Radiation-Induced Organizing Pneumonia after Hypofractionated Whole Breast Radiotherapy for Breast Cancer
Article Introduction: In-depth Understanding of RIOP: A Rare Complication Caused by Breast Cancer Radiotherapy!?
Rare Complications in Breast Cancer Patients After Radiotherapy
Dear readers, today we continue to explore an important but little-known topic - RIOP, which stands for Radiation-Induced Organizing Pneumonia. This is a rare pulmonary complication that can occur after radiotherapy. Although the incidence of RIOP is not high, its symptoms are extremely similar to those of ordinary pneumonia, making it crucial to understand its characteristics and treatment methods for the health of patients.
Radiation-Induced Organizing Pneumonia (RIOP)
Radiation-Induced Organizing Pneumonia (RIOP) is a form of secondary organizing pneumonia that may occur after breast radiotherapy. It differs from ordinary Radiation Pneumonitis (RP). RP usually appears in the lung area directly subjected to radiotherapy, while RIOP can appear anywhere in the lungs, including areas not directly irradiated. According to statistics, the incidence of RIOP in patients who have undergone breast radiotherapy is about 0.8% to 2.9%. RIOP usually occurs within 12 months after the end of radiotherapy, manifesting as cough, fever, shortness of breath, or fatigue and other systemic or respiratory symptoms lasting more than two weeks, accompanied by lung infiltration imaging outside the radiation field, without other causes.
Imaging Manifestations
Chest CT shows multiple patchy or nodular infiltrates, usually located outside or near the irradiated field.
Risk Factors
Medical history: A history of radiotherapy is an important clue for diagnosis.
Radiotherapy dose and fractionation method: Although the total dose of low-fraction radiotherapy is lower, the single dose is higher, which may increase the risk of RIOP.
Previous lung disease: Patients with chronic obstructive pulmonary disease (COPD), asthma, etc., are more likely to develop RIOP.
Irradiation range: A larger irradiation range may increase the risk of lung involvement.
Other common risk factors include age (over 50 years old), concurrent hormone therapy, and smoking history. Some studies have found that tamoxifen is a risk factor for pulmonary fibrosis, and the incidence of pulmonary fibrosis is similar in patients treated concurrently or sequentially with aromatase inhibitors such as anastrozole.
Differential Diagnosis
It is necessary to exclude infectious pneumonia, radiation pneumonitis (Radiation Pneumonitis), etc., and microbiological examination and empirical antibiotic treatment are required if necessary.
Drug Management
The drug treatment for RIOP mainly uses glucocorticoids, with common drugs such as prednisone, with an initial dose generally ranging from 0.5-1 mg/kg/day, and the symptoms are relieved gradually after the symptoms are relieved. Patients usually experience symptom relief within a month after hormone therapy. For patients who respond poorly to hormones or have an abnormal course, diagnosis can be made through bronchoscopy or image-guided biopsy.
Prognosis and Management
Most patients show significant improvement in symptoms and imaging findings after glucocorticoid treatment. However, some patients may relapse, so close follow-up is needed, with regular chest CT and lung function checks to monitor changes in the condition and recurrence.
Case Sharing
Case and Clinical History:
Patient: A 40-year-old pre-menopausal woman
Symptoms: Self-examination of a lump near the axillary tail of the right breast
Family history: Grandmother, aunt, and grandmother have a history of breast cancer
Lifestyle: Never smoked, marathon runner, has two children
Diagnosis:
Imaging examination: Diagnostic mammography and ultrasound in June 2022 showed a suspicious irregular hypoechoic 0.5 x 0.6 x 0.9 cm lump at the right axillary tail, with adjacent hypervascularity, no suspicious lymph nodes, BIRADS category 4C
Physical examination: Cardiovascular, pulmonary, and nervous system examinations were normal. Breast examination showed a 1 cm palpable lump at the right axillary tail, no palpable lumps in the left breast, no lymph node enlargement
Biopsy: Core biopsy of the lump at the right axillary tail showed well-differentiated infiltrating ductal carcinoma (IDC), Nottingham score 5/9, estrogen receptor positive (95%), progesterone receptor positive (75%), HER2 negative (IHC1+)
Treatment:
Surgery: Right breast lumpectomy and sentinel lymph node biopsy in July 2022, showing infiltrating carcinoma with mixed lobular and ductal features, multifocal (at least 5), maximum 1 cm, moderately differentiated (Nottingham score 6 or 7/9), sentinel lymph node negative (0/3), lower margin positive, showing lobular carcinoma in situ (LCIS). The final pathological staging was stage IA, pT1N0M0, right breast IDLC, grade 2, ER+/PR+
Endocrine therapy: Recommended anastrozole for 5 years, combined with goserelin for ovarian suppression
Radiotherapy: The patient underwent low-segment whole breast radiotherapy, with an appropriate volume dose to the right lung (Figure 1), 42.4 Gy in 16 daily fractions, and an additional 10 Gy to the right breast lumpectomy cavity. The treatment position was supine, using three-dimensional conformal radiotherapy (3D-CRT)
Post-treatment Situation:
Symptoms: In January 2023, about three months after the end of radiotherapy, the patient developed fever and cough, which did not improve with levofloxacin treatment, and then treated with prednisone for nine days, with some improvement in symptoms
Imaging examination: Chest X-ray in February 2023 showed dense infiltration in the right lower lobe, referred to a pulmonologist, CT in April 2023 showed ground-glass and solid infiltration in the right lower lobe, CT in May 2023 showed new turbidity in the right upper lobe and regression of basal turbidity in the right lower lobe, migratory solid turbidity
Diagnosis: Based on migratory solid turbidity, it was considered to be Radiation-Induced Organizing Pneumonia (RIOP)
Treatment and Management: The patient's symptoms improved after steroid treatment, with occasional cough and mild dyspnea on exertion. Due to unwillingness to use steroids for a long time, it was decided to follow up regularly with CT, and if symptoms recur, treatment or bronchoscopy will be considered. CT in August 2023 showed regression of turbidity in the right lower lobe, and the patient did not need further imaging examination, and soon participated in a marathon race
Other Cases
Ochiai Study
Among 78 patients who underwent stereotactic body radiotherapy (SBRT) for lung cancer, 5 (6.4%) developed RIOP, of which 2 improved after glucocorticoid treatment, 1 relapsed and needed to use medication again, and 3 patients with milder symptoms did not need glucocorticoid treatment and fully recovered.
Kawakami Case Study
Described 9 RIOP patients, 3 of whom received hormone therapy and all relapsed, 6 were treated only for fever and cough without recurrence.
Liu Case
A 71-year-old woman developed radiation recall dermatitis and RIOP during and after radiotherapy and chemotherapy, suggesting a shared inflammatory etiology.
These cases emphasize the importance of RIOP as a complication after radiotherapy and the importance of further research on its genetic susceptibility, risk factors, planning technology, and biological relevance.
Through the above sharing, we hope everyone can have a deeper understanding of RIOP. On the journey to health, we are willing to accompany you!
AHI's Commitment at Montefiore Medical Center
At Montefiore Medical Center, experts are committed to providing comprehensive breast cancer treatment plans to ensure that each patient receives the best treatment effects and can properly manage potential complications. The team has extensive clinical experience and professional knowledge to provide personalized treatment plans for each patient.