Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Prior Treatment for Non-small Cell Lung Cancer Is Associated With Improved Survival in Patients who Undergo Definitive Stereotactic Body Radiation Therapy for a Subsequent Lung Malignancy: A Retrospective Multivariate and Matched Pair Analysis

BACKGROUND

Despite occurring commonly, the prognoses of second early-stage non-small cell lung cancers (NSCLC) are not well known.

METHODS

The authors retrospectively reviewed the charts of inoperable patients who underwent thoracic stereotactic body radiation therapy (SBRT) from February 2007 to April 2019. Those with previous small cell lung cancers or SBRT treatments for tumors other than NSCLC were excluded. Multivariate Cox regression and a matched pair cohort analyses evaluated the prognoses of patients undergoing definitive SBRT for a new second primary.

RESULTS

Of 438 patients who underwent definitive SBRT for NSCLC, 84 had previously treated NSCLC. Univariate log-rank tests identified gender, Karnofksy performance status (KPS), prior lung cancer, anticoagulation use, and history of heart disease to correlate with overall survival (OS) (P<0.05). These factors were incorporated into a multivariate Cox regression model that demonstrated female sex (P=0.004, hazard ratio [HR]=0.68), KPS (P<0.001, HR=2.0), and prior lung cancer (P=0.049, HR=0.7) to be significantly associated with OS. A similar approach found only gender (P=0.017, HR=0.64) and tumor stage (P=0.02, HR=1.7) to correlate with relapse-free survival. To support the Cox regression analysis, propensity score matching was performed using gender, age, KPS, tumor stage, history of heart disease, and anticoagulation use. Kaplan-Meier survival analysis within the matched pairs found prior lung cancer to be associated with improved OS (P=0.011), but not relapse-free survival (P=0.44).

CONCLUSIONS

Compared with initial lung cancer SBRT inoperable cases, ablative radiotherapy for new primaries was associated with improved OS. Physicians should not be dissuaded from offering SBRT to such patients.