Interventional oncology adds hope, time to survival

Adding radiotherapy to thermal ablation treatment results in increased options for patients

Minimally invasive procedures have the potential to match, and possibly surpass, the standard of care for patients with certain types of cancer, according to a recent study conducted at Brown University (J Vasc Interv Radiol 2006;17[7]:1117-24). Patients in that study received a combination of thermal ablation and radiotherapy for their lung malignancies. None of them were supposed to live longer than one year. More than half survived well beyond that point, however.

To explore trends in the use of such minimally invasive approaches as thermal ablation and nonsurgical therapy for palliation and cancer treatment, Diagnostic Imaging spoke with Dr. John A. Rundback, chair of the Society of Interventional Radiology's Cooperative Alliance for Interventional Radiology Research (CAIRR) and an associate professor of radiology at Columbia University.

Diagnostic Imaging: In the Brown University study, Grieco et al reported on the treatment of 41 patients with inoperable stage I/II non-small cell lung cancer with a combination of thermal ablation and radiotherapy. Almost 60% of these patients survived two years beyond average life expectancy. What's your reaction to these findings?

Dr. John Rundback: In these cases, traditional therapy has been radiation therapy alone or occasionally combined with chemotherapy, with response rates no greater than about 30%. This study shows a dramatic one-year survival rate of 80% in this population, which was statistically better than in the group that received the traditional radiation therapy alone. Survival at two years was essentially double what you see with traditional therapy and at three years is even more so, demonstrating a sustained benefit from this type of procedure.

DI: Do the study's limitations dampen its impact?

JR: The study is not a prospective randomized trial, but it must be recognized that these are patients with stage I and IIA lung cancer. In general, this is a relatively confined comparative set. That said, the study proves that, in a small subset of individuals, an interventional radiology procedure in combination with standard nonsurgical therapy can accomplish adequate removal of the tumor and the surrounding microscopic infiltration of normal parenchyma to mimic surgical results.

DI: What combinations have proven most successful and in what organ systems?

JR: In nonoperable patients with stage I and stage IIA lung cancer, we have found the combination of RFA with respiratory-gated, intensity-modulated radiation therapy to be extraordinarily effective. The reason is that RFA effectively targets the tumor core, while external-beam radiation effectively treats the margins. We've also utilized this approach in combination with chemotherapy and external-beam radiation for lesion control in patients with advanced lung cancer, particularly with invasion of the pleura. While this remains largely exploratory, preliminary data show these patients have prolonged survival compared with treatment without RFA.

Long-term data show that RFA and other forms of ablation are as effective as surgical resection in liver tumors up to 4 cm in size. This now extends to renal tumors, and we generally expect patients with tumors up to 4 cm in size can be spared nephrectomy or even laparoscopic partial nephrectomy. The study by Grieco et al should have an impact on referral patterns for patients with nonoperable stage I and IIA lung cancer.

DI: What interventional oncology trials are on the horizon?

JR: CAIRR is developing the protocol for a trial to compare RFA plus conformal radiation with conformal radiation alone in a large cohort of patients with inoperable stage I and IIA lung cancer. It should start in early 2007.

We are also developing the Superiority Trial, which will compare RFA with external-beam radiation therapy for surgically inoperable stage I and IIA non-small cell lung cancer.

DI: What's in store for other organ systems?

JR: The combination of ablation and radiotherapy warrants investigation to evaluate treatment of painful bony metastases in a prospective fashion compared with external-beam radiation therapy alone. This is particularly true for patients with painful vertebral compression fractures, where RFA combined with osteoplasty appears to be highly effective. In breasts, this approach is extraordinarily effective as well. RFA has potential for a whole range of other applications, such as renal or other types of isolated metastases, which otherwise might not be amenable to treatment.