Cancer cells are mutated versions of normal human cells. The mutation will cause the cancer cells to grow without any external signal from the rest of the body. Despite the mutation, the cells can be otherwise normal.
In many types of cancer the abnormality causes the cells to proliferate from a single mutated cell into a tumor. As the tumor grows it can also cause the creation of additional arteries, veins, and capillaries in order to provide oxygen and nutrients to the tumor cells.
Now comes the important part.
If cancers are detected early enough, many patients can experience a complete cure by "simply" removing all of the cancer cells. This sometimes requires removing some or all of an organ that contains the tumor and some organs can tolerate partial or complete removal.
The problem is that recurrence of the cancer may happen if only a single cancer cell is left in the body. The removal of a cancerous tumor requires great care to ensure that no cancer cells are spilled from the tumor into the rest of the body.
Now comes another really important part.
Tumors sometimes tend to grow so much and so fast that they outgrow the ability of the circulatory system to keep them alive. This can result in necrosis of the tumor; that is, some of the cells die. The resulting tumor can then become very unstable and likely to shed cells into areas that were otherwise tumor-free.
The upshot of this is that the process of removing a tumor is complicated by the necessity of handling it with great care so as to ensure that every single cancer cell is removed.
I can understand how the risk of disturbing a tumor in a patient might be so high as to postpone treatment for a wound in order to evaluate the tumor and establish optimum conditions for successful surgery to remove it.
I'm not a doctor but I've met a lot of them recently and this is my understanding of the issues I have described.
What you say about figuring out the best way to deal with it makes sense. Thank you. That eases my mind. A lot.