Nonsurgical ablation of primary breast cancer

Tumor-Infiltrating Lymphocytes (TILs) as a Biomarker of Abscopal Effect of Cryoablation in Breast Cancer: A Pilot Study

Background

Morphological evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer is gaining momentum as an immunological biomarker. This experiment evaluates the role of TILs in distant tumors as a measure of abscopal effect from cryoablation of breast cancer.

Methods

BALB/c mice underwent bilateral orthotopic transplant with 4T1-12B (triple-negative) cells. At 2 weeks, left tumors were treated by either resection (standard of care group) or cryoablation (intervention group) followed by resection of the distant right tumors 1 week posttreatment. TIL scores were calculated from hematoxylin and eosin-stained sections and phenotyped for cytotoxic T-lymphocyte (CTL) markers by immunofluorescence. Primarily resected tumors served as baseline (Tbaseline), whereas resected distant right-sided served as the readout for abscopal effect (AbsRes or AbsCryo). Mice were monitored for tumor recurrence and metastasis.

Results

The AbsCryo had a significant mean (SD) increase in stromal (2.8 [1.1]%; p = 0.015) and invasive margin TILs (50 [12]%; p = 0.02) compared with TBaseline (1.0 [0]% and 31 [4.9]%, respectively). CTL phenotyping revealed a significant increase in mean (SD) CD8+ T cells (15.7 [12.1]; p = 0.02) and granzyme B (4.8 [3.6]; p = 0.048) for the AbsCryo compared with TBaseline (5.2 [4.7] and 2.4 [0.9], respectively). Posttreatment, the cryoablation group had no recurrence or metastasis, whereas the resected group showed local recurrence and lung metastasis in 40% of the mice. Postprocedure increase in TIL score of distant tumors was associated with decrease in tumor relapse (p = 0.02).

Conclusions

Cryoablation induced a robust tumor-specific TIL response compared with resection, suggesting an abscopal effect leading to the prevention of cancer recurrence and metastasis.

Cryoablation: A promising non-operative therapy for low-risk breast cancer

BACKGROUND

The aim of this study was to evaluate the feasibility of cryoablation for early-stage low-risk breast cancer without tumor resection.

METHODS

Women diagnosed with ER+, PR+, and HER2-infiltrating ductal carcinomas ≤1.5 cm were treated with cryoablation. The non-surgical procedure used a Visica® 2 Treatment System with ultrasound guidance for ablation of the tumor with a 1 cm margin. Patients were monitored at 6-month intervals by MRI, mammogram, and ultrasound.

RESULTS

Twelve patients with unifocal breast cancer were treated with cryoablation for local control without follow-up tumor resection. All patients received adjuvant endocrine therapy, and none had radiation. The median follow-up was 28.5 (range = 4-41) months with 11 patients having at least one six-month follow-up. All imaging modalities showed complete ablation of target zone 11/11 (100%). Four patients (33.3%) have been followed up for ≥ 2 years with no local failure or residual disease.

CONCLUSION

Cryoablation of early-stage low-risk (ER+, PR+, and HER2-) breast cancer is a safe alternative to surgery.