Cold temperatures, a potential ally against cancer
Exposure to cold temperatures can reduce tumour growth by slowing down the glucose metabolism of cancer cells.
Study in mice
According to a study published in Nature in August 2022, researchers at Karolinska Institutet compared tumour growth and survival rates in mice with various types of cancer, when exposed to cold versus warm living conditions. The researchers tested colorectal, breast and pancreatic cancer tumours. They found that mice acclimatized to a temperature of 4°C had significantly slower tumour growth and lived nearly twice as long as mice in rooms at 30°C.
The explanation lies in the glucose metabolism of cancer cells. Indeed, cancer cells typically need large amounts of glucose, or sugar, to grow. Researchers found that cold temperatures triggered significant glucose uptake in brown adipose tissue, also known as brown fat, a type of fat that is responsible for keeping the body warm during cold conditions. Meanwhile, the glucose signals were barely detectable in the tumour cells. When the researchers removed either the brown fat or a protein crucial for its metabolism, the beneficial effect of the cold exposure was essentially cancelled out and the tumours grew at a similar rate to those exposed to higher temperatures.
Interestingly, feeding tumour-bearing mice with a high sugar drink also obliterated the effect of cold temperatures and restored tumour growth. This finding suggests that limiting glucose supply is probably one of the most important methods for tumour suppression.
Application on a human clinical case
To study the human relevance of these findings, the researchers conducted a pilot trial on a cancer patient undergoing chemotherapy. The patient wore light clothing while spending time in rooms at 22°C for a week and then in rooms at 28°C for four days. The imaging scans showed increased brown fat and lowered glucose uptake by tumour tissue at 22°C.
Based on these results, the authors are optimistic that exposure to cold temperatures and activation of brown adipose tissue combined with other therapeutic approaches such as drugs could contribute to treating cancer.
 Cool room temperature inhibited cancer growth in mice. https://news.ki.se/cool-room-temperature-inhibited-cancer-growth-in-mice
 Seki, T., Yang, Y., Sun, X. et al. Brown-fat-mediated tumour suppression by cold-altered global metabolism. Nature 608, 421–428 (2022). https://doi.org/10.1038/s41586-022-05030-3