onc brain

About · curated by Nick Boehling, MD · @nb2276

    Retrospective

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    Confirmatory

    ctDNA and Local Regrowth/Distant Mets in Nonoperative Management of Stage II-III Rectal Cancer

    ForMSS stage II-III rectal adenoca in cCR/nCR on watch-and-wait after TNT

    TL;DRctDNA sensitivity 41% for local regrowth vs 74% for distant mets; positive result predicts both but can't replace endoscopy/MRI surveillance in rectal NOM.

    Why it mattersRadiation oncology

    The asymmetry is the actionable read: ctDNA caught only 41% of local regrowths vs 74% of distant mets, so for post-TNT organ-preservation surveillance it flags distant-met risk but can't replace endoscopy/MRI. ctDNA+ at regrowth also tracked more advanced ypT3-4 salvage pathology (75% vs 21%).

    ctDNA and Local Regrowth/Distant Mets in Nonoperative Management of Stage II-III Rectal Cancer
    7 details 1 trial watching
    Design

    Prospective single-center cohort (MD Anderson INTERCEPT program), N=110, 2020-2024. Serial tumor-informed ctDNA (Signatera Exome), 669 samples; median follow-up 25 mo (IQR 18-37).

    Population & inclusion

    MSS stage II-III rectal adenocarcinoma in cCR (69) or nCR (41) after NAT, managed non-operatively. Median age 56; cT3 in 72 and cN1-2 in 60 of 110; NAT almost entirely TNT (104/110).

    Endpoints

    Regrowth-free and distant-metastasis-free survival by longitudinal and first-post-NAT ctDNA; per-sample diagnostic accuracy (±90d of each draw); salvage-surgery pathology by ctDNA status. No registered primary endpoint (observational).

    Results

    Local regrowth in 23 (21%), distant mets in 12 (11%). Ever-positive ctDNA tracked worse regrowth-free and distant-met-free survival (log-rank p=0.0002 and p<0.0001). Per-sample sensitivity 41% local regrowth vs 74% distant mets.

    EndpointSensitivitySpecificityAccuracy
    Local regrowth41% (12/29)94% (480/509)91% (492/538)
    Distant metastasis74% (31/42)97% (611/627)96% (642/669)
    vs leading data

    Consistent with the emerging ctDNA-as-prognostic signal in rectal NOM, but quantifies a sensitivity ceiling (41%) that limits its use for local-regrowth surveillance.

    Applies to
    MSS stage II-III rectal adenocarcinoma in cCR/nCR pursuing organ preservation after TNT
    Does not represent MSI-H tumors, operative-intent pts, or short-course-RT / chemoRT-only NOM pathways.
    Limitations

    Single-center, N=110 with only 29 regrowth- and 42 distant-met-associated samples driving diagnostic estimates. Assay-specific (Signatera tumor-informed); no comparison vs imaging-alone surveillance.

    Rationale

    Single-center prospective cohort (N=110), no interventional comparator; prognostic association consistent with emerging ctDNA-in-NOM data and reaffirms imaging/endoscopy surveillance can't be replaced.

    Monday clinic

    Applies to the MSS stage II-III rectal pt in cCR/nCR pursuing watch-and-wait after TNT, in whom a negative ctDNA still can't exclude local regrowth; it does not extend to MSI-H tumors or pts not pursuing organ preservation.

    Open questions
    • Does ctDNA-guided surveillance improve organ-preservation outcomes vs imaging alone
      recruiting ctDNA Monitoring to Predict the Efficacy of TNT for Rectal Cancer
      n=100 · primary completion 2025-12 · candidate match
    • Can serial ctDNA kinetics raise local regrowth sensitivity above 41%
    • Generalizability beyond single-center tumor-informed Signatera cohort
    📚 Sources · 🐦 1 tweet

    Curative Retrospective Confirmatory ASCO Annual Meeting 2026

    Confirmatory

    Genomic Classifier + NCCN Risk Stratification (Abstract 5000)

    ForNCCN high-risk/very-high-risk localized prostate cancer

    TL;DR22-gene GC independently prognostic (MFS/DM/OS, p<0.001); combined NCCN+GC score reclassifies ~¼ of high-risk pts to gate AAP intensification on an RT+ADT backbone.

    Why it mattersRadiation oncology

    ~¼ of NCCN ≥HR pts are clinical/GC-discordant, so the 22-gene GC reclassifies who reaches CT-VHR (≥3 pts) and has AAP added onto the fixed RT+ADT backbone. The intensification it triggers carries STAMPEDE M0 magnitude (MFS HR 0.53, OS HR 0.60). It sharpens the intensification decision, not RT dose or target.

    Genomic Classifier + NCCN Risk Stratification (Abstract 5000)
    +2 more figures
    Genomic Classifier + NCCN Risk Stratification (Abstract 5000)
    EndpointHR (add AAP)95% CIp
    MFS0.530.44-0.64<0.0001
    OS0.600.48-0.73<0.0001
    Genomic Classifier + NCCN Risk Stratification (Abstract 5000)
    7 details
    Design

    Retrospective validation of the 22-gene GC (Decipher) layered on NCCN clinical risk in NCCN ≥ high-risk localized prostate (NRG cohort), externally benchmarked to STAMPEDE M0 curves (Attard, Lancet 2022). Not a prospective RCT.

    Population & inclusion

    NCCN high-risk and very-high-risk localized prostate cancer, all planned for definitive RT+ADT.

    Regimen

    CT-HR (≤2 pts) → RT+ADT; CT-VHR (≥3 pts) → RT+ADT+AAP (abiraterone acetate + prednisone) intensification.

    Results

    GC is independently prognostic for MFS, DM, and OS over clinical variables (multivariable, p<0.001). Roughly one-quarter of NCCN ≥HR pts are clinical/GC-discordant, reclassifying risk band and the intensification call.

    ComponentCategoryPoints
    NCCN clinicalHigh-risk+1
    NCCN clinicalVery-high-risk+2
    GC (Decipher)< 0.60
    GC (Decipher)0.6-0.85+1
    GC (Decipher)> 0.85+2
    vs leading data

    AAP intensification magnitude is borrowed from STAMPEDE M0 (Attard, Lancet 2022), not generated here; GC prognostic value aligns with prior Decipher/NRG validation.

    Applies to
    NCCN high-risk and very-high-risk localized prostate cancer on definitive RT+ADT
    Does not represent intermediate- or low-risk disease, node-positive or metastatic disease, or the radical-prostatectomy pathway.
    Limitations

    Prognostic, not predictive: no randomized biomarker×treatment interaction showing CT-VHR pts gain more from AAP. Intensification benefit imported from an external trial's average effect.

    Rationale

    Retrospective GC prognostic validation, not a randomized predictive-biomarker trial; consistent with prior Decipher/NRG data. Intensification benefit borrowed from STAMPEDE, not shown to be GC-predictive.

    Monday clinic

    In NCCN high-risk/very-high-risk localized prostate planned for definitive RT+ADT, this supports GC-informed CT-VHR (≥3 pts) selection for AAP intensification; it does not extend to intermediate-/low-risk disease or change RT dose or target.

    Open questions
    • Does GC-guided AAP intensification improve outcomes prospectively?
    • Is GC predictive of differential AAP benefit, not just prognostic?
    • Optimal AAP intensification threshold in clinical/GC-discordant pts
    📚 Sources · 🐦 2 tweets

    Curative Retrospective Confirmatory ASCO Annual Meeting 2026

    Caveats dominate

    SWOG S1007

    ForHR+/HER2− breast, 1-3 nodes, Oncotype RS ≤25

    TL;DR5y LRR 0.55% without RNI vs 0.85% with; IDFS unchanged by RNI (HR 1.03 premenopausal, 0.85 postmenopausal) in RS ≤25 N1 breast.

    Why it mattersRadiation oncology

    The RT read: RNI omission after breast conservation carries low locoregional risk, 5y LRR 0.55% without RNI vs 0.85% with, in RS ≤25 N1 disease. Chemo omission alone is not an RNI indication, so this supports withholding RNI in biologically favorable N1, pending randomized confirmation.

    6 details 3 trials watching
    Design

    Secondary analysis of SWOG S1007 (RxPONDER), a phase 3 RCT of chemo omission by 21-gene recurrence score. RNI receipt was prospectively recorded, not randomized. Median follow-up 6.1y; survival landmarked at 1y.

    Population & inclusion

    HR+/HER2−, Oncotype RS ≤25, 1-3 positive nodes. 4871 had RT forms; 81% received RT, and 59% of those with target data received RNI (targeting ≥ supraclavicular region).

    Radiotherapy

    RNI defined as targeting at least the supraclavicular region. The 59/41 split in RNI use reflects genuine practice equipoise in favorable N1 disease.

    Results

    LRR was low across every locoregional approach; only mastectomy without RT reached 1.7%. IDFS did not differ by RNI in either menopausal group (see tables).

    Locoregional therapy5y cumulative LRR
    BCS + RT + RNI0.85%
    BCS + RT, no RNI0.55%
    Mastectomy + PMRT0.11%
    Mastectomy, no RT1.7%
    Menopausal statusIDFS HR95% CIp
    Premenopausal1.030.74-1.430.87
    Postmenopausal0.850.68-1.070.16
    vs leading data

    Consistent with MA.20 / EORTC 22922, where RNI's benefit was concentrated in higher-risk node-positive disease. TAILOR RT (MA.39) is randomizing RNI in exactly this RS-low N1 population.

    Applies to
    HR+/HER2−, RS ≤25, 1-3 node breast cancer on modern systemic therapy
    Does not represent higher recurrence-score, >3 node, or HER2+/triple-negative disease.
    Limitations

    RNI comparison is non-randomized: confounding by indication (higher-risk pts selected for RNI) can mask a true RNI effect. Landmarking at 1y and diverse-setting RT reporting add noise.

    Rationale

    RNI vs no-RNI comparison is non-randomized within RxPONDER; confounding by indication limits the null IDFS and low-LRR read. Randomized RNI trial (TAILOR RT) pending.

    Monday clinic

    In HR+/HER2− breast with 1-3 positive nodes and Oncotype RS ≤25, this supports omitting regional nodal irradiation given low LRR; it does not extend to higher recurrence-score or >3 node disease.

    Open questions
    📚 Sources · 📄 1 paper
    📄 PAPER Jagsi; Barlow; Woodward et al. · JAMA oncology (2023-08)
    Radiotherapy Use and Incidence of Locoregional Recurrence in Patients With Favorable-Risk, Node-Positive Breast Cancer Enrolled in the SWOG S1007 Trial.
    PMID 37410451 → doi full text (PMC)
    Abstract
    IMPORTANCE: Little is known about regional nodal irradiation (RNI) practice patterns or rates of locoregional recurrence (LRR) with and without RNI in patients with limited nodal disease and favorable biology treated with modern surgical and systemic therapy, including approaches that de-escalate those latter treatments.<br/><br/>OBJECTIVE: To investigate how often patients with low-recurrence score breast cancer with 1 to 3 nodes involved receive RNI, incidence and predictors of LRR, and associations between locoregional therapy and disease-free survival.<br/><br/>DESIGN, SETTING, AND PARTICIPANTS: In this secondary analysis of the SWOG S1007 trial, patients with hormone receptor-positive, ERBB2-negative breast cancer, and a Oncotype DX 21-gene Breast Recurrence Score assay result of no more than 25, were randomized to endocrine therapy alone vs chemotherapy then endocrine therapy. Prospectively collected radiotherapy information was collected from 4871 patients treated in diverse settings. Data were analyzed June 2022 to April 2023.<br/><br/>EXPOSURE: Receipt of RNI (targeting at least the supraclavicular region).<br/><br/>MAIN OUTCOME(S) AND MEASURE(S): Cumulative incidence of LRR was calculated by locoregional treatment received. Analyses were assessed for associations between invasive disease-free survival (IDFS) and locoregional therapy, adjusted for menopausal status, treatment group, recurrence score, tumor size, nodes involved, and axillary surgery. Radiotherapy information was recorded in the first year after randomization, so survival analyses were landmarked as starting at 1 year among those still at risk.<br/><br/>RESULTS: Of 4871 female patients (median [range] age, 57 [18-87] years) with radiotherapy forms, 3947 (81.0%) reported radiotherapy receipt. Of 3852 patients who received radiotherapy and had complete information on targets, 2274 (59.0%) received RNI. With a median follow-up of 6.1 years, the cumulative incidence of LRR by 5 years was 0.85% among patients who received breast-conserving surgery and radiotherapy with RNI; 0.55% after breast-conserving surgery with radiotherapy without RNI; 0.11% after mastectomy with postmastectomy radiotherapy; and 1.7% after mastectomy without radiotherapy. Similarly low LRR was observed within the group assigned to endocrine therapy without chemotherapy. The rate of IDFS did not differ by RNI receipt (premenopausal: hazard ratio [HR], 1.03; 95% CI, 0.74-1.43; P&#x2009;=&#x2009;.87; postmenopausal: HR, 0.85; 95% CI, 0.68-1.07; P&#x2009;=&#x2009;.16).<br/><br/>CONCLUSIONS AND RELEVANCE: In this secondary analysis of a clinical trial, RNI use was divided in the setting of biologically favorable N1 disease, and rates of LRR were low even in patients who did not receive RNI. Disease-free survival was not associated with RNI receipt; omission of chemotherapy among patients similar to those enrolled in the S1007 trial is not an independent indication for use of RNI.

    Radiation Curative Retrospective Caveats dominate

    Caveats dominate

    Proton vs Photon PMRT Capsular Contracture

    ForPostmastectomy implant-based reconstruction (TE/I or DTI) receiving PMRT

    TL;DRProton PMRT trended toward higher capsular contracture vs IMRT photon (univariate HR 2.3; MVA HR 1.76 ns); proton+DTI worst, 50% 2yr CC.

    Why it mattersRadiation oncology

    The interaction is the read: DTI reconstruction, not modality, dominates CC risk (HR 3.0), and proton+DTI stacks to 50% 2yr CC vs 12% for photon+TE/I. When proton is chosen for cardiac/pulmonary sparing, reconstruction choice (favor TE/I over DTI) is the modifiable lever.

    8 details 2 trials watching
    Design

    Retrospective, IRB-approved, 2 centers within one institution, Jan 2017 to Dec 2023. N=175 (89 proton, 86 photon). CC estimated by Kaplan-Meier; Cox proportional hazards for HRs, logistic regression to verify. Median follow-up 42 mo (proton), 47 mo (photon).

    Population & inclusion

    Breast cancer pts with subpectoral 2-stage tissue expander/implant (TE/I) or direct-to-implant (DTI) reconstruction receiving PMRT. Median age 49 (24-78); 63% Hispanic. All TE/I pts had the expander irradiated. Groups imbalanced on laterality (P<.001) and reconstruction type (P<.001).

    Radiotherapy

    PBS proton vs IMRT photon PMRT. Dose and fractionation not reported in source. In TE/I, the tissue expander itself was the irradiated target.

    Results

    Proton vs photon CC: univariate HR 2.3 (1.26-4.30, P=.007), attenuating to HR 1.76 (0.93-3.32, P=.083, ns) on multivariable. DTI vs TE/I: HR 3.0 (1.7-5.5, P<.001), the dominant driver. Per-group 2yr CC rates in the table.

    Modality + reconstructionn2-yr CC rate
    Proton + DTI3650%
    Photon + DTI1535%
    Proton + TE/I5323%
    Photon + TE/I7112%
    vs leading data

    Prior proton PMRT evidence centered on improved cardiac and pulmonary dosimetry; head-to-head capsular-contracture data proton vs photon were scarce. This is the largest proton reconstruction cohort reported to date.

    Applies to
    postmastectomy implant-based reconstruction (TE/I or DTI) receiving PBS proton or IMRT photon PMRT at a single institution
    Does not represent autologous reconstruction, non-irradiated reconstruction, or a randomized proton-versus-photon comparison.
    Limitations

    Retrospective, single-institution, N=175, with groups imbalanced on reconstruction type and laterality. The proton effect lost significance after adjustment (P=.083), so residual confounding (reconstruction type driving both proton selection and CC) cannot be excluded.

    Discussion

    The modifiable variable is reconstruction, not beam: DTI carries roughly 3x the CC hazard, and proton stacked on DTI reaches 50% 2yr CC. Where proton is chosen for heart or lung sparing, staged TE/I may blunt the CC penalty; a prospective comparison is needed to confirm.

    Rationale

    Retrospective single-institution cohort; groups imbalanced on reconstruction type and laterality; proton effect lost significance on multivariable (HR 1.76, P=.083). Signal, not confirmation.

    Monday clinic

    In a postmastectomy pt weighing DTI vs staged TE/I reconstruction who will receive proton PMRT, the CC signal is concentrated in DTI (proton+DTI 50% vs proton+TE/I 23% 2yr); it does not resolve proton vs photon overall, which was ns on multivariable.

    Open questions
    • Prospective proton vs photon PMRT capsular contracture comparison
    • Whether staged TE/I reconstruction mitigates proton capsular contracture risk
      recruiting Breast Mesh Used in Two-staged Breast Reconstruction Phase NA
      n=300 · primary completion 2023-08 · 2-stage expander/implant, capsular contracture EP
      recruiting Breast Reconstruction and Radiotherapy
      n=750 · primary completion 2027-08 · recon timing + type vs RT complication risk
    • Mechanism: proton dose distribution vs selection bias driving contracture
    📚 Sources · 📄 2 papers
    📄 PAPER Zerey; Gal; Feenstra et al. · International journal of radiation oncology, biology, physics (2026-04)
    Does Pencil Beam Scanning Proton Therapy Impart a Higher Risk of Capsular Contracture Compared With Intensity Modulated Photon Radiation Therapy in the Postmastectomy Reconstruction Setting?
    PMID 42009110 → doi
    Abstract
    BACKGROUND: Postmastectomy radiation therapy (PMRT) may cause adverse events in the reconstruction setting. Proton-based PMRT is increasingly used and has been shown to improve cardiac and pulmonary dosimetry. Data on the risk of capsular contracture (CC) with proton versus photon PMRT remain scarce. We compared the CC rate of the largest cohort of patients undergoing reconstruction after pencil beam scanning proton PMRT reported to date with an intensity modulated radiation therapy photon cohort, hypothesizing that the proton cohort would have a higher rate of CC.<br/><br/>METHODS AND MATERIALS: An institutional review board -approved retrospective study was conducted on patients with breast cancer who underwent subpectoral 2-stage tissue expander/implant (TE/I) or direct-to-implant (DTI) breast reconstruction and received either pencil beam scanning proton or intensity modulated radiation therapy photon PMRT between January 2017 and December 2023 at 2 centers within a single institution. All patients undergoing TE/I had the TE irradiated. CC rates were estimated using the Kaplan-Meier method. Cox proportional hazards analysis, denoted as hazard ratios (HRs) with 95% CIs, was used to assess variables potentially associated with the outcome, and a binary logistic regression model was used to verify the results.<br/><br/>RESULTS: The study cohort comprised 175 patients (89 proton; 86 photon). The median age was 49 years (range, 24-78), 63% were Hispanic. Patient demographics were well balanced between the groups, except in tumor laterality (P < .001) and reconstruction type (TE/I vs DTI; P < .001). The median follow-up was 42 and 47 months for the proton and photon groups, respectively. In a multivariable analysis, DTI patients had a significantly higher risk of CC compared with TE/I patients (HR, 3.0; 95% CI, 1.7-5.5; P < .001). Proton patients had a higher risk of developing CC compared with the photon group in univariate analysis (HR, 2.3; 95% CI, 1.26-4.30; P = .007), although this effect did not reach statistical significance in the multivariable model (HR, 1.76; 95% CI, 0.93-3.32; P = .083). The 2-year CC rate for patients treated with protons and DTI (n = 36), photons and DTI (n = 15), protons and TE/I (n = 53), and photons and TE/I (n = 71) was 50%, 35%, 23%, 12%, respectively (P < .001). No other factors were significantly associated with CC development.<br/><br/>CONCLUSION: In this contemporary large proton versus photon PMRT cohort, patients treated with proton showed a trend toward an increased risk of CC. Patients undergoing DTI who were treated with protons had the highest risk of CC (50%). Careful consideration of reconstruction and radiation therapy modalities, assessing CC risk, and also involving patient input, is important for treatment selection.
    📄 PAPER Zerey, M.M.; Gal, O.; Feenstra, N. et al. · International Journal of Radiation Oncology*Biology*Physics (2025-09)
    Does Pencil Beam Scanning Proton Therapy Impart a Higher Risk of Capsular Contracture when Compared with Intensity Modulated Photon Radiotherapy in the Post-Mastectomy Reconstruction Setting?
    doi
    📝 https://doi.org/10.1016/j.ijrobp.2025.07.1298

    Radiation Curative Retrospective Caveats dominate

    Confirmatory

    Multicenter TMT Bladder Preservation Analysis (n=369)

    ForMuscle-invasive bladder, cT2-T4aN0M0, median age 76

    TL;DRCLR 63.7% in 369 MIBC pts on definitive TMT; 5-FU-based CRT and better image guidance predicted higher complete local response.

    Why it mattersRadiation oncology

    The two modifiable levers here are RT delivery and chemo backbone, both in the radonc's hands: 5-FU-based CRT predicted higher CLR (OR 4.9) and weekly portal imaging lower CLR (OR 0.35, p<0.001), favoring daily volumetric IGRT. Technique, not just patient selection, moved local control.

    8 details 4 trials watching
    Design

    Multicenter retrospective cohort, Spain 2010-2022, N=369 treated with definitive TMT (maximal TURBT + concurrent chemoRT). Multivariable logistic regression for predictors of complete local response.

    Population & inclusion

    cT2-T4aN0M0 muscle-invasive bladder. Median age 76, 85.1% male. Node-positive and metastatic disease excluded by staging.

    Radiotherapy

    Image-guidance quality tracked with local control: weekly portal imaging predicted lower CLR (OR 0.35, p<0.001), favoring daily volumetric IGRT; VMAT showed a non-significant favorable trend. RT dose/fractionation not reported in source.

    Regimen

    Concurrent chemoradiotherapy. 5-FU-based CRT predicted higher CLR (OR 4.9, 95% CI 1.1-22.1, p=0.038).

    Endpoints

    Primary: complete local response (CLR). Secondary: OS, CSS, recurrence patterns, salvage cystectomy.

    Results

    CLR 63.7%. Disease progression 28.8% (local 10.1%, systemic 10.7%, combined 8.7%). Salvage cystectomy 9.7%.

    Applies to
    cT2-T4aN0M0 MIBC selected for definitive bladder-preserving TMT at European centers
    Does not represent node-positive or metastatic disease, or pts triaged to upfront radical cystectomy.
    Limitations

    Retrospective, non-randomised; CLR predictors exploratory and confounded by treatment era. No head-to-head vs radical cystectomy; RT technique detail and CLR-survival effect sizes absent from source.

    Rationale

    Retrospective real-world European cohort; no randomised TMT-vs-cystectomy comparator. Reinforces guideline-recognized bladder preservation; predictor findings exploratory.

    Monday clinic

    In cT2-T4aN0M0 MIBC pts already committed to bladder-preserving TMT, this favors daily volumetric IGRT and 5-FU-based chemoRT for local control; it does not inform the upstream TMT-versus-radical-cystectomy choice or node-positive/metastatic disease.

    Open questions
    📚 Sources · 🐦 1 tweet

    Combined Curative Retrospective Confirmatory ESTRO Congress 2026

    Early signal

    Single-fraction SABR for primary NSCLC and lung oligomets (pooled, n=1687)

    ForPrimary NSCLC or pulmonary oligometastases, SABR candidates

    TL;DR2-yr local control 90-93% and G3+ AEs 2-3% across 1687 pts (1200 primary NSCLC, 487 oligomets) treated with single-fraction SABR.

    Why it mattersRadiation oncology

    The transfer gate is the fraction size the source omits: outcomes are labeled single-fraction but no Gy dose is given, so you cannot map this 2y LC of 90-93% onto a specific regimen before offering one visit instead of a multi-fraction course. Toxicity (G3+ 2-3%) comes from 2 of 3 sites only. Moves the single- vs multi-fraction choice for lung SABR.

    LC 90-93% at 2y; G3+ AEs 2-3%; N=1687 (1200 NSCLC, 487 oligomets)
    LC 90-93% at 2y; G3+ AEs 2-3%; N=1687 (1200 NSCLC, 487 oligomets)
    +2 more figures
    Single-fraction SABR for primary NSCLC and lung oligomets (pooled, n=1687)
    EndpointPrimary NSCLCOligomets
    1-yr OS84% (82-86)90% (86-92)
    2-yr OS67% (64-69)75% (71-79)
    Median OS40 mo (36-43)51 mo (42-58)
    AEs (NSCLC subset, n=789): any 215 (27%), G2+ 124 (15.7%), G3+ 23 (2.9%). Pneumonitis 52 (7%)
    AEs (NSCLC subset, n=789): any 215 (27%), G2+ 124 (15.7%), G3+ 23 (2.9%). Pneumonitis 52 (7%)
    7 details 1 trial watching
    Design

    Pooled retrospective analysis of 3 institutions (Peter MacCallum, Cleveland Clinic, Roswell Park). N=1687 (1200 primary NSCLC, 487 pulmonary oligometastases). No randomisation, no comparator arm; survival curves out to 60 months.

    Population & inclusion

    Primary NSCLC (n=1200) and pulmonary oligometastases (n=487) treated with single-fraction SABR. Stage, tumour location, and specific eligibility criteria not reported in source.

    Radiotherapy

    Single-fraction SABR across all pts. The Gy dose is not reported in source (single fraction only), so the specific regimen behind these outcomes is unknown, gating whether the result transfers to a given practice.

    Endpoints

    No prespecified primary endpoint stated. Reported: local control, overall survival, PFS, and adverse events.

    Results

    2y local control 90-93%; isolated local/locoregional failure very uncommon. Median PFS 30 mo (NSCLC) vs 11 mo (oligomets). OS by cohort shown in the figure.

    Safety

    G3+ AEs 2-3% (23/789, 2.9% in the assessed NSCLC subset); G2+ 124/789 (15.7%), any AE 215/789 (27%). AE data from 2 of 3 sites only (no Roswell Park).

    vs leading data

    Consistent with SAFRON II (TROG 13.01) and RTOG 0915 supporting single-fraction lung SABR, but those were randomised; this pooled cohort carries no comparator.

    Applies to
    pts with primary NSCLC or a pulmonary oligometastasis treated with single-fraction SABR at three academic centres
    Does not represent pts evaluated against a multi-fraction SABR comparator, which this cohort did not include.
    Limitations

    Retrospective, no randomised/matched comparator. Single-fraction Gy dose unstated. AE denominator excludes one of three sites (n=789 of 1687).

    Rationale

    Pooled retrospective single-arm cohort, no randomised or matched comparator vs multi-fraction SABR; single-fraction Gy dose unstated. Consistent with SAFRON II / RTOG 0915.

    Monday clinic

    In pts with primary NSCLC or a pulmonary oligometastasis being considered for SABR, this supports single-fraction delivery as a lower-visit option with high local control; it does not establish it over a multi-fraction schedule, which this cohort did not compare against.

    Open questions
    📚 Sources · 🐦 1 tweet

    Radiation Curative Retrospective Early signal ESTRO Congress 2026