onc brain

Retrospective, IRB-approved cohort from 2 centers within a single institution, Jan 2017 to Dec 2023. Hypothesis stated a priori: proton cohort would have higher CC. Median follow-up 42 mo proton, 47 mo photon.

Subpectoral 2-stage TE/I or DTI reconstruction with PMRT; N=175 (89 proton, 86 photon). Median age 49 (range 24-78), 63% Hispanic. Groups balanced except laterality and reconstruction type (both P<.001).

Pencil beam scanning proton vs IMRT photon PMRT; the TE was irradiated in all TE/I pts. Dose, fractionation, bolus and superficial dose constraints are not reported in source.

Capsular contracture by Kaplan-Meier; associated factors by Cox proportional hazards, verified with binary logistic regression.

Reconstruction type was the only factor that stayed associated on multivariable analysis; the proton effect did not reach significance after adjustment (see tables).

The source frames proton vs photon CC data as scarce and reports this as the largest PBS PMRT reconstruction cohort to date. RADCOMP compares proton vs photon breast RT on cardiac outcomes, not reconstruction complications, so it will not settle this question.

Photon DTI stratum is only n=15, so the within-DTI modality contrast is underpowered. CC grading scale and RT planning parameters are absent from the abstract, which blocks translation to a specific planning change.

Adjusted proton HR 1.76 with an interval of 0.93-3.32 excludes neither no effect nor a large one; P=.083 is not reassurance. The consistent direction within both reconstruction types is the stronger signal, and PBS plus DTI is where the risk concentrates.

Retrospective cohort with reconstruction type imbalanced between modalities (P<.001); proton effect lost significance on multivariable analysis, so the modality signal stays confounded.

Ancillary exploratory analysis combining the non-RT arm of NRG/RTOG 9804, which randomized good-risk DCIS to RT or no RT, with the good-risk E5194 cohort observed without RT. Tamoxifen was optional and not randomized in either trial. Univariate and multivariable Fine-Gray models; median follow-up 14.85 yr.

N=878 (317 RTOG 9804, 561 E5194); median age 59 (28-88). Good-risk: low- or intermediate-grade, ≤2.5 cm, excision margins ≥3 mm, lumpectomy without RT.

Tamoxifen, optional per trial; used by 43.1% overall (65.6% RTOG 9804 vs 30.3% E5194). Dose, duration and adherence not reported in source.

No RT in the analyzed population. The RTOG 9804 RT arm is not part of this analysis, so tamoxifen alone is not compared against RT here.

IBR (any), invasive IBR, DCIS-IBR, contralateral breast event and overall survival. CBE and OS results are not reported in the source text.

117 IBRs (65 invasive, 52 DCIS). The reduction tracked invasive IBR, not DCIS-IBR.

NSABP B-24 randomized tamoxifen after lumpectomy plus RT, and the UK/ANZ DCIS trial randomized tamoxifen and RT in a factorial design. Here tamoxifen is examined only in good-risk pts managed without RT, and without randomization.

Multivariable covariates are not listed in source, and trial membership also differs in follow-up (13.87 vs 16.15 yr). The DCIS-IBR result (p=0.089) rests on 52 events and does not exclude an effect.

Tamoxifen use tracked lower invasive recurrence in good-risk DCIS managed without RT, consistent in direction with randomized tamoxifen data. It does not settle whether tamoxifen alone approaches RT, or how much of the gap reflects the lower-risk profile of users.

Exploratory ancillary analysis; tamoxifen optional, not randomized, and imbalanced by trial, re-excision and size. Parent RCT tested RT, not tamoxifen, so residual confounding limits causal read.