PET/CT features of lung SABR chest wall toxicity.

Stereotactic ablative radiotherapy offers a radical treatment approach for early stage lung cancers and an aggressive local therapy for pulmonary oligometastases from other tumour sites. Chest wall toxicity is one of the key dose-limiting toxicities for intrathoracic stereotactic treatments. The description of stereotactic radiotherapy chest wall toxicity using functional imaging has not been reported previously. A 56-year-old male received 60 Gy in 8 fractions delivered by volumetric modulated arc therapy for a T1bN0M0 clinical left upper lobe lung cancer. The past medical history included poorly controlled type 1 diabetes mellitus, severe peripheral vascular disease and obesity. The patient attended 9 months later with left-sided, slowly progressive chest pain. An 18 FDG PET/CT performed in order to investigate contralateral pulmonary lesions revealed FDG-avid focal thickening at the left superio-lateral thoracic wall with overlying inflammatory stranding in keeping with an indolent inflammatory process. Chest wall toxicity may present as pain, swelling, fracture and skin changes, and has the 18 FDG PET/CT chjmirocteristics of an inflammatory process. Patients with risk factors for chest wall toxicity, such as obesity, diabetes and smoking should be informed of their higher propensity for this clinically significant treatment side effect. For patients developing chest wall toxicity as demonstrated in this case with associated functional imaging findings, anti-inflammatory treatment should be promptly commenced.

Spontaneous regression of ALK fusion protein-positive non-small cell lung carcinoma: a case report and review of the literature.

BACKGROUND: ALK-rearrangement is observed in < 5% non-small cell lung cancer (NSCLC) cases and prior to the advent of oral tyrosine kinase inhibitors, the natural history of oncogenic NSCLC was typically poor. Literature relating to regression of treatment-naïve NSCLC is limited, and regression without treatment has not been noted in the ALK-rearranged sub-population. CASE PRESENTATION: A 76 year old 'never smoker' female with an ALK-rearranged left upper lobe T2 N0 NSCLC experienced a stroke following elective DC cardioversion for new atrial fibrillation. Following a good recovery, updated imaging demonstrated complete regression of the left upper lobe lesion and a reduction of the previously documented mediastinal lymph node. Remaining atelectasis was non-avid on repeat PET-CT imaging, 8 months from the baseline PET-CT. When the patient developed new symptoms 6 months later a further PET-CT demonstrated FDG-avid local recurrence. She completed 55 Gy in 20 fractions but at 18 months post-radiotherapy there was radiological progression in the lungs with new pulmonary metastases and effusion and new bone metastases. Owing to poor performance status, she was not considered fit for targeted therapy and died 5 months later. CONCLUSION: All reported cases of spontaneous regression in lung cancer have been collated within. Documented precipitants of spontaneous regression across tumour types include biopsy and immune reconstitution; stroke has not been reported previously. The favourable response achieved with radical radiotherapy alone in this unusual case of indolent oncogenic NSCLC reinforces the applicability of radiotherapy in locally advanced ALK-rearranged tumours, in cases not behaving aggressively. As a common embolic event affecting the neurological and pulmonary vasculature is less likely, an immune-mediated mechanism may underpin the phenomenon described in this patient, implying that hitherto unharnessed principles of immuno-oncology may have relevance in oncogenic NSCLC. Alternatively, high electrical voltage applied percutaneously adjacent to the tumour during cardioversion in this patient may have induced local tumour cell lethality.

PET-CT as a predictor of outcome in resectable colorectal liver metastases.

INTRODUCTION: PET-computed tomography (PET-CT) is a useful staging imaging modality in colorectal liver metastases (CRLM). This study aimed to determine whether PET-CT parameters, standardized uptake value (SUV) and reconstructed tumour volume (RTV), are predictors of prognosis and survival. METHODS: A study of all resectable CRLM patients in the regional HPB unit from 2007-2009 was performed. Preoperative PET-CT scans were retrospectively reviewed; SUV, diameter and RTV for each lesion was recorded. Correlation analysis was performed with other pathological and biochemical parameters, by Pearson's correlation analysis. Survival analysis was performed using Cox regression hazard model. A P value of less than 0.05 was considered statistically significant. RESULTS: A total of 79 patients were included. SUV moderately correlated with tumour diameter, both PET-CT (r=0.4927; P<0.0001) and histology (r=0.4513; P=0.0003); RTV (r=0.4489; P<0.001), preoperative carcinoembryonic antigen (CEA) (r=0.4977; P=0.0001), and postoperative CEA (r=0.3727; P=0.004). Multivariate analysis found that an independent predictor of SUVmax was preoperative CEA (P=0.03). RTV strongly correlated with preoperative CEA (r=0.9389; P<0.0001). SUV and RTV had a negative effect on survival. CONCLUSION: PET-CT, in the setting of CRLM, may have a prognostic role in assessing survival. Although no definite conclusions can be drawn regarding the prognostic role of SUV and RTV, it acts to reinforce the need for further prospective studies to validate these findings.