Association between Radiotherapy and Risk of Cancer Associated Venous Thromboembolism: A Sub-Analysis of the COMPASS-CAT Study

Risk of Venous Thromboembolic Events After Surgery for Cancer

Importance

The risks and benefits of thromboprophylaxis therapy after cancer surgery are debated. Studies that determine thrombosis risk after cancer surgery with high accuracy are needed.

Objectives

To evaluate 1-year risk of venous thromboembolic events after major cancer surgery and how these events vary over time.

Design, Setting, and Participants

This register-based retrospective observational matched cohort study included data on the full population of Sweden between 1998 and 2016. All patients who underwent major surgery for cancer of the bladder, breast, colon or rectum, gynecologic organs, kidney and upper urothelial tract, lung, prostate, or gastroesophageal tract were matched in a 1:10 ratio with cancer-free members of the general population on year of birth, sex, and county of residence. Data were analyzed from February 13 to December 5, 2023.

Exposure

Major surgery for cancer.

Main Outcomes and Measures

The main outcome was incidence of venous thromboembolic events within 1 year after the surgery. Crude absolute risks and risk differences of events within 1 year and adjusted time-dependent cause-specific hazard ratios (HRs) of postdischarge events were calculated.

Results

A total of 432 218 patients with cancer (median age, 67 years [IQR, 58-75 years]; 68.7% women) and 4 009 343 cancer-free comparators (median age, 66 years [IQR, 57-74 years]; 69.3% women) were included in the study. The crude 1-year cumulative risk of pulmonary embolism was higher among the cancer surgery population for all cancers, with the following absolute risk differences: for bladder cancer, 2.69 percentage points (95% CI, 2.33-3.05 percentage points); for breast cancer, 0.59 percentage points (95% CI 0.55-0.63 percentage points); for colorectal cancer, 1.57 percentage points (95% CI, 1.50-1.65 percentage points); for gynecologic organ cancer, 1.32 percentage points (95% CI, 1.22-1.41 percentage points); for kidney and upper urinary tract cancer, 1.38 percentage points (95% CI, 1.21-1.55 percentage points); for lung cancer, 2.61 percentage points (95% CI, 2.34-2.89 percentage points); for gastroesophageal cancer, 2.13 percentage points (95% CI, 1.89-2.38 percentage points); and for prostate cancer, 0.57 percentage points (95% CI, 0.49-0.66 percentage points). The cause-specific HR of pulmonary embolism comparing patients who underwent cancer surgery with matched comparators peaked just after discharge and generally plateaued 60 to 90 days later. At 30 days after surgery, the HR was 10 to 30 times higher than in the comparison cohort for all cancers except breast cancer (colorectal cancer: HR, 9.18 [95% CI, 8.03-10.50]; lung cancer: HR, 25.66 [95% CI, 17.41-37.84]; breast cancer: HR, 5.18 [95% CI, 4.45-6.05]). The hazards subsided but never reached the level of the comparison cohort except for prostate cancer. Similar results were observed for deep vein thrombosis.

Conclusions and Relevance

This cohort study found an increased rate of venous thromboembolism associated with cancer surgery. The risk persisted for about 2 to 4 months postoperatively but varied between cancer types. The increased rate is likely explained by the underlying cancer disease and adjuvant treatments. The results highlight the need for individualized venous thromboembolism risk evaluation and prophylaxis regimens for patients undergoing different surgery for different cancers.

The interplay between tamoxifen and endoxifen plasma concentrations and coagulation parameters in patients with primary breast cancer

BACKGROUND

Tamoxifen is an effective treatment for primary breast cancer but increases the risk for venous thromboembolism. Tamoxifen decreases anticoagulant proteins, including antithrombin (AT), protein C (PC) and tissue factor (TF) pathway inhibitor, and enhances thrombin generation (TG). However, the relation between plasma concentrations of both tamoxifen and its active metabolite endoxifen and coagulation remains unknown.

METHODS

Tamoxifen and endoxifen were measured in 141 patients from the prospective open-label intervention TOTAM-study after 3 months (m) and 6 m of tamoxifen treatment. Levels of AT and PC, the procoagulant TF, and TG parameters were determined at both timepoints if samples were available (n = 53-135 per analysis). Levels of coagulation proteins and TG parameters were correlated and compared between: 1) quartiles of tamoxifen and endoxifen levels, and 2) 3 m and 6 m of treatment.

RESULTS

At 3 m, levels of AT, PC, TF and TG parameters were not associated with tamoxifen nor endoxifen levels. At 6 m, median TF levels were lower in patients in the 3rd (56.6 [33] pg/mL), and 4th (50.1 [19] pg/mL) endoxifen quartiles compared to the 1st (lowest) quartile (76 [69] pg/mL) (P=0.027 and P=0.018, respectively), but no differences in anticoagulant proteins or TG parameters were observed. An increase in circulating TF levels (3 m: 46.0 [15] versus 6 m: 54.4 [39] pg/mL, P < 0.001) and TG parameters was observed at the 6 m treatment timepoint, while AT and PC levels remained stable.

CONCLUSIONS

Our results indicate that higher tamoxifen and endoxifen levels are not correlated with an increased procoagulant state, suggesting tamoxifen dose escalation does not further promote hypercoagulability.

Prevention of venous thromboembolism in patients with cancer

Venous thromboembolism (VTE) is a major cause of both morbidity and mortality in patients with cancer. Venous thromboembolism, which includes both deep vein thrombosis and pulmonary embolism, affects a sizable portion of patients with malignancy and can have potentially life threatening complications. Accurate assessment of risk as well as diagnosis and treatment of this process is paramount to preventing death in this high risk population. Various risk models predictive of venous thromboembolism in patients with cancer have been developed, and knowledge of these rubrics is essential for the treating oncologist. Subgroups of particular interest are inpatients receiving chemotherapy, postoperative patients after surgical debulking, and patients undergoing radiotherapy. Numerous newer drugs have become available for the prevention of venous thromboembolism in patients with cancer who are at high risk of developing the disease. These include the class of drugs called direct oral anticoagulants, (DOACs) which do not require the same monitoring that other modalities have previously required and are taken by mouth, preventing the discomfort associated with subcutaneous strategies. The appropriate risk stratification and intervention to prevent venous thromboembolism are vital to the treatment of patients with cancer.

Derivation, validation and assessment of a novel nomogram-based risk assessment model for venous thromboembolism in hospitalized patients with lung cancer: A retrospective case control study

Purpose

This study aimed to develop and validate a specific risk-stratification nomogram model for the prediction of venous thromboembolism(VTE) in hospitalized patients with lung cancer using readily obtainable demographic, clinical and therapeutic characteristics, thus guiding the individualized decision-making on thromboprophylaxis on the basis of VTE risk levels.

Methods

We performed a retrospective case–control study among newly diagnosed lung cancer patients hospitalized between January 2016 and December 2021. Included in the cohort were 234 patients who developed PTE and 936 non-VTE patients. The patients were randomly divided into the derivation group (70%, 165 VTE patients and 654 non-VTE patients) and the validation group (30%, 69 VTE patients and 282 non-VTE patients). Cut off values were established using a Youden´s Index. Univariate and multivariate regression analyses were used to determine independent risk factors associated with VTE. Variance Inflation Factor(VIF) was used for collinearity diagnosis of the covariates in the model. The model was validated by the consistency index (C-index), receiver operating characteristic curves(ROC) and the calibration plot with the Hosmer-Lemeshow goodness-of-fit test. The clinical utility of the model was assessed through decision curve analysis(DCA). Further, the comparison of nomogram model with current models(Khorana, Caprini, Padua and COMPASS-CAT) was performed by comparing ROC curves using the DeLong’s test.

Results

The predictive nomogram modle comprised eleven variables: overweight(24-28) defined by body mass index (BMI): [odds ratio (OR): 1.90, 95% confidence interval (CI): 1.19-3.07], adenocarcinoma(OR:3.00, 95% CI: 1.88-4.87), stageIII-IV(OR:2.75, 95%CI: 1.58-4.96), Central venous catheters(CVCs) (OR:4.64, 95%CI: 2.86-7.62), D-dimer levels≥2.06mg/L(OR:5.58, 95%CI:3.54-8.94), PT levels≥11.45sec(OR:2.15, 95% CI:1.32-3.54), Fbg levels≥3.33 g/L(OR:1.76, 95%CI:1.12-2.78), TG levels≥1.37mmol/L (OR:1.88, 95%CI:1.19-2.99), ROS1 rearrangement(OR:2.87, 95%CI:1.74-4.75), chemotherapy history(OR:1.66, 95%CI:1.01-2.70) and radiotherapy history(OR:1.96, 95%CI:1.17-3.29). Collinearity analysis with demonstrated no collinearity among the variables. The resulting model showed good predictive performance in the derivation group (AUC 0.865, 95% CI: 0.832-0.897) and in the validation group(AUC 0.904,95%CI:0.869-0.939). The calibration curve and DCA showed that the risk-stratification nomogram had good consistency and clinical utility. Futher, the area under the ROC curve for the specific VTE risk-stratification nomogram model (0.904; 95% CI:0.869-0.939) was significantly higher than those of the KRS, Caprini, Padua and COMPASS-CAT models(Z=12.087, 11.851, 9.442, 5.340, all P<0.001, respectively).

Conclusion

A high-performance nomogram model incorporated available clinical parameters, genetic and therapeutic factors was established, which can accurately predict the risk of VTE in hospitalized patients with lung cancer and to guide individualized decision-making on thromboprophylaxis. Notably, the novel nomogram model was significantly more effective than the existing well-accepted models in routine clinical practice in stratifying the risk of VTE in those patients. Future community-based prospective studies and studies from multiple clinical centers are required for external validation.

Association of Gonadotropin-Releasing Hormone Therapies With Venous Thromboembolic Events in Patients With Prostate Cancer: A National Cohort Study

Although androgen deprivation therapy (ADT) has been proposed to be associated with a higher risk of venous thromboembolisms (VTEs), whether gonadotropin-releasing hormones (GnRHs), such as both agonists and antagonists, are also associated with VTEs remain unclear. Using the Taiwan Cancer Registry (TCR) linked with the National Health Insurance Research Database, we identified patients diagnosed with prostate cancer from 2008 to 2015. Patients who received GnRH were 1:1 propensity score matched with non-GnRH users by age and cancer stage at diagnosis and clinical stage. Cox regression analysis was applied to estimate the incidences of VTEs with death as a competing event at the 5-year follow-up. The VTE incidence among GnRH users was 1.13% compared with 0.98% among non-users. After adjusting with potential confounding factors, the risk of VTEs showed borderline statistical significance among GnRH users and non-users. Notably, in the subgroup analysis among patients receiving GnRH therapy, those younger than 70 years old or at an earlier stage (stage I/II) were at a higher risk of VTEs. Different from previous studies, our findings highlighted critical concerns regarding the cardiac safety of GnRH therapies in prostate cancer patients at a relatively younger age or at an earlier stage.

Venous thromboembolism and radiation therapy: The final radiation-induced thrombosis study analysis

Background

Thromboembolic events frequently complicate the course of malignancy and represent a major cause of morbidity and mortality in cancer patients. In contrast to chemotherapy and other systemic therapies, little is known about the impact of ionizing radiations on the incidence of venous thromboembolism (VTE) in cancer patients.

Methods

In the present prospective study, we aimed to investigate the incidence, management, and outcome of VTE in newly diagnosed cancer patients who received curative radiotherapy.

Results

VTE was found in 8 patients, out of 401 patients at a median time of 80 days after radiotherapy initiation. The incidence rate of VTE at 6 months post‐treatment was 2% (95% CI, 0.9–3.7), with 50% of cases occurring during the radiotherapy course and 50% of cases in patients who received or were receiving chemotherapy. As none of the patients harbored a personal history of VTE, no prophylactic measure was initiated during cancer therapy. Most patients received monotherapy with low‐molecular‐weight heparin and were still on surveillance at the end of the study. No specific clinical risk factor was identified that might systematically indicate the need of thromboprophylaxis in the context of curative radiotherapy.

Conclusions

Although this pan‐cancer descriptive study did not relate an increased risk of short‐term thrombosis following ionizing radiation, it provides important insight as a basis for future studies with subcategories of cancer, in order to in fine guide further recommendations in frail patients.

Clinical trial registration number

NCT02696447.