Electrochemotherapy in the Treatment of Bone Metastases: A Phase II Trial

Abstract

Introduction: Bone metastatic disease is a major cause of pain and decreased quality of life in patients with cancer. In addition to systemic therapy and pain control with narcotic analgesics, standard local treatments include palliation with radiation therapy and surgery. However, 20-30 % of patients do not respond to conventional treatments, increasing the interest in alternative therapies. We present the results of a new minimally invasive technique in the treatment of bone metastases.

Methods: Twenty-nine patients affected by painful bone metastases were treated with electrochemotherapy (ECT) from July 2009 to July 2011; the mean age was 60 years (range 37-87); 21 patients received a previous ineffective local treatment; the appendicular skeleton was affected in 15 patients while in 14 patients other sites were involved. ECT was performed using the Cliniporator Vitae under fluoroscopy or CT guidance depending on the site of the lesion. Clinical response was assessed using VAS scale and objective tumour response was evaluated according to the MD Anderson criteria for bone metastases.

Results: All patients well tolerated the procedure and no intraoperative or postoperative complications were observed. At a mean follow-up of 7 months, 24 patients were available for evaluation. 84 % of the patients (20 out of 24) referred improvement of pain ≥50 % with reduction of narcotics consumption. Radiographic evaluation after 3 months in 20 evaluable patients, showed "partial response" in 1 patient, "stable disease" in 17 and "progression" in two cases.

Discussion: Results reported in this study demonstrated ECT to be safe and feasible in the treatment of painful bone metastases even when other previous treatments were ineffective. Pain and disease progression control was achieved in the majority of the patients with consequent improvement of quality of life.

Conclusion: ECT should be considered a new feasible tool in the treatment of bone metastases in place or in combination with standard treatments; further developments are required to extend the use of this technique to spine metastases.

Fig. 1

Schematic representation of electrode insertion in proximal femur: electrodes and drill; positioning mask on skin surface; bone metastases in red

Fig. 2

Organogram of patients treated. Group 1 patients per protocol; Group 2 compassionate treatment. DOD dead of disease, AWD alive with disease

Fig. 3

a–c A 69-year-old patient: left femoral neck painful bone metastases, thyroid carcinoma, a CT-guided ECT needles positioning, coronal plane, b X-ray result at 6 months of follow-up; sclerotic rim surrounding the lesion: Partial Response (c)

Fig. 4

a–c A 57-year-old patient: left ischium painful bone metastases, kidney carcinoma, a CT-guided ECT needles positioning and multiplanar reconstruction, b CT scan at 7 months follow-up; central necrosis and shrinking of the metastatic lesion: Partial Response (c)