Cancer can spread from one part of the body to other areas. Where the cancer started is called the primary cancer and where it spreads to is called the secondary cancer. Your doctor has told you that you have a primary bowel cancer that has spread to your lungs. This is one of the commonest areas in the body for a bowel cancer to spread. Cancer cells have broken away from the primary bowel cancer and travelled round your body through the bloodstream. This probably happened some time ago, before your primary cancer was diagnosed and treated. These bowel cancer cells have lodged in your lungs and started to grow so the cancer in your lungs is secondary to your bowel cancer. This is different to a primary lung cancer where the cancer originates in the lung.

As the cancer in your lungs is made up of bowel cancer cells, it will respond to treatment that is designed for bowel cancer. The most common treatment for bowel cancer that has spread is chemotherapy. This may be with 5-FU and Folinic acid or, if you have had 5-FU before, with one of the newer chemotherapy drugs used for bowel cancer. Radiotherapy can also be used, but is less commonly given.

You mention that you are very breathless. Secondary cancer in the lungs can sometimes cause fluid to collect in the chest cavity, reducing the space available for the lungs to expand during normal breathing. It is possible to have this fluid drained off and this should relieve breathlessness almost immediately. If the fluid continues to collect, it is possible to have treatment to prevent or reduce it. This involves having an injection into the pleural cavity (the space surrounding the lungs). The injection irritates the two linings covering the lung and causes them to stick together. Once this has happened, there is no longer a space between the linings therefore preventing the build up of fluid again.