When to Watch; When to Act?

Both the panel in Kansas City and the Symposium in Freiburg addressed this key question: When to watch a kidney tumor, and when to act? With today's better diagnostic methods, we are able to see tumors when they are very small, but at what point should action be taken?

There is no simple formula on which all physicians agree. But the evidence is mounting that VHL tumors have different behavioral characteristics than sporadic renal cell carcinoma: they tend to grow more slowly, are less aggressive, are more numerous, and have a 50% chance that there will be more after some years in the future.

There are no definite rules to guide patients or physicians, and our speakers were divided on this subject. Dr. Mark J. Noble of the University of Kansas Medical Center said that most urologists familiar with VHL now agree that you need not remove kidney tumors less than 2-3 cm. in size. He then removes the tumors and saves as much functioning kidney as possible. Dr. Craig Hawkins shared that in the experience of the Mayo Clinic they did have one patient who seemed to have a metastatic cancer from a tumor smaller than 2 cm. While they also practice renal sparing surgery whenever possible, they tend to operate on smaller tumors and cysts. Dr. Hartmut Neumann and his colleagues at the University of Freiburg do not operate for cysts alone, but only for larger tumors. His experience is that the safety limit may be higher than 3 cm. He generally waits until 4 cm.

Because no one can be sure, it is important that the patient be involved in making the decision about when to remove the tumors. With today's surgical techniques it is unlikely that the kidney can be operated upon more than 3 times before it will need to be completely removed, so operating too soon may result in loss of the kidney earlier in life. On the other hand, waiting too long may result in the cancer spreading to another place in the body. Dr. Neumann works with his patients to evaluate the position of the tumors, their tissue densities and growth patterns, the family kidney history, and the risk the patient is willing to live with. He has ten patients with tumors ranging up to 4 cm. without metastasis.

New kidney treatments may make it possible to operate more often on the kidney with less damage to kidney function, but they still entail surgery. The best hope is that research such as Dr. Linehan's work on the genetics of kidney cancer will lead to non-surgical therapies which will constrain the growth of kidney tumors and prevent or reverse the spread of kidney cancer.

• pages 2-3, World Focuses Attention on VHL
• page 7, VHL Gene Linked to Kidney Cancer