Krishnan Patel, MD, MHS

Academic Radiation Oncologist. All views are my own and not reflective of my employer.

[Advances, an ASTRO Journal @Advances_ASTRO]

New biomarker analysis from NRG/RTOG 8610 & 9202 asks a key ❓: does p27 predict outcomes after radiotherapy for prostate cancer? 🔬

🧬 What is p27?
A cyclin-dependent kinase inhibitor that regulates the cell cycle and tumor growth.

In a cohort of 361 patients treated with RT ± ADT, nuclear p27 levels were not prognostic for:

📊 overall survival
🌍 distant metastases
🧪 biochemical failure

⚠️ This contrasts with the post-prostatectomy literature, where low p27 has been associated with worse outcomes.

💡 Hypothesis: the biologic effects of radiation + ADT may override the adverse impact of low p27, highlighting important differences between surgery and radiation mechanisms.

Takeaway:
🔬 Biomarkers may behave differently depending on treatment modality
⚡ RT biology may neutralize prognostic signals seen in surgical cohorts
🔎 More work needed to validate treatment-specific biomarkers

The author list is stacked! @krishnan_patel @ACurreyMD @drjefstathiou @DrPaulNguyen just to name a few!

https://t.co/FpVeM0Dm0D

@ASTRO_org

[Ravi A Madan M.D. @Dr_RaviMadan]

Many thanks🙏🏽to the team!
@melissaabel20 @Dr_JeannyAC @ArlenParlen @karen_autio @mbilusic @PChoyke @DeborahCitrin @JulieGr28180604 @FatimaKarzai @MarkowskiGUOnc @CathyHandy @RPachynski @krishnan_patel @EdwinPosadasMD @laurasenamd @xiaoweimd @HelenMoonMD @davidjeinstein

[Krishnan Patel, MD, MHS @krishnan_patel]

@VickersBiostats @5_utr I share this frustration. While graphically easy to explain, I have trouble discussing RMST with patients (or physicians). The best I have come up with is quoting RMST gain for a treatment at a patient’s life expectancy, which seems the most natural index. Problems here too.

[Krishnan Patel, MD, MHS @krishnan_patel]

@RafaelOliveLeit @5_utr I usually start by mentioning that we know nothing for certain. If asked, "Will X help me?" I might say, “Yes, probably so. For people like you, there is a small chance of a big benefit (HR <0.5), a medium chance of a meaningful benefit (HR <0.9), and small chance for harm (HR>1)

[Krishnan Patel, MD, MHS @krishnan_patel]

@radiolobt Congrats Baris! This is amazing!!! Thanks for all you've taught me!

[Krishnan Patel, MD, MHS @krishnan_patel]

@jryckman3 @aapmHQ Agree. Lots to say on this but I believe a majority of the clinical data establishing CTs as risk factors for cancer may in part suffer from confounding by indication. Re: health risks from low-dose exposure this brief paper may be of interest: https://t.co/ofW6BFBT65

[Krishnan Patel, MD, MHS @krishnan_patel]

@VedangMurthy @melissaabel20 @SBasourakos @DeborahCitrin @Dr_RaviMadan Likewise, kudos to you and the team: @DrSrinivas_C , @MutlaySayan & @a_dalpra for the nice summary of ENRT. I was not aware of your contouring study (https://t.co/rE6y5kQmtE) until reading your review. Long live the bowel bag! Very helpful for our upcoming study on ENRT!

[Krishnan Patel, MD, MHS @krishnan_patel]

Check out our recent review on enhanced systemic therapy for localized prostate cancer now freely available: https://t.co/WSXM1U6HvN

A big thanks to our team (@melissaabel20, @SBasourakos, @DeborahCitrin) and Ravi (@Dr_RaviMadan) for his leadership on this one!

[Krishnan Patel, MD, MHS @krishnan_patel]

@radiolobt @melissaabel20 @SBasourakos @DeborahCitrin @Dr_RaviMadan Thank you, Baris!

[Baris Turkbey MD @radiolobt]

2025 summary of our original research articles in #prostatecancer
🟢🟢🟢🟢🔵🟠🟡🟡🟡⚪️⚪️⚪️⚪️🟣🟣🟣🟣🟣🟣🟣🟣
(published=🟢, accepted=🔵, revision=🟠, under review=🟡, draft=⚪️, data analysis=🟣)
#CancerResearch #AI #Radiology #TeamScience #Teamwork #ArtificialIntelligence
👍🎉@DrSHarmon @OTEsengur @davidgelikman @spatkar94 @Haque_Fahmida_ @SandeepGurramMD @apkenigsberg @FatimaKarzai @krishnan_patel
Ben Simon, Nathan Lay, Hunter Stecko, Emma Stevenson and our collaborators everywhere in the World 🙏💙🥇

[Krishnan Patel, MD, MHS @krishnan_patel]

@ProtonStorey @ASTRO_org As you note, as absolute risk is lower the absolute benefit of ADT will be lower (although relative may be the same), so I try to make some judgement on the extent to which modern staging techniques alter the NCCN risk stratum in my patients for purposes of counseling.

[Krishnan Patel, MD, MHS @krishnan_patel]

Thanks @ASTRO_org for featuring our article (PMID: 39922318). I hope it will help to help practicing physicians understand, discuss, and recommend ADT in patients with intermediate-risk prostate cancer, especially in cases on the margin of the FIR and UIR stratification.

[Krishnan Patel, MD, MHS @krishnan_patel]

@ProtonStorey @ASTRO_org Thanks, @ProtonStorey, I have several thoughts hard to summarize here. I believe the favorable absolute bDFS in PACE-B is in part due to the low baseline risk / higher BED (40Gy/5# CTV as you note). While ≈75% were UIR, Gl. 4+3 excluded and stage migration(MRI, target bx).

[Krishnan Patel, MD, MHS @krishnan_patel]

@ChaurasiaMD @SbrtSean Well put @SbrtSean! I think conventional size restriction can be relaxed as we get more comfortable with SBRT. Speaking to this, @NRGOnc’s recent GU013 allows patients with ≤100 cc whereas GU005 was capped at 70cc. Papers which might be of interest PMIDs: 37984713, 36836467

[Krishnan Patel, MD, MHS @krishnan_patel]

@sujanapriya @jryckman3 Thanks, @sujanapriya , glad you enjoyed it and hope it is helpful for your practice!

[Krishnan Patel, MD, MHS @krishnan_patel]

@jryckman3 You're too kind buddy, it was a team effort for sure. Looking forward to additional posts about our ongoing and future work and further discussion on this forum.

[Krishnan Patel, MD, MHS @krishnan_patel]

Open access link: https://t.co/TKBN59TDHP

[Krishnan Patel, MD, MHS @krishnan_patel]

Work is in progress to enhance this analysis with individual patient level data until @neildesai2005 and @aleberlin2 can report the results of NRGOnc’s NRG GU010 which will hopefully will hopefully give us a more intelligent way of selecting ADT intensity for IR prostate cancer.