Predictive modeling for postoperative delirium in elderly patients with abdominal malignancies using synthetic minority oversampling technique

BACKGROUND

Postoperative delirium, particularly prevalent in elderly patients after abdominal cancer surgery, presents significant challenges in clinical management.

AIM

To develop a synthetic minority oversampling technique (SMOTE)-based model for predicting postoperative delirium in elderly abdominal cancer patients.

METHODS

In this retrospective cohort study, we analyzed data from 611 elderly patients who underwent abdominal malignant tumor surgery at our hospital between September 2020 and October 2022. The incidence of postoperative delirium was recorded for 7 d post-surgery. Patients were divided into delirium and non-delirium groups based on the occurrence of postoperative delirium or not. A multivariate logistic regression model was used to identify risk factors and develop a predictive model for postoperative delirium. The SMOTE technique was applied to enhance the model by oversampling the delirium cases. The model's predictive accuracy was then validated.

RESULTS

In our study involving 611 elderly patients with abdominal malignant tumors, multivariate logistic regression analysis identified significant risk factors for postoperative delirium. These included the Charlson comorbidity index, American Society of Anesthesiologists classification, history of cerebrovascular disease, surgical duration, perioperative blood transfusion, and postoperative pain score. The incidence rate of postoperative delirium in our study was 22.91%. The original predictive model (P1) exhibited an area under the receiver operating characteristic curve of 0.862. In comparison, the SMOTE-based logistic early warning model (P2), which utilized the SMOTE oversampling algorithm, showed a slightly lower but comparable area under the curve of 0.856, suggesting no significant difference in performance between the two predictive approaches.

CONCLUSION

This study confirms that the SMOTE-enhanced predictive model for postoperative delirium in elderly abdominal tumor patients shows performance equivalent to that of traditional methods, effectively addressing data imbalance.

CT and MRI of abdominal cancers: current trends and perspectives in the era of radiomics and artificial intelligence

Abdominal cancers continue to pose daily challenges to clinicians, radiologists and researchers. These challenges are faced at each stage of abdominal cancer management, including early detection, accurate characterization, precise assessment of tumor spread, preoperative planning when surgery is anticipated, prediction of tumor aggressiveness, response to therapy, and detection of recurrence. Technical advances in medical imaging, often in combination with imaging biomarkers, show great promise in addressing such challenges. Information extracted from imaging datasets owing to the application of radiomics can be used to further improve the diagnostic capabilities of imaging. However, the analysis of the huge amount of data provided by these advances is a difficult task in daily practice. Artificial intelligence has the potential to help radiologists in all these challenges. Notably, the applications of AI in the field of abdominal cancers are expanding and now include diverse approaches for cancer detection, diagnosis and classification, genomics and detection of genetic alterations, analysis of tumor microenvironment, identification of predictive biomarkers and follow-up. However, AI currently has some limitations that need further refinement for implementation in the clinical setting. This review article sums up recent advances in imaging of abdominal cancers in the field of image/data acquisition, tumor detection, tumor characterization, prognosis, and treatment response evaluation.

Effect of regional anesthesia and analgesia on long-term survival following abdominal cancer Surgery-A systematic review with meta-analysis

Background

The impact of regional anesthesia and analgesia (RAA) on long-term survival following cancer surgery is a topic of debate. The aim of this study was to investigate the effects of perioperative RAA on long-term oncological outcomes in patients undergoing major abdominal cancer surgery.

Methods

The authors searched computerized databases and reference lists from inception to December 20, 2022. All studies that investigated the effects of perioperative RAA on long-term oncological outcomes following major abdominal cancer surgery were included. Using the inverse variance method with a random-effects model, hazard ratios (HR) and 95% confidence intervals (CI) were calculated.

Results

The systematic review included 51 retrospective studies, one prospective study, and three randomized controlled trials (RCTs), with a total of 95,046 patients. The results showed that perioperative RAA may improve long-term overall survival (HR: 0.85, 95% CI: 0.80 to 0.91, P = 0.00, I2 = 60.2%). However, there was no significant association between perioperative RAA and reduced cancer recurrence (HR: 0.98, 95% CI: 0.90 to 1.03, P = 0.31, I2 = 52.3%). When performing a pooled analysis of the data from the three RCTs, no statistically significant effect of RAA was found in either case.

Conclusion

The systematic review suggests perioperative RAA may improve long-term overall survival but does not appear to reduce cancer recurrence in patients undergoing major abdominal cancer surgery. The limited number of RCTs included in this study did not confirm this finding, highlighting the need for further RCTs to corroborate these results.

Evaluating differences in respiratory motion estimates during radiotherapy: a single planning 4DMRI versus daily 4DMRI

Background

In radiotherapy, respiratory-induced tumor motion is typically measured using a single four-dimensional computed tomography acquisition (4DCT). Irregular breathing leads to inaccurate motion estimates, potentially resulting in undertreatment of the tumor and unnecessary dose to healthy tissue. The aim of the research was to determine if a daily pre-treatment 4DMRI-strategy led to a significantly improved motion estimate compared to single planning 4DMRI (with or without outlier rejection).

Methods

4DMRI data sets from 10 healthy volunteers were acquired. The first acquisition simulated a planning MRI, the respiratory motion estimate (constructed from the respiratory signal, i.e. the 1D navigator) was compared to the respiratory signal in the subsequent scans (simulating 5–29 treatment fractions). The same procedure was performed using the first acquisition of each day as an estimate for the subsequent acquisitions that day (2 per day, 4–20 per volunteer), simulating a daily MRI strategy. This was done for three outlier strategies: no outlier rejection (NoOR); excluding 5% of the respiratory signal whilst minimizing the range (Min95) and excluding the datapoints outside the mean end-inhalation and end-exhalation positions (MeanIE).

Results

The planning MRI median motion estimates were 27 mm for NoOR, 18 mm for Min95, and 13 mm for MeanIE. The daily MRI median motion estimates were 29 mm for NoOR, 19 mm for Min95 and 15 mm for MeanIE. The percentage of time outside the motion estimate were for the planning MRI: 2%, 10% and 32% for NoOR, Min95 and MeanIE respectively. These values were reduced with the daily MRI strategy: 0%, 6% and 17%. Applying Min95 accounted for a 30% decrease in motion estimate compared to NoOR.

Conclusion

A daily MRI improved the estimation of respiratory motion as compared to a single 4D (planning) MRI significantly. Combining the Min95 technique with a daily 4DMRI resulted in a decrease of inclusion time of 6% with a 30% decrease of motion. Outlier rejection alone on a planning MRI often led to underestimation of the movement and could potentially lead to an underdosage.

Trial registration: protocol W15_373#16.007

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01915-1.

Range optimization for target and organs at risk in dynamic adaptive passive scattering proton beam therapy - A proof of concept

PURPOSE

The purpose of this study was to design and develop a new range optimization for target and organs at risk (OARs) in dynamic adaptive proton beam therapy (PBT).

METHODS

The new range optimization for target and OARs (RO-TO) was optimized to maintain target dose coverage but not to increase the dose exposure of OARs, while the other procedure, range optimization for target (RO-T), only focused on target dose coverage. A retrospective analysis of a patient who received PBT for abdominal lymph node metastases was performed to show the effectiveness of our new approach. The original plan (OP), which had a total dose of 60 Gy (relative biological effectiveness; RBE), was generated using six treatment fields. Bone-based registration (BR) and tumor-based registration (TR) were performed on each pretreatment daily CT image dataset acquired once every four fractions, to align the isocenter.

RESULTS

Both range adaptive approaches achieved better coverage (D_95%) and homogeneity (D_5%-D_95%) than BR and TR only. However, RO-T showed the greatest increases in D_2cc and D_mean values of the small intestine and stomach and exceeded the limitations of dose exposure for those OARs. RO-TO showed comparable or superior dose sparing compared with the OP for all OARs.

CONCLUSIONS

Our results suggest that BR and TR alone may reduce target dose coverage, and that RO-T may increase the dose exposure to the OARs. RO-TO may achieve the planned dose delivery to the target and OARs more efficiently than the OP. The technique requires testing on a large clinical dataset.

Exhaled Breath Condensate Acidification Occurs During Surgery for Abdominal Cancer

BACKGROUND/AIM

Acidification of exhaled breath condensate (EBC), reflecting airway inflammation and oxidative stress, has been reported in lung cancer patients undergoing lobectomy. We undertook this study to examine EBC pH changes during surgery for abdominal cancer.

PATIENTS AND METHODS

EBC pH was measured from 20 patients undergoing abdominal cancer resection before and during surgery. Repeated-measures of ANOVA and random-effects linear models were applied to compare mean EBC pH values in samples collected at different times. Cox and linear regression models were used to determine the association of EBC pH with occurrence of acute bronchospasm intra-operatively and the duration of hospitalization.

RESULTS

Significant acidification of EBC was observed during surgery (p=0.007) associated with 0.77% (95% confidence interval=-0.14-1.68, p-value=0.097) increase in the risk for developing acute bronchospasm, after adjustment for potential confounders.

CONCLUSION

EBC acidification occurs in patients undergoing abdominal cancer resection and is associated with the occurrence of acute bronchospasm intraoperatively.

Couch height-based patient setup for abdominal radiation therapy

There are 2 methods commonly used for patient positioning in the anterior-posterior (A-P) direction: one is the skin mark patient setup method (SMPS) and the other is the couch height-based patient setup method (CHPS). This study compared the setup accuracy of these 2 methods for abdominal radiation therapy. The enrollment for this study comprised 23 patients with pancreatic cancer. For treatments (539 sessions), patients were set up by using isocenter skin marks and thereafter treatment couch was shifted so that the distance between the isocenter and the upper side of the treatment couch was equal to that indicated on the computed tomographic (CT) image. Setup deviation in the A-P direction for CHPS was measured by matching the spine of the digitally reconstructed radiograph (DRR) of a lateral beam at simulation with that of the corresponding time-integrated electronic portal image. For SMPS with no correction (SMPS/NC), setup deviation was calculated based on the couch-level difference between SMPS and CHPS. SMPS/NC was corrected using 2 off-line correction protocols: no action level (SMPS/NAL) and extended NAL (SMPS/eNAL) protocols. Margins to compensate for deviations were calculated using the Stroom formula. A-P deviation > 5mm was observed in 17% of SMPS/NC, 4% of SMPS/NAL, and 4% of SMPS/eNAL sessions but only in one CHPS session. For SMPS/NC, 7 patients (30%) showed deviations at an increasing rate of > 0.1mm/fraction, but for CHPS, no such trend was observed. The standard deviations (SDs) of systematic error (Σ) were 2.6, 1.4, 0.6, and 0.8mm and the root mean squares of random error (σ) were 2.1, 2.6, 2.7, and 0.9mm for SMPS/NC, SMPS/NAL, SMPS/eNAL, and CHPS, respectively. Margins to compensate for the deviations were wide for SMPS/NC (6.7mm), smaller for SMPS/NAL (4.6mm) and SMPS/eNAL (3.1mm), and smallest for CHPS (2.2mm). Achieving better setup with smaller margins, CHPS appears to be a reproducible method for abdominal patient setup.

The value of electrochemotherapy in the treatment of peristomal tumors

Electrochemotherapy (ECT) holds promise as a minimally invasive palliative tool for selected patients with peristomal tumors. We present the favorable short-term outcome of three patients (two with head and neck cancer, one with gastric cancer) successfully palliated by ECT. Treatment effectiveness and clinical benefit for patients with unresectable stoma recurrence need to be confirmed in future multicenter studies.