Around 90 percent of patients now overcome early-stage cancer, yet the toxic effects of chemotherapy and other types of treatment can have a detrimental effect on the overall health of survivors. According to a new commentary in the journal Cell, exercise-based therapy protocols devised by NASA to help astronauts withstand the stress of spaceflight could also aid recovery from cancer treatment.
Outside of Earth’s atmosphere, astronauts’ bodies are subjected to microgravity and higher levels of radiation, which the study authors say has a similar impact to being treated for cancer. Physical inactivity and changes in body weight compound these effects, for both astronauts and cancer patients.
Consequently, symptoms such as muscle atrophy, bone demineralization, anemia, and immune dysfunction are commonly experienced by those in orbit, as well as people undergoing chemotherapy, radiotherapy, immunotherapy, and other forms of cancer treatment.
Describing the similar cognitive effects of spaceflight and cancer treatment, study co-author Jessica Scott explained in a statement that "astronauts may get something called space fog, where they have trouble focusing or get a little forgetful. That's very similar to what some cancer patients experience, which is called chemo brain."
Back in the 1960s, NASA scientists calculated that astronauts taking part in the Gemini missions experienced a 25 percent decrease in cardiorespiratory fitness (CRF) after just four days of microgravity. Interestingly, various anticancer regimens have been found to produce a similar decline in CRF.
When devising a protocol to combat the effects of spaceflight, NASA opted against the use of pharmaceutical drugs due to their potential to cause unwanted side-effects like drowsiness or arrhythmia. Instead, an exercise-based program was introduced in order to improve the reserve capacity of all bodily systems before spaceflight, thereby enhancing astronauts’ ability to withstand the stresses of extra-terrestrial travel.
Continued exercise while in space is designed to help astronauts maintain their physiological functionality at around 75 percent of their pre-flight levels, and further training after landing back on Earth ensures they return to their baseline capacity as quickly as possible.
However, the researchers note that “structured exercise rehabilitation is not standard of care in any cancer population or setting,” despite growing evidence that it produces enhancements in CRF and other bodily functions for patients undergoing cancer treatment.
Summarising the paper’s findings, Scott says that “this NASA exercise framework could be applied to help the approximately 1 million individuals that will be diagnosed with cancer in the United States this year, as well as the over 15 million cancer survivors in the United States today."