Was told squamous nsclc did not need biomarker testing as no biomarkers would be found. I insisted. Tumor...
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This answer was generated by AI grounded in NCCN guidelines and published medical literature. It is not medical advice. Always consult your oncologist or care team before making treatment decisions.
Question asked:
Was told squamous nsclc did not need biomarker testing as no biomarkers would be found. I insisted. Tumor successfully resected- pT1cpN0M0. Pathology misreported someone else's result, and after clarification, was again squamous nsclc, not adenocarcinoma. Biomarker test (NEO Genomics) indicated both ROS1 via FISH at 66% and KRAS nonG12C. A second biomarker test (Caris) indicated KRAS G12D and TP53, but no ROS1. My research indicates that any of this is rare, especially in Squamous nsclc. I don't trust what has been found, but should I seek a 3rd opinion?
Your Biomarker Testing Situation: Facts & Next Steps
What Your Results Show
You're correct that biomarkers in squamous NSCLC are genuinely rare. According to NCCN Guidelines for Non-Small Cell Lung Cancer, squamous cell carcinoma historically has fewer actionable mutations compared to adenocarcinoma, which is why some clinicians historically didn't recommend biomarker testing for this subtype.
However, your insistence on testing revealed findings that warrant clarification:
Test 1 (NEO Genomics):
- ROS1 rearrangement at 66% (via FISH)
- KRAS non-G12C mutation
Test 2 (Caris):
- KRAS G12D mutation
- TP53 mutation
- No ROS1 detected
The Discrepancy Problem
The conflicting ROS1 results are the critical issue—one test found it at a substantial level (66%), the other found nothing. This is not a minor difference; ROS1 status fundamentally changes treatment considerations. KRAS mutations also show variation between tests (non-G12C vs. G12D specifically).
Should You Seek a Third Opinion?
Yes, but strategically:
Rather than a third biomarker test, request:
- Tumor tissue review — Ask if both labs tested the same tumor sample or if there's any possibility of specimen mix-up (given your earlier pathology error)
- Clarification from your oncologist on which result they consider more reliable and why
- Reflex testing or confirmation — Your oncologist may recommend sending the original tissue to a third reference lab (like Foundation Medicine or MSK-IMPACT) specifically to resolve the ROS1 discrepancy
- Technical explanation — Ask each lab why their results differ (FISH vs. NGS methodology, sample quality, etc.)
Why This Matters
According to NCCN Guidelines, ROS1-positive NSCLC (regardless of histology) typically qualifies for targeted therapy with crizotinib or other ROS1 inhibitors. If you truly have ROS1 at 66%, this changes your treatment landscape significantly. If you don't have it, it doesn't.
This is worth resolving before making treatment decisions.
This information is for educational purposes only. Always consult your healthcare team for personalized medical advice and decisions.
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