Senior dog (12 years old, 37lbs) with Grade 3 Lung Carcinoma - Treatment Failure & Rapid Decline

[AceV]

This is my first time posting here, and I'm honestly quite scared. I'm reaching out because I need perspective from people who've been through something similar. My dog's situation is changing rapidly, and I'm trying to make the right decisions while feeling overwhelmed.

Initial Diagnosis & Treatment Plan​

My 12-year-old dog was diagnosed with grade 3 pulmonary carcinoma (3.6 x 2.9 x 3.3cm) with hilar lymph node metastasis in July 2025. In September, surgery was attempted but aborted due to tumor enlargement and risk. Biopsy confirmed: grade 3 carcinoma with high mitotic index (MI-33), angioinvasion, and lymph node metastasis.

Initial medications: Codeine, Gabapentin, Carprofen. All baseline blood work was unremarkable before starting Palladia.

Treatment Attempt & Failure​

Palladia Trial (4-5 weeks after surgery):

• First dose (standard dose): Severe toxicity - bloody diarrhea and vomiting. Treated at ER, improved with supportive care.
• Second attempt (reduced dose 30mg every 48 hours + Pepcid + Ondansetron + Metronidazole ): Diarrhea and vomiting again (no blood). Continued for one week.
• Stopped Sunday, 2 days ago: Given the clear pattern of toxicity despite dose reduction and supportive medications, I made the decision to discontinue Palladia.

New Development: Rapid Disease Progression​

This week (days before stopping Palladia):

1. Appetite loss: Saturday and Sunday didn't eat. Ate some Monday. Started having diarrhea and vomiting Tuesday (today).
2. New suspicious lump: Hard, red lump appeared on right side between lower ribs. Started pea-sized, now approximately 1-1.5cm in just ONE WEEK.
3. Declining overall status:
   • Still alert and drinking some water
   • Mostly sleeping
   • Moving very slowly, not walking much
   • Not sure about pain level

My concern: This rapid appearance of a new lump (growing from pea to 1.5cm in one week) suggests either metastatic spread of lung cancer or a new aggressive primary tumor.

What I Know​

• My vet appointment is TODAY to discuss these new findings
• I want honest answers about realistic prognosis and disease trajectory
• I'm trying to balance "not giving up" with "not prolonging suffering"
• My priority is his comfort and dignity, not extending his life at any cost

Questions for the Community​

1. Has anyone had a dog that couldn't tolerate Palladia due to severe GI toxicity? What did you do? Did stopping it and focusing on comfort seem like the right call?
2. For those who've seen rapid new lumps appear in senior dogs with cancer: Did you pursue diagnosis (biopsy) or go straight to comfort care?
3. How do you know when it's time to stop treatments and focus purely on making the dog comfortable? What were the signs for you?
4. For dogs that stopped eating during end-stage cancer: What did you do? Force feeding, appetite stimulants, or just letting them eat what they wanted?
5. Euthanasia timing: How did you know it was time? What quality-of-life markers did you use?

Thank you for taking the time to read this and consider sharing your experience.

 

[HA! Support]

Thank you for your post, Ace. I am so sorry. As a pet mom myself, I know the pain of situations such as this.
I have tagged our experts so they see your post @Dr. Jeff @Dr. Christina @Dr. Jean Hofve
In the meantime, spend as much time with your pup as possible. The love and connection will only help you BOTH Kim @ Holistic Actions! Support

 

[Dr. Jeff]

Hi Ace!

I'm also very sorry to hear about your pup's metastatic lung cancer.

Yes, being scared and anxious about what to do and future uncertainty is really, really tough.

1. Has anyone had a dog that couldn't tolerate Palladia due to severe GI toxicity? What did you do? Did stopping it and focusing on comfort seem like the right call?

Yes. Palladia and any artificial strong strong can have these effects. Finding gentle, natural alternatives may be a better way to optimize and maintain quality of life.

1. For those who've seen rapid new lumps appear in senior dogs with cancer: Did you pursue diagnosis (biopsy) or go straight to comfort care?

It depends on the situation and the full context. In your situation I personally focus more on hospice care.

1. How do you know when it's time to stop treatments and focus purely on making the dog comfortable? What were the signs for you?

BEAM, frequency of the happy moments, etc. For example, what happens if you both sit outside?

1. For dogs that stopped eating during end-stage cancer: What did you do? Force feeding, appetite stimulants, or just letting them eat what they wanted?

Find whatever food they'll eat. Meats, fish, poultry, freeze dried, Wysong Dream Treats, etc.

1. Euthanasia timing: How did you know it was time? What quality-of-life markers did you use?

BEAM and good times vs. bad.

I also highly recommend @Gail Pope's course in the HA! member area about hospice, comfort care, etc. You can also contact Gail directly through Brighthaven:

BrightHaven Menu for Healing & Animal Wellbeing

BrightHaven is unique for the work we do and the results we get. Our holistic approach to healing is renowned as our animals seem to live longer and look healthier than most. For example, Frazier the cat survived cancer and lived to age 34 and Ollie the paralyzed Dachshund lived to age 24. It’s...

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What did your vet say yesterday?

Good luck.

 

[AceV]

Hi @Dr. Jeff ,

What the Vet Said About Palladia: My regular vet confirmed they suspect the poor eating, diarrhea, and vomiting are due to Palladia toxicity. They prescribed:

• Cerenia (for nausea/vomiting)
• Probiotics - haven't been able to give since he hasn't been wanting to eat.
• Pro-Bactelin (anti-diarrhea)

They advised giving it "some time" for the Palladia to wear off, but I need to call back to clarify exactly what timeline they mean—is this a couple of days or a few days? That would help me know what to expect.


The Eating/Symptom Timeline:

• Last Saturday & Sunday: Stopped eating completely (had final Palladia dose Sunday)
• Monday: Ate a little bit, then diarrhea and vomiting started
• Tuesday: Ate a small amount
• Wednesday: Diarrhea and vomiting stopped (good sign), but he didn't eat anything at all
• Thursday (this morning): Offered his favorite treats several times. He finally showed interest and tried to eat, but spit it back out immediately.

Energy Level & Movement: Beyond the appetite issue, I'm also noticing his energy level is very low. His movements are extremely slow, and he's not walking around much—mostly just staying in one spot resting. I know lameness/weakness can be a Palladia side effect, but I'm unsure if this slowness is from that, from the overall toxicity effects, or if it's something more serious related to disease progression. How do we know the difference? Should this improve as the Palladia wears off, or is this something I should be more concerned about?


My Main Concern: His appetite has basically flatlined. The GI symptoms are improving (diarrhea/vomiting stopped), which suggests some recovery is happening, but very slowly. I'm worried that if he doesn't eat, he'll continue declining and lose more strength. Additionally, his overall energy level is very low and his movements are extremely slow—I'm not sure if this is a residual Palladia side effect (lameness/weakness) that will improve as the drug wears off, or if it's something more serious related to the cancer progression.


My Questions:

1. Should I ask the vet for an appetite stimulant (like mirtazapine) to help him eat during this recovery period? I want to make sure he gets enough nutrition to recover from the Palladia toxicity, but I also don't want to force anything that could upset his stomach more.
2. Regarding the slow movement and low energy—how do we know if this is Palladia's side effects wearing off versus disease progression? Should his mobility improve as the Palladia leaves his system?

Any thoughts on either of these concerns?

My Question: Should I ask the vet for an appetite stimulant to help him eat during this recovery period? I want to make sure he gets enough nutrition to recover from the Palladia toxicity, but I also don't want to force anything that could upset his stomach more.

Any thoughts on whether an appetite stimulant would help at this stage, or if I should just give it more time?

---

​

 

[Dr. Jean Hofve]

Mirtazapine has worked well for me but it takes a few days to kick in. If you’re considering it, start now. It can be compounded into a topical so it doesn’t go through GI tract. If comfort and treat foods aren’t tempting enough, it’s probably worth a try.

Meat baby foods are a good option for this situation, with a glob on your finger if he doesn’t lick it off you can easily smush it in under the lips. Sometimes “priming the pump” that way will work!

 

[Dr. Jeff]

My Questions:

1. Should I ask the vet for an appetite stimulant (like mirtazapine) to help him eat during this recovery period? I want to make sure he gets enough nutrition to recover from the Palladia toxicity, but I also don't want to force anything that could upset his stomach more.

Yes. I agree that this drug is OK to try for now. However, like any drug, it does not address the energetic root of the dis-ease. However, at this point, adding a trained vet homeopath may not be ideal (time, energy, expense etc). Perhaps instead support the body to heal as best it can through nutrition, Reiki, massage, and joy

1. Regarding the slow movement and low energy—how do we know if this is Palladia's side effects wearing off versus disease progression? Should his mobility improve as the Palladia leaves his system?

Ideally, yes. The response will depend on the individual susceptibility and resilience.

My Question: Should I ask the vet for an appetite stimulant to help him eat during this recovery period? I want to make sure he gets enough nutrition to recover from the Palladia toxicity, but I also don't want to force anything that could upset his stomach more.

Yes, ask for the mirtaz. and give it a few days. At the same time, though, keep offering tempting foods and try not to get discouraged.