Pulmonary Comorbidities in HNSCC
Recently, an increased focus on competing causes of mortality among
patients with HNSCC has been observed, with respiratory causes of
particular interest.6,7,24 As advances in treatment
modalities improve disease control and survival, the estimated number of
HNSCC survivors is expected to increase.25 As a
result, clinicians will be required to consider longer-term treatment
effects and identify patients at highest risk for noncancer-related
morbidity and mortality. Multiple studies have shown increases in
adverse pulmonary outcomes among HNSCC patients compared to the general
population.3,6,8,26-30 The prevalence of respiratory
comorbidities in HNSCC patients approximates 10 to 15%, nearly twice as
common as healthy controls.29,30 Moreover, a
significant percentage (21%) of head and neck cancer patients have
moderate to severe comorbidities, second only to patients with lung
(40%) and colorectal (25%) cancer, with a significant relationship
between comorbidity severity and overall survival (p <
0.0013).31
An analysis by Rose et al. of 34,568 patients with nonmetastatic
squamous cell carcinoma identified through the Surveillance Epidemiology
and End Results (SEER) registry found that the most frequent causes of
noncancer mortality included cardiovascular disease (28.2%), chronic
obstructive pulmonary disease (COPD, 8.5%), and cerebrovascular disease
(5.6%); lung cancer was the most common cause of second primary cancer
mortality (45.8%) (Table 1).7 On multivariable
analysis, increased risk of noncancer mortality was associated with
higher age, black race, unmarried status, localized disease, and
nonsurgical treatment.7 Comparable results have been
reported through other analyses of competing mortality, examining
noncancer/comorbidity mortality and second primary cancer
mortality.8,26,27 In a population-based review of
23,494 patients, Shen et al. also found cardiovascular diseases, lung
cancer, COPD, and cerebrovascular disease to be the most frequent causes
of competing death with rates of 28.3%, 10.4%, 8.5%, and 5.7%,
respectively.8 These data demonstrate a
disproportionate impact on the pulmonary system and increasing mortality
that respiratory comorbidities may confer. Prior series have
demonstrated that a large proportion of patients continue to smoke both
during and after therapy. As expected, smokers have lower rates of
treatment response and poorer survival compared to non-smoking
counterparts, particularly if smoking continues during and after
treatment.32-38