Surgery (RMH) - Research Publications
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ItemUse and outcomes from neoadjuvant chemotherapy in borderline resectable pancreatic ductal adenocarcinoma in an Australasian population(WILEY, 2023-02-01)Background: Use of neoadjuvant (NA) chemotherapy is recommended when pancreatic ductal adenocarcinoma (PDAC) is borderline resectable. Method: A retrospective analysis of consecutive patients with localized PDAC between January 2016 and March 2019 within the Australasian Pancreatic Cancer Registry (PURPLE, Pancreatic cancer: Understanding Routine Practice and Lifting End results) was performed. Clinicopathological characteristics, treatment, and outcome were analyzed. Overall survival (OS) comparison was performed using log-rank model and Kaplan–Meier analysis. Results: The PURPLE database included 754 cases with localised PDAC, including 148 (20%) cases with borderline resectable pancreatic cancer (BRPC). Of the 148 BRPC patients, 44 (30%) underwent immediate surgery, 80 (54%) received NA chemotherapy, and 24 (16%) were inoperable. The median age of NA therapy patients was 63 years and FOLFIRINOX (53%) was more often used as NA therapy than gemcitabine/nab-paclitaxel (31%). Patients who received FOLFIRINOX were younger than those who received gemcitabine/nab-paclitaxel (60 years vs. 67 years, p =.01). Surgery was performed in 54% (43 of 80) of BRPC patients receiving NA chemotherapy, with 53% (16 of 30) achieving R0 resections. BRPC patients undergoing surgery had a median OS of 30 months, and 38% (9 of 24) achieved R0 resection. NA chemotherapy patients had a median OS of 20 months, improving to 24 months versus 10 months for patients receiving FOLFIRINOX compared to gemcitabine/nab-paclitaxel (Hazard Ratio (HR).3, p <.0001). Conclusions: NA chemotherapy use in BRPC is increasing in Australia. One half of patients receiving NA chemotherapy proceed to curative resection, with 53% achieving R0 resections. Patients receiving Infusional 5-flurouracil, Irinotecan and Oxaliplatin (FOLIRINOX) had increased survival than gemcitabine/nab-paclitaxel. Treatment strategies are being explored in the MASTERPLAN and DYNAMIC-Pancreas trials.
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ItemBiology and Clinical Implications of Fecal Occult Blood Test Screen-Detected Colorectal Cancer(OXFORD UNIV PRESS, 2022-01-05)BACKGROUND: Fecal occult blood test (FOBT)-based screening for colorectal cancer (CRC) reduces mortality, with earlier stage at diagnosis a prominent feature. Other characteristics of FOBT screen-detected cancers and any implications for clinical management have not been well explored. METHODS: We examined a multisite clinical registry to compare the characteristics and outcomes of FOBT screen-detected CRC via the Australian National Bowel Cancer Screening Program (NBCSP), which is offered biennially to individuals aged 50-74 years, and age-matched non-screen-detected CRC in the same registry. All statistical tests were 2-sided. Odds ratios (ORs) were calculated using the Baptista-Pike method, and hazard ratios via the log-rank method. RESULTS: Of 7153 registry patients diagnosed June 1, 2006, to June 30, 2020, 4142 (57.9%) were aged between 50 and 74 years. Excluding 406 patients with non-NBCSP screen-detected cancers and 35 patients with unknown method of detection, 473 (12.8%) were screen detected via the NBCSP, and 3228 (87.2%) were non-screen detected. Screen-detected patients were younger (mean age = 62.4 vs 64.2 years; P < .001) and more medically fit (OR for ASA score 1-2 = 1.91, 95% confidence interval [CI] = 1.51 to 2.41; P < .001). Pathologic characteristics within each stage favored the screen-detected patients. Stage III screen-detected colon cancers were more likely to receive adjuvant therapy (OR = 3.58, 95% CI = 1.52 to 8.36; P = .002). Screen-detected patients had superior relapse-free (hazard ratio = 0.41, 95% CI = 0.29 to 0.60; P < .001) and overall survival (hazard ratio = 0.22, 95% CI = 0.15 to 0.35; P < .001), which was maintained in matched stage comparisons and multivariable analysis. CONCLUSIONS: Beyond stage at diagnosis, multiple other factors associated with a favorable outcome are observed in FOBT screen-detected CRC. Given the substantial stage-by-stage differences in survival outcomes, if independently confirmed, individualized adjuvant therapy and surveillance strategies could be warranted for FOBT screen-detected cancers.
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ItemCirculating tumor DNA dynamics and recurrence risk in patients undergoing curative intent resection of colorectal cancer liver metastases: A prospective cohort study(PUBLIC LIBRARY SCIENCE, 2021-05)BACKGROUND: In patients with resectable colorectal liver metastases (CRLM), the role of pre- and postoperative systemic therapy continues to be debated. Previous studies have shown that circulating tumor DNA (ctDNA) analysis, as a marker of minimal residual disease, is a powerful prognostic factor in patients with nonmetastatic colorectal cancer (CRC). Serial analysis of ctDNA in patients with resectable CRLM could inform the optimal use of perioperative chemotherapy. Here, we performed a validation study to confirm the prognostic impact of postoperative ctDNA in resectable CRLM observed in a previous discovery study. METHODS AND FINDINGS: We prospectively collected plasma samples from patients with resectable CRLM, including presurgical and postsurgical samples, serial samples during any pre- or postoperative chemotherapy, and serial samples in follow-up. Via targeted sequencing of 15 genes commonly mutated in CRC, we identified at least 1 somatic mutation in each patient's tumor. We then designed a personalized assay to assess 1 mutation in plasma samples using the Safe-SeqS assay. A total of 380 plasma samples from 54 patients recruited from July 2011 to Dec 2014 were included in our analysis. Twenty-three (43%) patients received neoadjuvant chemotherapy, and 42 patients (78%) received adjuvant chemotherapy after surgery. Median follow-up was 51 months (interquartile range, 31 to 60 months). At least 1 somatic mutation was identified in all patients' tumor tissue. ctDNA was detectable in 46/54 (85%) patients prior to any treatment and 12/49 (24%) patients after surgery. There was a median 40.93-fold (19.10 to 87.73, P < 0.001) decrease in ctDNA mutant allele fraction with neoadjuvant chemotherapy, but ctDNA clearance during neoadjuvant chemotherapy was not associated with a better recurrence-free survival (RFS). Patients with detectable postoperative ctDNA experienced a significantly lower RFS (HR 6.3; 95% CI 2.58 to 15.2; P < 0.001) and overall survival (HR 4.2; 95% CI 1.5 to 11.8; P < 0.001) compared to patients with undetectable ctDNA. For the 11 patients with detectable postoperative ctDNA who had serial ctDNA sampling during adjuvant chemotherapy, ctDNA clearance was observed in 3 patients, 2 of whom remained disease-free. All 8 patients with persistently detectable ctDNA after adjuvant chemotherapy have recurred. End-of-treatment (surgery +/- adjuvant chemotherapy) ctDNA detection was associated with a 5-year RFS of 0% compared to 75.6% for patients with an undetectable end-of-treatment ctDNA (HR 14.9; 95% CI 4.94 to 44.7; P < 0.001). Key limitations of the study include the small sample size and the potential for false-positive findings with multiple hypothesis testing. CONCLUSIONS: We confirmed the prognostic impact of postsurgery and posttreatment ctDNA in patients with resected CRLM. The potential utility of serial ctDNA analysis during adjuvant chemotherapy as an early marker of treatment efficacy was also demonstrated. Further studies are required to define how to optimally integrate ctDNA analyses into decision-making regarding the use and timing of adjuvant therapy for resectable CRLM. TRIAL REGISTRATION: ACTRN12612000345886.
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ItemPrognostic significance of postsurgery circulating tumorDNAin nonmetastatic colorectal cancer: Individual patient pooled analysis of three cohort studies(WILEY, 2021-02-15)Studies in multiple solid tumor types have demonstrated the prognostic significance of ctDNA analysis after curative intent surgery. A combined analysis of data across completed studies could further our understanding of circulating tumor DNA (ctDNA) as a prognostic marker and inform future trial design. We combined individual patient data from three independent cohort studies of nonmetastatic colorectal cancer (CRC). Plasma samples were collected 4 to 10 weeks after surgery. Mutations in ctDNA were assayed using a massively parallel sequencing technique called SafeSeqS. We analyzed 485 CRC patients (230 Stage II colon, 96 Stage III colon, and 159 locally advanced rectum). ctDNA was detected after surgery in 59 (12%) patients overall (11.0%, 12.5% and 13.8% for samples taken at 4-6, 6-8 and 8-10 weeks; P = .740). ctDNA detection was associated with poorer 5-year recurrence-free (38.6% vs 85.5%; P < .001) and overall survival (64.6% vs 89.4%; P < .001). The predictive accuracy of postsurgery ctDNA for recurrence was higher than that of individual clinicopathologic risk features. Recurrence risk increased exponentially with increasing ctDNA mutant allele frequency (MAF) (hazard ratio, 1.2, 2.5 and 5.8 for MAF of 0.1%, 0.5% and 1%). Postsurgery ctDNA was detected in 3 of 20 (15%) patients with locoregional and 27 of 60 (45%) with distant recurrence (P = .018). This analysis demonstrates a consistent long-term impact of ctDNA as a prognostic marker across nonmetastatic CRC, where ctDNA outperforms other clinicopathologic risk factors and MAF further stratifies recurrence risk. ctDNA is a better predictor of distant vs locoregional recurrence.
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ItemNo Preview AvailableReal-world outcomes for neoadjuvant capecitabine versus infusional 5-fluorouracil in the treatment of locally advanced rectal cancer(WILEY, 2021-08)BACKGROUND: Neoadjuvant chemoradiation therapy is standard-of-care treatment for locally advanced rectal cancer (LARC). A pathological complete response (pCR) following chemoradiation therapy is an early indicator of treatment benefit and associated with excellent survival outcomes, with capecitabine largely replacing infusional 5-fluorouracil as the choice in routine care of LARC. AIMS: To analyse the uptake of capecitabine usage over time, and on the back of clinical trial data demonstrating equivalence between fluoropyrimidines, confirm that efficacy is maintained in the real-world setting. METHODS: We analysed data from a prospectively maintained colorectal cancer database at three Australian hospitals including patients diagnosed from January 2009 to December 2018. Pathological response was determined as either complete or incomplete and compared for patients receiving 5-FU or capecitabine. RESULTS: A total of 657 patients was analysed, 498 receiving infusional 5-FU and 159 capecitabine. Capecitabine use has markedly increased from approval in 2014 in Australia, now being used in more than 80% of patients. Patient characteristics were similar by treatment, including age, tumour location and pre-treatment stage. pCR was reported in 22/159 (13.8%) of capecitabine-treated patients and 118/380 (23.7%) that received 5-FU (P ≤ 0.01). More capecitabine-treated patients received post-operative oxaliplatin (44.2% vs 6.3%, P < 0.01). Two-year progression-free survival was similar (84.9% vs 88.0%, P = 0.34). CONCLUSIONS: Capecitabine is now the dominantly used neoadjuvant chemotherapy in LARC. Capecitabine use was associated with a lower rate of pCR versus infusional 5-FU, a difference not explained by examined patient or tumour characteristics. Poor treatment compliance with oral therapy in the real-world setting is one possible explanation.
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ItemResection of colorectal cancer liver metastases in older patients(WILEY, 2020-05)BACKGROUND: Colorectal cancer remains a common cancer in the western world, with liver resection being the only potentially curative option for isolated colorectal cancer liver metastases (CRCLM). Cancer is a disease of aging, with the optimum management of elderly patients with CRCLM presenting an ongoing dilemma. METHODS: We analysed the outcome of CRCLM using prospectively collected patient data from the multidisciplinary Treatment of Recurrent and Advanced Colorectal Cancer registry, collected from July 2009 to July 2018 at 12 Australian hospitals. RESULTS: Of 2742 patients with metastatic colorectal cancer, liver-limited disease was present in 977 (36%) patients, of whom 338 (35%) underwent hepatic resection. Resection rates varied with age, including 186 (43%) of 428 patients aged 64 years and younger, 99 (40%) of 245 aged 65-75 years and 53 (17%) of 303 aged 76 and older (P < 0.001). The 30-day mortality rate was 0.9%. Median survival post resection also varied with age, 96 versus 89 versus 68 months (P < 0.001). In a separate analysis of the oldest patients, those aged over 80 years, where only 11% underwent resection, the median survival was 49 months. CONCLUSION: The operative mortality for patients undergoing liver resection at Australian hospitals is low. With advancing age, the rate of liver resection of CRCLM and the post-resection survival decline. However, excellent survival outcomes can be achieved in selected elderly patients.
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ItemNo Preview AvailableSimulating Progression-Free and Overall Survival for First-Line Doublet Chemotherapy With or Without Bevacizumab in Metastatic Colorectal Cancer Patients Based on Real-World Registry Data(ADIS INT LTD, 2020-11)BACKGROUND: Simulation models utilizing real-world data have potential to optimize treatment sequencing strategies for specific patient subpopulations, including when conducting clinical trials is not feasible. We aimed to develop a simulation model to estimate progression-free survival (PFS) and overall survival for first-line doublet chemotherapy with or without bevacizumab for specific subgroups of metastatic colorectal cancer (mCRC) patients based on registry data. METHODS: Data from 867 patients were used to develop two survival models and one logistic regression model that populated a discrete event simulation (DES). Discrimination and calibration were used for internal validation of these models separately and predicted and observed medians and Kaplan-Meier plots were compared for the integrated DES. Bootstrapping was performed to correct for optimism in the internal validation and to generate correlated sets of model parameters for use in a probabilistic analysis to reflect parameter uncertainty. RESULTS: The survival models showed good calibration based on the regression slopes and modified Hosmer-Lemeshow statistics at 1 and 2 years, but not for short-term predictions at 0.5 years. Modified C-statistics indicated acceptable discrimination. The simulation estimated that median first-line PFS (95% confidence interval) of 219 (25%) patients could be improved from 175 days (156-199) to 269 days (246-294) if treatment would be targeted based on the highest expected PFS. CONCLUSIONS: Extensive internal validation showed that DES accurately estimated the outcomes of treatment combination strategies for specific subpopulations, with outcomes suggesting treatment could be optimized. Although results based on real-world data are informative, they cannot replace randomized trials.
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ItemPatient demographics and management landscape of metastatic colorectal cancer in the third-line setting: Real-world data in an australian population(WILEY, 2022-04)BACKGROUND: Colorectal cancer is the third most common cancer and second leading cause of cancer mortality in Australia, thus carrying a significant disease burden. AIMS: This analysis aims to explore real-world treatment landscape of metastatic colorectal cancer in the third-line setting. METHODS: We retrospectively analysed treatment of recurrent and advanced colorectal cancer (TRACC) registry database from 2009 onwards. Patients treated with palliative intent who progressed after two lines of therapies were included. One treatment line was defined as any combination of systemic therapy given until progression. RESULTS: Out of 1820 patients treated palliatively, 32% (590 patients) met study criteria. Of these, 43% (254 patients) proceeded to third-line therapy, equating to 14% of all metastatic patients. In KRAS mutant or unknown tumours (97 patients), fluoropyrimidine (FP)-oxaliplatin combination was the most common choice (51%), followed by FP-irinotecan (15%), trifluridine/tipiracil (11%), mono-chemotherapy (10%), regorafenib (5%) and others (7%). Majority of FP-doublet (83%) was given as rechallenge. In 157 patients with KRAS wildtype disease, monotherapy with EGFR inhibitor was most commonly used (41%), followed by EGFR inhibitor with chemotherapy (20%), FP-doublet (18%), mono-chemotherapy (6%), trifluridine/tipiracil (6%), regorafenib (1%) and others (8%). Median overall survival was 7.1 months (range 0.4-41.2), and median time on third-line treatment was 3 months (range 0.1-40). CONCLUSIONS: In real-world Australian population, treatment choices differed based on KRAS status and will likely change with the availability of newer drugs on the pharmaceutical benefits scheme. Survival outcomes are comparable to newer agents in clinical trials for select patients.
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ItemCancer clinical trial vs real-world outcomes for standard of care first-line treatment in the advanced disease setting(WILEY, 2021-07-15)Clinical trials have strict eligibility criteria, potentially limiting external validity. However, while often discussed this has seldom been explored, particularly across cancer types and at variable time frames posttrial completion. We examined comprehensive registry data (January 2014 to June 2019) for standard first-line treatments for metastatic colorectal cancer (CRC), advanced pancreatic cancer (PC), metastatic HER2-amplified breast cancer (BC) and castrate-resistant prostate cancer (CaP). Registry patient characteristics and outcomes were compared to the practice-changing trial. Registry patients were older than the matched trial cohort by a median of 2-6 years (all P = <.01) for the CRC, BC and PC cohorts. The proportion of Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-1 patients was lower for CRC (94.1% vs 99.2%, P = .001) and BC (94.9% vs 99.3%, P = .001). Progression-free survival (PFS) for registry patients was similar to the trial patients or significantly longer (CaP, Hazard Ratio [HR] = 0.65, P = <.001). Overall survival (OS) was also similar or significantly longer (CaP, HR 0.49, P = <.001). In conclusion, despite real-world patients sometimes being older or having inferior PS to trial cohorts, the survival outcomes achieved were consistently equal or superior to those reported for the same treatment in the trial. We suggest that this is potentially due to optimised use of each treatment over time, improved multidisciplinary care and increased postprogression options. We can reassure clinicians and patients that outcomes matching or exceeding those reported in trials are possible. The potential for survival gains over time should routinely be factored into future trial statistical plans.