Manufacturing cancer drugs, and drug resistance

Don't know about the second question, but the first is plausible. Off the top of my head: compounds derived from yew (Taxus) and Madagascar periwinkle (Vinca) are used in chemotherapy. Blushwood (Fontainea picrosperma) is being investigated as a potential anti-cancer agent. (I don't know where that one is at the moment. Last I heard, they were hoping to move into clinical trials.)

Cancers become resistant to drugs. I've not heard of populations (of people) doing so.

liz, you could conceivably use metals, too. These have a history in medicine.

https://www.ncbi.nlm.nih.gov/pubmed/15274320

Yes, it's plausible—for the reasons Helix mentions—and you might find more of the information you're looking for at NCBI starting with "Medicinal Plants and Cancer Chemoprevention". Of particular interest might be section 2: MEDICINAL PLANTS AND CANCER.

As explained to me by my spouse's oncologist, cancer cells that are not killed by chemo can mutate and become resistant to the chemo in that person. I wouldn't know how that chemoresistance might translate in an entire population, though. It might be dependent on the type of cancer and its cause.

ETA: We know certain cultural populations are remarkably free of specific types of cancer (comparatively speaking) and it's believed this is because of diet. So another approach if viable for your MS might be that segments of your population might no longer adhere to traditional diets which have been preventive. With the reason for those diets having been lost to time, new research hasn't yet explored or is only beginning to explore the dietary connection. (Just a thought.)

Individuals (or their cancers, rather) can and do develop resistance to cancer drugs. It's why cancers can be harder and harder to treat when they recur and the arsenal of new drugs that effectively target that particular cancer runs dry. The mechanism is similar to what we see with infectious agents developing resistance, with the cells that resist the drug best surviving the treatment and continuing to grow (or being stunned temporarily but not killed, then starting to grow again), causing a recurrence of a cancer that has been knocked down for a while.

Cancer cells often accumulate multiple mutations as they divide very quickly and generally have mechanisms to repair DNA damage as well, so new drug resistant mutations can develop in a population within a patient too.

I don't think a population level resistance to a particular cancer drug is likely, however. Doxorubicin (one of the "workhorse" chemotherapy drugs), for instance, can lose its effectiveness over time in a particular patient, but it hasn't lost its power as a chemotherapy drug for other patients after decades of use by oncologists.

Cancers arise in individuals spontaneously as a consequence of gene mutations in their somatic cells. Cancers are not communicable diseases, so you won't have the issue of a person who had some cells with a resistance to a drug passing those cells onto another individual in the same population.

There are a very small number of cancers that are communicable. The ones I know of occur in dogs or in Tasmanian devils, though, not in humans (there may be some rare cancer that works that way in us, however, but I don't know of any offhand). Communicable cancers could potentially develop drug resistance that could spread to other people if the first patient manages to pass cancer cells on after their cancer recurs. I don't know if this has ever been tested in the dog and Tasmanian devil cancers.

The use of particular plants to fight cancer actually goes back a ways, though the effectiveness would have been less without the capacity to isolate the effective compounds and concentrate them. I believe women used Yew bark to fight breast cancer long before the compound taxol was isolated and developed into a drug. There are also fungi that have been shown clinically to improve outcomes for some patients. However, it's not going to be as effective on its own as a more scientifically targeted regimen of more purified drugs. We're starting to learn about why some drugs will have a great effect on a given patient's disease and have little to no benefit for a different patient whose disease looks similar on the surface, but there's a long ways to go.

https://sciencebasedmedicine.org/why-we-dont-prescribe-bark-for-cancer/

(The cancers associated with STDs are arguably communicable.)

Patty said:

(The cancers associated with STDs are arguably communicable.)

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You guys are all so smart. You covered all the things I would have said.

I can add to this list:

lizmonster said:

Sounds like I'm safe with the plants. As for the rest...hrm. I knew about specific cancers being able to become immune to treatment, but I need something that'd work over a larger population, and either be abruptly environmentally systemic or inherited.

Which may steer me back toward gene modification. It's SF; I can posit some tech that will let them do it, I suppose. But then I need to come up with a credible mistake they made, that they still somehow think they can fix (even if they actually can't). Hrm. I don't love that; it's a bit complication ex machina.

I know many (most) the chemo drugs are teratogenic, and some result in permanent fertility issues. The thing is, to survive as long as they have (about 250 years), they'd both know this and have adapted to it. I need something to have changed.

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It's fiction, you can give your population a genetic mutation that results in the liver metabolizing said cancer drug before it has a chance to work.

Or people can inherit an allergy to said drug. Speaking from experience, serum sickness caused by a drug you are allergic to (differs from anaphylaxis) means you can never take that drug again if you want to live.

The plants your cancer drug comes from can suffer a massive loss from an infectious agent. That's what caused the potato famine in Ireland. It's why we all worry about Monsanto growing crops that are so genetically similar one new pathogen can wipe them out. Diversity in food crops is a critical thing.


Yay, I had something to add.

lizmonster said:

Sounds like I'm safe with the plants. As for the rest...hrm. I knew about specific cancers being able to become immune to treatment, but I need something that'd work over a larger population, and either be abruptly environmentally systemic or inherited.

<snip>

ETA: All of this is in aid of an R&R in which the agent asked me "but why?" and I'm trying to come up with a reason for a fairly swift population crisis. Cancer made sense, because they're living on a planet with a fairly weak magnetosphere, so they're both prone to cancer and well aware of the need to proactively fight it where they can.

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Does it need to be cancer? Is she concerned about the collapsing population?

A population-wide collapse b/c of environmental insult is easy enough to build. (heh. I mean...) I'd go for some tipping-point calculation to do with the temperature on your world--or alternatively in order to deal with the extreme temp they used geo-engineering (or whatever) to tap the planet's heat and volatiles in the mantle are reaching toxic levels in their breathable air. Think along the lines of fracking and how the benzene levels in blood are astronomical in some of these places (non-fiction, US, although the benzene is from the solvents but the idea is a starting point.). I can see a way to give all your people benzene-induced cancer with that--or some other ailment not cancer. Or, they're at the limit of what human's can stand cold -wise, and the temperature just nudged down to a dangerous level. Frostbite, gangrene on a population level...

Aha!

*snort* Yeah, I'm about to betray my ignorance 'cause I'm not at all science-y. If you're going to go with plant-based chemo and knowing plants are affected by the MF, then what degree shift (positive or negative) in the MF of your world would it take to affect germination or root growth negatively? Is that something you could play around with?

lizmonster said:

<snip> I need something to have changed.

ETA: All of this is in aid of an R&R in which the agent asked me "but why?" and I'm trying to come up with a reason for a fairly swift population crisis. Cancer made sense, because they're living on a planet with a fairly weak magnetosphere, so they're both prone to cancer and well aware of the need to proactively fight it where they can.

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Why not use animal or bacterial producers. Vaccines are made using yeast, drugs are produced in goat milk, pigs' blood vessels work well as human vascular replacements.

Medicine From Milk: Gene Therapy Could Transform Goats Into Pharmaceutical Factories

Creating Human Drugs From Genetically Engineered Animals

Turning Plants into Drug Factories

Why cancer? There are few chemotherapy drugs that can be replicated through plant-based options although there are some cancers that can be treated with plant-based chemicals. There hasn't been enough research to verify that cancer adapts to drug resistance in the same way a virus will and, given the medical process involved, it would be highly unlikely for a population to develop a cancer resistant to specific medications. But new cancers are found all the time and a new cancer that can't be treated by known options is always possible.

You might want to rethink cancer as your disease and choose something viral if you want a population resistant to treatments.

Jeff