Cancerous tumor norm?

There is no "norm".   Every cancer is going to follow it's own course.   Cancers can be slow or fast growing.  There are no "one size fits all" answers when it comes to cancer.

It;s easy enough to ask a doctor.

Some tumors are very indolent.  Certain lymphomas for example can remain small for many years -- and they can occur in the abdomen.

But most cancers grow and spread -- until the person dies.

It depends on the type of tumor. For the most part it will not only grow in size, it will also invade nearby tissues and in the final stages metastasize- which means it will spread to other organs. There are some cancers that stay asymptomatic for the longest time and are only detected in the final stage due to metastasis. These have a bad prognosis in general. Some tumors take years to grow and metastasize, some are very aggressive and it all happens fast, for example a certain type of brain tumor. 

Leaving malignant tumors untreated almost always results in death sooner than later.

A cancerous tumour will continue to grow.

The rate at which it grows can vary depending on the cell type.

The likelyhood of it spreading (metastasis) can vary depending on the cell type.

Some tumours will grow rapidly - doubling in size every week.

Others can take a year to double in size.

All start as a single cell so if it only doubles every year it could be years before it is even the size of a grain of rice.