Response to Chemo and Tumor Aggressiveness - 1264717

Oh Seth, you've been doing homework. ;) That's a good question and one I've wrestled with and one I think has an answer akin to, "it depends" or maybe better "there are many factors of which aggressiveness and responsiveness are each one". If a person's cancer were to stay the same throughout its course it would respond a certain amount to chemo, a lot, a little, or somewhere in between. Add to that equation how aggressive the cancer is such as small cell usually responds very well to first line because it's more aggressive than nsclc. Also an individual's cancer changes over time, adapting to becoming less responsive to treatments. Then when you think you have a handle on its biology, it changes altogether. Hopefully your dad's cancer will respond long and well and you'll get a good understanding of his cancer.

All best,
Janine

I agree that's the extended interpretation of the general concept, but the issue is that long-term survival is a product of several factors, of which the natural history/underlying pace of the cancer is just one. Another very important one is the degree to which treatment leads to tumor shrinkage/regression, which can effectively "turned back the clock" on the cancer. Another factor is the underlying health of the patient and the overall "tumor burden" of the cancer (essentially, a measure of the volume of disease).

If you read this post (http://cancergrace.org/lung/2013/01/20/mf-bac-algorithm/ ), you will see that the underlying pace of the cancer is clearly a very important factor: Essentially, it is a reason that so many patients with an indolent cancer (like many BACs) can do so well for so long despite often demonstrating an underwhelming response to treatment. Essentially, the issue is that you can end up getting to the same place with a slow process that doesn't change or a faster one that responds and then grows, responds and then grows. The best would be a slow process that also reverses well with treatment, and that's better than a slow process that doesn't respond.

I think the key issue with your thought process here is that tumor shrinkage is a favorable result and that stable disease can either be from the cancer moving slowly anyway or being faster growing but potentially tripped up transiently. If you think of tumor shrinkage as turning back the clock, that's clearly preferable to keeping things where they are. But then, you also want the clock to run slower too.

-Dr. West

Thanks Seth,

I couldn't agree more about Grace and the fear of the unknown.
There's an excellent rationale for Grace that the knowledge we gain here can help with treatment decisions and that's clearly a good enough reason for Grace. Though the satisfaction of understanding is a real physical game changer for so many people, not especially for my husband but for you and me and many others who have suggested the same. It makes me want to put a number with data on it. :wink:

Janine

I think more and more people are inclined to know. I'm of the mindset that knowledge is power, and having some sense of understanding ofthe options gives a bit of control in an all too uncontrollable situation.

That said, I also feel that if someone has the right to something, they also have the right to decline to exercise that option...in other words, if ignorance is bliss for some people, who am I to force feed them information?

-Dr. West

This discussion really got me thinking, and I have a related conceptual question.

How do we reconcile the adage "responders respond" and the knowledge that the efficacy of treatment reduces over time?

If a patient has had stable (but visible) disease for say 5 years with ongoing treatment, he clearly is a responder. But how does his prognosis at the 5 year mark compare with that of a newly diagnosed patient who hasn't begun treatment?

Does "responders respond" win? Or does the fact that he's been on treatment for 5 years suggest that the efficacy of treatment must very soon run its course and give way to the disease imminently?

Hi Luke,

I think that when you look at a patient whose cancer remains controlled with treatment for a very extended period (such as the five years you mention), it is either a case of someone who responds very well to a targeted agent (and doesn't develop resistance) or a patient whose cancer is somewhat indolent. Either way, they are on the "tail" of the survival chart, and don't represent the typical patient. They don't tend to follow the "rules".

I think "responders respond" is most apt when you're talking about the likelihood of response to second or third line treatment in a patient who has responded well to previous treatment vs. one who has not. I don't think you can compare the prognosis of a newly-diagnosed, untreated patient to one who is still responding at five years, because you don't know how well that new patient will respond, or how aggressive their cancer is.

JimC
Forum moderator

I'm afraid that these kinds of questions entail reading too much into some general ideas as if they are well studied truisms. As uncommon as 5-year survivors are, they are individual cases and are never compared in any systematic way to newly diagnosed patients. There is no way to glean rules from a population like 5-year survivors with advanced NSCLC, particularly in terms of what to expect after the 5 year mark. Some may be on their way to a survival of 8 or 10 or more years, and some may have a survival that is destined to be limited to 5.5 years.

-Dr. West