It has been recently disclosed in a new study that cancer can be developed if people have sleep apnea commonly leading to interrmittent hypoxia.
Hypoxia is where a tissue or organ does not get enough oxygen. It is one of the common side effects of sleep apnea (or sleep disordered breathing – SDB). SDB is a common disorder in which you have at least one pause in breathing or shallow breaths while sleeping. Such pauses can last from seconds up to a few minutes, and they can happen as many as 30 times in an hour.
There were many studies proving the link between SDB and greater risk of several conditions, including hypertension, cardiovascular disease, depression, and early death. While the exact mechanisms underlying the possible connection between sleep apnea and cancer have been unclear, the authors implied that the hypoxia coming with the sleep disorder may play a role.
Sleep apnea affects more than 18 million Americans in the U.S. There are many risk factors for the disorder, such as a small upper airway, smoking, alcohol use, being overweight and having a large neck, small jaw or a large overbite.
According to the findings, the hypoxia pushes the formation of blood vessels within tumors. It is probably because of an increased production of Vascular Endothelial Growth Factor (VEGF), which is known to promote blood vessels formation.
“This is of course an early animal study, so we need to be cautious in applying this to humans. Nevertheless, this work indicates a plausible mechanism for just why conditions which restrict oxygen flow to tissues, like sleep apnea, may promote cancers,” said lead researchers Dr. Antoni Vilaseca.
Professor Arnulf Stenzl (Tübingen), Chair of the EAU Congress Committee said: “Although this is an experimental study, it is remarkable, because it demonstrates the influence of oxygen deficiency on the growth of renal cell carcinoma tissue (both primary tumor as well as metastases).”
In order to take a closer look, the scientists analyzed 24 mice that had been induced with kidney tumors. Half of the mice were subjected to intermittent hypoxia, and the other half were used as controls.
The research team explored that mice subjected to intermittent hypoxia had significantly more vascular progenitor cells and endothelial cells in their tumors. They also had higher circulation of Vascular Endothelial Growth Factor, compared with the tumors of mice that were not subjected.
In general, the researchers suggest that based on the results, sleep apnea may worsen outcomes for cancer patients through hypoxia-induced blood vessel growth in tumors.
The findings was discovered by lead author Dr. Antoni Vilaseca, of the Hospital Clinic De Barcelona in Spain, and his colleagues. It was presented at the European Association of Urology (EAU) Congress in Munich, Germany.