Comparison of the Test-negative Design and Cohort Design With Explicit Target Trial Emulation for Evaluating COVID-19 Vaccine Effectiveness

BACKGROUND

Observational studies are used for estimating vaccine effectiveness under real-world conditions. The practical performance of two common approaches-cohort and test-negative designs-need to be compared for COVID-19 vaccines.

METHODS

We compared the cohort and test-negative designs to estimate the effectiveness of the BNT162b2 vaccine against COVID-19 outcomes using nationwide data from the United States Department of Veterans Affairs. Specifically, we (1) explicitly emulated a target trial using follow-up data and evaluated the potential for confounding using negative controls and benchmarking to a randomized trial, (2) performed case-control sampling of the cohort to confirm empirically that the same estimate is obtained, (3) further restricted the sampling to person-days with a test, and (4) implemented additional features of a test-negative design. We also compared their performance in limited datasets.

RESULTS

Estimated BNT162b2 vaccine effectiveness was similar under all four designs. Empirical results suggested limited residual confounding by healthcare-seeking behavior. Analyses in limited datasets showed evidence of residual confounding, with estimates biased downward in the cohort design and upward in the test-negative design.

CONCLUSION

Vaccine effectiveness estimates under a cohort design with explicit target trial emulation and a test-negative design were similar when using rich information from the VA healthcare system, but diverged in opposite directions when using a limited dataset. In settings like ours with sufficient information on confounders and other key variables, the cohort design with explicit target trial emulation may be preferable as a principled approach that allows estimation of absolute risks and facilitates interpretation of effect estimates.

Emulating Target Trials Comparing Early and Delayed Intubation Strategies

BACKGROUND

Whether intubation should be initiated early in the clinical course of critically ill patients remains a matter of debate. Results from prior observational studies are difficult to interpret because of avoidable flaws including immortal time bias, inappropriate eligibility criteria, and unrealistic treatment strategies.

RESEARCH QUESTION

Do treatment strategies that intubate patients early in the critical care admission improve 30-day survival compared with strategies that delay intubation?

STUDY DESIGN AND METHODS

We estimated the effect of strategies that require early intubation of critically ill patients compared with those that delay intubation. With data extracted from the Medical Information Mart for Intensive Care-IV database, we emulated three target trials, varying the flexibility of the treatment strategies and the baseline eligibility criteria.

RESULTS

Under unrealistically strict treatment strategies with broad eligibility criteria, the 30-day mortality risk was 7.1 percentage points higher for intubating early compared with delaying intubation (95% CI, 6.2-7.9). Risk differences were 0.4 (95% CI, -0.1 to 0.9) and -0.9 (95% CI, -2.5 to 0.7) percentage points in subsequent target trial emulations that included more realistic treatment strategies and eligibility criteria.

INTERPRETATION

When realistic treatment strategies and eligibility criteria are used, strategies that delay intubation result in similar 30-day mortality risks compared with those that intubate early. Delaying intubation ultimately avoids intubation in most patients.

Critical elements in the operative management of pediatric malignant ovarian germ cell tumors

Performance of the appropriate operation is highly important to ensure that any patient with a suspected ovarian germ cell tumor receives optimal therapy that prioritizes cure while simultaneoulsy minimizing risk of short and long-term toxicities of treatment. The following critical elements of any operative procedure performed for a suspected pediatric or adolescent ovarian germ cell tumor are reviewed: 1. Complete resection of the tumor via ipsilateral oophorectomy while avoiding tumor rupture and spillage, and 2. Performance of complete intraperitoneal staging at the time of initial tumor resection.

Addressing the longitudinal components of surgical treatments

Despite their pre- and postoperative components, surgical treatment strategies have typically been cast as point interventions in causal inference research. When longitudinal perioperative components affect outcomes of interest, leaving them unspecified or failing to measure adherence to them complicates the interpretation of effect estimates. Inspired by two recent landmark trials that assessed the risk of stroke or death after transcatheter aortic valve replacement (TAVR) compared with surgical aortic valve replacement (SAVR), the PARTNER 3 trial and the Evolut Low Risk trial, we discuss possible ways that different postoperative therapies in treatment arms and incomplete adherence to those therapies can impact the interpretation of intention-to-treat effect estimates in surgical trials. We argue that surgical treatments are not necessarily point interventions, and make recommendations for improving the design and analysis of trials involving surgical interventions. Central to these recommendations is the need for investigators to specify and report adherence to longitudinal perioperative treatment components.

Late Health Outcomes Among Survivors of Wilms Tumor Diagnosed Over Three Decades: A Report From the Childhood Cancer Survivor Study

PURPOSE

To evaluate long-term morbidity and mortality among unilateral, nonsyndromic Wilms tumor (WT) survivors according to conventional treatment regimens.

METHODS

Cumulative incidence of late mortality (≥ 5 years from diagnosis) and chronic health conditions (CHCs) were evaluated in WT survivors from the Childhood Cancer Survivor Study. Outcomes were evaluated by treatment, including nephrectomy combined with vincristine and actinomycin D (VA), VA + doxorubicin + abdominal radiotherapy (VAD + ART), VAD + ART + whole lung radiotherapy, or receipt of ≥ 4 chemotherapy agents.

RESULTS

Among 2,008 unilateral WT survivors, 142 deaths occurred (standardized mortality ratio, 2.9, 95% CI, 2.5 to 3.5; 35-year cumulative incidence of death, 7.8%, 95% CI, 6.3 to 9.2). The 35-year cumulative incidence of any grade 3-5 CHC was 34.1% (95% CI, 30.7 to 37.5; rate ratio [RR] compared with siblings 3.0, 95% CI, 2.6 to 3.5). Survivors treated with VA alone had comparable risk for all-cause late mortality relative to the general population (standardized mortality ratio, 1.0; 95% CI, 0.5 to 1.7) and modestly increased risk for grade 3-5 CHCs compared with siblings (RR, 1.5; 95% CI, 1.1 to 2.0), but remained at increased risk for intestinal obstruction (RR, 9.4; 95% CI, 3.9 to 22.2) and kidney failure (RR, 11.9; 95% CI, 4.2 to 33.6). Magnitudes of risk for grade 3-5 CHCs, including intestinal obstruction, kidney failure, premature ovarian insufficiency, and heart failure, increased by treatment group intensity.

CONCLUSION

With approximately 40% of patients with newly diagnosed WT currently treated with VA alone, the burden of late mortality/morbidity in future decades is projected to be lower than that for survivors from earlier eras. Nevertheless, the risk of late effects such as intestinal obstruction and kidney failure was elevated across all treatment groups, and there was a dose-dependent increase in risk for all grade 3-5 CHCs by treatment group intensity.

Comparative effectiveness of third doses of mRNA-based COVID-19 vaccines in US veterans

Vaccination against SARS-CoV-2 has been effective in reducing the burden of severe disease and death from COVID-19. Third doses of mRNA-based vaccines have provided a way to address waning immunity and broaden protection against emerging SARS-CoV-2 variants. However, their comparative effectiveness for a range of COVID-19 outcomes across diverse populations is unknown. We emulated a target trial using electronic health records of US veterans who received a third dose of either BNT162b2 or mRNA-1273 vaccines between 20 October 2021 and 8 February 2022, during a period that included Delta- and Omicron-variant waves. Eligible veterans had previously completed an mRNA vaccine primary series. We matched recipients of each vaccine in a 1:1 ratio according to recorded risk factors. Each vaccine group included 65,196 persons. The excess number of events over 16 weeks per 10,000 persons for BNT162b2 compared with mRNA-1273 was 45.4 (95% CI: 19.4, 84.7) for documented infection, 3.7 (2.2, 14.1) for symptomatic COVID-19, 10.6 (5.1, 19.7) for COVID-19 hospitalization, 2.0 (-3.1, 6.3) for COVID-19 intensive care unit admission and 0.2 (-2.2, 4.0) for COVID-19 death. After emulating a second target trial of veterans who received a third dose between 1 January and 1 March 2022, during a period restricted to Omicron-variant predominance, the excess number of events over 9 weeks per 10,000 persons for BNT162b2 compared with mRNA-1273 was 63.2 (95% CI: 15.2, 100.7) for documented infection. The 16-week risks of COVID-19 outcomes were low after a third dose of mRNA-1273 or BNT162b2, although risks were lower with mRNA-1273 than with BNT162b2, particularly for documented infection.

Comparative Safety of BNT162b2 and mRNA-1273 Vaccines in a Nationwide Cohort of US Veterans

Importance

The risk of adverse events has been found to be low for participants receiving the BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna Inc) vaccines in randomized trials. However, a head-to-head comparison of their safety for a broader range of potential adverse events over longer follow-up and in larger and more diverse populations is lacking, to our knowledge.

Objective

To compare the head-to-head safety in terms of risk of adverse events of the BNT162b2 and mRNA-1273 vaccines in the national health care databases of the US Department of Veterans Affairs, the largest integrated health care system in the US.

Design, Setting, and Participants

In this cohort study, the electronic health records of US veterans who received a first dose of the BNT162b2 or mRNA-1273 vaccine between January 4 and September 20, 2021, were used. Recipients of each vaccine were matched in a 1:1 ratio according to their risk factors.

Exposures

Vaccination with either the BNT162b2 vaccine, with a second dose scheduled 21 days later, or the mRNA-1273 vaccine, with a second dose scheduled 28 days later.

Main Outcomes and Measures

A large panel of potential adverse events was evaluated; the panel included neurologic events, hematologic events, hemorrhagic stroke, ischemic stroke, myocardial infarction, other thromboembolic events, myocarditis or pericarditis, arrhythmia, kidney injury, appendicitis, autoimmune events, herpes zoster or simplex, arthritis or arthropathy, and pneumonia. Risks over 38 weeks were estimated using the Kaplan-Meier estimator.

Results

Among 433 672 persons included in the matched vaccine groups, the median age was 69 years (IQR, 60-74 years), 93% of individuals were male, and 20% were Black. Estimated 38-week risks of adverse events were generally low after administration of either the BNT162b2 or the mRNA-1273 vaccine. Compared with the mRNA-1273 group, the BNT162b2 group had an excess per 10 000 persons of 10.9 events (95% CI, 1.9-17.4 events) of ischemic stroke, 14.8 events (95% CI, 7.9-21.8 events) of myocardial infarction, 11.3 events (95% CI, 3.4-17.7 events) of other thromboembolic events, and 17.1 events (95% CI, 8.8-30.2 events) of kidney injury. Estimates were largely similar among subgroups defined by age (<40, 40-69, and ≥70 years) and race (Black, White), but there were higher magnitudes of risk differences of ischemic stroke among older persons and White persons, kidney injury among older persons, and other thromboembolic events among Black persons. Small-magnitude differences between the 2 vaccines were seen within 42 days of the first dose, and few differences were seen within 14 days of the first dose.

Conclusions and Relevance

The findings of this cohort study suggest that there were few differences in risk of adverse events within 14 days of the first dose of either the BNT162b2 or the mRNA-1273 vaccine and small-magnitude differences within 42 days of the first dose. The 38-week risks of adverse events were low in both vaccine groups, although risks were lower for recipients of the mRNA-1273 vaccine than for recipients of the BNT162b2 vaccine. Although the primary analysis was designed to detect safety events unrelated to SARS-CoV-2 infection, the possibility that these differences may partially be explained by a lower effectiveness of the BNT162b2 vaccine in preventing the sequelae of SARS-CoV-2 infection compared with the mRNA-1273 vaccine could not be ruled out. These findings may help inform decision-making in future vaccination campaigns.

Comparison of Mortality Risk With Different Surgeon and Hospital Operative Volumes Among Individuals Undergoing Pancreatectomy by Emulating Target Trials in US Medicare Beneficiaries

IMPORTANCE

The association of surgeons' and hospitals' operative volumes with postoperative patient outcomes has been studied for decades and holds important policy implications; however, in many volume-outcome analyses, this association is described without the envisioning of a clear intervention, which often introduces unintentional bias. Acting on such results may lead to unintended consequences from policy interventions or patient recommendations.

OBJECTIVE

To specify how (hypothetical) target trials would be designed to estimate the association between postoperative mortality of patients undergoing operations and a range of surgeon and hospital volume conditions and then to emulate these trials by using observational data.

DESIGN, SETTING, AND PARTICIPANTS

This observational data analysis emulated 4 hypothetical target trials of increasing complexity, ranging from a poorly defined trial that would randomly assign participants only to surgeon volume to one that would randomly assign participants to surgeon volume, hospital volume, and specific surgeon and hospital. This population-based cohort study included 9136 Medicare beneficiaries with a first diagnosis of pancreatic malignant neoplasm who did not require neoadjuvant therapy and underwent pancreatectomy between January 1, 2012, and September 30, 2016. Data analysis was performed between September 1, 2019, and October 8, 2021.

EXPOSURES

Number of pancreatectomies performed by surgeon and hospital during the prior year.

MAIN OUTCOMES AND MEASURES

Ninety-day mortality.

RESULTS

The analyses included 9136 Medicare beneficiaries treated by 1358 surgeons at 697 hospitals; median age was 73.3 years (IQR, 69.1-78.1 years), and 4642 were men (51%). When trials with poorly defined interventions on surgeon volume were emulated, the estimated 90-day mortality was 7.9% (95% CI, 6.4%-9.4%) for lower-volume surgeons and 5.2% (95% CI, 2.7%-10.9%) for higher-volume surgeons. When trials with better-defined interventions were emulated, the difference was reduced: 7.8% (95% CI, 6.3%-9.3%) for lower-volume surgeons and 7.2% (95% CI, 6.0%-8.7%) for higher-volume surgeons.

CONCLUSIONS AND RELEVANCE

In this cohort study that emulated 4 different target trials with data from Medicare beneficiaries undergoing pancreatectomy, mortality differences across surgical volume levels were attenuated when the interventions were well defined. The application of the hypothetical target trial framework to this specific volume-outcomes scenario revealed the complexities of this research question and the unintentional biases introduced in prior studies, which emulated poorly defined trials whose results are therefore difficult to interpret. The target trial framework may be of value to outcomes researchers asking questions that correspond to well-defined interventions for the real world.

Comparative Effectiveness of BNT162b2 and mRNA-1273 Vaccines in U.S. Veterans

BACKGROUND

The messenger RNA (mRNA)-based vaccines BNT162b2 and mRNA-1273 are more than 90% effective against coronavirus disease 2019 (Covid-19). However, their comparative effectiveness for a range of outcomes across diverse populations is unknown.

METHODS

We emulated a target trial using the electronic health records of U.S. veterans who received a first dose of the BNT162b2 or mRNA-1273 vaccine between January 4 and May 14, 2021, during a period marked by predominance of the SARS-CoV-2 B.1.1.7 (alpha) variant. We matched recipients of each vaccine in a 1:1 ratio according to their risk factors. Outcomes included documented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, symptomatic Covid-19, hospitalization for Covid-19, admission to an intensive care unit (ICU) for Covid-19, and death from Covid-19. We estimated risks using the Kaplan-Meier estimator. To assess the influence of the B.1.617.2 (delta) variant, we emulated a second target trial that involved veterans vaccinated between July 1 and September 20, 2021.

RESULTS

Each vaccine group included 219,842 persons. Over 24 weeks of follow-up in a period marked by alpha-variant predominance, the estimated risk of documented infection was 5.75 events per 1000 persons (95% confidence interval [CI], 5.39 to 6.23) in the BNT162b2 group and 4.52 events per 1000 persons (95% CI, 4.17 to 4.84) in the mRNA-1273 group. The excess number of events per 1000 persons for BNT162b2 as compared with mRNA-1273 was 1.23 (95% CI, 0.72 to 1.81) for documented infection, 0.44 (95% CI, 0.25 to 0.70) for symptomatic Covid-19, 0.55 (95% CI, 0.36 to 0.83) for hospitalization for Covid-19, 0.10 (95% CI, 0.00 to 0.26) for ICU admission for Covid-19, and 0.02 (95% CI, -0.06 to 0.12) for death from Covid-19. The corresponding excess risk (BNT162b2 vs. mRNA-1273) of documented infection over 12 weeks of follow-up in a period marked by delta-variant predominance was 6.54 events per 1000 persons (95% CI, -2.58 to 11.82).

CONCLUSIONS

The 24-week risk of Covid-19 outcomes was low after vaccination with mRNA-1273 or BNT162b2, although risks were lower with mRNA-1273 than with BNT162b2. This pattern was consistent across periods marked by alpha- and delta-variant predominance. (Funded by the Department of Veterans Affairs and others.).

The Effect of Facility Volume on Survival Following Proctectomy for Rectal Cancer

BACKGROUND

Prior studies assessing colorectal cancer survival have reported better outcomes when operations are performed at high-volume centers. These studies have largely been cross-sectional, making it difficult to interpret their estimates. We aimed to assess the effect of facility volume on survival following proctectomy for rectal cancer.

METHODS

Using data from the National Cancer Database, we included all patients with complete baseline information who underwent proctectomy for non-metastatic rectal cancer between 2004 and 2016. Facility volume was defined as the number of rectal cancer cases managed at the treating center in the calendar year prior to the patient's surgery. Overall survival estimates were obtained for facility volumes ranging from 10 to 100 cases/year. Follow-up began on the day of surgery and continued until loss to follow-up or death.

RESULTS

A total of 52,822 patients were eligible. Patients operated on at hospitals with volumes of 10, 30, and 50 cases/year had similar distributions of grade, clinical stage, and neoadjuvant therapies. 1-, 3-, and 5-year survival all improved with increasing facility volume. One-year survival was 94.0% (95% CI: 93.7, 94.3) for hospitals that performed 10 cases/year, 94.5% (95% CI: 94.2, 94.7) for 30 cases/year, and 94.8% (95% CI: 94.5, 95.0) for 50 cases/year. Five-year survival was 68.9% (95% CI: 68.0, 69.7) for hospitals that performed 10 cases/year, 70.8% (95% CI: 70.1, 71.5) for 30 cases/year, and 72.0% (95% CI: 71.2, 72.8) for 50 cases/year.

CONCLUSIONS

Treatment at a higher volume facility results in improved survival following proctectomy for rectal cancer, though the small benefits are less profound than previously reported.

Strengthening Health Services Research Using Target Trial Emulation: An Application to Volume-Outcomes Studies

The number of operations that surgeons have previously performed is associated with their patients' outcomes. However, this association may not be causal, because previous studies have often been cross-sectional and their analyses have not considered time-varying confounding or positivity violations. In this paper, using the example of surgeons who perform coronary artery bypass grafting, we describe (hypothetical) target trials for estimation of the causal effect of the surgeons' operative volumes on patient mortality. We then demonstrate how to emulate these target trials using data from US Medicare claims and provide effect estimates. Our target trial emulations suggest that interventions on physicians' volume of coronary artery bypass grafting operations have little effect on patient mortality. The target trial framework highlights key assumptions and draws attention to areas of bias in previous observational analyses that deviated from their implicit target trials. The principles of the presented methodology may be adapted to other scenarios of substantive interest in health services research.

Early Convalescent Plasma Therapy and Mortality Among US Veterans Hospitalized With Nonsevere COVID-19: An Observational Analysis Emulating a Target Trial

BACKGROUND

Early convalescent plasma transfusion may reduce mortality in patients with nonsevere coronavirus disease 2019 (COVID-19).

METHODS

This study emulates a (hypothetical) target trial using observational data from a cohort of US veterans admitted to a Department of Veterans Affairs (VA) facility between 1 May and 17 November 2020 with nonsevere COVID-19. The intervention was convalescent plasma initiated within 2 days of eligibility. Thirty-day mortality was compared using cumulative incidence curves, risk differences, and hazard ratios estimated from pooled logistic models with inverse probability weighting to adjust for confounding.

RESULTS

Of 11 269 eligible person-trials contributed by 4755 patients, 402 trials were assigned to the convalescent plasma group. Forty and 671 deaths occurred within the plasma and nonplasma groups, respectively. The estimated 30-day mortality risk was 6.5% (95% confidence interval [CI], 4.0%-9.7%) in the plasma group and 6.2% (95% CI, 5.6%-7.0%) in the nonplasma group. The associated risk difference was 0.30% (95% CI, -2.30% to 3.60%) and the hazard ratio was 1.04 (95% CI, .64-1.62).

CONCLUSIONS

Our target trial emulation estimated no meaningful differences in 30-day mortality between nonsevere COVID-19 patients treated and untreated with convalescent plasma. Clinical Trials Registration. NCT04545047.

Late-onset kidney failure in survivors of childhood cancer: a report from the Childhood Cancer Survivor Study

BACKGROUND

The incidence of and risk factors for late-onset kidney failure among survivors over the very long term remains understudied.

MATERIALS AND METHODS

A total of 25,530 childhood cancer survivors (median follow-up 22.3 years, interquartile range 17.4-28.8) diagnosed between 1970 and 1999, and 5045 siblings from the Childhood Cancer Survivor Study were assessed for self-reported late-onset kidney failure, defined as dialysis, renal transplantation, or death attributable to kidney disease. Piecewise exponential models evaluated associations between risk factors and the rate of late-onset kidney failure.

RESULTS

A total of 206 survivors and 10 siblings developed late-onset kidney failure, a 35-year cumulative incidence of 1.7% (95% confidence interval [CI] = 1.4-1.9) and 0.2% (95% confidence interval [CI] = 0.1-0.4), respectively, corresponding to an adjusted rate ratio (RR) of 4.9 (95% CI = 2.6-9.2). High kidney dose from radiotherapy (≥15Gy; RR = 4.0, 95% CI = 2.1-7.4), exposure to high-dose anthracycline (≥250 mg/m2; RR = 1.6, 95% CI = 1.0-2.6) or any ifosfamide chemotherapy (RR = 2.6, 95% CI = 1.2-5.7), and nephrectomy (RR = 1.9, 95% CI = 1.0-3.4) were independently associated with elevated risk for late-onset kidney failure among survivors. Survivors who developed hypertension, particularly in the context of prior nephrectomy (RR = 14.4, 95% CI = 7.1-29.4 hypertension with prior nephrectomy; RR = 5.9, 95% CI = 3.3-10.5 hypertension without prior nephrectomy), or diabetes (RR = 2.2, 95%CI = 1.2-4.2) were also at elevated risk for late-onset kidney failure.

CONCLUSIONS

Survivors of childhood cancer are at increased risk for late-onset kidney failure. Kidney dose from radiotherapy ≥15 Gy, high-dose anthracycline, any ifosfamide, and nephrectomy were associated with increased risk of late-onset kidney failure among survivors. Successful diagnosis and management of modifiable risk factors such as diabetes and hypertension may mitigate the risk for late-onset kidney failure. The association of late-onset kidney failure with anthracycline chemotherapy represents a novel finding that warrants further study.

Variation in complications and mortality following ALPPS at early-adopting centers

BACKGROUND

Various, often conflicting, estimates for post-operative morbidity and mortality following ALPPS have been reported in the literature, suggesting that considerable center-level variation exists. Some of this variation may be related to center volume and experience.

METHODS

Using data from seventeen centers who were early adopters of the ALPPS technique, we estimated the variation, by center, in standardized 90-day mortality and comprehensive complication index (CCI) for patients treated between 2012 and 2018.

RESULTS

We estimated that center-specific 90-day mortality following treatment with ALPPS varied from 4.2% (95% CI: 0.8, 9.9) to 29.1% (95% CI: 13.9, 50.9), and that center-specific CCI following treatment with ALPPS varied from 17.0 (95% CI: 7.5, 26.5) to 49.8 (95% CI: 38.1, 61.8). Declines in estimated 90-day mortality and CCI were observed over time, and almost all individual centers followed this trend. Patients treated at centers with a higher number of ALPPS cases performed over the prior year had a lower risk of post-operative mortality.

CONCLUSION

Despite considerable center-level variation in ALPPS outcomes, perioperative outcomes following ALPPS have improved over time and treatment at higher volume centers results in a lower risk of 90-day mortality. Morbidity and mortality remain concerningly high at some centers.

Association and interplay of surgeon and hospital volume with mortality after open abdominal aortic aneurysm repair in the modern era

OBJECTIVE

Operative volume has been used as a marker of quality. Research from previous decades has suggested minimum open abdominal aortic aneurysm (AAA) repair volume requirements for surgeons of 9 to 13 open AAA repairs annually and for hospitals of 18 open AAA repairs annually to purportedly achieve acceptable results. Given concerns regarding the decreased frequency of open repairs in the endovascular era, we examined the association of surgeon and hospital volume with the 30- and 90-day mortality in the Vascular Quality Initiative (VQI) registry.

METHODS

Patients who had undergone elective open AAA repair from 2013 to 2018 were identified in the VQI registry. We performed a cross-sectional evaluation of the association between the average hospital and surgeon volume and 30-day postoperative mortality using a hierarchical Bayesian model. Cross-level interactions were permitted, and random surgeon- and hospital-level intercepts were used to account for clustering. The mortality results were adjusted by standardizing to the observed distribution of relevant covariates in the overall cohort. The outcomes were compared to the Society for Vascular Surgery guidelines recommended criteria of <5% perioperative mortality.

RESULTS

A total of 3078 patients had undergone elective open AAA repair by 520 surgeons at 128 hospitals. The 30- and 90-day risks of postoperative mortality were 4.1% (n = 126) and 5.4% (n = 166), respectively. The mean surgeon volume and hospital volume both correlated inversely with the 30-day mortality. Averaged across all patients and hospitals, we found a 96% probability that surgeons who performed an average of four or more repairs per year achieved <5% 30-day mortality. Substantial interplay was present between surgeon volume and hospital volume. For example, at lower volume hospitals performing an average of five repairs annually, <5% 30-day mortality would be expected 69% of the time for surgeons performing an average of three operations annually. In contrast, at higher volume hospitals performing an average of 40 repairs annually, a <5% 30-day mortality would be expected 96% of the time for surgeons performing an average of three operations annually. As hospital volume increased, a diminishing difference occurred in 30-day mortality between lower and higher volume surgeons. Likewise, as surgeon volume increased, a diminishing difference was found in 30-day mortality between the lower and higher volume hospitals.

CONCLUSIONS

Surgeons and hospitals in the VQI registry achieved mortality outcomes of <5% (Society for Vascular Surgery guidelines), with an average surgeon volume that was substantially lower compared with previous reports. Furthermore, when considering the development of minimal surgeon volume guidelines, it is important to contextualize the outcomes within the hospital volumes.

Treatment intensity and risk of chronic health conditions and late mortality among long-term survivors of Wilms tumor: A report from the Childhood Cancer Survivor Study

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Background: Refinement in risk stratification has led to intensification of therapy for Wilms tumor (WT) patients with adverse prognostic factors. Chronic health conditions (CHCs) including cardiac conditions, subsequent malignant neoplasms (SMNs), and late mortality are known risks for WT survivors, however the impact of specific treatment regimens on these outcomes is largely unknown. Methods: Late mortality (all-cause and non-recurrence death > 5 years from diagnosis), SMNs, and severity-graded CHCs (2 = moderate, 3 = severe, 4 = life-threatening, 5 = fatal) were assessed in 5-year WT survivors in the Childhood Cancer Survivor Study diagnosed from 1970-99. Survivors were categorized according to therapy received (Table). Cumulative incidence of mortality and standard mortality ratios (SMR) were estimated. Piecewise exponential models estimated rate ratios (RR) with 95% confidence intervals (CI). Results: Among 1507 survivors (median age at follow-up 26 yrs; range 6-55), 35-year cumulative incidence of all-cause mortality was 7.9% (SMR 2.9, CI 2.3-3.6) and 5.1% (SMR 1.9, CI 1.4-2.4) for non-recurrence mortality. RRs for developing any grade 2-5 CHC, grade 3-5 SMN, and grade 2-5 cardiac CHCs were higher for survivors compared to sibling controls (2.0, CI 1.8-2.3; 7.4, CI 5.0-10.8; 2.6, CI 2.2-3.1, respectively). Compared with VA and no RT, RR for non-recurrence late mortality and CHCs among survivors were higher for VAD + any RT, and for ≥ 4 drugs + any RT (Table). Conclusions: Administering increased-intensity therapy for WT is associated with increased late health consequences and non-recurrence late mortality, necessitating strategies to monitor and improve long-term health among survivors. [Table: see text]

Incidence of and risk factors for late cholecystectomy in survivors of childhood cancer: A report from the Childhood Cancer Survivor Study

BACKGROUND

Gallbladder disease and need for cholecystectomy are common and significant contributors to patient morbidity and healthcare costs. Childhood cancer survivors are at elevated risk for developing cholelithiasis. However, their incidence of and risk factors for late (>5 years from diagnosis) cholecystectomy have not been studied.

METHODS

A total of 25,549 survivors (median age at diagnosis 6.9 years, range 0-21.0; current age 30.7 years, range 5.6-65.9) diagnosed between 1970 and 1999 and 5037 siblings were queried for self-reported cholecystectomy occurring five or more years from primary cancer diagnosis. Piecewise exponential models evaluated associations between cancer treatment exposures and late cholecystectomy.

RESULTS

Over a median follow-up period of 21.9 and 26.0 years, respectively, 789 survivors and 168 siblings underwent late cholecystectomy (cumulative incidence 7.2%, 95% confidence interval [CI] = 6.5-7.8% and 6.6%, 95% CI = 5.4-7.6%, respectively; rate ratio [RR] = 1.3, 95% CI = 1.1-1.5). Compared with siblings, survivors of acute lymphoblastic leukaemia (RR = 1.4, 95% CI = 1.2-1.8), soft tissue sarcoma (RR = 1.4, 95% CI = 1.0-1.8) and bone cancer (RR = 1.3, 95% CI = 1.0-1.8) were at the greatest risk. In addition to attained age, female sex and increasing body mass index, exposure to high-dose (≥750 mg/m²) platinum chemotherapy (RR = 2.6, 95% CI = 1.5-4.5), vinca alkaloid chemotherapy (RR = 1.4, 95% CI = 1.1-1.8) or total body irradiation (TBI; RR = 2.2, 95% CI = 1.2-4.2) were each associated with late cholecystectomy.

CONCLUSIONS

Independent of traditional risk factors for gallbladder disease, exposure to high-dose platinum chemotherapy, vinca alkaloid chemotherapy or TBI increased risk for late cholecystectomy. These findings should inform current long-term follow-up guidelines and education regarding risk for late cholecystectomy.

Adjusting for adherence in randomized trials when adherence is measured as a continuous variable: An application to the Lipid Research Clinics Coronary Primary Prevention Trial

Background:

Clinicians and patients may be more interested in per-protocol effect estimates than intention-to-treat effect estimates from randomized trials. However, per-protocol effect estimates may be biased due to insufficient adjustment for prognostic factors that predict adherence. Adjustment for this bias is possible when appropriate methods, such as inverse probability weighting, are used. But, when adherence is measured as a continuous variable, constructing these weights can be challenging.

Methods:

In the placebo arm of the Lipid Research Clinics Coronary Primary Prevention Trial, we estimated the 7-year cumulative incidence of coronary heart disease under 100% adherence and 0% adherence to placebo. We used dose-response discrete-hazards models with inverse probability weighting to adjust for pre- and post-randomization covariates. We considered several continuous distributions for constructing the inverse probability weights.

Results:

The risk difference estimate for 100% adherence compared with 0% adherence ranged from −7.7 to −6.1 percentage points without adjustment for baseline and post-baseline covariates, and ranged from −1.8 to 2.2 percentage points with adjustment using inverse probability weights, depending on the dose-response model and inverse probability weight distribution used.

Conclusions:

Methods which appropriately adjust for time-varying post-randomization variables can explain away much of the bias in the “effect” of adherence to placebo. When considering continuous adherence, investigators should consider several models as estimates may be sensitive to the model chosen.

Evaluation of the diagnostic biopsy approach for children with hepatoblastoma: A report from the children's oncology group AHEP 0731 liver tumor committee

BACKGROUND

The histopathological assessment of pediatric liver tumors at presentation is critical to establish a diagnosis, guide treatment, and collect appropriate research samples. The purpose of this study was to evaluate complications associated with different approaches to liver biopsy for newly diagnosed hepatoblastoma.

METHODS

Children with hepatoblastoma were enrolled on Children's Oncology Group study AHEP0731 (September 2009-March 2012). This analysis evaluated the study cohort of initially unresectable patients who therefore underwent a biopsy procedure at diagnosis. The primary endpoint was clinically significant postbiopsy hemorrhage, defined as requiring red blood cell transfusion.

RESULTS

We identified 121 children who underwent open (n = 76, 63%), laparoscopic (n = 17, 14%), or percutaneous (n = 28, 23%) liver biopsies. All biopsy procedures yielded adequate tissue for diagnosis. Postbiopsy hemorrhage requiring transfusion occurred after 26% (n = 31) of biopsies. Need for blood product transfusion most frequently occurred following open (n = 27/76, 36%) and laparoscopic (n = 4/17, 24%) biopsies, compared with percutaneous (n = 0/28, 0%) biopsies (p < 0.01).

CONCLUSIONS

Pretreatment biopsy of pediatric liver tumors via a percutaneous approach yielded the lowest frequency of clinically significant hemorrhage requiring transfusion, without evidence of sacrificing diagnostic accuracy.

LEVEL OF EVIDENCE

Level I.

Comparison of Military Health System Data Repository and American College of Surgeons National Surgical Quality Improvement Program-Pediatric

Background

Given the rarity of pediatric surgical disease, it is important to consider available large-scale data resources as a means to better study and understand relevant disease-processes and their treatments. The Military Health System Data Repository (MDR) includes claims-based information for > 3 million pediatric patients who are dependents of members and retirees of the United States Armed Services, but has not been externally validated. We hypothesized that demographics and selected outcome metrics would be similar between MDR and the previously validated American College of Surgeons National Surgical Quality Improvement Program-Pediatric (NSQIP-P) for several common pediatric surgical operations.

Methods

We selected five commonly performed pediatric surgical operations: appendectomy, pyeloplasty, pyloromyotomy, spinal arthrodesis for scoliosis, and facial reconstruction for cleft palate. Among children who underwent these operations, we compared demographics (age, sex, and race) and clinical outcomes (length of hospital stay [LOS] and mortality) in the MDR and NSQIP-P, including all available overlapping years (2012–2014).

Results

Age, sex, and race were generally similar between the NSQIP-P and MDR. Specifically, these demographics were generally similar between the resources for appendectomy (NSQIP-P, n = 20,602 vs. MDR, n = 4363; median age 11 vs. 12 years; female 40% vs. 41%; white 75% vs. 84%), pyeloplasty (NSQIP-P, n = 786 vs. MDR, n = 112; median age 0.9 vs. 2 years; female 28% vs. 28%; white 71% vs. 80%), pyloromyotomy, (NSQIP-P, n = 3827 vs. MDR, n = 227; median age 34 vs. < 1 year, female 17% vs. 16%; white 76% vs. 89%), scoliosis surgery (NSQIP-P, n = 5743 vs. MDR, n = 95; median age 14.2 vs. 14 years; female 75% vs. 67%; white 72% vs. 75%), and cleft lip/palate repair (NSQIP-P, n = 6202 vs. MDR, n = 749; median age, 1 vs. 1 year; female 42% vs. 45%; white 69% vs. 84%). Length of stay and 30-day mortality were similar between resources. LOS and 30-day mortality were also similar between datasets.

Conclusion

For the selected common pediatric surgical operations, patients included in the MDR were comparable to those included in the validated NSQIP-P. The MDR may comprise a valuable clinical outcomes research resource, especially for studying infrequent diseases with follow-up beyond the 30-day peri-operative period.

Multicenter pre-operative assessment of pediatric ovarian malignancy

PURPOSE

The purpose of this study was to develop a pre-operative risk assessment tool for childhood and adolescent ovarian malignancy, in order to guide operative management of pediatric ovarian masses.

METHODS

We conducted a retrospective analysis of patients <18 years old who underwent ovarian surgery at two quaternary care pediatric centers over 4 years (1/1/13-12/31/16). Probability of malignancy was estimated based on imaging characteristics (simple cyst, heterogeneous, or solid), maximal diameter, and tumor markers (α-fetoprotein, β-human chorionic gonadotropin).

RESULTS

Among 188 children with ovarian masses, 11% had malignancies. For simple cysts, there were no malignancies (0/24, 95% CI = 0-17%). Among solid lesions, 44% (15/34, 95% CI = 28-62%) were malignant. Among marker-elevated heterogeneous masses, 40% (2/5, 95% CI = 12-77%) were malignant. Conversely, small (≤10 cm) and large (>10 cm) marker-negative heterogeneous lesions had malignancy proportions of 0% (0/39, 95% CI = 0-11%) and 5% (2/40, 95% CI = 1-18%), respectively.

CONCLUSIONS

Given the malignancy estimates identified from these multi-institutional data, we recommend an attempt at ovarian-sparing resection for simple cysts or tumor marker-negative heterogeneous lesions ≤10 cm. Oophorectomy is recommended for solid masses or heterogeneous lesions with elevated markers. Finally, large (>10 cm) heterogeneous masses with non-elevated markers warrant a careful discussion of ovarian-sparing techniques. Complete surgical staging is mandatory regardless of operative procedure.

TYPE OF STUDY

Study of Diagnostic Test.

LEVEL OF EVIDENCE

Level I.

Late-onset anorectal disease and psychosocial impact in survivors of childhood cancer: A report from the Childhood Cancer Survivor Study

BACKGROUND

The prevalence and associated psychosocial morbidity of late-onset anorectal disease after surgery and radiotherapy for the treatment of childhood cancer are not known.

METHODS

A total of 25,530 survivors diagnosed between 1970 and 1999 (median age at cancer diagnosis, 6.1 years; age at survey, 30.2 years) and 5036 siblings were evaluated for late-onset anorectal disease, which was defined as a self-reported fistula-in-ano, self-reported anorectal stricture, or pathology- or medical record-confirmed anorectal subsequent malignant neoplasm (SMN) 5 or more years after the primary cancer diagnosis. Piecewise exponential models compared the survivors and siblings and examined associations between cancer treatments and late-onset anorectal disease. Multiple logistic regression with generalized estimating equations was used to evaluate associations between late-onset anorectal disease and emotional distress, as defined by the Brief Symptom Inventory 18 (BSI-18), and health-related quality of life, as defined by the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36).

RESULTS

By 45 years after the diagnosis, 394 survivors (fistula, n = 291; stricture, n = 116; anorectal SMN, n = 26) and 84 siblings (fistula, n = 73; stricture, n = 23; anorectal neoplasm, n = 1) had developed late-onset anorectal disease (adjusted rate ratio [RR] for survivors vs siblings, 1.2; 95% confidence interval [CI], 1.0-1.5). Among survivors, pelvic radiotherapy with ≥30 Gy within 5 years of the cancer diagnosis was associated with late-onset anorectal disease (adjusted RR for 30-49.9 Gy vs none, 1.6; 95% CI, 1.1-2.3; adjusted RR for ≥50 Gy vs none, 5.4; 95% CI, 3.1-9.2). Late-onset anorectal disease was associated with psychosocial impairment in all BSI-18 and SF-36 domains.

CONCLUSIONS

Late-onset anorectal disease was more common among childhood cancer survivors who received higher doses of pelvic radiotherapy and was associated with substantial psychosocial morbidity.

Incidence and risk factors for sepsis after childhood splenectomy

BACKGROUND

Children who have undergone splenectomy may develop impaired immunologic function and heightened risk of overwhelming postsplenectomy infection. We sought to define the long-term rate of and risk factors for postsplenectomy sepsis.

METHODS

We leveraged the Military Health System Data Repository, a nationally representative claims database including >3 million children registered as dependents of members of the United States Armed Services (2005-2014). Inclusion criterion was splenectomy at age 18 years or prior. The primary outcome was hospitalization for sepsis.

RESULTS

Among 195 children who underwent splenectomy, 7% (n = 13) were hospitalized with sepsis, with an incidence of 1.8 (95% CI = 1.0-3.1) events per 100 person-years. The median time to sepsis was 224 days (IQR = 109-606) and 38% (5/13) of events occurred within the first postsplenectomy year. The postsplenectomy mortality rate was 1% (n = 3). After adjusting for underlying diagnosis, older age at splenectomy (HR = 0.90 per year, 95% CI = 0.81-0.99) was associated with decreased hazard of sepsis.

CONCLUSIONS

In a contemporary national cohort, the prevalence of postsplenectomy sepsis was 7% (1.8 events per 100 person-years). Although most presented during the first year after splenectomy, many (62%) sepsis events occurred later, suggesting that postsplenectomy immunologic dysfunction persists beyond one year. The immunologic consequences of asplenia must continue to be acknowledged, as postsplenectomy sepsis remains a serious concern.

TYPE OF STUDY

Prognosis study.

LEVEL OF EVIDENCE

Level III.

Therapeutic Impact and Complications Associated with Surgical Lung Biopsy after Allogeneic Hematopoietic Stem Cell Transplantation in Children

Hematopoietic stem cell transplantation (HSCT) in the pediatric population is associated with pulmonary complications in 25% of recipients. The role of surgical lung biopsy (SLB) remains unclear because of concerns about both the therapeutic impact and morbidity associated with the procedure. A retrospective review of consecutive allogeneic HSCT recipients at Dana-Farber and Boston Children's Hospital Cancer and Blood Disorders Center between 2006 and 2016 was performed. All recipients who underwent SLB during the study period were identified and charts reviewed for perioperative complications, histopathologic findings, and changes in therapy delivered. Pearson's chi-square test and Student's t-test (or appropriate nonparametric test) were used to evaluate the associations between perioperative complication and categorical and continuous variables, respectively. Five hundred fifty-five HSCTs were included, among which 48 SLBs (8.6%) were identified. Median follow-up time was 24 months (range, 0 to 139). Thirty-day postoperative morbidity was 16.7% and 30-day postoperative mortality 10.4% (n = 5). The overall 30-day postoperative complication rate (including mortality) was 20.8% (n = 10). No mortalities were directly attributable to SLB. Definitive diagnoses were identified in 70.8% of SLBs (n = 34), and therapeutic changes occurred in 79.2% (n = 38). Overall, 83.3% of SLBs (n = 40) either provided a diagnosis or led to a change in therapy. SLB has an acceptable risk of perioperative complications in this medically complicated and often severely ill population. In most HSCT patients, SLB aids in defining the etiology of pulmonary infiltrates and can inform therapeutic decisions in patients where noninvasive diagnostic modalities have failed to provide a definitive diagnosis.

Late cholecystectomy in survivors of childhood cancer: A report from the Childhood Cancer Survivor Study

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Background: Cholecystectomy (CCY) is among the most common operations performed in the developed world and is offered as a cure for symptomatic gallbladder disease. Whether survivors of childhood cancer undergo CCY at a higher rate than the general population is unknown. Methods: We identified 5-year survivors diagnosed between 1970 and 1999 who self-reported late (> 5 years after cancer diagnosis) CCY. Rates of CCY were determined among the entire cohort and in association with various risk factors and treatment exposures. Adjusted rate ratios (ARR) were estimated with multivariable piecewise exponential models. Results: Among 24,248 survivors (median follow-up 22.3, interquartile range [IQR] 16.2-30.1 years) and 5,038 siblings (median follow-up 26.4, IQR 19.3-33.7 years), the unadjusted cumulative incidence of CCY at age 50 was 7.2% (n = 757) in survivors and 6.5% (n = 168) in siblings. After adjusting for age, sex and race/ethnicity, survivors underwent CCY at higher rates compared to siblings (ARR = 1.3, 95% CI = 1.1-1.5). Relative to siblings, acute lymphoblastic leukemia survivors underwent CCY at a higher rate (ARR = 1.6, 95% CI = 1.3-2.0), all other diagnoses were not independently associated with higher rates of CCY. Among survivors, risk factors for late CCY included female sex, increasing body mass index (BMI) class, exposure to platinum agents and total body irradiation (TBI) (Table). Conclusions: CCY is performed more commonly among childhood cancer survivors relative to siblings. In addition to known risk factors for gallbladder disease, cancer treatment exposures may further enhance risk for CCY. Awareness and education regarding this observation may ensure timely diagnosis and treatment of symptomatic disease. [Table: see text]

Timing and Outcomes of Abdominal Surgery in Neutropenic Patients

BACKGROUND

Surgery in neutropenic patients is challenging due to both atypical manifestations of common conditions and higher perioperative risk. We sought to describe the outcomes of neutropenic patients undergoing abdominal surgery and to identify factors contributing to morbidity and mortality.

METHODS

A retrospective chart review was performed for all patients neutropenic in the 24-hours prior to an abdominal operation at our institution between 1998 and 2017. The primary and secondary outcomes were 30-day mortality and morbidity, respectively. The chi-square test and two-tailed Student's t test were used for univariable comparisons (non-parametric tests used when appropriate). To determine the optimal threshold of absolute neutrophil count (ANC) to discriminate 30-day mortality, we maximized the Youden index (J).

RESULTS

Amongst 237 patients, mortality was 11.8% (28/237) and morbidity 54.5% (130/237). Absolute neutrophil count < 500 cells/μL (50% vs. 20.6%, P < 0.01) and perforated viscus (35.7% vs. 14.8%, P = 0.01) were associated with mortality. Perforated viscus (25.4% vs. 7.5%) was also associated with morbidity. Urgent operations were associated with higher morbidity (63.6% vs 34.7%, P < 0.001) and mortality (16.4% vs 1.4%, P = 0.002) when compared to elective operations. Transfer from an outside hospital (22.3% vs. 11.2%, P = 0.02) and longer median time from admission to operation (2 days (IQR 0-6) vs. 1 day (IQR 0-3), P < 0.01) were associated with morbidity. An ANC threshold of 350 provided the best discrimination for mortality.

CONCLUSIONS

Elective surgery in the appropriately chosen neutropenic patient is relatively safe. For patients with obvious surgical pathology, we advocate for earlier operation and a lower threshold for surgical consultation in an effort expedite the diagnosis and necessary treatment.

Pulmonary Hypertension in Patients with Congenital Diaphragmatic Hernia: Does Lung Size Matter?

PURPOSE

 The relationship between pulmonary hypoplasia and pulmonary arterial hypertension (PHTN) in patients with congenital diaphragmatic hernia (CDH) remains ill-defined. We hypothesized that prenatal estimates of lung size would directly correlate with PHTN severity.

METHODS

 Infants with isolated CDH (born 2004-2015) at a single institution were included. Estimates of lung size included observed-to-expected LHR (o:eLHR) and %-predicted lung volumes (PPLV = observed/predicted volumes). The primary outcome was severity of PHTN (grade 0-3) on echocardiography performed between day of life 3 and 30.

RESULTS

 Among 62 patients included, there was 32% mortality and 65% ECMO utilization. PPLV (odds ratio [OR] = 0.94 per 1 grade in PHTN severity, 95% confidence interval [CI] = 0.89-0.98, p < 0.01) and o:eLHR (OR = 0.97, 95% CI = 0.94-0.99, p < 0.01) were significantly associated with PHTN grade. Among patients on ECMO, PPLV (OR = 0.92, 95% CI = 0.84-0.99, p = 0.03) and o:eLHR (OR = 0.95, 95% CI = 0.92-0.99, p = 0.01) were more strongly associated with PHTN grade. PPLV and o:eLHR were significantly associated with the use of inhaled nitric oxide (iNO) (OR = 0.90, 95% CI = 0.83-0.98, p = 0.01 and OR = 0.94, 95% CI = 0.91-0.98, p < 0.01, respectively) and epoprostenol (OR = 0.91, 95% CI = 0.84-0.99, p = 0.02 and OR = 0.93, 95% CI = 0.89-0.98, p < 0.01, respectively).

CONCLUSION

 Among infants with isolated CDH, PPLV, and o:eLHR were significantly associated with PHTN severity, especially among patients requiring ECMO. Prenatal lung size may help predict postnatal PHTN and associated therapies.

Long-Term Risk of Venous Thromboembolism in Survivors of Childhood Cancer: A Report From the Childhood Cancer Survivor Study

Purpose To estimate the incidence of late-occurring venous thromboembolism (VTE) among survivors of childhood cancer and to identify risk factors for VTE to facilitate diagnosis and prevention. Methods The Childhood Cancer Survivor Study is a multi-institutional cohort of 24,355 5-year childhood cancer survivors (diagnosed between 1970 and 1999; median age at last follow-up, 28.7 years [range, 5.6 to 58.9 years]; median follow-up since diagnosis, 21.3 years [range, 5.0 to 39.2 years]) and 5,051 sibling participants. The primary end point was self-reported late (≥ 5 years after cancer diagnosis) VTE. Rate ratios (RRs) were estimated with multivariable piecewise exponential models. Results Late VTE incidence among survivors and siblings was 1.1 and 0.5 events per 1,000 person-years, respectively (RR, 2.2; 95% CI, 1.7 to 2.8), with 2.5 excess events per 100 survivors over 35 years. Among survivors, risk factors for VTE were female sex (RR, 1.3; 95% CI, 1.1 to 1.6), cisplatin (reference none; 1 to 199 mg/m2: RR, 3.0 [95% CI, 1.4 to 6.5]; 200 to 399 mg/m2: RR, 1.9 [95% CI, 1.0 to 3.6]; ≥ 400 mg/m2: RR, 2.0 [95% CI, 1.2 to 3.3]), l-asparaginase (RR, 1.3; 95% CI, 1.0 to 1.7), obesity or underweight (reference body mass index [BMI] 18.5 to 24.9 kg/m2; BMI ≥ 30.0 kg/m2: RR, 1.6 [95% CI, 1.2 to 2.0]; BMI < 18.5 kg/m2: RR, 2.4 [95% CI, 1.7 to 3.4]), and late cancer recurrence or subsequent malignant neoplasm (RR, 4.6; 95% CI, 3.6 to 5.8). Among lower-extremity osteosarcoma survivors, limb salvage (reference amputation; RR, 3.1; 95% CI, 1.2 to 7.5) and cisplatin 200 to 399 or ≥ 400 mg/m2 (reference none; RR, 4.0 [95% CI, 1.1 to 14.6] and 2.9 [95% CI, 1.1 to 8.0], respectively) were independently associated with late VTE. VTE was associated with increased risk for nonexternal cause late mortality (RR, 1.9; 95% CI, 1.6 to 2.3). Conclusion Childhood cancer survivors are at increased risk for VTE across their lifespan and a diagnosis of VTE increases mortality risk. Interventions that target potentially modifiable comorbidities, such as obesity, warrant consideration, with prophylaxis for high-risk survivors, including those treated with cisplatin and limb-sparing approaches.

Contemporary Factors Associated with the Use of Laparoscopy for Inguinal Hernia Repair Among Department of Defense Beneficiaries

INTRODUCTION

The factors that contribute to variation in utilization of laparoscopic inguinal hernia repair are unknown. We sought to determine the current usage patterns of laparoscopic and open surgery in the elective repair of uncomplicated unilateral inguinal hernia in a large population with universal health care coverage comprised of Department of Defense (DoD) beneficiaries.

MATERIALS AND METHODS

The DoD Military Health System Data Repository (MDR) tracks health care delivered to a universally insured population of active/reserve/retired members of the U.S. Armed Services and their dependents. The MDR was queried for elective unilateral inguinal hernia repair among adult patients between 2008 and 2014. The primary outcome was laparoscopic (vs. open) approach to hernia repair. We conducted univariable and multivariable analyses of patient- and systems-level factors associated with approach to inguinal hernia repair. This research was approved by our institutional review board prior to commencement of the study and need for informed consent was waived given the design of this study.

RESULTS

Among 37,742 elective uncomplicated unilateral inguinal hernia repairs, 35% (n = 13,114) were performed laparoscopically. In 2014, 40% of inguinal hernia repairs were performed laparoscopically, compared with 27% of repairs in 2008 (P < 0.01). In multivariable analysis, laparoscopic hernia repair was more likely for male patients (OR = 1.38, 95% CI = 1.23-1.54, P < 0.01), military (vs. civilian) institutions (OR = 1.34, 95% CI = 1.28-1.41, P < 0.01), active-duty officers (vs. active-duty enlisted; OR = 1.21, 95% CI = 1.12-1.30, P < 0.01), and more recent year of surgery (P < 0.01). Laparoscopic repair was significantly less likely among patients with greater than one comorbidity (vs. none; OR = 0.68, 95% CI = 0.61-0.76, P < 0.01).

CONCLUSION

In a large, universally insured population of military service members and their dependents, laparoscopic inguinal repair is increasingly used and was preferred over open repair for younger, healthier, active-duty patients and those treated within the military (vs. non-military) care system.

Thirty-year trends in aortofemoral bypass for aortoiliac occlusive disease

OBJECTIVE

Endovascular intervention has supplanted open bypass as the most frequently used approach in patients with aortoiliac segment atherosclerosis. We sought to determine whether this trend together with changing demographic and clinical characteristics of patients undergoing aortobifemoral bypass (ABFB) for aortoiliac occlusive disease (AOD) have an association with postoperative outcomes.

METHODS

Using a prospectively maintained institutional database, we identified patients who underwent ABFB for AOD from 1985 to 2015. Patients were divided into two cohorts: the historical cohort (HC) included patients who underwent ABFB for AOD from 1985 to 1999 and the contemporary cohort (CC) who underwent ABFB for AOD from 2000 to 2015. Medical and demographic data, procedural information, postoperative complications, and follow-up data were extracted. Cox proportional hazards regression was used to evaluate associations with the end point of primary patency. A similar analysis was performed for major adverse limb events (MALEs; the composite of above-ankle amputation, major reintervention, graft revision, or new bypass graft of the index limb) in the subset of patients with critical limb ischemia.

RESULTS

There were a total of 359 cases: 226 in the HC and 133 in the CC. The CC had more women (56.4% vs 43.8%; P = .02), smokers (87.2% vs 67.7%; P = .001), and patients who failed prior aortoiliac endovascular intervention (17.3% vs 4.8%; P = .0001), but fewer patients with coronary artery disease (32.3% vs 47.3%; P = .005). Thirty-day mortality was less than 1% in both cohorts, but 10-year survival was higher in the CC (67.7% vs 52.6%; P = .02). Five-year primary, primary-assisted, and secondary patency were higher in the HC (93.3% vs 82.2%; P = .005; 93.8% vs 85.7%; P = .02; 97.5% vs 90.4%; P = .02, respectively). CC membership, decreasing age, prior aortic surgery, and decreasing graft diameter were significant independent predictors of loss of primary patency after adjustment (hazard ratio [HR], 7.03; 95% confidence interval [CI], 2.80-17.63; P < .0001; HR, 0.93; 95% CI, 0.90-0.96; P < .0001; HR, 18.80; 95% CI, 5.94-59.58; P < .0001; and HR, 0.73; 95% CI, 0.55-0.95; P = .02, respectively). Similarly, CC membership, prior aortic surgery, and decreasing graft diameter were significant independent predictors of MALE in the critical limb ischemia cohort after adjustment (HR, 21.13; 95% CI, 4.20-106.40; P = .0002; HR, 40.40; 95% CI, 3.23-505.61; P = .004; and HR, 0.51; 95% CI, 0.30-0.86; P = .01, respectively).

CONCLUSIONS

Compared with the pre-endovascular era, demographic and clinical characteristics of patients undergoing ABFB for AOD in the CC have changed. Although long-term patency is slightly lower among patients in the CC during which a substantial subset of AOD patients are being treated primarily via the endovascular approach, durability remains excellent and limb salvage unchanged. After adjustment, the time period of index ABFB independently predicted primary patency and MALE, as did graft diameter and prior aortic surgery. These changing characteristics should be considered when counseling patients and benchmarking for reintervention rates and other outcomes.

Late Infection-Related Mortality in Asplenic Survivors of Childhood Cancer: A Report From the Childhood Cancer Survivor Study

Purpose Infection-related outcomes associated with asplenia or impaired splenic function in survivors of childhood cancer remains understudied. Methods Late infection-related mortality was evaluated in 20,026 5-year survivors of childhood cancer (diagnosed < 21 years of age from 1970 to 1999; median age at diagnosis, 7.0 years [range, 0 to 20 years]; median follow-up, 26 years [range, 5 to 44 years]) using cumulative incidence and piecewise-exponential regression models to estimate adjusted relative rates (RRs). Splenic radiation was approximated using average dose (direct and/or indirect) to the left upper quadrant of the abdomen (hereafter, referred to as splenic radiation). Results Within 5 years of diagnosis, 1,354 survivors (6.8%) had a splenectomy and 9,442 (46%) had splenic radiation without splenectomy. With 62 deaths, the cumulative incidence of infection-related late mortality was 1.5% (95% CI, 0.7% to 2.2%) at 35 years after splenectomy and 0.6% (95% CI, 0.4% to 0.8%) after splenic radiation. Splenectomy (RR, 7.7; 95% CI, 3.1 to 19.1) was independently associated with late infection-related mortality. Splenic radiation was associated with increasing risk for late infection-related mortality in a dose-response relationship (0.1 to 9.9 Gy: RR, 2.0; 95% CI, 0.9 to 4.5; 10 to 19.9 Gy: RR, 5.5; 95% CI, 1.9 to 15.4; ≥ 20 Gy: RR, 6.0; 95% CI, 1.8 to 20.2). High-dose alkylator chemotherapy exposure was also independently associated with an increased risk of infection-related mortality (RR, 1.9; 95% CI, 1.1 to 3.4). Conclusion Splenectomy and splenic radiation significantly increase risk for late infection-related mortality. Even low- to intermediate-dose radiation exposure confers increased risk, suggesting that the spleen is highly radiosensitive. These findings should inform long-term follow-up guidelines for survivors of childhood cancer and should lead clinicians to avoid or reduce radiation exposure involving the spleen whenever possible.

Infection related late mortality in survivors of childhood cancer with asplenia or radiation-induced hyposplenism: A report from the Childhood Cancer Survivor Study

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Background: Asplenia or hyposplenism can develop in survivors of childhood cancer following splenectomy or radiotherapy exposure to the left upper quadrant of the abdomen (LUQ). Knowledge regarding long-term infection related outcomes for these survivors is limited. Methods: Infection related late mortality (sepsis, meningitis or pneumonia) was evaluated in 20,805 5-year survivors (diagnosed <21 years of age from 1970-1999, median follow-up 26 years, range 5-44) using cumulative incidence and Poisson regression models to calculate adjusted relative risk (RR) and 95% confidence intervals (CI). Average LUQ radiation was calculated as a surrogate for splenic radiation. Results: Treatment included splenectomy for 1328 survivors (6%). An additional 10,295 (49%) were exposed to LUQ radiotherapy without splenectomy. The cumulative incidence of infection related late mortality was 1.4% (95%CI: 0.7%-2.2%) at 35 years after splenectomy and 0.6% (95%CI: 0.4%-0.8%) after LUQ radiotherapy, with a total of 78 deaths attributable to infectious causes (25 sepsis, 1 meningitis, 52 pneumonia). Splenectomy (RR=8.4, p<0.001) and increasing LUQ radiotherapy dose (p<0.001) were independently associated with infection related late mortality (Table). Conclusions: Splenectomy and LUQ radiotherapy increased risk for infection related late mortality. While infectious mortality increased with increasing LUQ radiation dose, even lower dose exposure (<10Gy) increased risk substantially. Accordingly, cancer survivors exposed to LUQ radiotherapy should be considered at risk for functional asplenia and managed similarly to asplenic individuals with respect to vaccinations and febrile illnesses. [Table: see text]

Long-term incidence of venous thromboembolism (VTE) among survivors of childhood cancer: A report from the Childhood Cancer Survivor Study (CCSS)

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Background: This study aimed to estimate the incidence of late-occurring VTE among survivors of childhood cancer, and to identify associated demographic and clinical factors that define high-risk subgroups for potential screening and prevention. Methods: Using data from CCSS, a multi-institutional, longitudinal cohort of 5-year survivors of childhood cancer (diagnosed 1970-1999) and their siblings, the primary endpoint of self-reported late VTE (occurring ≥5 years after diagnosis) was estimated using multivariable piecewise exponential models adjusted for age, sex, and race. Generalized estimating equations accounted for potential within-family correlation where applicable. Results: Among 23,601 survivors and 5051 siblings, the incidence of VTE was 1.15 and 0.48 events per 1000 person-years, respectively. For survivors, median age at last follow-up was 28.6 years (range 5.6-58.3) and median follow-up time from diagnosis was 21.2 years (range 5.0-39.3). The adjusted rate ratio (RR) for survivors compared to siblings was 2.2 (95% confidence interval [CI] = 1.7-2.8, P< 0.01). Among survivors, risk factors for VTE included BMI≥30kg/m2 (ref. BMI 18.5-24.5; RR = 1.5, CI = 1.2-2.0, P< 0.01), increasing number of severe or life-threatening (i.e. CTCAE grades 3 or 4) non-VTE chronic conditions (ref. 0 conditions; 1-2 conditions: RR = 2.5, CI = 2.0-3.1, P< 0.01 ; ≥3 conditions: RR = 3.5, CI = 2.5-4.9, P< 0.01), and cancer recurrence or second malignant neoplasm (RR = 3.5, CI = 2.7-4.6, P< 0.01). Incidence of late VTE was associated with increased subsequent mortality, independent of non-VTE chronic conditions (RR 2.2, 95% CI = 1.7-2.8, P< 0.01). Conclusions: Survivors of childhood cancer remain at increased risk for VTE across their lifespan. While typically not causal, late VTE was associated with subsequent mortality. Care providers should be aware of this increased risk and consider interventions that target modifiable co-morbidities such as obesity. Surveillance and education should be directed toward high-risk survivors.

Prolyl Hydroxylase Domain-2 Inhibition Improves Skeletal Muscle Regeneration in a Male Murine Model of Obesity

Obesity leads to a loss of muscle mass and impaired muscle regeneration. In obese individuals, pathologically elevated levels of prolyl hydroxylase domain enzyme 2 (PHD2) limit skeletal muscle hypoxia-inducible factor-1 alpha and vascular endothelial growth factor (VEGF) expression. Loss of local VEGF may further impair skeletal muscle regeneration. We hypothesized that PHD2 inhibition would restore vigorous muscle regeneration in a murine model of obesity. Adult (22-week-old) male mice were fed either a high-fat diet (HFD), with 60% of calories derived from fat, or a regular diet (RD), with 10% of calories derived from fat, for 16 weeks. On day 5 following cryoinjury to the tibialis anterior muscle, newly regenerated muscle fiber cross-sectional areas were significantly smaller in mice fed an HFD as compared to RD, indicating an impaired regenerative response. Cryoinjured gastrocnemius muscles of HFD mice also showed elevated PHD2 levels (twofold higher) and reduced VEGF levels (twofold lower) as compared to RD. Dimethyloxalylglycine, a cell permeable competitive inhibitor of PHD2, restored VEGF levels and significantly improved regenerating myofiber size in cryoinjured mice fed an HFD. We conclude that pathologically increased PHD2 in the obese state drives impairments in muscle regeneration, in part by blunting VEGF production. Inhibition of PHD2 over activity in the obese state normalizes VEGF levels and restores muscle regenerative potential.

Surgical Management of Wild-Type Gastrointestinal Stromal Tumors: A Report From the National Institutes of Health Pediatric and Wildtype GIST Clinic

Purpose Wild-type gastrointestinal stromal tumors (WT-GISTs) that lack KIT or PDGFRA mutations represent a unique subtype of GIST that predominantly affects children. We sought to determine the effect on event-free survival (EFS) of staging variables, extent of resection, and repeat resection of tumors. Methods In 2008, a WT-GIST clinic was established at the National Cancer Institute, allowing the development of a large clinical database. We included participants who underwent resection of WT-GIST. Associations with EFS (ie, freedom from disease progression or recurrence) were evaluated using the Kaplan-Meier method and Cox proportional hazards modeling. Results Among 76 participants with WT-GISTs, the median follow-up was 4.1 years. Overall EFS (± SE) was 72.6 ± 5.4% at 1 year, 57.6 ± 6.2% at 2 years, 23.7 ± 6.0% at 5 years, and 16.3 ± 5.5% at 10 years postoperatively. Hazard of disease progression or recurrence was significantly increased for patients with metastatic disease (adjusted hazard ratio [AHR], 2.3; 95% CI, 1.0 to 5.1; P = .04) and > 5 mitoses per 50 high-power fields (AHR, 2.5; 95% CI, 1.1 to 6.0; P = .03), whereas there was no significant effect of negative microscopic resection margins (AHR, 0.9; 95% CI, 0.4 to 2.2; P = 0.86). There was no association between type of gastric resection (ie, anatomic v partial/wedge) and EFS ( P = .67). Repeated resection after the initial resection was significantly associated with decreasing postoperative EFS ( P < .01). Five patients (6%) died after initial enrollment in 2008. Conclusion WT-GIST is an indolent disease, and most patients survive with disease progression. We found no improvement in EFS with more extensive or serial resections. Disease progression or recurrence may be more closely related to tumor biology than surgical management. These data suggest that resections for WT-GISTs be restricted to the initial procedure and that subsequent resections be performed only to address symptoms such as obstruction or bleeding.

High dose-rate brachytherapy for the treatment of lower extremity in-stent restenosis

OBJECTIVE

Historically, edge stenosis and late thrombosis limited the effectiveness of adjunctive endovascular brachytherapy (EVBT) for in-stent restenosis (ISR) after percutaneous transluminal angioplasty (PTA) and stenting. We evaluated an updated protocol of PTA and EVBT for ISR among patients with lower extremity occlusive disease.

METHODS

This is a retrospective, single-center review of patients treated with PTA and EVBT for ISR in the iliac and femoropopliteal segments between 2004 and 2012. A dose of 20 Gy was given at a depth of 0.5 mm beyond the radius of the largest PTA balloon using iridium 192, with at least 2-cm-long margins of radiation coverage proximal and distal to the injured area. Stents were assessed for patency by duplex ultrasound imaging at 1, 3, 6, 9, 12, and 18 months and then yearly. The primary end point was freedom from ≥50% restenosis in the treated segment at 6 months, 1 year, and 2 years. Patency data were estimated using the Kaplan-Meier method. Secondary end points were early and late thrombotic occlusion.

RESULTS

Among 42 consecutive cases in 35 patients of EVBT for ISR in common or external iliac (9 [20.8%]) and superficial femoral or popliteal (33 [76.7%]) arteries, or both, 21 patients (50%) had claudication, asymptomatic hemodynamically significant stenoses were identified on duplex ultrasound imaging in 16 (38.1%), and 4 (9.8%) had critical limb ischemia. Mean treated length was 23.5 ± 12.3 cm over a mean duration of 16.1 ± 9.6 minutes. There was one technical failure (2.3%). Median post-EVBT follow-up time was 682 days (range, 1-2262 days). There were two (4.9%) and five (11.9%) cases of early and late thrombotic occlusions, respectively. There was one death, believed to be secondary to acute coronary syndrome. Primary, assisted primary, and secondary patency in the entire cohort was 75.2%, 89.1%, and 89.1%, respectively, at 1 year and 63.7%, 80.6%, and 85.6%, respectively, at 2 years.

CONCLUSIONS

This contemporary protocol of PTA and adjunctive EVBT for lower extremity ISR, which is updated from those used in prior trials and includes a surveillance strategy that identifies at-risk stents for reintervention before occlusion, may be a promising treatment for lower extremity ISR at institutions where a close collaboration between vascular surgeons and radiation oncologists is feasible.

Safety and cost-effectiveness of port removal outside of the operating room among pediatric patients

PURPOSE

The current emphasis on fiscally responsible health spending in the era of the Affordable Care Act and other health care reform necessitates cost-conscious delivery of care. "Value" in health care is defined as the quality of care divided by the cost. As such, health systems optimize value by providing the most cost-effective care possible without sacrificing safety or outcomes. Elective, minimal risk surgical procedures in children may be value-enhanced by moving from an operating room (OR) to a more cost-efficient setting. The purpose of this study was to assess the safety and cost of performing the removal of implantable central venous access devices ("ports") in locations other than the main OR.

METHODS

We compared port removal at three sites: 1. Main OR, 2. Satellite OR, and 3. Clinic Procedure Room. This was a mixed-methods study including a retrospective review of medical records and prospective observation/interviewing. To calculate cost without the inherent biases of hospital charges, costs, and payments, we utilized the methodology of time-driven activity based costing. Specifically, we recorded time spent by the patient in hospital facilities and with health care personnel. This duration was then weighted with the hourly cost of each health care professional and hospital space. The Mann-Whitney U test compared time and cost across the three sites. Overall cost at each site was divided by overall cost at the referent site (Main OR) to obtain a ratio of cost savings.

RESULTS

A total of 120 patients (40 per site) were included in the analysis. Demographic and clinical factors were not significantly different between sites. No complication occurred with port removal at any site. Time of the entire care episode was significantly decreased in the Clinic (median 161min, 95% confidence interval [CI] 134-188min), compared to the Main OR (median 235min, 95% confidence interval [CI] 209-251min) or Satellite OR (median 228min, 95% confidence interval [CI] 211-245min). Overall cost was decreased by 25% (95% CI: 13-34%) at the Clinic and by 6% (95% CI: -2-11%) at the Satellite OR, compared to the Main OR (referent, P<0.01).

CONCLUSION

In our study, port removal in the Clinic Procedure Room was not associated with increased risk of negative outcomes. Shifting port removal from the Main OR to the Clinic may result in substantial cost savings.

Implementation of a Comprehensive Post-Discharge Venous Thromboembolism Prophylaxis Program for Abdominal and Pelvic Surgery Patients

BACKGROUND

Prophylactic anticoagulation is routinely used in the inpatient setting; however, the risk of venous thromboembolism (VTE) remains elevated after discharge. Extensive evidence and clinical guidelines suggest post-discharge VTE prophylaxis is critical in at-risk populations, but it remains severely underused in practice.

STUDY DESIGN

We performed a single-institution retrospective, nonrandomized, pre- and post-intervention analysis of a systematic post-discharge pharmacologic prophylaxis program against the primary end point, which is post-discharge symptomatic VTE. An institutional American College of Surgeons NSQIP dataset was used to identify patients and outcomes. Patients undergoing major abdominal surgery for malignancy or inflammatory bowel disease were eligible for the post-discharge VTE prevention program.

RESULTS

Among 1,043 patients who underwent abdominal surgery for malignancy or inflammatory bowel disease, 800 (77%) were in the pre-intervention cohort and 243 (23%) patients were in the post-intervention cohort. Rates of inpatient VTE did not significantly differ between cohorts (0.7%, n = 6 pre-intervention vs 1.7%, n = 4 post-intervention; p = 0.25). However, compared with the pre-intervention cohort, patients in the post-intervention cohort demonstrated a significantly lower post-discharge VTE rate (2.5%, n = 20 pre-intervention vs 0.0%, n = 0 post-intervention; p < 0.01).

CONCLUSIONS

A systematic post-discharge VTE prophylaxis program including provider education, local guideline adaptation, bedside medication delivery, and education for at-risk patients, was associated with significantly fewer post-discharge VTE events.

Preoperative risk stratification of children with ovarian tumors

BACKGROUND

The appropriate operative approach to pediatric patients with ovarian tumors must balance real risk of malignancy with maximal preservation of reproductive potential. We evaluate preoperative risk of malignancy in order to more precisely guide treatment, so as to err on the side of ovarian preservation if at all possible.

METHODS

We retrospectively reviewed the records of all patients undergoing surgical intervention for ovarian tumors at a single institution. The primary endpoint was ovarian malignancy.

RESULTS

Of 502 patients who underwent surgery for ovarian tumors, 44 (8.8%) had malignancies. Malignancy rate (95% confidence interval) was low for cystic lesions <9cm (0.0%, 0.0-2.9%) and for tumor marker-negative heterogeneous lesions <9cm (2.3%, 0.4-12.1%). High-risk profiles for malignancy included tumor marker-positive heterogeneous lesions (66.7%, 35.4-87.9%) and solid tumors ≥9cm (69.2%, 16.2-40.3%). Intermediate risk tumors included cystic tumors ≥9cm (6.8%, 3.5-20.7%), tumor marker-negative heterogeneous lesions ≥9cm (31.2%, 18.0-48.6%), and solid tumors <9cm (11.1%, 4.4-25.3%).

CONCLUSIONS

We developed a decision strategy to help determine who may and may not require an ovarian-sparing approach, which warrants prospective application and validation. Ultimately, the decision to pursue an oncologic surgery with oophorectomy and staging (as opposed to fertility-preserving surgery) should be made after individualized discussion involving the surgeon, patient, and family.

Safety of peritoneal and pleural drain placement in pediatric stem cell transplant recipients with severe veno-occlusive disease

Hepatic VOD (veno-occlusive disease) is a serious complication of HSCT (hematopoietic stem cell transplantation) and has historically been associated with high mortality. This obstruction to hepatic flow often results in fluid collections in the peritoneal and pleural cavities. Catheter placement to drain ascites or pleural fluid may reduce intra-abdominal hypertension and/or improve respiratory parameters. The safety of these interventions among critically ill, immunocompromised children is unknown. Among 32 HSCT recipients (2000-2012) with severe VOD, we assessed the primary outcome of procedural complication from peritoneal drain placement. Twenty-four (75%) patients underwent peritoneal drain placement. No patient sustained visceral perforation or hemorrhage with drain placement. Overall mortality was 47% (n = 15). The procedure was not associated with increased overall mortality (p > 0.99). Eight (25%) peritoneal drains required replacement for malfunction. Of 24 patients with peritoneal drains, one (4%) patient had a positive culture from ascitic fluid. Eight (25%) patients underwent pleural drain placement. No pleural drain-related procedural complication or infection occurred. Four (50%) of the eight patients with pleural drains had de-escalation in oxygen requirement at drain removal, compared to time of placement. In this study, peritoneal and pleural drains were safe interventions for children with severe VOD.

Intestinal Obstruction in Survivors of Childhood Cancer: A Report From the Childhood Cancer Survivor Study

PURPOSE

For adult survivors of childhood cancer, knowledge about the long-term risk of intestinal obstruction from surgery, chemotherapy, and radiotherapy is limited.

METHODS

Intestinal obstruction requiring surgery (IOS) occurring 5 or more years after cancer diagnosis was evaluated in 12,316 5-year survivors in the Childhood Cancer Survivor Study (2,002 with and 10,314 without abdominopelvic tumors) and 4,023 sibling participants. Cumulative incidence of IOS was calculated with second malignant neoplasm, late recurrence, and death as competing risks. Using piecewise exponential models, we assessed the associations of clinical and demographic factors with rate of IOS.

RESULTS

Late IOS was reported by 165 survivors (median age at IOS, 19 years; range, 5 to 50 years; median time from diagnosis to IOS, 13 years) and 14 siblings. The cumulative incidence of late IOS at 35 years was 5.8% (95% CI, 4.4% to 7.3%) among survivors with abdominopelvic tumors, 1.0% (95% CI, 0.7% to 1.4%) among those without abdominopelvic tumors, and 0.3% (95% CI, 0.1% to 0.5%) among siblings. Among survivors, abdominopelvic tumor (adjusted rate ratio [ARR], 3.6; 95% CI, 1.9 to 6.8; P < .001) and abdominal/pelvic radiotherapy within 5 years of cancer diagnosis (ARR, 2.4; 95% CI, 1.6 to 3.7; P < .001) increased the rate of late IOS, adjusting for diagnosis year; sex; race/ethnicity; age at diagnosis; age during follow-up (as natural cubic spline); cancer type; and chemotherapy, radiotherapy, and surgery within 5 years of cancer diagnosis. Developing late IOS increased subsequent mortality among survivors (ARR, 1.8; 95% CI, 1.1 to 2.9; P = .016), adjusting for the same factors.

CONCLUSION

The long-term risk of IOS and its association with subsequent mortality underscore the need to promote awareness of this complication among patients and providers.

Surgical consultation and intervention during pediatric hematopoietic stem cell transplantation

Children undergoing HSCT are at risk for complications due to immune system impairment, toxicity from prior therapies and conditioning regimens, and long-term use of indwelling catheters. These problems may require assessment by the surgical team. We sought to characterize the role of surgical consultation during primary hospital stay for HSCT. We retrospectively reviewed the records of consecutive patients undergoing HSCT between September 2010 and September 2012. One hundred and seventy-three patients underwent 189 HSCTs. General surgery consultations occurred during 33% (n = 62) of primary hospitalizations for HSCT, with a total of 85 consults. Sixty-three (73%) consults resulted in an intervention in the operating room or at the bedside. The majority of consults were for CVL issues (59%, n = 50), followed by abdominal complaints (16%, n = 14). Patients requiring surgical consultation had significantly higher in-hospital mortality (16% vs. 2%, p < 0.01) and 100-day TRM (10% vs. 2%, p < 0.01), compared with those not requiring consultation. Patients undergoing HSCT often require surgical consultation, most commonly for line-related issues. Surgical consultation heralded an increased risk of in-hospital and 100-day TRM. Issues among this high-risk cohort of children who have undergone HSCT must be familiar to the general surgeon and oncologist alike.