occur through direct invasion of contiguous organs, through

implantation, and by passage through the lymphatic system or

blood stream. That different histologic types tend to

metastasize at different rates (and to particular sites) is

an important consideration in the design of studies seeking

to identify psychosocial variables in the progression of

disease. That is, the site and histology of the cancer must

be limited or controlled for when comparisons of survival of

patients are made.

 Staging of disease. It is not uncommon for individuals

to hope that one with cancer will be given attention before

it is "too late." The concepts of "early" and "late" in

cancer care are integrally related to the extent of spread of

the disease from the primary site of development. As Haller

and Glick (1983) have pointed out, smaller and more localized

cancer can be treated more successfully and less radically.

Because of this, at the time treatment is initiated, an

important feature of an individual tumor is the extent of

spread, or metastasis. The assessment of the metastasis of

cancer is made through a process called staging which takes

into account such characteristics as tumor size, invasion

into adjacent tissues, metastasis to lymph nodes in the

region of the tumor, and metastasis to distant sites

(Haller & Glick, 1983).