Cancer is a very "greedy", and it will go to any place it might reach, but there are three main paths:

1, lymph node metastasis
Lymph node metastasis in general the earliest, so for tumor excision, it is necessary for lymph node dissection; Radiotherapy In addition to exposure to the primary tumor lesions, but also exposure to the surrounding lymph nodes. The lymphatic system throughout the whole body, is ideal for the transfer of cancer cells and the preferred channel. Lymph node metastasis is often from near and far, such as breast cancer metastasis to the ipsilateral axillary lymph nodes first, then transferred to the supraclavicular and lower lymph nodes, and even contralateral axillary lymph nodes. Direct invasion of vascular or lymphatic cancer cells into the blood vessels will arrive with the blood flow in other parts, such as lung, brain, liver and bones, which is the blood line of the transfer. Gastrointestinal cancer often transferred to the liver and lung, breast, kidney, osteosarcoma, and so often transferred to the lungs, lung cancer and easily transferred to the brain, prostate cancer metastasis to the bone easily.

2, blood metastasis
Chemotherapy is to avoid the transfer of cancer cells through blood lines, while the drug "along the" destroy cancer cells.
Third, implantation metastasis

There is also a transfer of relatively small, that is cultivation. If you fall off the surface of cancer cells from the tumor, "off" in the chest, abdomen and brain spinal cord cavity, etc., will "take root." Takes place usually in the lower part of the cavity, such as the costophrenic angle, rectal bladder fossa, skull base, etc.. Ordinary people are fond of saying that what the total carcinogenic, in fact, we can not say anything as long as the eating will not get cancer, or what will get access to cancer. Has yet to find any kind of factor is a necessary factor in causing cancer.

 

The most important thing is to overcome cancer, early detection, early cancer, most can be cured. To this end, we must, first regular medical examinations, and second, that depends on a number of uncomfortable symptoms may be linked to cancer, do not feel the pain, and we have to see a doctor.