Untreated severe obstructive sleep apnea (OSA) appears to be associated with increased aggressiveness of malignant cutaneous melanoma, according to a multicentre prospective study examining the relationship between sleep-disordered breathing (apnea or hypopnea) and cancer.
“This is the first large prospective multicentre study that was specifically constructed to look at the relationship between sleep apnea and a specific cancer,” said lead author Dr. Miguel Ángel Martinez-Garcia, from the Hospital Universitario y Politécnico La Fe, Valencia, Spain.
The study involved 412 patients, average age 55.8 years, with confirmed cases of cutaneous malignant melanoma. The number of men and women in the study group was approximately equal.
During the study, Dr. Martinez-Garcia and colleagues looked at a number of factors that indicated the prognosis of the patients, including the Clark and Breslow indices, which, taken together, determine the stage of melanoma.
All of the patients underwent a sleep study, and patients previously treated with continuous positive airway pressure (CPAP) were excluded, the authors noted.
Relationship found between aggressive cancers, obstructive sleep apnea
Findings suggested that patients diagnosed with the most aggressive cancers had higher prevalence and severity of obstructive sleep apnea. This relationship held true independent of age, gender, body mass index (BMI), skin type, sun exposure and other risk factors for melanoma.
“The relationship between sleep apnea and heart disease, as well as with automotive accidents, is already well established,” said Dr. Martinez-Garcia, who was quoted in a press release. “Based on our study, it seems a relationship between sleep apnea and cancer may also exist. It is very important, however, that people with sleep apnea do not infer that they will necessarily develop cancer.”
The researchers chose to focus the study on melanoma for a number of reasons.
Cutaneous melanoma can be easily observed and measured, and its aggressiveness determined using well- validated measures such as the Clark and Breslow indices. Members of the study group have also published a growth rate index for melanoma. In addition, earlier animal studies showed a link between melanoma growth and sleep apnea.
“Our findings have implications for both patients and physicians,” Dr. Martinez-Garcia added. “People who snore, frequently wake up at night or have daytime sleepiness should see a sleep specialist, especially if they have other risk factors for cancer or already have cancer. Physicians—especially dermatologists, cancer surgeons and medical oncologists—should ask their patients about potential sleep apnea symptoms, and refer them for a sleep study if they have these symptoms.”
While more research is needed, this study shows that patients in the study had markers of poor prognosis for their melanoma. It also highlights the importance of diagnosing and treating sleep apnea, said Dr. Martinez-Garcia.