Tumor Measurements Predict Survival in Advanced Non–Small Cell Lung Cancer
For the two-thirds of lung cancer patients with locally advanced or metastatic disease, tumor size is not used currently to predict overall survival times. However, a new study led by researchers at UT Southwestern Medical Center has shown that even in advanced stages total tumor size can have a major impact on survival. The findings were published online in the British Journal of Cancer.
“The traditional view is that once a cancer has spread to the lymph nodes or to other organs, tumor dimensions are unlikely to affect patient outcomes,” explained lead author David Gerber, MD, Assistant Professor of Internal Medicine at UT Southwestern. “However, the survival differences we found are not only statistically significant, but also clinically meaningful.”
Trial Details
Using data from a National Cancer Institute–sponsored phase III trial involving 850 patients with advanced lung cancer, Dr. Gerber and colleagues reviewed the recorded total tumor dimensions—which may include not only the primary tumor, but also those in lymph nodes and other sites of metastatic disease. The researchers found found that total tumor measurements greater than 7.5 cm predicted shorter survival times.
The average total tumor dimension of patients in the study was 7.5 cm. Patients with total tumor dimensions above this size lived an average of 9.5 months. Patients with total dimensions below 7.5 cm lived an average of 12.6 months, representing a 30% increase in survival.
When total tumor dimension was further divided into quartiles, the survival differences were even greater, ranging from 8.5 months to 13.3 months. These differences persisted even when multiple prognostic factors, such as age, gender, and type of treatment, were included in the analysis.
Implications for Future Trials
Dr. Gerber explained that, if confirmed in other populations, these findings could affect future clinical trials and patient care. “Ultimately, clinical researchers might consider this information as they review outcome data, making sure survival differences are attributed to treatment effects and not to baseline differences in total tumor dimensions,” he said. “Practicing physicians may also use the information to estimate prognosis.”
Precise measurements of lung cancer tumors can be used in tailoring therapy and helping doctors steer patients to the best clinical trials, he added.
While the study did not seek to explain the biologic reasons why this size association may hold true, a number of preclinical observations link tumor size with therapeutic resistance. It is generally thought that as tumors grow, the proportion of cells resistant to chemotherapy increases. Larger cancers may also have relatively poor blood supply and more pronounced gradients in interstitial pressure, hypoxia, and acidity, which may influence tumor cell sensitivity to chemotherapeutics and radiation treatments.
The analysis was completed with support from the National Institutes of Health and the Department of Health and Human Services. This work was also supported in part by a National Cancer Institute Cancer Clinical Investigator Team Leadership Award and the North and Central Texas Clinical and Translational Science Initiative.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
