Spontaneous regression of thoracic malignancies.
BACKGROUND
Clinicians are frequently questioned by patients about the possibility of spontaneous regression of tumors. Although there are many reports and a few case series documenting spontaneous regression, there is concern that these cases may not represent true regression. Using specific criteria, we attempted to determine the incidence and types of thoracic malignancy most likely to regress spontaneously.


METHODS
We used a PubMed search of the phrase "spontaneous regression of thoracic lesions" reported from 1951 to December 2008. Using a modified Everson and Cole criterion we developed to define spontaneous regression, this search was refined for true spontaneous regression of primary and metastatic thoracic malignancies.


RESULTS
Only 5 cases in the literature involved spontaneous regression of a primary thoracic malignancy. These include pleural mesothelioma, primary lung cancer and adenoid cystic carcinoma. 71 cases involved true spontaneous regression of metastatic thoracic neoplasms, of which 5 cases showed regression of the primary extrapulmonary tumors along with the pulmonary metastasis. Thoracic metastasis from renal cell carcinoma was the most common malignancy found to regress spontaneously.


CONCLUSIONS
Spontaneous regression of primary thoracic malignancy is rare. Renal cell carcinoma accounts for most reported cases.
Kumar
Toshita
T
Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, North Shore University Hospital and Long Island Jewish Medical Center, New Hyde Park, NY 11040, USA. tkumar@nshs.edu
Patel
Nick
N
Talwar
Arunabh
A
D000328:Adult; D002292:Carcinoma, Renal Cell / Q000453:epidemiology* / Q000556:secondary; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000453:epidemiology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009365:Neoplasm Regression, Spontaneous / Q000473:pathology; D010997:Pleural Neoplasms / Q000453:epidemiology* / Q000473:pathology; D013899:Thoracic Neoplasms / Q000453:epidemiology* / Q000556:secondary