Image-guided percutaneous cryoablation of a solitary subpleural lung metastasis from breast cancer

Abstract

This case presents CT-guided percutaneous cryoablation as a treatment option in a patient with oligometastatic breast cancer who previously had received standard-of-care treatment for metastatic breast cancer. Before cryoablation, the patient received two systemic lines of therapy, several surgeries and radiotherapy for oligometastatic disease. The cryoablation was performed in a single 7 mm subpleural oligometastatic lesion 42 months after diagnosis of metastatic breast cancer. It was performed without complications, and the patient experienced no complaints or discomfort after the procedure. A 3-month, 6-month, 9-month and 12-month follow-up fluorodeoxyglucose-positron emission tomography/CT scans showed no sign of disease progression.

Background

Breast cancer is the most common malignancy in women worldwide. Despite screening and improved treatments for early breast cancer, 20%–30% will be diagnosed with metastatic breast cancer (MBC).^{1 2} MBC is an incurable disease for whom prolonged survival and symptom relief are main treatment goals.³ While MBC often is a widespread disease, up to 20% of patients with stage IV breast cancer are diagnosed with oligometastatic disease (OMD).⁴ OMD is defined as a limited number of low-volume metastases in a limited number of sites and, therefore, with a lower disease burden.⁵ Consequently, sensitive imaging such as fluorodeoxyglucose-positron emission tomography/CT (FDG-PET/CT) or MRI scans and a final histological verification is of paramount importance for the correct diagnosis and staging of OMD from breast cancer.^{6 7}

Besides standard systemic therapies, local alternatives, including surgery and ablative therapies, can be used in the oligometastatic setting.⁸ Within ablative therapies, percutaneous cryoablation is a well-established treatment choice in primary renal cancer^{9 10} that can be used for treating solid masses in various tissues.¹¹ Only a few cases have been reported for treating metastasis from breast cancer in general and for pulmonary metastasis in specifically.¹²

Case presentation

A woman in her 60s without a history of comorbidities presented with a palpable mass in her left breast 6 years earlier. Initial imaging revealed a 42 mm tumour from which a biopsy confirmed the diagnosis of invasive ductal carcinoma (T2N0M0), human epidermal growth factor receptor 2 (HER2) positive and oestrogen receptor (ER) negative. In the right breast, she further presented an 18 mm ductal carcinoma in situ. After a normal multigated acquisition scan, the patient received two neoadjuvant series of epirubicin and cyclophosphamide without sufficient response yet stabile disease without progression (tumour size 37 mm). She continued neoadjuvant treatment with weekly paclitaxel plus pertuzumab and trastuzumab. Following bilateral lumpectomy and sentinel node biopsy after 5 months, the patient received adjuvant radiotherapy bilaterally and continued adjuvant trastuzumab for 1 year. Sixteen months after the initial diagnosis, the patient was diagnosed with local recurrence in the left breast and had an FDG-PET/CT performed, revealing two bilateral lung metastases. CT-guided biopsy of one of the metastases failed, resulting in a small pneumothorax, for which further invasive diagnostics were discontinued. The patient initiated systemic treatment with 14 months of vinorelbine, trastuzumab and pertuzumab. At this point, the patient had a limited burden of disease with a tumour in the left breast and two lung metastases. Therefore, a surgical strategy was discussed with the patient to optimise the chance of tumour control. Consequently, the anti-HER2 treatment with trastuzumab and pertuzumab was continued while the patient had a left-sided mastectomy and video-assisted thoracic surgery resection (VATS) of both lung metastases. FDG-PET/CT 3 months later revealed a new subpleural metastasis in the right lung as the only metastatic lesion. The lesion was resected by another VATS procedure, and the pathology report of all three lesions revealed metastases from breast cancer, HER2 positive, ER-negative. The patient continued regular follow-ups by FDG-PET/CT with no signs of progression until three and a half years from baseline. At that time, FDG-PET/CT revealed two subpleural lung metastases of 7 and 10 mm. Systemic treatment was changed to trastuzumab emtansine (TDM1). After 6 months, the two subpleural metastases progressed—the bigger lesion to 18 mm and the smaller with increased FDG uptake. The treatment with TDM1 was stopped, and stereotactic radiotherapy (50 Gy in five fractions and 45 Gy in three fractions) was administered to the two metastases. The patient tolerated the treatment well but was diagnosed with paroxysmal atrial fibrillation during treatment. A haematoma related to the left-sided lumpectomy scar and dermal reactions to radiotherapy were also reported. After 12 months, a single 7 mm subpleural metastasis in the previously irradiated field became FDG avid, as presented in figure 1. Surgery was not considered possible due to the lesion being indifferentiable from consolidated tissue, and the patient was offered cryoablation to achieve local tumour control. The cryoablation was performed in sedation 42 months after diagnosis of MBC and without complications. Follow-up FDG-PET/CT 3, 6, 9 and 12 months after revealed no signs of progression or new lesions. The patient timeline is graphically presented in figure 2.

Figure 1.

Axial CT (A) and FDG-PET (B) images depicting the subpleural metastasis prior to cryoablation (blue arrows). FDG-PET, fluorodeoxyglucose-positron emission tomography.

Figure 2.

Patient timeline. PET-CT, positron emission tomography-CT; VATS, video-assisted thoracic surgery.

Treatment

The cryoablation procedure was performed in the department of radiology as an outpatient procedure. The patient was awake and sedated using dexmedetomidine and remifentanil during the procedure. The patient was placed in a supine position in a CT-scanner (Somatom flash system, Siemens Healthineers, Forchheim, Germany). Under local anaesthesia using 10 mL Lidocaine and 10 mL Marcain, two IceRod needles (Boston Scientific, Arden Hills, Minnesota, USA) were placed CT guided in the subpleural metastasis as shown in figure 3. A biphasic freeze cycle of 10 min on 100% with an 8 min thawing period was performed. The last 90 s of the thawing period was performed with active thawing. CT scans were performed at the 4 min and 8 min mark to ensure that the metastasis was fully covered by ice and that adjacent organs were not affected. The whole procedure lasted around 40 min.

Figure 3.

Axial CT images depicting the cranially placed needle (A), the ice-ball during treatment (dotted blue line) (B) and the caudally placed needle (C).

The patient was observed after the procedure and was subsequently discharged 2 hours after the needles were removed without any discomfort or complications except for a small amount of haemoptysis. The haemoptysis stopped after 2 days.

Outcome and follow-up

After cryoablation, the patient was independently contacted by the radiologist and the oncologist and reported only slight discomfort, but no pain or dyspnoea. Follow-up FDG-PET/CT without systemic oncological treatment 3, 6, 9 and 12 months after cryoablation showed no signs of progression or new lesions. A snapshot of the FDG-PET/CT scan after 12 months is presented in figure 4.

Figure 4.

Axial CT (A) and FDG-PET (B) images after twelve months showing treatment sequelae (blue arrows). FDG-PET, fluorodeoxyglucose-positron emission tomography.

Discussion

In this case, percutaneous cryoablation was performed on a solitary subpleural pulmonary metastasis in a patient with MBC. At the time of cryoablation, the patient had a limited burden of disease and was in good clinical shape. Hence, systemic therapy was considered less favourable, and other local therapies were explored, leading to percutaneous cryoablation.

A literature review revealed no case reports of percutaneous cryoablation on pulmonary metastases from breast cancer, but Ridouani et al describe one patient treated with cryoablation of MBC in the lung.¹² There are two similar case reports from our institution with successful cryoablation on solitary metastases in the thoracic wall from renal cell carcinoma and the kidney from lung cancer.^{13 14} The case report on treating metastasis in the thoracic wall describes successful cryoablation, with the only complication being sore without the need for analgesics and the follow-up scans without signs of recurrence or disease progression.

There are several studies on cryoablation of malignancies in the lungs.^{15 16} Tafti et al also report cryoablation being used in managing patients with metastatic disease in the lungs with the addition that patients with four or fewer lesions per lung can effectively be managed with percutaneous ablation, which fits in the definition of OMD. Furthermore, they claim that a favourable response is more frequently observed in smaller (3 cm or less) and peripheral lesions.

In regard to complications following cryoablation in the lungs or subpleural masses, parenchymal haemorrhage and haemoptysis is common and expected, with complication rates varying and are reported as occurring from 15% up to 62% depending on the literature. It is most often self-limited and very rarely requires intervention.^{17 18}

In the SOLSTICE study by Callstrom et al, ablation therapy in the lungs is regarded as a safe procedure, with the most common complication being an intraprocedural or postprocedural pneumothorax.¹⁹ Furthermore, the study concludes a primary local treatment response efficacy of 77% and a secondary of 84% at 24 months of follow-up. They compare with stereotactic body radiation therapy (SBRT), which is reported with a local efficacy of 83% at 18.7 months and 85% at 2 years from two different studies.^{20 21} The same study concludes that image-guided percutaneous cryoablation of lung metastases had no impact on patients’ performance score or quality of life. In contrast, treatment with SBRT resulted in patients reporting chest pain with and without resolution of symptoms as well as rib fractures.

Studies suggesting a synergistic effect of cryoablation with systemic treatments have shown promising results. In the review by Aarts et al, 41 out of 45 publications show beneficial results for cryoablation combined with other systemic therapies.²² These publications address data on tumours and metastases with different aetiologies with data on MBC arising from a study by Niu et al. In this study, patients receiving multiple and timely (directly after detection of metastases) cryoablation sessions and immunotherapy resulted in significantly higher median overall survival.²³

Lastly, an abstract presented at the American Society of Oncology annual summit in 2022 suggested no beneficial effect on overall or progression-free survival in patients with OMD when adding stereotactic body radiotherapy and/or surgical resection to standard-of-care systemic therapy. However, the type of imaging used for diagnosing was not presented, which might have had an impact on the overall outcome of the study. Further prospective research is needed to determine the best way of treating patients with oligo-MBC.²⁴

When surgery may not be a suitable option for patients, ablative therapy may have a role, as described in this case report. As an alternative to focal therapy, systemic oncological treatment would be the treatment of choice.

Patient’s perspective.

The experience was very good, from arriving at the hospital, meeting the radiologist before and after treatment, and having the oncologist call me in the evening. It was incredible to lie in the scanner in the morning and be home again at noon. I was sleepy but awake during the procedure, and I only experienced slight nausea after the procedure that spontaneously disappeared. I felt no pain and can barely see any marks after the needles. I had a burning sensation like a sunburn on the skin of my breast for a few weeks after the treatment, but it did not affect my everyday living. In general, it was nowhere near as painful as when I had surgeries in my lungs, where I experienced a lot of pain.

Learning points.

• Cryoablation is a safe and well-established procedure for local tumours without metastasis.

• Cryoablation can be used as focal treatment in patients with metastatic disease where the metastasis is located favourably, and other treatments are deemed impossible.

• Patients can be treated in an outpatient setting which is more cost and time-efficient than other surgical options.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).