Electrospray ionization (ESI) of tetrameric platinum(II) acetate, [Pt4(CH3COO)8], in methanol generates the formal platinum(III) dimeric cation [Pt2(CH3COO)3(CH2COO)(MeOH)2]+, which, upon harsher ionization conditions, sequentially loses the two methanol ligands, CO2, and CH2COO to form the platinum(II) dimer [Pt2(CH3COO)2(CH3)]+. Next, intramolecular sequential double hydrogen‐atom transfer from the methyl group concomitant with the elimination of two acetic acid molecules produces Pt2CH+ from which, upon even harsher conditions, PtCH+ is eventually generated. This degradation sequence is supported by collision‐induced dissociation (CID) experiments, extensive isotope‐labeling studies, and DFT calculations. Both PtCH+ and Pt2CH+ react under thermal conditions with the hydrocarbons C2Hn (n=2, 4, 6) and C3Hn (n=6, 8). While, in ion–molecule reactions of PtCH+ with C2 hydrocarbons, the relative rates decrease with increasing n, the opposite trend holds true for Pt2CH+. The Pt2CH+ cluster only sluggishly reacts with C2H2, but with C2H4 and C2H6 dihydrogen loss dominates. The reactions with the latter two substrates were preceded by a complete exchange of all of the hydrogen atoms present in the adduct complex. The PtCH+ ion is much less selective. In the reactions with C2H2 and C2H4, elimination of H2 occurs; however, CH4 formation prevails in the decomposition of the adduct complex that is formed with C2H6. In the reaction with C2H2, in addition to H2 loss, C3H3+ is produced, and this process formally corresponds to the transfer of the cationic methylidyne unit CH+ to C2H2, accompanied by the release of neutral Pt. In the ion–molecule reactions with the C3 hydrocarbons C3H6 and C3H8, dihydrogen loss occurs with high selectivity for Pt2CH+, but in the reactions of these substrates with PtCH+ several reaction routes compete. Finally, in the ion–molecule reactions with ammonia, both platinum complexes give rise to proton transfer to produce NH4+; however, only the encounter complex generated with PtCH+ undergoes efficient dehydrogenation of the substrate, and the rather minor formation of CNH4+ indicates that CN bond coupling is inefficient.

Background The role of radiation therapy (RT) following breast-conserving surgery (BCS) in ductal carcinoma in situ (DCIS) remains controversial. Trials have not identified a low-risk cohort, based on clinicopathologic features, who do not benefit from RT. A biosignature (DCISionRT®) that evaluates recurrence risk has been developed and validated. We evaluated the impact of DCISionRT on clinicians’ recommendations for adjuvant RT. Methods The PREDICT study is a prospective, multi-institutional, observational registry in which patients underwent DCISionRT testing. The primary endpoint was to identify the percentage of patients where testing led to a change in RT recommendations. Results Overall, 539 women were included in this study. Pre DCISionRT testing, RT was recommended to 69% of patients; however, post-testing, a change in the RT recommendation was made for 42% of patients compared with the pre-testing recommendation; the percentage of women who were recommended RT decreased by 20%. For women initially recommended not to receive an RT pre-test, 35% had their recommendation changed to add RT following testing, while post-test, 46% of patients had their recommendation changed to omit RT after an initial recommendation for RT. When considered in conjunction with other clinicopathologic factors, the elevated DCISionRT score risk group (DS > 3) had the strongest association with an RT recommendation (odds ratio 43.4) compared with age, grade, size, margin status, and other factors. Conclusions DCISionRT provided information that significantly changed the recommendations to add or omit RT. Compared with traditional clinicopathologic features used to determine recommendations for or against RT, the factor most strongly associated with RT recommendations was the DCISionRT result, with other factors of importance being patient preference, tumor size, and grade.

Background Patients treated for head and neck cancer are at high risk of developing head and neck lymphedema (HNL). We describe outcomes of HNL management at an Australian institution from 2018 to 2020. Methods Electronic records from Chris O'Brien Lifehouse were retrospectively reviewed from January 1, 2018 to December 31, 2020. Objective changes in HNL were assessed using The M. D. Anderson Cancer Center (MDACC) HNL rating scale and Assessment of Lymphedema of the Head and Neck (ALOHA). Results Among the 100 patients referred for management of HNL, surgery was the most frequent treatment modality (80%; 70% with neck dissection) and 69% underwent radiotherapy. Manual lymphatic drainage (MLD) was most often prescribed (96%), followed by self‐MLD (93%). Small but significant improvements in ALOHA measurements were observed for 50 patients (50%). Only 5/29 (17%) patients had post‐treatment improvements on the MDACC scale. Conclusions Standardized, prospective measurement of treatment approaches and outcomes is needed to further evaluate the service.

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