Temporary unilateral microembolization of the lung-a new approach to regional chemotherapy for pulmonary metastases

Toward Transpulmonary Chemoembolization with Degradable Starch Microspheres: Systematic Analysis of Local and Systemic Effects in a Porcine Model

PURPOSE

To investigate local and systemic effects of transpulmonary chemoembolization (TPCE) with degradable starch microspheres (DSM) and doxorubicin. The long-term goal is to establish DSM-TPCE as a treatment option for pulmonary malignancies.

MATERIALS AND METHODS

Nine pigs underwent TPCE of either the right or left lower lobe pulmonary artery (LLPA) and bland embolization (TPE) of the contralateral LLPA. Before the procedures, macroaggregated albumin (MAA) particles were injected into both LLPAs, to exclude systemic shunting. Pulmonary arterial pressure, heart rate and oxygenation were recorded immediately before and at 1, 3, 5 and 10 min after treatment. To investigate possible nontarget embolization, animals underwent cerebral MRI (cMRI). We killed the animals after a contrast-enhanced chest computed tomography (CT) and performed a pathologic examination at 12 h (3), 24 h (3) and 72 h (3) after treatment.

RESULTS

All experiments were technically successful. Mean injected DSM dose until stasis was similar in TPCE and TPE (4.3 ± 1.4 vs. 4.0 ± 1.4 mL). Pulmonary arterial pressure increased significantly 3 min after treatment (TPE: 17 ± 5 vs. 27 ± 7 mmHg; TPCE: 22 ± 6 vs. 36 ± 8 mmHg). No significant changes in heart rate or peripheral oxygenation levels occurred. We observed no evidence of structural lung damage or permanent perfusion disruption on CT. MAA test injection and cMRI revealed no shunting or nontarget embolization. The pathologic assessment revealed nonspecific local inflammation of the lung parenchyma.

CONCLUSION

In this large-animal model, TPCE and TPE appear feasible and safe. We observed a mild increase in pulmonary arterial pressure. Nontarget embolization did not occur. TPCE, as well as TPE, did not cause structural damage to the normal lung parenchyma.

Regional chemotherapy of the lung: transpulmonary chemoembolization in malignant lung tumors

Standard treatment options in patients with lung cancer and pulmonary metastases are surgery, radiotherapy, chemotherapy, and immunotherapy. For reducing clinical complications of surgery and achieving a better local response, transpulmonary chemoembolization of the lungs is a possible interventional technique in which anticancer drugs are administered directly into a tumor through its feeding vessels followed by occlusive agents that are injected through the delivery catheter for blocking the vessel. This allows a longer contact period in the tumor with a higher cytostatic drug concentration. The technique is safe and results present promising local response rates, but the influence on survival is still questionable. This article describes the current role of intravascular therapies in the treatment of pulmonary malignancies.

Unresectable lung malignancy: combination therapy with segmental pulmonary arterial chemoembolization with drug-eluting microspheres and radiofrequency ablation in 17 patients

PURPOSE

To evaluate the feasibility, safety, and effectiveness of combining segmental pulmonary arterial chemoembolization (SPACE) and percutaneous radiofrequency (RF) ablation in patients with unresectable lung neoplasms or patients with resectable neoplasms who refused surgery and to compare the local tumor progression (LTP) rate with that in previous studies of RF ablation alone.

MATERIALS AND METHODS

After institutional review board approval and informed consent, 17 patients with primary and metastatic lung cancer were enrolled in this prospective study. Between January 2008 and February 2011, 20 nodules (median diameter, 3.0 cm; range, 2.0-5.0 cm) were treated during 19 sessions. Antineoplastic agents loaded on 50-100-µm microspheres were selectively infused into specific pulmonary arteries. Percutaneous computed tomography (CT)-guided RF ablation of lung nodules was performed 48 hours after SPACE. Follow-up consisted of enhanced CT 48 hours after combination treatment was completed, after 30 days, and every 3 months thereafter. Fluorine 18 fluorodeoxyglucose positron emission tomography was performed 3 months after combination therapy and then every 6 months. The t test was used to compare groups.

RESULTS

Technical success was achieved in 100% of cases. Ventilation-lung single photon emission computed tomography showed a wide area without ventilation in the lung parenchyma treated with SPACE. The LTP rate was 21% (three of 14 nodules) in 3-5-cm-diameter tumors and 0% (zero of six nodules) in tumors of 3 cm or smaller in diameter. Complete response was achieved in 65% (11 of 17) of patients at minimum follow-up of 6 months. Overall, treatment was well tolerated. Major complications were pneumothorax in five of 19 sessions (26%) and one bronchopleural fistula (one of 19, 5%). No treatment-related changes in general lung function were noted.

CONCLUSION

Combination therapy with RF ablation after SPACE to treat unresectable lung tumors is technically feasible, safe, and effective and may represent an advantage over RF ablation alone.

A polylactide/fibrin gel composite scaffold for cartilage tissue engineering: fabrication and an in vitro evaluation

A composite scaffold for cartilage tissue engineering was fabricated by filling a porous poly (L: -lactide) (PLLA) scaffold with fibrin gel. The porous PLLA scaffold prepared by a method of thermally induced phase separation has an average pore diameter of 200 microm and a porosity of 93%. Incorporation of fibrin gel into the scaffold was achieved by dropping a fibrinogen and thrombin mixture solution onto the scaffold. For a couple of minutes the fibrin gel was in situ formed within the scaffold. The filling efficiency was decreased along with the increase of the fibrinogen concentration. After fibrin gel filling, the compressive modulus and the yield stress increased from 5.94 MPa and 0.37 MPa (control PLLA scaffold in a hydrated state) to 7.21 MPa and 0.53 MPa, respectively. While the fibrin gel lost its weight in phosphate buffered saline up to approximately 50% within 3 days, 85% and 70% of the fibrin gel weight in the composite scaffold was remained within 3 and 35 days, respectively. A consistent significant higher level of rabbit auricular chondrocyte viability, cell number and glycosaminoglycan was measured in the composite scaffold than that in the control PLLA scaffold. Rabbit auricular chondrocytes with round morphology were also observed in the composite scaffold by confocal microscopy and scanning electron microscopy. Altogether with the features of better strength and cytocompatibility, this type of composite scaffold may have better performance as a matrix for cartilage tissue engineering.

Treatment of unresectable lung metastases with transpulmonary chemoembolization: preliminary experience

Transpulmonary chemoembolization (TPCE) was evaluated as a new treatment for unresectable lung metastases. Institutional review board approval and patient consent were obtained. In 23 patients, 26 lung metastases of different origins were treated locally by using a transpulmonary approach. After femoral vein puncture, tumor-supplying pulmonary arteries were selectively explored, and 5-10 mg mitomycin C and 5-10 mL iodized oil and microsphere particles were applied with balloon protection. Diagnosis and follow-up (3-month intervals) were performed with unenhanced and contrast material-enhanced computed tomography (CT). Treatment was well tolerated in all patients, with no major side effects or complications. As indicated by using morphologic criteria, volume regression of embolized areas was achieved in eight patients, while stable disease was revealed at follow-up in six patients. In nine patients, progression of treated intrapulmonary metastases was recorded. TPCE could be a well-tolerated palliative treatment option in patients with pulmonary metastases.

Biodistribution of 10B in a rat liver tumor model following intra-arterial administration of sodium borocaptate (BSH)/degradable starch microspheres (DSM) emulsion

We reported that intra-arterial administration of borocaptate sodium (BSH)/lipiodol emulsion provided selectively high (10)B concentrations (approximately 200 ppm 6 h after administration) in experimental liver tumors. In the present study, we investigated the pharmacokinetics of BSH following intra-arterial administration of BSH with other embolizing agent, degradable starch microspheres (DSM). The (10)B concentration in the tumor at 1 h after administration of BSH with DSM was 231 ppm. At 6 h, the (10)B concentration in the tumor in BSH with DSM group was 81.5 ppm. The (10)B concentration in the liver at 1 h after administration of BSH with DSM was 184 ppm. At 6 h, the(10)B concentration in the liver in BSH with DSM group was 78 ppm. The tumor/liver (10)B concentration ratios (T/L ratio) in the "BSH+DSM" group were significantly smaller than those in the "BSH+lipiodol" group at 1 h (1.4 vs. 3.6) and 6h (1.1 vs. 14.9). BSH/DSM-boron neutron capture therapy (BNCT) was not suitable for treatment of multiple liver tumors due to the low T/L (10)B concentration ratio. However, the high (10)B accumulation in the liver tumors following intra-arterial administration of BSH/DSM emulsion suggests that BSH/DSM-BNCT has the potential for application to malignant tumors in other sites.