Could breast cancer surgery be completely replaced by cryoablation - tumor-freezing treatment?

Cryoablation—destroying a tumor by freezing—has shown itself to be successful in breast cancer as well as early-stage prostate and kidney cancer. It also has the potential to treat all tumors of certain sizes in different parts of the body.

The current standard treatment for early-stage breast cancer is breast cancer surgery called lumpectomy . In this operation, the breast is not completely emptied; the tumor is removed with some surrounding normal tissue. A newer treatment than lumpectomy, called cryoablation-cryosurgery, destroying the tumor by freezing, is being tested in early-stage breast tumors and found as successful as lumpectomy.

Breast cancer surgery techniques have advanced significantly in patients’ favor, especially in recent years. First, in patients with large or multifocal tumors, preserving the breast skin rather than removing the entire breast and its skin helps maintain cosmetic appearance. In other words, the plastic-surgery approach to breast cancer, even in advanced and multifocal tumors, has contributed importantly to patient psychology and preserving bodily integrity. Another development is that minimal axillary surgery—removing a few marked lymph nodes—has been found sufficient in breast cancer patients without large tumors. This has greatly reduced excessive axillary surgery and the resulting arm swelling—lymphedema.

For years, following tumor-shrinking (neoadjuvant) chemotherapy in patients with large tumors, extensive breast tissue was removed according to the initial tumor size. Now, removing only the reduced, remaining tumor size has begun to be considered sufficient. This has prevented substantial breast loss. Especially in recent years, advances in chemotherapy, targeted therapies and immunotherapies for breast cancer have reached almost unbelievable levels. Success with drug treatment given before surgery (neoadjuvant) has risen from %15 to %60 in terms of complete response, meaning regression/disappearance of breast cancer to the point that no live tumor cells remain, prompting questions about breast surgery.

Can early-stage breast cancer patients or those responding well after tumor-shrinking chemotherapy be treated without surgery?

The minimally invasive approach to breast cancer treatment has raised the question, especially for patients with small breast cancers or initially large tumors showing complete or near-complete responses on imaging after tumor-shrinking treatment, of whether treatment without surgery may be possible.

Cryoablation received preliminary approval on May 27, 2017 from the FDA , establishing its place and importance in cancer treatment. This method has been applied to thousands of patients with many different cancers and scientifically demonstrated to be a local ablative method, destroying tumors regionally. It is an alternative to surgery for early-stage prostate and kidney cancers. It has also entered routine practice for patients with limited recurrent metastatic disease in various parts of the body and many cancer patients for whom surgery and other methods are unsuitable.

Study

A clinical trial involving 86 breast cancer patients treated with cryoablation, in phase-2, was conducted by the American Society of Surgical Oncology. It had 2 arms: one followed patients older than 70, whose tumors were expected to be slow-growing because of age and who did not require radiotherapy or axillary lymph node biopsy in follow-up; the other followed patients aged 50-69. The younger group received radiotherapy to reduce long-term recurrence risk, and chemotherapy and axillary sentinel lymph node surgery when necessary.

All patients’ tumors measured 1.5 cm or less. All belonged to the estrogen receptor-positive and HER2-negative breast cancer subgroup—which constitutes %70 of all breast cancers. For all patients, 5 years of breast cancer hormone-suppressing therapy were planned.

Results

After tumor freezing with cryoablation, all patients underwent breast cancer surgery to measure cryoablation’s efficacy. The tumor was completely destroyed by freezing in %76, while in the remaining %24 a tumor averaging 0.6 cm in diameter or DCIS was found. For target lesions, meaning a well-defined single tumor, cryoablation success was %92. In tumors smaller than 1 cm, success was %100.

DCIS—ductal carcinoma in situ—is the beginning of abnormal changes in cells lining the breast’s milk ducts and is a very early stage of breast cancer. DCIS may be scattered within a region of the breast without forming a distinct tumor and is one of the conditions in which cryoablation is less effective. Cryoablation is also less effective in multifocal breast cancers. Better pretreatment radiological imaging to identify these conditions will improve cryoablation success.

These results support effective, safe cryoablation—treating tumors by freezing—in selected breast cancer patients. Its efficacy is limited in multifocal breast cancer; in that situation, protective radiotherapy may complement treatment. Ultimately, cryoablation, a nonsurgical option, could become standard treatment for early-stage breast cancer in the future through improved technique and better patient selection.