Cancer Statistics - Karmanos Cancer Institute

Gender Differences in Lung Cancer Survival
Investigator: Michele L. Cote, PhD
Lung cancer is the leading cause of cancer
death in the United States. 1 It is estimated that
in 2005, 172,570 individuals in the United
States were diagnosed with lung cancer, and
163,510 died of the disease. 1 Men are more
likely to be diagnosed with lung cancer than
women. In 2002, the age-adjusted incidence
rates of lung cancer were 77.8 cases per
100,000 men, and 50.8 cases per 100,000
women. 2 Only prostate cancer in men and breast cancer in women
were diagnosed more often. Survival from lung cancer is poor, with
a five-year survival rate of 13.6% for men and 17.5% in women
from 1995-2001. 2 Approximately 6 in 10 individuals with lung
cancer die within a year of diagnosis. 1 Survival is greater for women
than for men at every stage of diagnosis. Little is known about
gender-related differences in risk and survival.
Current or former cigarette smoking remains the greatest risk
factor for lung cancer development, yet women are more likely to
report never smoking than men, and also tend to smoke less than
their male counterparts. 3 Histologic type of lung cancer varies by
gender as well, with women more likely to develop adenocarcinomas
compared to men. 4 Evidence suggests these differences could be
due, in part, to hormonal variation and exposure to estrogens. 5
Women have higher circulating endogenous levels of estrogen compared
to men, and are also exposed to synthetic estrogens through
hormone replacement therapy and oral contraceptives. Estrogens
can increase cell proliferation. 6 Estrogens may also increase lung
cancer risk by modulating gene expression of other enzymes, particularly
the polycyclic aromatic hydrocarbon metabolizing enzymes
such as the cytochrome p450s. 7 Several other genes thought to
increase risk of lung cancer, including the c-erbB2 receptor, are also
activated by estrogens. 8 Cellular response to estrogens is mediated
by estrogen receptors (ER). Two receptors, ER-α and ER-β, which
are encoded by separate genes have been identified and are expressed
in the lung. It is feasible that ER status plays a role in lung
carcinogenesis, may impact survival, and may be a potential target
for therapy.
We have recently received funding by the National Lung Cancer
Partnership and the LUNGevity Foundation to examine the effect
of ER expression on survival after a lung cancer diagnosis. We seek
to clarify whether ER status and aromatase expression is associated
with prognosis and may serve as therapeutic targets. Targeting
hormone receptors has been successful in both chemoprevention
and treatment in a variety of cancers. The role hormones play in
lung cancer prognosis in humans has yet to be fully explored. These
analyses will aid in the understanding of the underlying biological
processes of lung cancer, and potentially lead to novel targets for
treatment of lung cancer.
PERCENTAGE
25
20
15
10
5
References:
5 Year Relative Survival Rates for Lung Cancer
by Gender in Metropolitan Detroit, 1973 – 2004
1975 1980 1985 1990 1995
YEAR DIAGNOSED - 3 YEAR MOVING AVERAGE
Female
Male
2000
2000
1. American Cancer Society I. Key Statistics for Lung Cancer, 2004
2. Ries LAG EM, Kosary CL, Hankey BF, Miller BA, Clegg L, Mariotto A, Feuer EJ,
Edwards BK (eds). SEER Cancer Statistics Review, 1975-2002. In: Ries LAG EM,
Kosary CL, Hankey BF, Miller BA, Clegg L, Mariotto A, Fay MP, Feuer EJ, Edwards
BK (eds). ed: National Cancer Institute. Bethesda, MD, 2005
3. (CDC) CfDCaP. Behavioral Risk Factor Surveillance System Survey Data.
In: Services USDoHaH, ed. Atlanta, Georgia, 2003
4. Charloux A, Quoix E, Wolkove N, et al. The increasing incidence of lung
adenocarcinoma: reality or artefact? A review of the epidemiology of lung
adenocarcinoma. Int J Epidemiol 1997; 26:14-23.
5. Taioli E, Wynder EL. Re: Endocrine factors and adenocarcinoma of the lung
in women. J Natl Cancer Inst 1994; 86:869-870
6. Ethier SP. Growth factor synthesis and human breast cancer progression.
J Natl Cancer Inst 1995; 87:964-973
7. Thomsen JS, Wang X, Hines RN, et al. Restoration of aryl hydrocarbon (Ah)
responsiveness in MDA-MB-231 human breast cancer cells by transient expression
of the estrogen receptor. Carcinogenesis 1994; 15:933-937
8. Matsuda S, Kadowaki Y, Ichino M, et al. 17 beta-estradiol mimics ligand activity
of the c-erbB2 protooncogene product. Proc Natl Acad Sci U S A 1993;
90:10803-10807
* Source: Surveillance, Epidemiology, and End Results (SEER) Program
(www.seer.cancer.gov) SEER*Stat Database: Incidence - SEER 17 Regs Limited-Use,
Nov 2006 Sub (1973-2004 varying) - Linked To County Attributes - Total U.S.,
1969-2004 Counties, National Cancer Institute, DCCPS, Surveillance Research
Program, Cancer Statistics Branch, released April 2007, based on the November
2006 submission.
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