Steph, is this why you "push" radiation therapy a lot?

http://www.merck.com/mrkshared/mmanual/section11/chapter142/142a.jsp
Cancer: A proliferation of cells whose unique trait--loss of normal
controls--results in unregulated growth, lack of differentiation, local
tissue invasion, and metastasis.

Cancer (malignancy) can develop in any tissue of any organ at any age.
Most cancers are potentially curable if detected at an early stage. By
performing self-examinations, patients can help recognize early signs of
some possible malignancies. Diagnostic testing and therapy are essential
for optimal results. When cure or reasonable palliation is likely,
physicians must discuss all therapeutic options.

Patients with cancer that is unlikely to be cured need to be informed
about what treatment is likely to accomplish and the side effects it may
produce. Intensive care may be needed for treatment-related complications.
Psychologic support from the physician and the health care team (which may
include a psychiatrist and a social worker) helps patients through therapy
(see Complications, below).

Physicians must be truthful, yet convey a sense of optimism. Some patients
may need to be advised against health care practitioners who falsely
promise cure. The patient should feel that members of the health care team
are concerned and available to answer questions. The physician should
initiate frank discussions about end-of-life care and advance medical
directives at an appropriate time (see Ch. 294).
Cellular Kinetics

Generation time is the time it takes for cells to enter the cell cycle
(see Fig. 142-1) and give rise to two daughter cells. Malignant cells
usually have a shorter cycle than nonmalignant cells. Most nonmalignant
cells have a larger percentage of cells in G0 (resting phase), so that
there is a smaller proliferation fraction. Initial exponential tumor
growth is followed by a plateau phase when cell death equals the rate of
formation of daughter cells. Compared with large tumors, small tumors have
a greater percentage of cells in cycle and thus greater proliferation.

Cellular kinetics are important in the design of antineoplastic drug
regimens. Many antineoplastic drugs are effective only if cells are in
cell cycle, and some drugs work only during a specific phase of the cycle.
Cellular kinetics may influence the dosage schedules and timing of
treatment.
Tumor Growth and Metastasis

As a tumor grows, nutrients are provided by direct diffusion from the
circulation. Local tissue invasion can result in pressure on normal
tissues, which can lead to inflammation, or the tumor may produce
substances (eg, collagenase) that lead to enzymatic destruction of
tissues. Subsequently, synthesis of tumor angiogenesis factor causes
formation of an independent vascular supply to the tumor. Almost from
inception, a tumor may shed cells into the circulation. From animal
models, it is estimated that a 1-cm tumor sheds > 1 million cells/24 h
into the venous circulation. In animals, circulating tumor cells usually
die as a result of intravascular trauma; the longer a tumor cell spends in
the circulation, the greater the chance of its death. The probability that
a circulating tumor cell will become a metastatic tumor is estimated at <
1:1 million.

Metastases develop when tumor cells adhere to vascular endothelium and
penetrate into surrounding tissues, surviving and spawning independent
tumors at distant sites. Thus, tumor growth resumes, disrupting normal
tissue and organ function. Metastatic tumors can give rise to other
metastases.

Experiments suggest that metastasis is not a random event and that the
primary tumor may regulate the growth of metastatic tumors (eg, in renal
cell carcinoma, the rate of growth is often similar in the primary and
metastatic nodules). Theoretically, removal of the primary tumor can
result in rapid growth of the metastases.[]

Is the above the reason for your "Questions to Ask"?
Does radiation therapy "contain" (or even stop) "rapid growth"?
J