About one in a hundred patients with apparently incurable non-small cell lung cancer (NSCLC) survive five or more years after being given relatively small doses of radiation therapy (RT) meant to ease symptoms, according to a new study. Published in the March 1, 2006 issue of CANCER, a peer-reviewed journal of the American Cancer Society, the study says a new subset of patients with NSCLC appears to have disease that is curable with minimal therapy, and may explain occasional cures attributed to unconventional therapies or faith healing.
NSCLC is by far the most common type of lung cancer. With an overall five year survival of only 40 percent, it is also one of the deadliest. If caught early, five year survival can reach 60 percent. Five year survival in farther advanced disease is approximately 15 percent. Patients who are diagnosed with disease that is too advanced for curative treatment remain eligible for palliative therapies intended to provide symptom relief, including comparatively low doses of localized RT. Physicians have long made clinical observations that some patients receiving palliative RT long outlive their estimated survival and a few report even cures. Given that therapeutic doses of RT are much higher, it is not surprising that these reports require evidence-based confirmation. Michael Mac Manus, M.D., a radiation oncologist at the Peter MacCallum Cancer Centre in Melbourne, Australia, and colleagues clinically followed 2337 confirmed and apparently incurable NSCLC patients who had received palliative dose RT. Approximately 1.1 percent of the 2337 survived five or more years, including 18 who achieved an apparent cure. Although five year survivors were more likely to have higher functional scores at diagnosis and less likely to have metastatic disease compared to patients who lived less than five years, there were no other conventional prognostic factors to predict survival with palliative-dosed RT. “Our data,” conclude the researchers “show that close to 1 percent of patients with NSCLC have prolonged survival with doses of palliative RT that would not normally be considered sufficient for long term disease control.” Future studies should focus on identifying patient characteristics because “prospective identification of such patients could potentially profoundly influence treatment.”(Source: “Unexpected Long-Term Survival after Low-Dose Palliative Radiotherapy for Nonsmall Cell Lung Cancer,” Michael P. Mac Manus, Jane P. Matthews, Morikatsu Wada, Andrew Wirth, Valentina Worotniuk, CANCER; Published Online: January 23, 2006 (DOI: 10.1002/cncr.21704 ); Print Issue Date: March 1, 2006: John Wiley & Sons, Inc: January 2006.)