Association between radiation dose to the heart and myocardial fatty acid metabolic impairment due to chemoradiation-therapy: Prospective study using I-123 BMIPP SPECT/CT

Nuclear medicine imaging methods of early radiation-induced cardiotoxicity: a ten-year systematic review

Introduction

Radiotherapy has significantly improved cancer survival rates, but it also comes with certain unavoidable complications. Breast and thoracic irradiation, for instance, can unintentionally expose the heart to radiation, leading to damage at the cellular level within the myocardial structures. Detecting and monitoring radiation-induced heart disease early on is crucial, and several radionuclide imaging techniques have shown promise in this regard.

Method

In this 10-year review, we aimed to identify nuclear medicine imaging modalities that can effectively detect early cardiotoxicity following radiation therapy. Through a systematic search on PubMed, we selected nineteen relevant studies based on predefined criteria.

Results

The data suggest that incidental irradiation of the heart during breast or thoracic radiotherapy can cause early metabolic and perfusion changes. Nuclear imaging plays a prominent role in detecting these subclinical effects, which could potentially serve as predictors of late cardiac complications.

Discussion

However, further studies with larger populations, longer follow-up periods, and specific heart dosimetric data are needed to better understand the relationship between early detection of cardiac abnormalities and radiation-induced heart disease.

Cardiac metabolic changes on 18 F-positron emission tomography after thoracic radiotherapy predict for overall survival in esophageal cancer patients

PURPOSE

Heart doses have been shown to be predictive of cardiac toxicity and overall survival (OS) for esophageal cancer patients. There is potential for functional imaging to provide valuable cardiac information. The purpose of this study was to evaluate the cardiac metabolic dose-response using 18 F-deoxyglucose (FDG)-PET and to assess whether standard uptake value (SUV) changes in the heart were predictive of OS.

METHODS

Fifty-one patients with esophageal cancer treated with radiation who underwent pre- and post-treatment FDG-PET scans were retrospectively evaluated. Pre- and post-treatment PET-scans were rigidly registered to the planning CT for each patient. Pre-treatment to post-treatment absolute mean SUV (SUVmean) changes in the heart were calculated to assess dose-response. A dose-response curve was generated by binning each voxel in the heart into 10 Gy dose-bins and analyzing the SUVmean changes in each dose-bin. Multivariate cox proportional hazard models were used to assess whether pre-to-post treatment cardiac SUVmean changes predicted for OS.

RESULTS

The cardiac dose-response curve demonstrated a trend of increasing cardiac SUV changes as a function of dose with an average increase of 0.044 SUV for every 10 Gy dose bin. In multivariate analysis, disease stage and SUVmean change in the heart were predictive (p < 0.05) for OS.

CONCLUSIONS

Changes in pre- to post-treatment cardiac SUV were predictive of OS with patients having a higher pre- to post-treatment cardiac SUV change surviving longer.

Impact of Blood Parameters and Normal Tissue Dose on Treatment Outcome in Esophageal Cancer Patients Undergoing Neoadjuvant Radiochemotherapy

Despite technological advances, normal tissue sparing in photon beam irradiation is still challenging. Since in esophageal cancer this may inflict damage on the lungs, heart and bone marrow, possibly impacting on outcome, the aim of this study was to investigate the association of normal tissue dose and blood parameters on the survival of patients having undergone neoadjuvant radiochemotherapy (RCTx) followed by surgery. This retrospective study included 125 patients irradiated to 40−41.4 Gy with photons or protons combined with concurrent chemotherapy. On initial and restaging 18F-FDG-PET/CT, the lungs and heart were contoured as organs at risk for which standardized uptake values (SUV) were evaluated. The mean radiation dose (Dmean) to the lungs and heart, the volume of the lungs receiving at least 20 Gy (V20Gy_lung) and various pre- and per-treatment blood parameters were included in the Cox regression analyses. Results: The median follow-up time was 19.8 months and median overall survival 37 months (95% confidence interval: 16−58.9 months). In multivariate analysis, higher radiation doses to the lungs and heart were statistically significantly associated with decreased overall survival (Dmean_lung: p < 0.001; V20Gy_lung: p < 0.002; Dmean_heart: p = 0.005). Neither the 18F-FDG-PET nor blood parameters were predictive for overall survival. In patients with locally advanced esophageal cancer treated with RCTx, the radiation dose to the heart and lungs was significantly associated with overall survival.

Dose-Dependent Radiation-Induced Myocardial Damage in Esophageal Cancer Treated With Chemoradiotherapy: A Prospective Cardiac Magnetic Resonance Imaging Study

Purpose

The purpose of this prospective study was to evaluate radiation-induced myocardial damage after mediastinal radiation therapy (RT) using late gadolinium-enhancement (LGE) magnetic resonance imaging (MRI).

Methods and Materials

We enrolled 19 patients with esophageal cancer who were expected to have long-term survival by definitive treatment. They underwent delayed contrast-enhanced MRI (19 patients before treatment, 19 patients 6 months after treatment, and 12 patients 1.5 years after treatment). Dose distribution of the left ventricle was made using computed tomography, and the dose volume histogram of the left ventricle was calculated. Myocardial signal intensities in individual MRIs were normalized by the mean values in regions receiving low doses (<5 Gy). Changes in the normalized signal intensities after mediastinal radiation therapy were compared among regions where irradiation doses were 0 to 10 Gy, 10 to 20 Gy, 20 to 30 Gy, 30 to 40 Gy, 40 to 50 Gy, and 50 to 60 Gy, and we investigated whether intensity change was detected in a dose-dependent manner.

Results

The registered patients were treated with concurrent chemoradiotherapy with a median total dose of 60 Gy (50.4-66 Gy). Chemotherapy consisting of cisplatin and 5-fluorouracil was administered. In the population-based dose-response curve, dose-dependent intensity changes progressively increased in regions receiving more than 30 Gy. The averages of relative intensity change at 6 months and 1.5 years after treatment were 1.1% and −1.9% at 20 to 30 Gy and 37.5% and 17.5% at 40 to 50 Gy, respectively. LGE in regions receiving more than 30 Gy was detected in 68% (13/19) of the patients.

Conclusions

A dose-dependent relationship for myocardial signal intensity change was found by using LGE MRI. It may be necessary to reduce the volume of the myocardium receiving more than 30 Gy.

Clinical implication of myocardial FDG uptake pattern in oncologic PET: retrospective comparison study with stress myocardial perfusion imaging as the reference standard

OBJECTIVE

The purpose of this study was to determine the clinical implication of the myocardial FDG uptake patterns by comparing with the results of stress myocardial perfusion imaging (MPI) as the reference standard.

METHODS

By reviewing the medical records, 86 pairs of stress MPI and FDG PET/CT of 84 patients who underwent stress MPI and oncologic FDG PET/CT in 1 month were included in this study. The patterns of the myocardial FDG uptake were classified into five patterns such as 'low', 'diffuse', 'basal ring', 'focal high', and 'focal defect on diffuse high'. MPI was evaluated using a 5-point scoring model ranging from 0 (normal uptake) to 4 (uptake absent) based on the 17-segment model. The summed stress score of 4 or higher was defined as 'abnormal MPI'. Factors predictive of abnormal MPI were analyzed using a log-rank multivariate test and p < 0.05 was set as significant.

RESULTS

Abnormal MPI was observed in only 16 of 36 (44%) patients with 'low' pattern, 10 of 23 (43%) patients with 'diffuse high' pattern, and 1 of 9 (11%) patients with 'basal ring' pattern, but in 8 of 9 (89%) patients with 'focal high' pattern, and 8 of 9 (89%) patients with 'focal defect on diffuse high' pattern. The log-rank multivariate test revealed that 'focal high' and 'focal defect on diffuse high' pattern were correlated with an abnormal MPI.

CONCLUSIONS

These results indicate that further cardiac work-up might be helpful in the patients with 'focal high' pattern or 'focal defect on diffuse high' pattern of myocardial FDG at oncologic PET. A prospective study should be needed to further support this conclusion.

Evidence for a cardiac metabolic switch in patients with Hodgkin's lymphoma

AIMS

Our aim was to investigate the glucose uptake in cancer patients suffering from different entities, using ¹⁸ F-FDG positron emission tomography-computed tomography scans. We further aimed at identifying potential variables altering cardiac and skeletal muscle glucose metabolism.

METHODS AND RESULTS

In a retrospective cohort study, we analysed cardiac and skeletal muscle ¹⁸ F-FDG uptake in onco-positron emission tomography-computed tomography scans in adult patients suffering from Hodgkin's lymphoma, non-Hodgkin's lymphoma, and non-lymphatic cancer including patients suffering from thyroid cancer, bronchial carcinoma, and malignant melanoma. Univariate logistic regression models were created for increased cardiac and skeletal muscle ¹⁸ F-FDG uptake using cancer entity, sex, age, previous radiation, previous chemotherapy, diabetes, obesity, serum glucose levels, renal function, and thyroid function as parameters. Multivariate models were created by selecting variables according to Akaike's information criterion in a step-down approach. Between 2014 and 2018, a total of 337 consecutive patients suffering from Hodgkin's lymphoma (n = 52), non-Hodgkin's lymphoma (n = 57), and non-lymphatic cancer (n = 228) were included in the analysis. Univariate logistic regression models showed high serum glucose levels to be associated with lower absorption rates in both cardiac and skeletal muscle (odds ratio [OR] 0.38 [0.23, 0.60, 95% confidence interval-CI], P < 0.0001, and 0.52 [0.33, 0.82, 95% CI], P < 0.005, respectively). Hodgkin's lymphoma was associated with an increase in cardiac uptake (OR 2.4 [1.3, 4.5, 95% CI], P < 0.005). Decreased skeletal muscle ¹⁸ F-FDG uptake was noted in elderly and obese patients. In our multivariate analysis, Hodgkin's lymphoma patients showed higher cardiac ¹⁸ F-FDG uptake, while non-Hodgkin's lymphoma patients did not differ significantly from non-lymphatic cancer patients (OR 1.6 [0.7, 3.3, 95% CI], P = 0.24). High serum glucose levels and prior chemotherapy were both associated with a significantly decreased cardiac ¹⁸ F-FDG uptake (OR 0.40 [0.24, 0.65, 95% CI], P < 0.0005, and 0.50 [0.27, 0.90, 95% CI], P < 0.05, respectively). Notably, prior chemotherapy did not influence FDG uptake in skeletal muscle to the same extent. Obesity and older age were both significantly associated with decreased gluteal ¹⁸ F-FDG uptake (OR 0.49 [0.27, 0.89, 95% CI], P < 0.05, and 0.47 [0.25, 0.87, 95% CI], P < 0.05).

CONCLUSIONS

Our data provide evidence for metabolic alterations in patients with Hodgkin's lymphoma related to cardiac glucose uptake in humans. This effect was independent from skeletal muscle metabolism.

Risk factors for pericardial effusion after chemoradiotherapy for thoracic esophageal cancer-comparison of four-field technique and traditional two opposed fields technique

Pericardial effusion is an important late toxicity after concurrent chemoradiotherapy (CCRT) for locally advanced esophageal cancer. We investigated the clinical and dosimetric factors that were related to pericardial effusion among patients with thoracic esophageal cancer who were treated with definitive CCRT using the two opposed fields technique (TFT) or the four-field technique (FFT), as well as the effectiveness of FFT. During 2007-2015, 169 patients with middle and/or lower thoracic esophageal cancer received definitive CCRT, and 94 patients were evaluable (51 FFT cases and 43 TFT cases). Pericardial effusion was observed in 74 patients (79%) and appeared at 1-18.5 months (median: 5.25 months) after CCRT. The 1-year incidences of pericardial effusions were 73.2% and 76.7% in the FFT and TFT groups, respectively (P = 0.6395). The mean doses to the pericardium were 28.6 Gy and 31.8 Gy in the FFT and TFT groups, respectively (P = 0.0259), and the V40 Gy proportions were 33.5% and 48.2% in the FFT and TFT groups, respectively (P < 0.0001). Grade 3 pericardial effusion was not observed in patients with a pericardial V40 Gy of <40%, or in patients who were treated using the FFT. Although the mean pericardial dose and V40 Gy in the FFT group were smaller than those in the TFT group, the incidences of pericardial effusion after CCRT were similar in both groups. As symptomatic pericardial effusion was not observed in patients with a pericardial V40 Gy of <40% or in the FFT group, it appears that FFT with a V40 Gy of <40% could help minimize symptomatic pericardial effusion.