When we talk about 'lung cancer' we mean a cancer that has first started in the lung. This is also known as 'primary' lung cancer.

Some testicular cancers can send seedlings of tumour cells through the blood stream to the lungs and these can form what are called 'secondary' testicular cancers in the lung tissue. These are also called 'metastases' or 'metastatic testicular cancer'.

Secondary testicular cancer in the lung is made up of cells that have come from the original testicular tumour, so it behaves differently to primary lung cancer. This means that it is treated differently (usually with chemotherapy, although occasionally surgery may be used). Fortunately, this treatment is very effective and can often bring about a complete cure.

So in answer to your question, a testicular cancer that has spread to the lung is not the same as a primary lung cancer.