title: Thoracic masses treated with percutaneous cryotherapy: initial experience with more than 200 procedures.
abstract: OBJECTIVE
  To perform and report initial experience with percutaneous cryotherapy (PCT) of the thorax.
  
  
  METHODS
  A human investigation committee approved the study protocol, and all patients gave informed consent. One hundred eighty-seven patients who were not surgical candidates underwent computed tomography (CT)-guided PCT for treatment of thoracic cancer masses. CT-visualized low-attenuating ice formation after PCT was compared with initial tumor size and location. At 1 week and at 1, 3, 6, and 12 months after PCT, the various findings seen on available CT scans and any complications were noted. chi(2) and Student t tests were used to identify significant differences in frequencies and mean values of imaging observations, respectively.
  
  
  RESULTS
  Ice formation was identified at CT as reduced attenuation values (in Hounsfield units) within soft-tissue masses, the mean sizes of which were 4.3 cm +/- 0.2 (standard deviation) in peripheral locations and 6.4 cm +/- 0.3 in central locations. Tumor size and location were independent predictors of tumor coverage by low-attenuating ice: Mean coverage was 99% for peripheral masses 4 cm or smaller (n = 101) and 80% for central masses larger than 4 cm (n = 58) (P < .001). An area of necrotic cavitation larger than the original mass developed in 80% (77 of 96) of masses within 1 week and was nearly resolved by 3 months in 7% (five of 76) of masses. By 6 months, minimal pulmonary scarring was noted in 56 patients and 86% of masses showed reduced or stable size. The overall rate of pneumothorax was only 12% (22 of 187 patients), and other side effects appeared to be self limited. No major bleeding or bronchial damage was noted. Two deaths in debilitated patients were temporally related, and two complications involved brachial and recurrent laryngeal nerve damage. The patient with laryngeal nerve damage regained speech within 2 months.
  
  
  CONCLUSIONS
  CT-guided PCT yielded low procedural morbidity given the extent of freezing, even near mediastinal structures. Ongoing advances in cryotechnology, imaging guidance, and treatment planning may help to avoid the degree of undertreatment of larger central masses observed in this study.
authors.affiliation: Tumor Targeted Cryotherapy Center, PLA General Navy Hospital, Beijing, China.
authors.forename: Hongwu
authors.initials: H
authors.lastname: Wang
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Littrup
authors.forename: Yunyou
authors.initials: Y
authors.lastname: Duan
authors.forename: Yanqun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Huasong
authors.initials: H
authors.lastname: Feng
authors.forename: Zhoushan
authors.initials: Z
authors.lastname: Nie
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017679:Cryotherapy / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed