patients experienced grade 3 adverse events, most commonly abdominal pain. The majority of the patients had mild-to-moderate kidney stress, with a modest decline in kidney function that plateaued after two years. Only one patient required dialysis following treatment.
The high efficacy rate and the preservation of kidney function can be attributed to rigorous quality control and the effectiveness of stereotactic radiation, according to Dr. Siva. He further stated that the findings of this phase II trial justify the design of a randomized phase III trial to compare stereotactic radiation to surgery as the primary treatment modality for patients with operable kidney cancer.
Given the choice between non-invasive radiation and surgery, Dr. Siva believes that a lot of patients would opt for the former. The results of this study provide hope for individuals with inoperable kidney tumors, offering a potential alternative treatment option to address an unmet need in curing kidney cancer.
