According to a recent article published in the Journal of Clinical Oncology, reanalysis of the data obtained from the Mayo Lung Project indicate that screening actually may improve survival for patients who develop non-small cell lung cancer (NSCLC).
In the United States, nearly 155,000 people die of lung cancer annually. Approximately 75% of people who have lung cancer have a type of cancer referred to as non-small cell lung cancer. There are actually many different types of lung cancer that are considered to be NSCLC and they are named according to the type of cell within the lung that the cancer originated. These may include epidermoid or squamous carcinoma, adenocarcinoma, large cell carcinoma, adenosquamous carcinoma and undifferentiated carcinoma. Treatment options depend on the stage of cancer and may consist of surgery, chemotherapy, radiation and /or biologic therapy (treatment utilizing the patient’s immune system to fight cancer).
Optimal chances for achieving a cure in NSCLC involve the complete surgical removal of the cancer (complete resection). However, complete resections can only be obtained if the cancer is not yet too advanced or widespread. Therefore, the medical community has been evaluating approaches to detect NSCLC prior to it causing symptoms in the patient – when in its earliest stages and most treatable. Screening methods for NSCLC may include chest x-rays and cellular observation of saliva samples (sputum cytology). Clinical trials are also evaluating novel screening procedures for NSCLC, such as spiral computerized tomography (CT) scans and detection of certain proteins in the blood.
The Mayo Lung Project trial was a large clinical trial evaluating the effects of screening for lung cancer and survival. The trial involved over 9,000 individuals who were considered to be at a high risk for developing lung cancer. One group of patients, referred to as the experimental group, underwent chest x-rays and sputum cytology every four months. The other group of patients referred to as the control group were advised to receive annual chest x-rays; however, their screening was performed on their own time and not as part of the trial. At five and nine years, the results of these two groups were directly compared.
Previous reports on results from the Mayo Lung Project indicated that there was no benefit to extra screening, as lung cancer-related mortality was not improved in the experimental group. However, Dr. Strauss from Boston University School of Medicine re-analyzed the data from the Mayo Lung Project, taking into account variables that had not been reported in other well-publicized documents.
The statistical analysis of Dr. Strauss indicates that although previous documents had reported that death from lung cancer was not improved in the experimental group, some other variables may need to be taken into consideration. It is important to note that significantly more patients in the experimental group actually developed NSCLC through the course of this trial. However, of all patients in both groups who actually developed NSCLC, the experimental group who underwent regular screening did have a significantly improved survival over patients in the control group. The improved survival was due to the fact that a larger number of patients in the experimental group had their cancer detected early enough through the consistent screening procedures to undergo complete resection compared to the control group. Overall, 50% of patients who were able to undergo resection were cured, compared to 0% of patients who were not able to undergo resection.
It is important to understand that statistical analysis may be interpreted in many different ways, and although data presented by one group may be correct, the uncovering of results of differing variables may reveal a different story. Patients at a high risk for developing lung cancer may wish to speak with their physician about the risks and benefits of regular screening or the participation in a clinical trial further evaluating screening efforts. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (cancer.gov) and www.CancerConsultants.com . CancerConsultants.com also provides personalized clinical trial searches on behalf of patients.
Reference: Strauss, G. The Mayo lung cohort: a regression analysis focusing on lung cancer incidence and mortality.
Journal of Clinical Oncology. 2002;20:1973-1983.
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