Cryoablation

A Novel Therapy for Mesothelioma Patients

Management of mesothelioma has been among the most challenging of cancer therapy. Most decisive factor in survival remains stage at diagnosis and type of mesothelioma, with epitheloid type having better survival compared to sarcomatous type. Chemotherapy has shown little success in increasing survival.

Although not curative, best results to improve survival comes from patients surviving surgery namely pleurectomy (decortication) or extrapleural pneumonectomy, in combination with chemotherapy and radiotherapy. Both the surgical procedures are associated with morbidity and mortality and require expertise such that only few surgeons have the stamina or dare take on these operations. Almost all patients who undergo surgery have recurrence at some point in their disease course.

Cryoablation is an alternative minimally invasive procedure used in adjunct with standard therapies described. Cryoablation uses principles of cold temperature dissipation to induce thermal injury in target tissues. The applicators allow conduction of compressed argon gas in applicators interior hollow chambers (large needle approximately 2 mm in diameter) which in turn lead to subzero temperatures in the applicator and surrounding tissue [1], forming an ice ball (cryo zone) which will kill any cells it engulfs. Currently the maximum size of iceball attained remains at 4 cm, which limits ablating large tumors. Although multiple applicators can be used to reach larger ice balls (with the maximum ice ball obtained by my team being 9 cm), it does come with increased risk of morbidity [2].

Currently there are a handful of centers with enough expertise to use cryoablation in management of mesothelioma. The principal indications to improve survival include ablation of localized invasive tumor to make the patient eligible for surgery and ablation of tumor following recurrence. As mentioned previously almost all patients have localized recurrences and are ineligible for repeat surgery. Cryoablation can be performed on multiple lesions at a time.

Infrequently, I have ablated up to four lesions in a single ablation setting. Another set of indications for cryoablation is palliative control of pain. These tumors invade the chest wall and the ribs and can cause neurogenic and osseous pain. Even though the survival may not increase, most of my patients have had improved quality of life after cryoablation. I have found cryoablation a safe and relatively quick method to control pain.

Finally, cryoablation has been used for focal control of tumor invading into vital organs like heart to improve quality of life or even survival. Like all procedures there are some risks involved particularly hemorrhage and damage to vital structures, which needs to be considered while selecting patients.

Mesothelioma management requires multidisciplinary, strong and individualized approach to control the tumor early in the course to improve survival or quality of life.