What's the next step for a patient with a history of oropharyngeal cancer and left lung metastasis, status post radiation, who continues to experience left-sided torso pain despite negative Fluorodeoxyglucose Positron Emission Tomography (FDG PET) scan and Computed Tomography Angiography (CT angio) chest?

Management of Persistent Left-Sided Torso Pain in a Patient with History of Oropharyngeal Cancer and Lung Metastasis

For a patient with history of oropharyngeal cancer with left lung metastasis who continues to experience left-sided torso pain despite negative imaging studies, a focused evaluation for bone metastasis is strongly recommended as the next step.

Clinical Context Assessment

The patient presents with:

• History of oropharyngeal cancer with left lung metastasis
• Status post radiation therapy
• Negative FDG PET scan (4/9/2025)
• Negative CT angio chest (6/26/2025)
• Persistent left-sided torso pain

Diagnostic Approach

Step 1: Evaluate for Bone Metastasis

Persistent pain in cancer patients, especially in the torso region, should raise suspicion for bone metastases despite negative imaging studies. Lung cancer accounts for approximately 50% of all brain metastases and commonly metastasizes to the skeletal system 1, 2.

• Recommended imaging:
  • MRI of the painful area (chest wall/spine): Superior for detection of early bone metastases and soft tissue involvement 1
  • Bone scintigraphy (bone scan): Can detect focal abnormalities in nearly half (49.4%) of patients with atypical chest pain 1

Step 2: Consider Additional Advanced Imaging

If initial bone-focused imaging is negative:

• CT chest with bone algorithm/reformats: Unfolded rib reformatted images may improve diagnostic accuracy for rib involvement 1
• Targeted ultrasound: For evaluation of chest wall soft tissues if clinically indicated 1

Rationale for Bone Metastasis Evaluation

1. High clinical suspicion: Persistent pain in a cancer patient is concerning for metastatic disease until proven otherwise
2. Common metastatic pattern: Bone is a common site for metastasis from oropharyngeal cancer with lung involvement
3. Limitations of prior imaging:
   • FDG-PET has limitations in detecting small or low-metabolic bone metastases
   • CT angio focuses on vascular structures and may miss bone lesions

Management Algorithm

1. If bone metastasis is detected:

   • External radiation therapy (Grade 1A recommendation) 1
     • A single fraction of 8 Gy is equally effective for immediate pain relief and more cost-effective than higher fractionated doses 1
   • Add bisphosphonates (Grade 1A recommendation) 1
   • Consider surgical fixation if lesion involves >50% of cortex in weight-bearing bones 1
   • For vertebral compression fractures, vertebral augmentation procedures are recommended (Grade 1A) 1

2. If no bone metastasis is detected:

   • Evaluate for other treatable causes of pain (Grade 1C) 1
   • Consider opioids for pain management (Grade 1B) 1
   • Consider corticosteroids if pain is attributed to radiation-induced inflammation (Grade 1C) 1

Important Considerations

Pitfalls to Avoid

1. Missing early metastases: Up to 36% of lung metastases can be missed on initial CT scans 3
2. Attributing pain to non-cancer causes: Musculoskeletal symptoms may be the first sign of metastatic disease 4
3. Inadequate pain management: Pain control should be prioritized while diagnostic workup proceeds

Special Considerations

1. Radiation recall: Pain could be related to radiation-induced inflammation
2. Chest wall invasion: Extension of tumor into the pleura or chest wall can cause localized pain, which may be severe 1
3. Post-radiation changes: May complicate imaging interpretation and require specialized protocols

By following this approach, you can systematically evaluate the persistent left-sided torso pain in this patient with a history of oropharyngeal cancer and lung metastasis, focusing on the most likely and concerning etiology while ensuring appropriate pain management.