Filling in of radiation therapy-induced bronchiectatic change: a reliable sign of locally recurrent lung cancer

Imaging after radiation therapy of thoracic tumors

Radiation-induced lung disease (RILD) is frequent after therapeutic irradiation of thoracic malignancies. Many technique-, treatment-, tumor- and patient-related factors influence the degree of injury sustained by the lung after irradiation. Based on the time interval after the completion of the treatment RILD presents as early and late features characterized by inflammatory and fibrotic changes, respectively. They are usually confined to the radiation port. Though the typical pattern of RILD is easily recognized after conventional two-dimensional radiation therapy (RT), RILD may present with atypical patterns after more recent types of three- or four-dimensional RT treatment. Three atypical patterns are reported: the modified conventional, the mass-like and the scar-like patterns. Knowledge of the various features and patterns of RILD is important for correct diagnosis and appropriate treatment. RILD should be differentiated from recurrent tumoral disease, infection and radiation-induced tumors. Due to RILD, the follow-up after RT may be difficult as response evaluation criteria in solid tumours (RECIST) criteria may be unreliable to assess tumor control particularly after stereotactic ablation RT (SABR). Long-term follow-up should be based on clinical examination and morphological and/or functional investigations including CT, PET-CT, pulmonary functional tests, MRI and PET-MRI.

Diagnostic efficacy of PET and PET/CT for recurrent lung cancer: a meta-analysis

BACKGROUND

Lung cancer is one of the most common malignant tumors in the world, and is the leading cause of cancer-related mortality. Although there are no conclusive data to support the survival benefits of early detection or early treatment for recurrence, an early and accurate diagnosis of recurrence is critical to optimize therapy.

PURPOSE

To compare the diagnostic value of positron emission tomography (PET) and positron emission tomography/computed tomography (PET/CT) using fluorine-18 deoxyglucose (18FDG) with conventional imaging techniques (CITs) for the detection of lung cancer recurrence.

MATERIAL AND METHODS

A meta-analysis was performed, with systematic searches conducted using PubMed and EMBASE databases (up to 31 December 2011). Pooled sensitivity, specificity, and diagnostic odds ratio (DOR) values were calculated for 1035 patients reported in 13 articles. Summary receiver-operating characteristic curves (SROC) were also generated.

RESULTS

The pooled sensitivity (95% CI) for PET, PET/CT, and CITs were 0.94 (0.91-0.97), 0.90 (0.84-0.95), and 0.78 (0.71-0.84), respectively. The pooled specificity (95% CI) for PET, PET/CT, and CITs were 0.84 (0.77-0.89), 0.90 (0.87-0.93), and 0.80 (0.75-0.84), respectively. Regarding sensitivity, lower values were associated with CITs than PET (P = 0.000) and PET/CT (P = 0.005), and there was no significant difference between PET/CT and PET (P = 0.102). Regarding specificity, values for PET/CT and PET were significantly higher than for CITs (both P = 0.000), and there was no significant difference between PET/CT and PET (P = 0.273). In the SROC curves, a better diagnostic accuracy was associated with PET/CT than PET and CITs.

CONCLUSION

PET/CT and PET were found to be superior modalities for the detection of recurrent lung cancer, and PET/CT was superior to PET.

Lung abnormalities at multimodality imaging after radiation therapy for non-small cell lung cancer

Three-dimensional (3D) conformal radiation therapy (CRT) and stereotactic body radiation therapy (SBRT) are designed to deliver the maximum therapeutic radiation dose to the tumor, allowing improved local disease control, while minimizing irradiation of surrounding normal structures. The complex configuration of the multiple beams that deliver the radiation dose to the tumor in 3D CRT and SBRT produces patterns of lung injury that differ in location and extent from those seen after conventional radiation therapy. Radiation-induced changes in lung tissue after 3D CRT and SBRT occur within the radiation portals. The imaging appearance of irradiated tissues varies according to the time elapsed after the completion of therapy, with acute-phase changes of radiation pneumonitis represented by ground-glass opacities and consolidation and with late-phase changes of radiation fibrosis manifesting as volume loss, consolidation, and traction bronchiectasis. Knowledge of treatment timelines and radiation field locations, as well as familiarity with the full spectrum of possible radiation-induced lung injuries after 3D CRT and SBRT, is important to correctly interpret the abnormalities that may be seen at computed tomography (CT). Differential diagnoses in this context might include infections, lymphangitic carcinomatosis, local recurrence of malignancy, and radiation-induced tumors. The integration of morphologic information obtained at CT with metabolic information obtained at positron emission tomography is helpful in distinguishing radiation-induced parenchymal abnormalities from residual, recurrent, and new cancers. Thus, multimodality follow-up imaging may lead to substantial changes in disease management.

Evaluation of treatment response after nonoperative therapy for early-stage non-small cell lung carcinoma

Nonsurgical management of early primary lung cancer has grown tremendously in recent years, and today, available options extend far beyond that of conventional radiation therapy (CRT) to include minimally invasive image-guided delivery of thermal energies, specifically radiofrequency ablation, microwave ablation, and cryoablation, and more conformal stereotactic body radiation therapy. Because the tumor is never resected with these nonoperative interventions, histopathological evaluation of tumor margins for the presence of residual tumor is impossible, and as such, tumor response after each of these therapies is largely based on imaging. To date, computerized tomography and computerized tomography-positron emission tomography remain the most readily available modalities for assessment of therapeutic efficacy, and to this end as detailed within this article, strict imaging survey and familiarity with the expected imaging characteristics of the treated tumor will aid in recognition of unexpected findings, specifically those of incomplete therapy and/or tumor recurrence.

[Imaging and PET/CT of lung cancer]

Lung cancer is one of the most frequently occurring cancer in the world. Imaging plays a critical role for screening, diagnosing, staging, and following patients. Although morphologic imaging such as chest X-ray and CT are still useful for these purpose, major limitations occur in the proper evaluation of diagnosing and staging. Metabolic imaging using PET significantly increases the accuracy of staging. This paper will review the role of imaging in patients suspected or diagnosed with lung cancer.

Possible Misinterpretation of Demarcated Solid Patterns of Radiation Fibrosis on CT Scans as Tumor Recurrence in Patients Receiving Hypofractionated Stereotactic Radiotherapy for Lung Cancer

PURPOSE

To retrospectively analyze opacity changes near primary lung cancer tumors irradiated by using hypofractionated stereotactic radiotherapy (HSRT) to determine the presence or absence of tumor recurrence.

METHODS AND MATERIALS

After review-board approval for a retrospective study, we examined data from 50 patients treated with curative intent for proven or highly suspected localized peripheral-lung cancer and followed up for at least 12 months. All patients had received 50 Gy in five fractions (80% isodose) and were followed up monthly with chest X-ray until clinical and X-ray findings stabilized. Follow-up computed tomography scans were performed 1 and 3 months after HSRT and thereafter at 3-month intervals during the first 2 years.

RESULTS

Median follow-up was 30.4 months (range, 12.0-73.8 months). Abnormal opacities that were suspicious for recurrent tumor appeared in 20 patients at a median of 20.7 months (range, 5.9-61.4 months). Only 3 patients were finally found to have recurrence; 14 were recurrence free but were suspected to have fibrosis, and findings for the other 3 patients were considered equivocal because of a short follow-up period (<or=6 months).

CONCLUSION

Radiation fibrosis, which may occur 1 year or longer after completion of HSRT, is difficult to distinguish from tumor recurrence. Even when opacities increase on follow-up radiologic scans, recurrence cannot be diagnosed conclusively based on image findings; biopsy occasionally is warranted.

Effectiveness of intensive follow-up after response in patients with small cell lung cancer

We investigated whether intensive follow-up leads to earlier diagnosis of recurrence, more effective treatment, and longer survival in patients with small cell lung cancer (SCLC) who had shown a complete or partial response to first-line chemotherapy. The subjects of this retrospective study were 94 patients with SCLC who had shown a complete or partial response to first-line chemotherapy. The patients were separated into two arms: an intensive follow-up arm in which patients underwent regular blood tests, chest radiography, computed tomography of the chest and upper abdomen, magnetic resonance or computed tomography of the brain, and bone scintigraphy bimonthly for 6 months and then quarterly for 1.5 years; and a nonintensive follow-up arm in which these examinations were performed at the physician's discretion. All patients also underwent interviews and physical examinations monthly for 2 years and bimonthly for a further 3 years. Patient characteristics did not differ significantly between the arms. Disease recurred in 55 of 62 patients of the intensive arm and 29 of 32 patients of the nonintensive arm. Asymptomatic recurrences were detected more frequently in the intensive arm than in the nonintensive arm. The response rate to salvage therapy among all patients with recurrent disease was significantly higher in the intensive arm (61.8%) than in the nonintensive arm (37.9%; p=0.04). Both median postrelapse survival and overall median survival were significantly longer in the intensive arm (9 and 20 months, respectively, p=0.04 and p=0.001) than in the nonintensive arm (4 and 13 months, respectively). Intensive follow-up helps detect recurrence earlier, enhances the effectiveness of treatment, and lengthens survival in patients with SCLC. Well-designed prospective, randomized trials including a cost-benefit analysis are needed to compare intensive and nonintensive follow-up regimens.

Follow-up and surveillance of the lung cancer patient following curative intent therapy: ACCP evidence-based clinical practice guideline (2nd edition)

BACKGROUND

To develop an evidence-based approach to follow-up of patients after curative intent therapy for lung cancer.

METHODS

Guidelines on lung cancer diagnosis and management published between 2002 and December 2005 were identified by a systematic review of the literature, and supplemental material appropriate to this topic was obtained by literature search of a computerized database (Medline) and review of the reference lists of relevant articles.

RESULTS

Adequate follow-up by the specialist responsible for the curative intent therapy should be ensured to manage complications related to the curative intent therapy and should last at least 3 to 6 months. In addition, a surveillance program should be considered to detect recurrences of the primary lung cancer and/or development of a new primary lung cancer early enough to allow potentially curative retreatment. A standard surveillance program for these patients, coordinated by a multidisciplinary tumor board and overseen by the physician who diagnosed and initiated therapy for the original lung cancer, is recommended based on periodic visits with chest imaging studies and counseling patients on symptom recognition. Smoking cessation and, if indicated, facilitation in participation in special programs is recommended for all patients following curative intent therapy for lung cancer.

CONCLUSIONS

The current evidence favors follow-up of complications related to curative intent therapy, and a surveillance program at regular intervals with imaging and review of symptoms. Smoking cessation after curative intent therapy to prevent recurrence of lung cancer is strongly supported by the available evidence.

Does intensive follow-up alter outcome in patients with advanced lung cancer?

BACKGROUND

Despite aggressive multimodality treatment, 5-year survival of stage III non-small cell lung cancer (NSCLC) remains <30%. To detect relapse, progression, or development of a second primary cancer early, many clinicians perform follow-up scans. To assess the impact of routine scanning, we compared clinical trial patients who had study-mandated scans with those treated off-study who had less intensive radiologic follow-up.

METHODS

The hospital cancer registry and trials databases were searched for patients with locally advanced NSCLC who had undergone multimodality treatment with curative intent. Baseline demographics were collected as well as frequency and results of clinical and radiologic follow-up.

RESULTS

Forty trial patients and 35 nontrial control patients were identified. Trial patients underwent significantly more imaging, particularly in the first 2 years (2.9 versus 2.0 body scans per year, p = 0.0016; 1.1 versus 0.4 brain scans per year, p < 0.001) but did not have more frequent follow-up visits. Forty-five cancers were detected (41 relapses, four metachronous primary tumors) in 44 (59%) patients. Of these, 28 (64%) sought medical attention that led to detection before a scheduled appointment or procedure. There was no significant difference in time to relapse or second primary in trial and nontrial patients (p = 0.80). Twenty-three patients had localized relapse, but only 15 could be treated with curative intent. Despite the trial group demonstrating a higher number of asymptomatic cancers and being offered potentially curative therapy more frequently, there was no significant difference in survival between trial and nontrial patients.

CONCLUSION

In patients with locally advanced NSCLC, frequent cross-sectional imaging does not alter survival after combined modality therapy.

Lung cancer

Lung cancer is the most frequently occurring cancer in the world, and in the United States it is the second most common cancer diagnosed. Accurate staging by imaging can have a significant impact on appropriate treatment and surgical options. Familiarity with the different histologic subtypes of lung cancer and the typical and atypical appearances of lung cancer is vital. Radiologists serve a critical role in the diagnosis, staging, and follow-up of patients with lung cancer.

Radiation injury: imaging findings in the chest, abdomen and pelvis after therapeutic radiation

Radiation may be used as adjuvant or primary therapy in a variety of tumors in the chest, abdomen and pelvis. Therapeutic radiation affects not only malignant tumors but also surrounding normal tissues. The risk of injury depends on the size, number and frequency of radiation fractions, volume of irradiated tissue, duration of treatment, and method of radiation delivery. Concomitant chemotherapy can act synergistically to produce injury. Other predisposing factors include infection, prior surgery and chronic illness like hypertension, diabetes mellitus and atherosclerosis. Radiation changes vary, based on the target organ and the time from completion of therapy. While most serious complications related to radiotherapy are relatively uncommon, given the number of patients that are treated and the relatively long latency period for development of radiation changes, follow-up imaging studies frequently have findings that should be recognized as radiation related. Familiarity with the spectrum of imaging findings after radiation injury permits differentiation from other etiologies such as recurrent malignancy. The following will discuss imaging findings that may be seen during imaging surveillance in patients with malignancy affecting the chest, abdomen and pelvis.

CT and MRI of Lung Cancer

Computed tomography (CT) is still the cornerstone of imaging studies in the preoperative staging and post- therapeutic evaluation of lung cancer. The most recent developments in multidetector technology have dramatically improved the temporal and spatial resolution of CT. In the mean time, magnetic resonance imaging (MRI) has not become a routine examination in lung imaging and is today only used as a problem-solving tool in patients in whom CT remains equivocal. This article will describe the current tools developed in the multidetector CT era for evaluating the lung, and state-of-the-art MR examination of the chest. Then, the role of CT and MRI in nodule detection, the distinction between benign and malignant nodules, and the benefit of CT and MRI in the staging and post-therapeutic evaluation of lung cancer will be covered.

Imaging of the Patient with Non–Small Cell Lung Cancer

Lung cancer is the most common type of cancer and is the leading cause of cancer deaths in the United States for both men and women. Even though the 5-year survival rate of patients with lung cancer remains dismal at 14% for all cancer stages, treatments are improving and newer agents for lung cancer appear promising. Therefore, an accurate assessment of the extent of disease is critical to determine whether the patient is treated with surgical resection, radiation therapy, chemotherapy, or a combination of these modalities. Radiologic imaging plays an important role in the staging evaluation of the patient; however, radiologists need to be aware that there are also important differences in what each specialist needs from imaging to provide appropriate treatment. This article reviews the role of imaging in patients with non-small cell lung cancer, with an emphasis on the radiologic imaging findings relevant for each specialty.

Imaging of non-small cell lung cancer

Radiologic evaluation is an important component of the clinical staging evaluation of lung cancer and can greatly influence whether the patient is treated with surgical resection, radiation therapy, chemotherapy, or a combination of these modalities. In addition to staging, the radiologic evaluation of the patient undergoing treatment and subsequent follow-up is important to the clinician for assessing treatment effects and complications. This article discusses the imaging of patients with non-small cell lung cancer and its use in management of these patients.

Imaging for lung cancer restaging

Diagnostic imaging plays an important role in the monitoring of tumor response during lung cancer restaging to evaluate the efficacy of chemotherapy and/or radiation therapy during treatment, and in the detection of recurrent or metastatic neoplasm after treatment has been completed. While CT represents the primary imaging modality for lesion evaluation during restaging and for surveillance imaging once therapy has been completed, studies evaluating the role of 18-fluoro-2 deoxyglucose positron emission tomography (FDG-PET) in lung cancer restaging have shown promise regarding the detection of residual and recurrent neoplasm, and in evaluating for early response to first line therapy. With both CT and FDG-PET, residual or recurrent disease should, when possible, be differentiated from therapy-related changes in the lungs. We review the role of imaging in lung cancer restaging with attention to CT and FDG-PET for treatment assessment and the detection of recurrent or metastatic disease.

Follow-up and surveillance of the lung cancer patient following curative-intent therapy

The following two distinctly different issues should be taken into account when planning patient care following curative-intent therapy for lung cancer: adequate follow-up to manage complications related to the curative-intent therapy; and surveillance to detect recurrences of the primary lung cancer and/or development of a new primary lung cancer early enough to allow potentially curative retreatment. Follow-up for complications should be performed by the specialist responsible for the curative-intent therapy and should last 3 to 6 months. Recurrences of the original lung cancer will be more likely during the first 2 years after curative-intent therapy, but there will be an increased lifelong risk of approximately 1 to 2% per year of developing a metachronous, or new primary, lung cancer. A standard surveillance program for these patients is recommended based on periodic visits, with chest-imaging studies and counseling patients on symptom recognition. Whether subgroups of patients with a higher risk of developing a metachronous lung cancer (eg, those patients whose primary lung cancer was radiographically occult or central and those patients surviving for > 2 years after treatment for small cell lung cancer) should have a more intensive surveillance program is presently unclear. The surveillance program should be coordinated by a multidisciplinary tumor board and overseen by the physician who diagnosed and initiated therapy for the original lung cancer. Smoking cessation is recommended for all patients following curative-intent therapy for lung cancer.