zzoe
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My healthy non-smoking middle-aged husband was diagnosed out of the blue with stage IV poorly differentiated NSC lung adenocarinoma (negative for EGFR, ROS1, ALK1). His cancer is responding very well to chemo (carbo/alimta) and the primary tumor shrunk by half after 2 rounds.
I understand that poorly differentiated NSCLC means this type of cancer grows fast and therefore initially responds well to chemo. But I also have gleaned that it can mutate and become chemoresistant sooner than slower-growing types of cancer.
I'd like to learn more about the specifics of chemoresistance and how long that takes.
Thank you.
Forums
Reply # - July 15, 2014, 10:26 AM
Reply To: How long until chemoresistance?
Hi mamasan,
It's good to hear your husband's cancer is responding well to treatment. Chemo resistance varies from patient to patient and so it can't be predicted for an individual case.
Dr. West has said:
Here's a general introductory post on tumor grade and survival:
http://cancergrace.org/lung/2007/03/20/tumor-grade-and-prognosis-in-nsc…
It's true that oncologists tend to see that the slowest growing cancers often don't respond very briskly to chemo, which works largely by taking advantage of the fact that cancer cells divide more quickly and sloppily than normal non-cancer cells (it's what we think gives some selectivity to the general anti-DNA sledgehammer approach of conventional chemotherapy). We also see that some of the fastest-growing cancers, like small cell lung cancer, some lymphomas and leukemias, etc., can have rapid and dramatic responses to standard chemotherapy. However, within the field of lung cancer, there really isn't much in the way of detailed research that shows that a poorly differentiated cancer is more sensitive to chemotherapy than a well differentiated one.
In fact, there are many factors. A rapidly dividing, poorly differentiated cancer may be more responsive initially but may be more likely to develop resistance sooner because those rapidly and sloppily dividing cells could be more likely to develop new mutations that lead to resistance to any given treatment. So there could easily be a difference between responsiveness to treatment and duration of benefit, rate of progression whenever treatment is not effective, and other factors. These are still very individualized, so whatever we might predict based on a population of people may be very different for any individual person and their individual cancer, so I would be hesitant to make any great predictions of how things will go. It's not rare to see a cancer behave differently than the way we might predict based on how it appears "on paper"
JimC
Forum moderator
Reply # - July 15, 2014, 06:28 PM
Reply To: How long until chemoresistance?
Yes -- there is great variability in how individual patients respond, even with similar descriptions of their tumor pathology. Please remember that if there is a reported median progression-free survival of 5 months, this means that half of the patients will progress before then, and half will progress after that. But with individual results quite variable, the range could fall anywhere from progression within weeks to progression 3 years later, yet the median progression-free survival is still 5 months.
The most important thing is just seeing how someone actually does on treatment. As another general rule, the better the response, the longer it tends to last before the cancer demonstrates progression.
Good luck.
-Dr. West