IntraOperative Cryoablation Therapy (IOCT): A Novel Alternative to Post-Lumpectomy Radiation Therapy

Today, breast cancer patients have two choices for initial treatment of their breast cancer: 1) surgical excision of the cancer followed by radiation therapy or 2) removal of the cancerous breast (mastectomy). SenoGuard, an investigational intraoperative cryoablative therapy (IOCT) administered by a surgical team as an essential element of breast sparing surgery, offers a third option that would eliminate the need for radiation. We aimed to evaluate the feasibility and safety of cryoablation of the surgical cavity using a new 2 cm cryoablation probe and cryogenic system as a potential alternative to RT.

An excision was made within the breast tissue of a porcine animal model to simulate the technique used for tumor lumpectomy. A probe delivering a novel nitrogen-based cryogen was inserted into the surgical cavity to cryoablate the surrounding cavity. Data on the delivery of specific isotherms at various depths and time points within the surgical cavity using engineering and ex-vivo models was collected to assess the technique's precision and efficacy.

The study found that the cryoprobe was able to deliver -20 °C isotherm to a depth of 1 cm from the cryoprobe surface following a 3-minute freeze cycle, demonstrating the potential for effective tissue cell destruction within this range. Extending the freeze cycle to 5 minutes resulted in delivery of the -40 °C isotherm to reach a depth of 1 cm, indicating a more intense and potentially more effective treatment for slightly larger tumor cavities.

Data from this feasibility study demonstrates that cryoablation could achieve similar results as those created by radiation therapy and that adjusting the duration of the freeze cycle could provide flexibility in treating a range of tumor cavity sizes. The ability to adjust freeze cycle duration based on tumor cavity size could eliminate the need for post-lumpectomy radiation therapy in certain patients. IOCT of the surgical cavity tissue immediately following tumor lumpectomy offers several potential advantages over traditional radiation therapy, including improved cosmetic outcome, a lower risk of side effects and greater accessibility and affordability for all patients.