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P1.06 - Poster Session 1 - Prognostic and Predictive Biomarkers (ID 161)
- Event: WCLC 2013
- Type: Poster Session
- Track: Biology
- Presentations: 1
- Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P1.06-036 - Relationship between Serum Sodium Levels and Tumor characteristics in Non-Small Cell Lung Cancer. (ID 2452)
09:30 - 16:30 | Author(s): E.B. Geara
Lung cancer (LC) is the second most common cancer diagnosed in men and women. The age-adjusted incidence rates are 62.6 per 100,000 populations per year. LC is also the most common cause of cancer mortality in the United States with 56% of the cases being metastatic at the time of diagnosis. Hyponatremia has classically been associated with Small Cell LC. Studies have shown Non Small Cell LC (NSCLC) to be associated with Hyponatremia. Hyponatremia is a predictor of mortality and worse prognosis in NSCLC. We studied the association of sodium (Na) levels with histological type, level of differentiation and staging in NSCLC.
We retrospectively enrolled 490 patients with NSCLC from the tumor registry data of our hospital from 2001 to 2011. One hundred one patients were excluded based on the following criteria: 1) patients without biopsy proven NSCLC, 2) medical records unavailable, and/or 3) age < 18 years at time of diagnosis. The following variables were collected: TNM staging (Stage 1, 2,3 as low stage and 4 as high stage),histological type, level of differentiation (well differentiated, moderately differentiated, or poorly differentiated) and Na levels at the time of diagnosis. Na level of 136meq/l or lower was used as a cut-off between high and low sodium groups. Data was analyzed using Chi Square statistical analysis and the Fishers Exact Test. Inferences were tested to be significant at P value of 0.05 or less.
There were 234 (59.7%) males out of 389 patients. The mean age was 67.3 ± 11.4 years. The distribution of race was 227 (58%) white patients, 91 (23%) black patients, and 71 (20%) other races. Patients in low stage constituted 218 (55%) of the patients. Low Na levels were significantly more common in patients with high stage NSCLC [Odds ratio 1.85, CI 95% (1.19, 2.87), P<0.006]. On further sub-group analysis, low sodium levels were found to be significantly associated with higher stage in patients with Adenocarcinoma (n=183, 47%), [Odds ratio 2.07, CI 95% (1.12, 3.84), P<0.021]. No statistical association was seen between Na levels and other tumor variables.
We demonstrated higher stages of NSCLC and Adenocarcinoma Lung were associated with lower sodium levels. Possible mechanisms explaining this phenomenon includes Syndrome of Inappropriate Anti Diuretic Hormone secretion, increased levels of Atrial Natriuretic Peptides, release of Neuropeptide Y stimulating the posterior pituitary & metastases to adrenal or brain. Previous studies have demonstrated that lower sodium levels are associated with poor prognosis in LC. Serum sodium is an inexpensive and a routinely ordered test. Further prospective and larger studies are needed to substantiate the role of serum sodium levels as an easily assessable biomarker for advanced disease. It might also be useful to explore its potential as a marker of the disease progression.