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

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What did your vet say yesterday?

Good luck.