Management Plan: Revabhai Patel, 76M - mHSPC with Bone Metastases

Clinical Summary from the PSMA PET-CT

Step-by-Step Management

1. Confirm Disease Status / Baseline Work-up

• Confirm castration status - obtain serum testosterone. If not already on ADT, this is de novo mHSPC.
• PSA: 24.5 ng/mL (14-05-26) - document as baseline
• Gleason/ISUP grade from biopsy - essential for risk stratification (LATITUDE criteria: Gleason ≥8, ≥2 bone lesions, visceral mets = high risk; this patient has only 2 bone lesions, so LATITUDE low risk)
• Labs: CBC, LFTs, RFTs, serum calcium, alkaline phosphatase, LDH, HbA1c (before starting steroids if abiraterone used)
• Bone densitometry (DEXA scan) - ADT causes bone loss; baseline needed
• Germline testing (BRCA1/2, ATM, etc.) + somatic tumor profiling - 2025 CUA guidelines give this a strong recommendation for all metastatic PCa; BRCA2 mutations may qualify for PARP inhibitor later

2. Primary Systemic Treatment - ADT + ARPI Doublet (Standard of Care for Low-Volume mHSPC)

In synchronous low-volume mHSPC, ARPI + ADT provides statistically significant OS benefit over ADT alone (HR 0.65; 95% CI 0.52-0.80). Adding docetaxel to ARPI+ADT does not improve OS in low-volume disease (HR 1.08; 0.65-1.79 - non-significant).

• Enzalutamide 160 mg/day orally (ARCHES/ENZAMET trial)
• Apalutamide 240 mg/day orally (TITAN trial)
• Darolutamide 600 mg twice daily orally (ARASENS/ARANOTE trials - new 2025 data)
• Abiraterone acetate 1000 mg/day + prednisone 5 mg twice daily (LATITUDE/STAMPEDE)

For a 76-year-old, darolutamide or apalutamide may be preferred due to a more favorable CNS/falls/seizure risk profile compared to enzalutamide - important in elderly patients.

• LHRH agonist (leuprolide/goserelin) - add bicalutamide 50mg x 2 weeks at initiation to prevent testosterone flare
• LHRH antagonist (degarelix/relugolix) - preferred in patients with cardiovascular risk or spine mets (no flare risk); relugolix (oral) offers convenience

Given D12 vertebral metastasis with high SUVmax (18.8), avoid testosterone flare - prefer LHRH antagonist or cover with bicalutamide.

3. Bone Health Management (Mandatory)

• Zoledronic acid 4 mg IV every 4 weeks (or denosumab 120 mg SC every 4 weeks) to prevent skeletal-related events (SREs)
• Calcium 1200 mg/day + Vitamin D 800-1000 IU/day supplementation (mandatory with bone-targeting agents)
• Dental review before starting bisphosphonate/denosumab (risk of osteonecrosis of the jaw)
• Monitor renal function before each zoledronate dose (contraindicated if GFR <30)

4. Prostate-Directed Radiotherapy - Consider in Low-Volume Disease

• In patients with low-volume mHSPC, addition of prostate radiotherapy (hypofractionated EBRT) to systemic therapy improved rPFS (HR=0.65 in PEACE-1 abiraterone arm)
• OS benefit was not proven, but radiotherapy is recommended as an option for low-volume mHSPC to delay progression
• This patient has no SV/rectal invasion and bladder neck abutment without infiltration - prostate RT is feasible

• Hypofractionated prostate EBRT (e.g., 36.25 Gy in 5 fractions, or 60 Gy in 20 fractions)

5. Stereotactic Body Radiotherapy (SBRT) to Bone Metastases

• Metastasis-directed therapy (MDT) with SBRT to D12 vertebra (high SUVmax 18.8 - high local risk) and sternum can be considered for local control and pain prevention
• D12 vertebral involvement - monitor for cord compression symptoms (back pain, neurological signs); urgent MRI spine if these develop

6. Monitoring Plan

• PSA every 3 months initially, then every 6 months on stable treatment
• Testosterone level to confirm castrate levels (<50 ng/dL or <1.7 nmol/L)
• Imaging: repeat PSMA PET-CT or bone scan at 6-12 months, or sooner if PSA rises or symptoms develop
• Metabolic monitoring: lipid profile, fasting glucose (on ARPI), blood pressure, LFTs (on abiraterone), ECG (enzalutamide carries seizure/fall risk)
• Watch for CRPC: PSA rising despite castrate testosterone on 2 consecutive measurements 1 week apart = CRPC - triggers next-line therapy planning

7. Incidental Findings to Address

• Cystitis with bladder diverticulum: urine culture, treat if infected; urological follow-up
• Mosaic perfusion pattern in bilateral lungs: low priority but consider respiratory review if symptomatic (likely chronic change)
• Left adrenal: non-PSMA expressive, marginally bulky - low suspicion; note and follow
• Spondylotic changes: physiotherapy, pain management as needed

8. MDT and Supportive Care

• Refer to Uro-oncology MDT: Urologist + Medical Oncologist + Radiation Oncologist + Nuclear Medicine
• Geriatric assessment given age 76: assess frailty, comorbidities, polypharmacy before ARPI initiation
• Counsel on ADT side effects: hot flashes, fatigue, loss of libido, gynecomastia, metabolic syndrome, osteoporosis, cardiac risk
• Psychosocial support and patient/family counseling about disease prognosis and goals of care

Summary Algorithm

mHSPC, LOW VOLUME, 76M
       |
       ├─ Start ADT (LHRH antagonist preferred) + ARPI doublet
       |   (Darolutamide or Apalutamide preferred in elderly)
       |
       ├─ Bone protection: Zoledronate + Ca/Vit D
       |
       ├─ Discuss prostate EBRT (low-volume mHSPC benefit)
       |
       ├─ Consider SBRT to D12 vertebra (high SUVmax lesion)
       |
       ├─ Germline + somatic genomic testing
       |
       └─ 3-monthly PSA + castrate testosterone monitoring

• 2026 AUA/SUO Advanced Prostate Cancer Guideline
• 2025 CUA-CUOG Guideline (PMID: PMC12091045)
• Riaz IB et al., Eur Urol 2026 - Living NMA by disease volume (PMID 41193370) - confirms doublet (not triplet) is optimal for low-volume synchronous mHSPC
• Smith and Tanagho's General Urology, 19th Ed., p. 426

Disclaimer: This is clinical decision support for a qualified treating physician. Final management must be individualized after full clinical assessment, patient preferences, comorbidities, and local drug availability.

No - This Cannot Be Cured

Why Surgery Is Not the Answer Here

• Put a 76-year-old through major operative risk for zero survival benefit
• Not address the bone metastases at all
• Still leave him needing all the same systemic treatments afterward

What Treatment Actually Does Here

The Honest Prognosis

• Low-volume mHSPC (like this patient - only 2 bone lesions, no visceral spread) actually carries a relatively favorable prognosis among metastatic patients
• With ADT + ARPI doublet therapy, median overall survival in clinical trials has been 6-8+ years
• This patient may respond very well - PSA can drop dramatically (sometimes to undetectable) within months
• However, most patients eventually develop castration-resistant prostate cancer (CRPC) where the cancer grows despite low testosterone - this typically happens after a median of 2-3 years, at which point next-line therapies are available

The Right Mindset for This Patient

"We cannot cure this cancer, but we can control it for years, keep you feeling well, and continue to have active treatment options as the disease evolves."

The Core Concept: Prostate Cancer Feeds on Testosterone

ADT - Androgen Deprivation Therapy

How it works:

Brain (Hypothalamus)
       ↓  releases GnRH/LHRH
Pituitary Gland
       ↓  releases LH
Testicles
       ↓  produce Testosterone
Cancer cells GROW

ADT drugs available in India:

For this patient (D12 vertebral met), prefer LHRH antagonist (degarelix/relugolix) - it drops testosterone immediately without a dangerous initial "flare" that can worsen spinal cord compression.

ADT side effects to warn patient about:

• Hot flashes
• Loss of sex drive
• Fatigue
• Weight gain
• Bone thinning (osteoporosis) - why we add zoledronate
• Mild memory/mood changes

ARPI - Androgen Receptor Pathway Inhibitor

Testosterone (very low after ADT)
       ↓
Androgen Receptor (the LOCK on cancer cell)
       ← ARPI BLOCKS THIS LOCK
Cancer cell cannot grow

ARPI drugs (choose ONE):

For a 76-year-old like this patient, darolutamide is preferred - it does not cross the blood-brain barrier well, so lower risk of falls, dizziness, and seizures compared to enzalutamide.

The Combination - Why Both Together?

Practical Starting Plan for This Patient

Day 1:
  → Degarelix 240mg SC (loading dose) - immediate testosterone suppression
  → Start Darolutamide 600mg twice daily orally
  → Start Zoledronate 4mg IV (bone protection)
  → Calcium + Vitamin D daily

Month 1 onwards:
  → Degarelix 80mg SC monthly
  → Continue Darolutamide daily
  → Check PSA + Testosterone at 3 months
      - PSA should fall significantly (often >90% drop)
      - Testosterone should be <50 ng/dL (castrate level)

Survival Without Proper Treatment

The Short Answer:

What Happens Without Treatment - The Timeline

Months 0-6:
  PSA continues rising rapidly
  Bone lesions enlarge and multiply
  Bone pain begins (especially back pain from D12 vertebra)

Months 6-12:
  Severe bone pain requiring strong opioids
  D12 vertebral lesion enlarges → risk of SPINAL CORD COMPRESSION
    (sudden paralysis of legs - a medical emergency)
  Pathological fractures (bone breaks spontaneously without injury)
  Fatigue, weight loss, anemia

Months 12-24:
  Cancer spreads to more bones, possibly liver/lungs
  Hypercalcemia (high calcium from bone destruction - causes confusion)
  Urinary obstruction from prostate enlarging further
  Kidney failure (from ureteric obstruction or hypercalcemia)
  Death - typically from:
    → Complications of bone metastases
    → Infection/sepsis
    → Organ failure

Comparison - With vs Without Treatment

The Most Dangerous Risk for THIS Patient Specifically

Spinal cord compression can happen suddenly - the patient wakes up one morning unable to move his legs. This is irreversible if not treated within hours. It is one of the most feared complications of untreated spinal bone mets.

Why Families Sometimes Hesitate

• Age 76 is not too old - many 76-year-olds live active lives for another 10+ years
• ADT injections are well tolerated - not like chemotherapy; no hair loss, no severe nausea
• The cost of not treating is much worse - severe pain, paralysis, hospital admissions are far more expensive and distressing than preventive treatment
• Quality of life on treatment is significantly better than without it

Bottom Line

Why D12 (T12) is Dangerous in This Patient

First - Where is D12?

MRI of thoracic spine - note how the spinal cord runs as a white stripe behind each vertebral body. Any lesion pressing on it causes catastrophic neurological damage. - Rosen's Emergency Medicine

The Anatomy - Why This Location is Critical

Spinal Cord ends at approximately L1-L2
(called the CONUS MEDULLARIS)

D12/T12 is right above this termination point

   T10 ─── Spinal cord running here
   T11 ─── Spinal cord running here
   T12 ─── ← THIS PATIENT'S METASTASIS (SUVmax 18.8)
    L1 ─── Conus medullaris (tip of spinal cord)
    L2 ─── Cauda equina begins

1. The spinal canal is narrowest in the thoracic region - very little room for any extra mass
2. D12 sits right at the conus medullaris - the most critical junction of the entire spinal cord
3. Damage here causes both upper and lower motor neuron signs simultaneously

What Happens When the D12 Met Grows

Normal:                    With met growing:
[vertebra][cord][space]    [collapsed vertebra ──→ CORD SQUEEZED]

What MSCC at D12 Causes - The Warning Signs

Back pain that is WORSE LYING DOWN is the classic red flag - this is the opposite of disc pain (which is better lying down). In a cancer patient, this pattern = spinal met until proven otherwise.

If MSCC Happens - Time is Everything

MSCC develops
     ↓
<24 hours: Patient can still walk → treat urgently → good chance of recovery
     ↓
24-48 hours: Partial weakness → treat now → partial recovery possible
     ↓
>48 hours complete paralysis: Permanent paralysis very likely
     ↓
No treatment: Permanent paraplegia (cannot walk ever again)

Emergency Treatment if MSCC Occurs

1. IV Dexamethasone 10mg bolus immediately - reduces edema around cord, buys time
2. Urgent MRI whole spine - to confirm level and extent
3. Emergency radiotherapy (SBRT/EBRT) to D12 - best option for this patient
4. Neurosurgical decompression - if bone collapse is causing direct mechanical compression

What to Do NOW (Preventively)

• Start systemic treatment (ADT + ARPI) urgently - shrinks the met over weeks to months
• Refer to Radiation Oncology for prophylactic SBRT to D12 - local radiotherapy to this specific vertebra to kill the cancer cells there and prevent collapse
• Educate patient and family about the warning signs above
• MRI spine (whole spine) - to see if any cord indentation is already happening that the PET-CT may not have fully captured

Sternal Body Metastasis - This Patient's Findings

• Sternal body: sclerotic lesion, SUVmax 3.7
• Compare to D12: SUVmax 18.8

What the Sternum Is and Why It Matters Less (But Still Matters)

Anatomy of the Sternum

         Manubrium (top)
              │
         Sternal body ← THIS PATIENT'S MET
              │
         Xiphoid process (bottom)

Behind the sternum:
   Heart (anterior surface)
   Great vessels (aorta, SVC)
   Thymus / anterior mediastinum

Why the Sternal Met is LESS Dangerous Than D12

• Local pain - anterior chest pain / tenderness on pressing the sternum
• Pathological fracture of the sternum - painful but not life-threatening
• In extreme cases of very large lesion - could theoretically encroach on the pericardium or great vessels, but this is rare and would take a very long time

The SUVmax 3.7 - What Does It Mean?

SUVmax 3.7  →  Low-moderate PSMA avidity
               Sclerotic (bone hardening reaction)
               Relatively indolent/slow-growing lesion

SUVmax 18.8 →  Very high PSMA avidity
               Highly active cancer deposit
               Growing fast, high risk

Symptoms to Watch For from the Sternum Met

• NSAIDs (if renal function allows) or paracetamol for mild pain
• Opioids (tramadol/morphine) if pain is significant
• Local radiotherapy (SBRT) if pain becomes troublesome and uncontrolled

Should SBRT Be Given to the Sternum Too?

• If the patient is asymptomatic from the sternum - systemic treatment (ADT + ARPI) alone is sufficient; the met will likely shrink/stabilize
• If he develops significant sternal pain that is not controlled by oral analgesics - then palliative radiotherapy (single fraction 8 Gy or 20 Gy in 5 fractions) to the sternum gives excellent pain relief in >70% of patients
• No urgency like D12

Summary - Comparing Both Mets

D12 Vertebra (SUVmax 18.8)          Sternal Body (SUVmax 3.7)
────────────────────────────         ──────────────────────────
⚠️ HIGH URGENCY                      ✓ LOW-MODERATE CONCERN
Spinal cord immediately behind       No neural tissue nearby
Paralysis risk if untreated          Pain / fracture risk only
Needs prophylactic SBRT NOW          Treat only if symptomatic
Most dangerous lesion in this pt     "Watch and treat if needed"