Incidence of organizing pneumonia after whole-breast radiotherapy for breast cancer, and risk factor analysis

[Bronchiolitis obliterans organizing pneumonia after radiotherapy: A systematic review and case report]

PURPOSE

Bronchiolitis obliterans with pneumonic organization, or organizing pneumonia (OP), is an inflammatory disorder of the lungs, which can be triggered following pulmonary attacks of infectious or non-infectious origin. The non-infectious origins of OP include various entities including connective tissue diseases, exposure to toxic substances, medications, autoimmune diseases, and thoracic radiotherapy. The objective of this article is to summarize the literature on post-radiotherapy organized pneumonia, its etiologies, its clinical and radiological characteristics, as well as its treatment.

MATERIALS AND METHODS

A systematic review was performed in Medline database using the search engine PubMed. Keywords for the search included cryptogenic organizing pneumonia, bronchiolitis obliterans organizing pneumonia (BOOP), idiopathic organizing pneumonia and radiation, radiotherapy, breast cancer. The selected articles had to study the link between bronchiolitis obliterans with pneumonic organization and radiotherapy.

RESULTS

A total of 96 articles were identified. Of these 96 articles, 49 fulfilled the defined selection criteria. Fourteen epidemiological studies were found in the literature. These epidemiological studies have published incidences of post-radiotherapy organizing pneumonia of less than 2.9% for patients treated for breast cancer. The predictive risk factors for bronchiolitis obliterans with pneumonic organization syndrome were age, smoking and the volume of irradiated lung. In a post-radiation context, bronchiolitis obliterans with pneumonic organization could be diagnosed several months, or even up to a year, after the end of irradiation. Treatment was based on the prescription of long-term corticosteroid therapy. Bronchiolitis obliterans with pneumonic organization should not be confused with post-radiation pulmonary fibrosis, which is inflammatory, dose-dependent, non-immunological, and localized in the irradiation area.

CONCLUSION

Organized pneumonia secondary to radiotherapy is a syndrome affecting approximately 1.4 to 3% of patients treated with radiotherapy for breast cancer. The main risk factors found are age, smoking and the volume of lung irradiated. Post-radiotherapy organized pneumonia needs to be known to all radiotherapists to improve patient care.

Correlation of new two-dimensional geometrical parameters to lung and heart dose-volume parameters in breast cancer radiation therapy

OBJECTIVE

To develop new two-dimensional geometric parameters for pulmonary and cardiac dose estimation in left-sided breast cancer radiation therapy without dose-volume histogram (DVH).

METHODS

On the CT image of 90 patients with left breast cancer, treatment planning was performed using two opposed tangent fields with/without supraclavicular. The field-in-field technique and 6MV photons were used. From DVH dosimetric parameters of mean dose, Vx (x (Gy) =5, 10, 15, 20, 30, 40, 50) were calculated, and from heart and lung outlines on the beam's eye view, new geometric parameters of percent of lung area in tangent and supraclavicular fields (%area of the lung in the tangent (ALT), %ALS) and percent of heart in tangent field (%area of the heart in the tangent (AHT)) were measured. Correlation, regression, and diagnostic performance by receiver operating characteristic curve (ROC) were investigated for statistical analysis.

RESULTS

The Pearson coefficient between %ALT and Vx (x = 10, 15, 20, 30, 40) show strong correlation in patient treatment with only opposed tangents (>0.85) and weaker in treatment by opposed tangents with supraclavicular (0.56-0.88), the %ALS indicate weak correlation (<0.5) and %AHT show strong correlation (0.93-0.98). The regression analysis shows a positive relation between %ALT and mean dose (R2 = 0.8), V20Gy (R2 = 0.9) in the lung (tangent treatment), and between %AHT and mean dose (R2 = 0.9), V20Gy (R2 = 1.0) in the heart. The ROC analysis shows by %ALT <20.3 for treatment by just opposed fields, %ALT <22.1% for treatment tangents with supra, and %AHT <11.6%, practical lung and heart dose constraints are addressed.

CONCLUSION

The proposed geometric parameters could replace previous one-dimensional maximum and central distances for predicting doses to lung and heart.

ADVANCES IN KNOWLEDGE

This study presents simple geometric parameters that could estimate pulmonary and cardiac dose in left breast cancer treatment from a 2D radiograph.

Dosimetric analysis of six whole-breast irradiation techniques in supine and prone positions

In breast cancer radiation therapy, minimizing radiation-related risks and toxicity is vital for improving life expectancy. Tailoring radiotherapy techniques and treatment positions can reduce radiation doses to normal organs and mitigate treatment-related toxicity. This study entailed a dosimetric comparison of six different external beam whole-breast irradiation techniques in both supine and prone positions. We selected fourteen breast cancer patients, generating six treatment plans in both positions per patient. We assessed target coverage and organs at risk (OAR) doses to evaluate the impact of treatment techniques and positions. Excess absolute risk was calculated to estimate potential secondary cancer risk in the contralateral breast, ipsilateral lung, and contralateral lung. Additionally, we analyzed the distance between the target volume and OARs (heart and ipsilateral lung) while considering the treatment position. The results indicate that prone positioning lowers lung exposure in X-ray radiotherapy. However, particle beam therapies (PBTs) significantly reduce the dose to the heart and ipsilateral lung regardless of the patient's position. Notably, negligible differences were observed between arc-delivery and static-delivery PBTs in terms of target conformity and OAR sparing. This study provides critical dosimetric evidence to facilitate informed decision-making regarding treatment techniques and positions.

Radiation Dermatitis and Pneumonitis in Patients Irradiated for Breast Cancer

BACKGROUND/AIM

Adjuvant radiotherapy (RT) for breast cancer can be associated with acute dermatitis (ARD) and pneumonitis (RP). Prevalence and risk factors were characterized.

PATIENTS AND METHODS

This study included 489 breast cancer patients receiving adjuvant RT with conventional fractionation (CF) ± sequential or simultaneous integrated boost, or hypo-fractionation ± sequential boost. RT-regimen and 15 characteristics were investigated for grade ≥2 ARD and RP.

RESULTS

Prevalence of grade ≥2 ARD and RP was 25.3% and 2.5%, respectively. On univariate analyses, ARD was significantly associated with CF and radiation boost (p<0.0001), age ≤60 years (p=0.008), Ki-67 ≥15% (p=0.012), and systemic treatment (p=0.002). On multivariate analysis, RT-regimen (p<0.0001) and age (p=0.009) were associated with ARD. Chronic inflammatory disease was significantly associated with RP on univariate (p=0.007) and multivariate (p=0.016) analyses.

CONCLUSION

Risk factors for grade ≥2 ARD and RP were determined that may help identify patients who require closer monitoring during and after RT.

Incidence and prevalence of interstitial lung diseases worldwide: a systematic literature review

Interstitial lung disease (ILD) is a collective term representing a diverse group of pulmonary fibrotic and inflammatory conditions. Due to the diversity of ILD conditions, paucity of guidance and updates to diagnostic criteria over time, it has been challenging to precisely determine ILD incidence and prevalence. This systematic review provides a synthesis of published data at a global level and highlights gaps in the current knowledge base. Medline and Embase databases were searched systematically for studies reporting incidence and prevalence of various ILDs. Randomised controlled trials, case reports and conference abstracts were excluded. 80 studies were included, the most described subgroup was autoimmune-related ILD, and the most studied conditions were rheumatoid arthritis (RA)-associated ILD, systemic sclerosis associated (SSc) ILD and idiopathic pulmonary fibrosis (IPF). The prevalence of IPF was mostly established using healthcare datasets, whereas the prevalence of autoimmune ILD tended to be reported in smaller autoimmune cohorts. The prevalence of IPF ranged from 7 to 1650 per 100 000 persons. Prevalence of SSc ILD and RA ILD ranged from 26.1% to 88.1% and 0.6% to 63.7%, respectively. Significant heterogeneity was observed in the reported incidence of various ILD subtypes. This review demonstrates the challenges in establishing trends over time across regions and highlights a need to standardise ILD diagnostic criteria.PROSPERO registration number: CRD42020203035.

Fluence map analyzer reduces low dose volume in locally advanced post mastectomy breast cancer patients

Multi-leaf collimator dose leakage in intensity-modulated radiotherapy (IMRT) plans causes higher low dose volume which increases the long-term risks of radiotherapy. We have developed Fluence Map Analyzer (FMA) program that suggests the ideal field geometry to reduce low dose volume in locally advanced breast cancer IMRT plans. In this comparative experimental study, FMA has been applied to standard IMRT plans (STD-IMRT) of randomly selected 15 left and 15 right-sided locally advanced breast cancer patients. All patients underwent a modified radical mastectomy. The chest wall, IMN, axillary, and supraclavicular lymph nodes are included in planning target volume (PTV). The heart, lungs, contralateral breast, and medulla spinalis were delineated as organs at risk (OARs). Two sets of plans, namely STD-IMRT and FMA-IMRT, were generated for each patient. The dosimetric analysis was performed using dose-volume histogram (DVH) and standard evaluation parameters of PTV and OARs. No differences could be observed among the two techniques for PTV coverage. However, FMA-IMRT plans achieved significantly lower V5volumes and mean doses of the heart, lungs, contralateral breast, and body contours. FMA-IMRT used a smaller number of sub-fields and fewer monitor units (MU). FMA automizes the field geometry determination process for locally advanced breast cancer IMRT planning while reducing low dose volume significantly.

Final analysis of a Multicenter Single-Arm Confirmatory Trial of hypofractionated whole breast irradiation after breast-conserving surgery in Japan: JCOG0906

OBJECTIVE

To evaluate the safety and efficacy of hypofractionated whole breast irradiation for Asian women after breast-conserving surgery. This is an updated report with 5-year follow-up.

METHODS AND MATERIALS

Asian women who had invasive breast cancer with clinical tumor size ≤3 cm, pN0-1c and negative inked margins were enrolled. Hypofractionated whole breast irradiation of 42.56 Gy/16 fractions was delivered, and boost irradiation of 10.64 Gy/4 fractions was added when the surgical margin was ≤5 mm. The primary endpoint was the proportion of grade ≥ 2 late adverse reactions within 3 years. Secondary endpoints included early adverse events, overall survival, disease-free survival, ipsilateral breast relapse-free survival, late adverse reactions and cosmetic outcome. Toxicities were evaluated using CTCAE ver3.0. Cosmetic outcomes were assessed using a 4-point scale and CTCAE ver3.0 for hyper/hypopigmentation, breast nipple/areolar deformity and breast volume/deformity.

RESULTS

Between February 2010 and August 2012, 312 patients were enrolled, and 306 received hypofractionated whole breast irradiation. Median follow-up was 70.5 (range 7.6-88.9) months. The proportion of grade ≥ 2 late adverse reactions within 3 years was 4.3% (90% confidence interval 2.5-6.7%). Grade 2 early adverse events occurred in 38 (12.4%); none had grade 3/4. Five-year overall survival, disease-free survival and ipsilateral breast relapse-free survival were 98.7, 95.4 and 98.0%, respectively. Of the 304 evaluable patients, 29 (9.5%; 95% confidence interval 6.5-13.4%) had grade 2/3 late adverse reactions; none had grade 4/5. At 5 years, 70/289 (24.2%) showed any worsening of breast cosmetic changes.

CONCLUSIONS

Hypofractionated whole breast irradiation is considered a standard treatment for Asian women with margin-negative invasive breast cancer after breast-conserving surgery.

MicroRNA: a novel implication for damage and protection against ionizing radiation

Ionizing radiation (IR) is a form of high energy. It poses a serious threat to organisms, but radiotherapy is a key therapeutic strategy for various cancers. It is significant to reduce radiation injury but maximize the effect of radiotherapy. MicroRNAs (miRNAs) are posttranscriptionally regulatory factors involved in cellular radioresponse. In this review, we show how miRNAs regulate important genes on cellular response to IR-induced damage and how miRNAs participate in IR-induced carcinogenesis. Additionally, we summarize the experimental and clinical evidence for miRNA involvement in radiotherapy and discuss their potential for improvement of radiotherapy. Finally, we highlight the role that miRNAs play in accident exposure to IR or radiotherapy as predictive biomarker. miRNA therapeutics have shown great perspective in radiobiology; miRNA may become a novel strategy for damage and protection against IR.

Factors Associated With Radiation Pneumonitis in Patients Receiving Electron Boost Radiation for Breast-Conserving Therapy: A Retrospective Review

PURPOSE

This study aimed to investigate risk factors for radiation pneumonitis (RP) caused by electron beam (EB) boost irradiation during breast-conserving therapy.

METHODS AND MATERIALS

This single-institution retrospective study included patients with breast cancer treated with breast-conserving therapy from 2013 to 2019. Radiation therapy comprised whole-breast irradiation with a dose of 50 Gy and 10 Gy EB boost dose to the tumor bed. EB energies were 4, 6, 9, 12, and 15 MeV. The lung volume receiving ≥1.25 Gy (V1.25) was calculated and considered because the EB energies have a short range. All patients underwent computed tomography and positron emission tomography/computed tomography within 1 year of irradiation. Imaging evaluation was based on the Common Terminology Criteria for Adverse Events, version 5.0.

RESULTS

Overall, 105 patients (median age, 62 years; range, 33-85) were included for analysis with a median follow-up period of 5 months. Average area of EB boost irradiation was 72 cm2 (range, 36-196). Grade 1 RP developed in the EB irradiation field in 22 (20.6%) patients; grade 2 RP developed in 1 (0.93%) patient. Even in patients with central lung distance (CLD) ≥1.8 cm, a positive correlation was found between RP and both energy (r = 0.36; P = .005) and V1.25 (r = 0.26; P = .04). No correlation was found between RP and irradiation field size (P = .47). The EB energy and V1.25 cutoff values were 12 MeV and 24 cm3, respectively.

CONCLUSIONS

CLD of ≥1.8 cm, EB energy of ≥12 MeV, and V1.25 of ≥24 cm3 were risk factors associated with RP. Although the frequency of severe RP was not high, patients receiving high-energy electron treatment and those with a large CLD should be closely monitored.

Spontaneous resolution of thoracic radiation therapy-induced organizing pneumonia: A case series

We retrospectively analyzed the data of 9 patients with organizing pneumonia induced by radiation therapy. Radiation therapy had been administered for breast cancer in 8 patients and for lung cancer in 1 patient. Symptoms were detected in 8 patients; however, none of the patients developed hypoxemia or respiratory failure, and the clinical course was good. Steroid therapy was administered to 3 patients; however, all 3 patients developed recurrence. In contrast, none of the 6 patients who received symptomatic treatment developed recurrence. Steroid treatment is often provided for patients with organizing pneumonia; however, the effect of steroid administration on recurrence rate needs to be examined. In addition, none of the patients died and only 1 patient with lung cancer required mechanical ventilation. Therefore, considering the serious side effects of steroid use, initial symptomatic treatment, and not steroid administration, may be best for patients. One exception would be for patients with hypoxemia or those whose symptoms adversely affect the activities of daily living. The incidence of radiation therapy-induced organizing pneumonia in lung cancer patients is higher and its severity is greater than that in breast cancer patients; however, the time to onset may be longer in lung cancer patients. Therefore, more attention should be paid towards the diagnosis and treatment of radiation therapy-induced organizing pneumonia in patients with lung cancer as compared to that in patients with breast cancer.

Breast cancer and organising pneumonia: the importance of correlating the pathological findings with the clinical and radiological picture

This case describes a female patient with a history of breast cancer who presented with a persistent cough and weight loss after a 17-year disease-free period. Radiologically there were new bilateral intrapulmonary nodules and areas of consolidation with a broad differential diagnosis. Brushings gained via bronchoscopy were suggestive of malignancy, but subsequent video-assisted thoracoscopic surgery wedge resection demonstrated organising pneumonia (OP) with no evidence of malignancy. Diagnostic uncertainty remained after this, and after a period of observation, there was evidence of disease progression. Further tissue was obtained for cytological and histological assessment which provided conclusive evidence of metastatic breast cancer. In this case, OP was secondary to proximal bronchial obstruction due to metastatic infiltration, of which there are no reported similar cases in the current literature. We discuss the importance of differentiating secondary OP from cryptogenic OP.