Current estimates for head and neck cancer survival are largely inaccurate because they widely disregard many of the most common diseases such patients have in addition to their primary cancer, says Jay Piccirillo, M.D., a head and neck specialist at Washington University School of Medicine in St. Louis, the Siteman Cancer Center and Barnes-Jewish Hospital.
This highlights a broader problem with cancer survival statistics, which generally don't take into account the effect of co-existing conditions, or comorbidities, according to Piccirillo.
In a recent study, Piccirillo, director of the Clinical Outcomes Research Office at Washington University School of Medicine and professor of otolaryngology, showed that the risk of death increased up to seven-fold when patients with head and neck cancer developed new or more severe co-existing ailments such as heart problems, diabetes or lung disorders after cancer diagnosis.
The study, published in the Archives of Otolaryngology, Head and Neck Surgery, is the first to look at comorbidities in head and neck cancer patients in the period following diagnosis.
"For decades, we have used a cancer staging system based on tumor size, lymph node involvement and whether cancer has spread to other parts of the body when estimating a patient's survival while mostly ignoring how sick patients are from other diseases," Piccirillo says. "In fact, national databases used to estimate cancer survival don't account for comorbidities, and as a result, we don't have very accurate estimates of how long patients are likely to survive their cancers."
Some past studies of head and neck cancer have investigated the effect of comorbidities present at diagnosis, but this study shows that comorbidities grow in severity and frequency in about a third of head and neck cancer patients after their primary cancer treatment is complete.
The outcomes for patients with head and neck cancer who survive the initial period after diagnosis and treatment may be more dependent on their comorbidities than on their initial malignant tumor, says Piccirillo.
Survival estimates have an impact on the care of cancer patients such as selection of initial treatment and evaluation of treatment effectiveness. They also affect funding for cancer research, coverage of cancer care by insurance agencies and other health policy decisions.
Inaccurate statistics undermine physicians' ability to give patients a true prognosis, which prevents patients from deciding how best to spend their future time. "There are a lot of reasons an accurate prognosis is valuable to patients," Piccirillo says. "Do you start thinking about palliative care? Do you retire to spend more time with family? Do you make changes in your behavior such as exercising more, eating better or quitting smoking?"
In the United States, an estimated 35,310 new cases of oral cavity and throat cancer are expected in 2008. People with head and neck cancer have nearly the highest rate of comorbidities — only lung and colorectal cancer patients have more concurrent health problems.
The use of smoked and smokeless tobacco products and excessive consumption of alcohol increases a person's chances of head and neck cancer, and some studies show that together smoking and alcohol use increases risk by more than 30 times. Recently, head and neck cancer specialists have noticed that cancers of the tonsil and back of the throat are increasingly linked to human papilloma virus (HPV), the same virus responsible for nearly all cervical cancers.
The researchers reviewed the medical records of 183 patients with squamous cell carcinoma of the oral cavity, throat and larynx who were treated in 1997 and 1998 at Barnes-Jewish Hospital in St. Louis, which has carefully tracked comorbidities since 1995.
Comorbid ailments in these patients included heart attack, coronary artery disease, tumors other than the primary tumor, psychiatric disease, lung disease, stroke, diabetes and alcohol abuse. Many of these disorders can be traced to smoking or alcohol consumption — the same behaviors that may contribute to the occurrence of head and neck cancer, says Piccirillo.
The study showed that 33 percent of the head and neck cancer patients developed new comorbidities or a worsening of existing comorbid ailments in the time following their initial diagnosis and treatment. Patients with severe comorbidities during the follow-up period on average had a 6.7 times greater risk of dying.
The most common comorbidities that developed or worsened after diagnosis were malignant tumors unrelated to the original tumor and psychiatric illnesses. The type of treatment patients received, whether it was chemotherapy, radiation therapy, surgery or some combination of these, made no difference in the number or severity of comorbidities.
The added risk of comorbid ailments is very important to the 11 million United States residents who have been treated for cancer and have survived. "We are getting better at curing cancer, so we have an exponential increase in the numbers of cancer survivors," Piccirillo says. "Survivors have begun recognizing that the medical profession has not paid enough attention to the consequences of cancer and of cancer treatment."
- Yung et al. The Incidence and Impact of Comorbidity Diagnosed After the Onset of Head and Neck Cancer. Archives of Otolaryngology - Head and Neck Surgery, Oct 2008; 134 (10): 1045 DOI: 10.1001/archotol.134.10.1045
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