Feasibility of Using 18F-FDG PET/CT Radiomics and Machine Learning to Detect Drug-Induced Interstitial Lung Disease

BACKGROUND

Bleomycin is an oncolytic and antibiotic agent used to treat various human cancers because of its antitumor activity. Unfortunately, up to 46% of the patients treated with bleomycin develop drug-induced interstitial lung disease (DIILD) and potentially life-threatening interstitial pulmonary fibrosis. Tools and biomarkers for predicting and detecting DIILD are limited. Therefore, we aimed to evaluate the feasibility of 18F-FDG PET/CT, PET radiomics, and machine learning in distinguishing DIILD in an explorative pilot study.

METHODS

Eighteen Hodgkin's lymphoma (HL) patients, of whom 10 developed DIILD after treatment with bleomycin, were retrospectively included. Five diffuse large B-cell lymphoma (DLBCL) patients were included as a control group since they were not treated with bleomycin. All patients underwent 18F-FDG PET/CT scans before (baseline) and during treatment (interim). Structural changes were assessed by changes in Hounsfield Units (HUs). The 18F-FDG PET scans were used to assess metabolic changes by examining the feasibility of 504 radiomics features, including the mean activity of the lungs (SUVmean). A Random Forest (RF) classifier evaluated the identification and prediction of DIILD based on PET radiomics features.

RESULTS

HL patients who developed DIILD showed a significant increase in standard SUV metrics (SUVmean; p = 0.012, median increase 37.4%), and in some regional PET radiomics features (texture strength; p = 0.009, median increase 101.6% and zone distance entropy; p = 0.019, median increase 18.5%), while this was not found in HL patients who did not develop DIILD and DLBCL patients. The RF classifier correctly identified DIILD in 72.2% of the patients and predicted the development of DIILD correctly in 50% of the patients. There were no significant differences in HUs over time within all three patient groups.

CONCLUSIONS

Our explorative longitudinal pilot study suggests that certain regional 18F-FDG PET radiomics features can effectively identify DIILD in HL patients treated with bleomycin, as significant longitudinal increases were observed in SUVmean, texture strength, and zone distance entropy after the development of DIILD. The metabolic activity of these features did not significantly increase over time in DLBCL patients and HL patients who did not develop DIILD. This indicates that 18F-FDG PET radiomics, with and without machine learning, might serve as potential biomarkers for detecting DIILD.

Bleomycin-Induced Lung Toxicity in Hodgkin's Lymphoma: Risk Factors in the Positron Emission Tomography Era

Introduction

Bleomycin is a major antimitotic agent in the first-line treatment for Hodgkin's lymphoma. The main limitation of its use is its pulmonary toxicity. The objectives of this study are to find out the risk factors for the occurrence of bleomycin-induced lung toxicity in patients with Hodgkin's lymphoma and, on the other hand, to determine if positron emission tomography scan is a reliable means of early detection of this toxicity.

Methods

This is a retrospective study conducted in the clinical Hematology Department of Mohammed V Military Instruction Hospital, Rabat, Morocco. All patients with Hodgkin's lymphoma and treated with a bleomycin-based chemotherapy were included. The impact of different clinical and biological factors on the risk of bleomycin-induced lung toxicity occurrence was assessed using univariate and multivariate logistic regression. The benefit of positron emission tomography, usually performed as part of the re-assessment of Hodgkin’s lymphoma after two and four cycles, has been evaluated in the detection of bleomycin-induced lung toxicity.

Results

Among 124 patients included in the study, 18 (14.5%) patients experienced bleomycin-induced lung toxicity. On multivariate analysis, smoking (p = 0.038) and the use of the ABVD regimen (doxorubicin, bleomycin, vinblastine, and dacarbazine) compared to the escalated BEACOPPe regimen (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone) (p = 0.018) were statistically significant risk factors.

After two and four courses of therapy, the positron emission tomography was able to predict the occurrence of bleomycin-induced lung toxicity before the appearance of clinical symptoms only in 36.4 % and 12.5% of patients, respectively.

Conclusion

Studies to identify risk factors for the development of bleomycin-induced lung toxicity are crucial to reduce toxicity in the treatment of Hodgkin's lymphoma. However, two- and four-cycle positron emission tomography scans cannot be considered as a reliable means of early detection of this toxicity.

Drug-Related Pneumonitis in Cancer Treatment during the COVID-19 Era

Interstitial lung disease is recognized as a group of diseases with a different etiopathogenesis characterized by chronic lung inflammation with the accumulation of inflammatory cells, lymphocytes and macrophages, and the consequent release of proinflammatory cytokines. Various degrees of pulmonary fibrosis can be associated with this inflammatory condition. Interstitial lung disease related to oncological drugs is a relevant problem in clinical practice. The etiopathogenetic mechanisms underlying this adverse event are not completely known but can be partly explained by the mechanism of action of the drug involved. Therefore, knowledge of the relevance of this potentially fatal adverse event supported by the reported safety data of pivotal studies becomes fundamental in the management of patients. The prompt diagnosis of drug-related pneumonia and the consequent differential diagnosis with other forms of pneumonia allow a rapid suspension of treatment and the establishment of an immunosuppressive treatment if necessary. In the context of the health emergency related to SARS CoV2 infection and COVID-19-related interstitial lung disease, such knowledge holds decisive relevance in the conscious choice of cancer treatments. Our intent was to describe the oncological drugs most correlated with this adverse event by reporting, where possible, the percentages of insurgency in pivotal studies to provide an overview and therefore promote greater awareness of this important toxicity related to oncological treatment.

The Role of Hypertension and Renin-angiotensin-aldosterone System Inhibitors in Bleomycin-induced Lung Injury

INTRODUCTION

The risk factors for bleomycin-induced lung injury (BLI), a fatal complication of cancer chemotherapy, are not well-established. The renin-angiotensin-aldosterone system (RAAS) has recently been suggested to play a role in the development of lung injury. This study clarified the impact of hypertension (HTN) and the administration of RAAS inhibitors on BLI occurrence in patients treated with bleomycin-containing regimens.

PATIENTS AND METHODS

We retrospectively analyzed the data of 190 patients treated with a bleomycin-containing regimen for Hodgkin lymphoma or germ cell tumors at our institutions from 2004 to 2018.

RESULTS

Overall, 190 patients received bleomycin, and symptomatic BLI occurred in 21 (11.1%) cases. In the multivariate analysis, age ≥ 65 years (odd ratio, 10.90; 95% confidence interval, 3.72-32.20; P < .001) and history of HTN (odds ratio, 3.32; 95% confidence interval, 1.07-10.30; P = .04) were found to be significant risk factors for BLI onset. BLI occurred in 3.6% (n = 5) of patients with no risk, 11.8% (n = 2) of those whose only risk factor was HTN, 31.6% (n = 6) of those whose only risk factor was age ≥ 65 years, and 57.1% (n = 8) of those with both risk factors (P < .001). BLI-induced mortality rates in each group were 0.0% (n = 0), 5.9% (n = 1), 10.5% (n = 2), and 42.9% (n = 6) (P < .001), respectively. Among 31 patients with HTN, BLI incidence was 12.5% in patients who were administered RAAS inhibitors and 53.3% in those who were not (P = .02).

CONCLUSION

Older age and history of HTN were independent risk factors for the development of BLI, and the administration of RAAS inhibitors might reduce the onset of BLI.

Can We Predict Bleomycin Toxicity with PET-CT?

AIM

Bleomycin is an antitumor antibiotic used successfully to treat a variety of malignancies, predominantly germ cell tumors and Hodgkin's lymphoma (HL). The major limitation of bleomycin therapy is the potential for life-threatening interstitial pulmonary fibrosis. Early identification of asymptomatic patients who may develop toxicity is important. We aimed to evaluate fluorodeoxyglucose positron-emission tomography (FDG-PET/CT) findings to predict bleomycin toxicity (BT) early after chemotherapy with doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) chemotherapy before clinical symptoms and radiological changes occur.

MATERIALS AND METHODS

HL patients who were treated with ABVD were evaluated. SUVmax values of lung parenchyma were analyzed in FDG-PET/CT at diagnosis and after 4 cycles of chemotherapy in all patients. At the end of the chemotherapy cycles, lung parenchymal SUVmax values of patients with BT and without BT were compared statistically.

RESULTS

Twenty (66.7%) male and 10 (33.3%) female patients with HL were included. Five (16.7%) HL patients developed BT. In 3 HL patients, BT was determined after 5 cycles and in 2 patients, BT was seen after 6 cycles. In all 5 of these patients with BT, FDG uptake in PET-CT was increased after 4 cycles of chemotherapy and BT was predicted before clinical and radiological findings by FDG-PET/CT. After 4 cycles of chemotherapy, lung parenchymal SUVmax of patients with BT (3.24 ± 0.76) was significantly higher than in patients without toxicity (1.84 ± 0.52) (p < 0.001). In patients with BT, a significant increase was established in lung parenchymal SUVmax after 4 cycles of chemotherapy when compared to the time of diagnosis (p = 0.043).

CONCLUSION

BT can be fatal. Early detection of BT is essential in clinical practice. FDG-PET/CT can predict BT before clinical and radiological findings occur.

Prospective Study of Drug-induced Interstitial Lung Disease in Advanced Breast Cancer Patients Receiving Everolimus Plus Exemestane

BACKGROUND

Everolimus-related interstitial lung disease (ILD) (also: pneumonitis) poses a difficulty for physicians, as it is hard to discriminate ILD from other causes of respiratory symptoms and to decide on safe treatment continuation.

OBJECTIVE

We investigated the capability of pulmonary function tests (PFT), plasma biomarkers, everolimus pharmacokinetics, and FDG-PET to discriminate between everolimus-related ILD and other causes of respiratory problems and to predict the severity of ILD.

PATIENTS AND METHODS

Women starting treatment with everolimus plus exemestane for advanced breast cancer were included. At baseline and during the first 3 months, respiratory symptoms, PFT with diffusion capacity of the lungs for carbon monoxide corrected for hemoglobin (DLCOc) and forced vital capacity, serum plasma biomarkers (including SP-D and YKL-40), everolimus trough concentration, and 18F-FDG-PET were prospectively recorded.

RESULTS

Twenty-seven (out of 29 included) patients were evaluable for analysis. Fifteen patients (56%) developed everolimus-related respiratory signs or symptoms and four patients (15%) needed everolimus discontinuation and received corticosteroids. Change in DLCOc differentiated ILD from alternative diagnoses with 0.91 sensitivity and 0.78 specificity. Decrease in DLCOc (non-significant) was greatest in patients who needed everolimus discontinuation. Serum SP-D and YKL-40 could differentiate ILD from alternative diagnoses with 0.83 and 0.83 sensitivity, and 0.85 and 0.62 specificity, respectively. 18F-FDG-PET abnormalities did not precede clinical symptoms. No relationship between ILD and everolimus trough concentration was found.

CONCLUSIONS

This study shows that everolimus-related ILD occurs frequently. Prospective monitoring of DLCOc in combination with measurement of serum SP-D and YKL-40 appear useful to discriminate ILD from other causes of respiratory symptoms. Clinicaltrials.gov identifier: NCT01978171.

Radionuclide Imaging of Infection and Inflammation in Children: a Review

With the exception of radiolabeled monoclonal antibodies, antibody fragments and radiolabeled peptides which have seen little application in the pediatric population, the nuclear medicine imaging procedures used in the evaluation of infection and inflammation are the same for both adults and children. These procedures include (1) either a two- or a three-phase bone scan using technetium-99m methylene diphosphonate; (2) Gallium 67-citrate; (3) in vitro radiolabeled white blood cell imaging (using ¹¹¹Indium-oxine or ^99mTechnetium hexamethyl-propylene-amine-oxime-labeled white blood cells); and (4) hybrid imaging with ¹⁸F-FDG. But children are not just small adults. Not only are the disease processes encountered in children different from those in adults, but there are developmental variants that can mimic, but should not be confused with, pathology. This article discusses some of the differences between adults and children with osteomyelitis, illustrates several of the common developmental variants that can mimic disease, and, finally, focuses on the increasing use of ¹⁸F-FDG PET/CT in the diagnosis and response monitoring of children with infectious and inflammatory processes. The value of and need for pediatric specific imaging protocols are reviewed.

The Use of Imaging in the Prediction and Assessment of Cancer Treatment Toxicity

Multimodal imaging is commonly used in the management of patients with cancer. Imaging plays pivotal roles in the diagnosis, initial staging, treatment response assessment, restaging after treatment and the prognosis of many cancers. Indeed, it is difficult to imagine modern precision cancer care without the use of multimodal molecular imaging, which is advancing at a rapid pace with innovative developments in imaging sciences and an improved understanding of the complex biology of cancer. Cancer therapy often leads to undesirable toxicity, which can range from an asymptomatic subclinical state to severe end organ damage and even death. Imaging is helpful in the portrayal of the unwanted effects of cancer therapy and may assist with optimal clinical decision-making, clinical management, and overall improvements in the outcomes and quality of life for patients.

Short review of potential synergies of immune checkpoint inhibition and radiotherapy with a focus on Hodgkin lymphoma: radio-immunotherapy opens new doors

Radiotherapy is an established local treatment in patients with various malignancies. Systemic responses following local irradiation have been described as abscopal effects. Modern cancer immunotherapy with immune checkpoint inhibitors has shown impressive response rates and prolongation of survival even in heavily pretreated patients with advanced solid malignancies and lymphomas. Radiotherapy has been shown to modulate immune response, and its application in the context of immune checkpoint inhibition has recently evolved into an active field of research. Prospective studies investigating combination treatment are currently ongoing and will answer questions as to the optimal schedule and radiation dosing. This short review focuses on the immunomodulatory role of radiotherapy and the use of immune checkpoint inhibition with a special focus on Hodgkin lymphoma.

FDG PET-CT: Need for Vigilance in Patients Treated with Bleomycin

Bleomycin-induced interstitial lung disease is not a rare complication of treatment and may prove to be fatal if not suspected early in its course. As FDG PET-CT has become an essential clinical tool for interim and end-of-treatment response assessment in oncology, it is important that radiologists/nuclear medicine specialists be aware of the features of this potentially treatable condition so that treatment can be instigated during an early reversible phase before pulmonary damage has occurred. Herein, we report two cases of bleomycin toxicity featuring different patterns on the treatment-response assessment FDG PET-CT scan.

Omission of dacarbazine or bleomycin, or both, from the ABVD regimen in treatment of early-stage favourable Hodgkin's lymphoma (GHSG HD13): an open-label, randomised, non-inferiority trial

BACKGROUND

The role of bleomycin and dacarbazine in the ABVD regimen (ie, doxorubicin, bleomycin, vinblastine, and dacarbazine) has been questioned, especially for treatment of early-stage favourable Hodgkin's lymphoma, because of the drugs' toxicity. We aimed to investigate whether omission of either bleomycin or dacarbazine, or both, from ABVD reduced the efficacy of this regimen in treatment of Hodgkin's lymphoma.

METHODS

In this open-label, randomised, multicentre trial (HD13) we compared two cycles of ABVD with two cycles of the reduced-intensity regimen variants ABV (doxorubicin, bleomycin, and vinblastine), AVD (doxorubicin, vinblastine, and dacarbazine), and AV (doxorubicin and vinblastine), in patients with newly diagnosed, histologically proven, classic or nodular, lymphocyte predominant Hodgkin's lymphoma. In each treatment group, 30 Gy involved-field radiotherapy (IFRT) was given after both cycles of chemotherapy were completed. From Jan 28, 2003, patients were centrally randomly assigned (1:1:1:1) with a minimisation method to the four groups. Because of high event rates, assignment to the AV and ABV groups stopped early, on Sept 30, 2005, and Feb 10, 2006; assignment to ABVD and AVD continued (1:1) until Sept 30, 2009. Our primary objective was to show non-inferiority of the experimental variants compared with ABVD in terms of freedom from treatment failure (FFTF), by excluding a difference of 6% after 5 years corresponding to a hazard ratio (HR) of 1.72, via a 95% CI. Analyses reported here include qualified patients only, and between-group comparisons include only patients recruited during the same period. The trial was registered, number ISRCTN63474366.

FINDINGS

Of 1502 qualified patients, 566, 198, 571, and 167 were randomly assigned to receive ABVD, ABV, AVD, or AV, respectively. 5 year FFTF was 93.1%, 81.4%, 89.2%, and 77.1% with ABVD, ABV, AVD, and AV, respectively. Compared with ABVD, inferiority of the dacarbazine-deleted variants was detected with 5 year differences of -11.5% (95% CI -18.3 to -4.7; HR 2.06 [1.21 to 3.52]) for ABV and -15.2% (-23.0 to -7.4; HR 2.57 [1.51 to 4.40]) for AV. Non-inferiority of AVD compared with ABVD could also not be detected (5 year difference -3.9%, -7.7 to -0·1; HR 1.50, 1.00 to 2.26). 178 (33%) of 544 patients given ABVD had WHO grade III or IV toxicity, compared with 53 (28%) of 187 given ABV, 142 (26%) of 539 given AVD, and 40 (26%) of 151 given AV. Leucopenia was the most common event, and highest in the groups given bleomycin.

INTERPRETATION

Dacarbazine cannot be omitted from ABVD without a substantial loss of efficacy. With respect to our predefined non-inferiority margin, bleomycin cannot be safely omitted either, and the standard of care for patients with early-stage favourable Hodgkin's lymphoma should remain ABVD followed by IFRT.

FUNDING

Deutsche Krebshilfe and Swiss State Secretariat for Education and Research.

Late pulmonary complications of treating Hodgkin lymphoma: bleomycin-induced toxicity

INTRODUCTION

Survival of Hodgkin lymphoma (HL) patients has significantly improved in recent decades. The current first-line therapy is doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) ± irradiation and may cause pulmonary toxicity. Strategies to reduce late toxicity as well as increase survival rate are of interest.

PATIENTS AND METHODS

Pulmonary function of previously treated HL patients was collected over a 12-month period using St. George Respiratory Questionnaire (SGRQ), chest X-ray, dynamic inhalation lung scintigraphy and spirometry.

RESULTS

A total of 137 patients' data were reviewed. Median time elapsed since diagnosis was 11 years (range was 2 - 30 years). Chest irradiation did not significantly worsen pulmonary function. Number of ABVD cycles with consequential bleomycin dose showed significant correlation with SGRQ total score in patients receiving ABVD plus chest irradiation (p = 0.01). Scintigraphy results correlated with bleomycin dose in patients receiving ABVD without chest irradiation (right side: p = 0.099, left side: p = 0.051).

DISCUSSION

An additive negative effect of chest irradiation was not confirmed as reflected in the literature; however, increasing cumulative bleomycin dose worsened pulmonary function.

Bleomycin-Induced Lung Injury

Bleomycin is a chemotherapeutic agent commonly used to treat curable diseases such as germinative tumors and Hodgkin’s lymphoma. The major limitation of bleomycin therapy is pulmonary toxicity, which can be life threatening in up to 10% of patients receiving the drug. The mechanism of bleomycin-induced pneumonitis (BIP) involves oxidative damage, relative deficiency of the deactivating enzyme bleomycin hydrolase, genetic susceptibility, and the elaboration of inflammatory cytokines. Ultimately, BIP can progress to lung fibrosis. The diagnosis of BIP is established by the combination of systemic symptoms, radiological and histological findings, and respiratory function tests abnormalities, while other disorders should be excluded. Although the diagnosis and pathophysiology of this disease have been better characterized over the past few years, there is no effective therapy for the disease. In general, the clinical picture is extremely complex. A greater understanding of the BIP pathogenesis may lead to the development of new agents capable of preventing or even treating the injury already present. Physicians who prescribe bleomycin must be aware of the potential pulmonary toxicity, especially in the presence of risk factors. This review will focus on BIP, mainly regarding recent advances and perspectives in diagnosis and treatment.

Combined PET and X-ray computed tomography imaging in pulmonary infections and inflammation

PURPOSE OF REVIEW

This review addresses issues relating to the use of the relatively new combined PET and X-ray computed tomography (PET/CT) modality for imaging pulmonary infections and inflammation, as well as assessing its potential for this purpose.

RECENT FINDINGS

Accurate definition and monitoring of the extent of lung infection is difficult using conventional chest radiograph, CT scan, MRI, and radioisotope scintigraphy. In the last decade, PET/CT using radiolabeled fluorodeoxyglucose has been added to the imaging armamentarium, mostly for imaging lung cancer. To date, very few data are available on the application of this technique for imaging pulmonary infections and inflammation; however, this situation is changing, and there is now more interest in using PET/CT for this purpose. In addition, there are new tracers on the horizon which remain to be exploited.

SUMMARY

This review addresses some of these issues and outlines the potential to use PET/CT for noncancer pulmonary indications.

Recent trends in soft-tissue infection imaging

This article discusses the current techniques and future directions of infection imaging with particular attention to respiratory, central nervous system, abdominal, and postoperative infections. The agents currently in use localize to areas of infection and inflammation. An infection-specific imaging agent would greatly improve the utility of scintigraphy in imaging occult infections. The superior spatial resolution of (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET) and its lack of reliance on a functional immune system, gives this agent certain advantages over the other radiopharmaceuticals. In respiratory tract infection imaging, an important advancement would be the ability to quantitatively delineate lung inflammation, allowing one to monitor the therapeutic response in a variety of conditions. Current studies suggest PET should be considered the most accurate quantitative method. Scintigraphy has much to offer in localizing abdominal infection as well as inflammation. We may begin to see a gradual increase in the usage of (18)F-FDG-PET in detecting occult abdominal infections. Commonly used modalities for imaging inflammatory bowel disease are scintigraphy with (111)In-oxine/(99m)Tc-HMPAO labeled autologous white blood cells. The literature on central nervous system infection imaging is relatively scarce. Few clinical studies have been performed and numerous new agents have been developed for this use with varying results. Further studies are needed to more clearly delineate the future direction of this field. In evaluating the postoperative spine, (99m)Tc-ciprofloxacin single-photon emission computed tomography (SPECT) was reported to be >80% sensitive in patients more than 6 months after surgery. FDG-PET has also been suggested for this purpose and may play a larger role than originally thought. It appears PET/computed tomography (CT) is gaining support, especially in imaging those with fever of unknown origin or nonfunctional immune systems. Although an infection-specific agent is lacking, the development of one would greatly advance our ability to detect, localize, and quantify infections. Overall, imaging such an agent via SPECT/CT or PET/CT will pave the way for greater clinical reliability in the localization of infection.