Paper spray ionization (PSI) is a direct, fast, and low-cost ambient ionization technique which may have clinical utility for qualitative and quantitative analysis of therapeutic drugs and metabolites from patient specimens. We developed and validated a PSI-mass spectrometry (PSI-MS/MS) method according to the US-FDA guidelines for bioanalytical studies to measure the prostate cancer drug abiraterone directly from patient plasma. The established linearity range was 3.1-156.8 ng/mL with a precision (%CV) and an accuracy (%) range of 0.5-10.7 and 93.5-103.2, respectively. The mean internal standard normalized matrix factor for abiraterone was just below 1 with highest %CV of 10.2 at the low-level quality control. In benchmarking the performance of this assay against a published LC-MS/MS assay, we showed they were mostly equivalent, with the exception of accuracy with clinical samples. We found the quantitative values observed for abiraterone measured directly from patient plasma using PSI-MS/MS showed positive bias. Upon investigation, we concluded the increased values were due to summed quantitation of isomeric abiraterone conjugates and metabolites which are separable by LC-MS/MS, but not with the current PSI-MS/MS configuration. Despite demonstrating the utility of PSI-MS/MS for rapid bioanalysis, this study also highlighted a limitation encountered with the direct analysis of abiraterone in clinical samples.
Background: There are few studies examining retroperitoneal lymph node dissection (RPLND) for testicular cancer in Australia. This study examines the perioperative outcomes, complications and survival rates following RPLND, by a high volume, single surgeon. Methods: A retrospective, case series of a single surgeon, multi-centre study included all patients who underwent RPLND following testicular cancer at Westmead Public Hospital, Westmead Private Hospital, and Macquarie University Hospital 2005-2020. One hundred one patients identified, with 94 having sufficient available data. Results: At time of operation, median age was 29.5 years. 84.2% had T1 or T2 primary tumours at diagnosis. Most common RPLND indication was residual mass postchemotherapy (92.6%), with bleomycin, etoposide and cisplatin (BEP)x3 and BEPx4 most common chemotherapy regimens (50% and 35% respectively). Post-chemotherapy, largest residual mass ranged from 0.9 to 20 cm (median 3.32 cm). Post-chemotherapy, 95.7% masses were found in retroperitoneum (64.4% para-aortic region). 93.6% had open approach. 42.5% had bilateral nerve sparing. Majority (97.1%) did not require blood transfusion. No complications reported in 52.1% of patients. No deaths recorded within 90 days of surgery. At time of analysis, 91.5% had recurrence free survival, and 92.6% overall survival, at a median follow-up since surgery of 47.5 months (range 11 to 200 months). Conclusions: This retrospective study, addressing peri-operative surgical outcomes for RPLND surgery in Australia, is comparable to high-volume international urological centre studies, and shows that centralisation of post-chemotherapy RPLND to an experienced surgeon, results in low perioperative morbidity and mortality.
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