Cancer treatment more than a decade ago focused on surgical removal of tumors and systemic chemotherapy or radiation therapy to kill malignant cells. It has since expanded into new areas. Pioneers in interventional radiology realized that percutaneous techniques could be applied to cancer treatment, aided by advances in imaging. Early interventional techniques for cancer treatment included chemical or radiofrequency ablation and transcatheter chemoembolization.
During the past several years, technological innovation building on those two approaches has flourished. The thirst for information about this emerging field is so great that the International Symposium on Endovascular Therapy hosted an inaugural Symposium on Clinical Interventional Oncology in January to kick off its annual conference in Hollywood, FL.
As with all cancer treatments, interventional approaches face the challenge of ridding the body of malignant cells while preserving healthy cells. Interventional oncology treatments are increasingly able to pinpoint and kill cancer cells using improvements in imaging techniques that allow more accurate targeting of these cells. The introduction of entirely new approaches is expanding and refining treatments as well.
For instance, the best approach to liver cancer is surgical removal of the tumor. Surgery is not an option, however, for more than two-thirds of primary and 90% of secondary liver cancer patients. That proscription may be due to the size or location of the tumor(s) or to the fact that the tumor has grown into key blood vessels or vital structures. Surgery may be too traumatic because the patient has significant comorbidities. Early research suggests that interventional oncology treatments in specific organs are not only effective; they are significantly easier on the patient than surgery and systemic chemotherapy.
From the beginning, interventional oncology therapy has tended to fall within two categories: ablative and transcatheter.
ABLATIVE THERAPIES
Ablation is a relatively straightforward, minimally invasive method that in most cases involves placing a needle or needles directly into a lesion percutaneously and using one of several forms of energy to destroy it. Several ablative cancer therapies are available to kill tumors via a number of modalities, ranging from heat and cold to chemicals and focused ultrasound energy. Most are guided by CT or ultrasound. MRI is emerging as a valuable guide due to its ability to differentiate tissue, but equipment compatibility issues hamper its more widespread use.
One of the first ablation techniques involved the injection of a chemical, typically ethanol, directly into the tumor to sclerose the malignant tissue (vinegar works, too). This method is used less frequently today because of an increased risk of cardiovascular complications.
