Positron emission tomography is superior to computed tomography scanning for response-assessment after radical radiotherapy or chemoradiotherapy in patients with non-small-cell lung cancer.

PURPOSE: To prospectively study the capacity of positron emission tomography (PET) and computed tomography (CT) to determine response soon after radical radiotherapy or chemoradiotherapy and, thereby, predict survival. PET is known to provide a more accurate estimate of true extent of disease than CT when used to stage non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Seventy-three patients with NSCLC underwent [(18)F]fluorodeoxyglucose PET and CT scans before and after radical radiotherapy (n = 10) or chemoradiotherapy (n = 63). Follow-up PET scans were performed at a median of 70 days after radiotherapy. The median PET-CT interval was 1 day. Each patient had determinations of response to therapy made with PET and CT, categorized as complete response, partial response, no response, progressive disease, or nonassessable. Responses were correlated with subsequent survival. RESULTS: Median survival after follow-up PET was 24 months. There was poor agreement between PET and CT responses (weighted kappa = 0.35), which were identical in only 40% of patients. There were significantly more complete responders on PET (n = 34) than CT (n = 10), whereas fewer patients were judged to be nonresponders (12 patients on PET v 20 on CT) or nonassessable (zero patients on PET v six on CT) by PET. Both CT and PET responses were individually significantly associated with survival duration; but on multifactor analysis that included the known prognostic factors of CT response, performance status, weight loss, and stage, only PET response was significantly associated with survival duration (P <.0001). CONCLUSION: In NSCLC, a single, early, posttreatment PET scan is a better predictor of survival than CT response, stage, or pretreatment performance status.

Measurement of lung tumor volumes using three-dimensional computer planning software.

PURPOSE: To examine the interclinician variation in the definition of gross tumor volume (GTV) in patients undergoing radiotherapy for non-small-cell lung cancer (NSCLC), develop methods to minimize this variation, and test these methods. METHODS AND MATERIALS: The radiotherapy planning computed tomography (CT) scans of 6 consecutive patients with NSCLC in which the radiologist was able to define and outline the GTV were used. Six oncologists independently contoured the tumors with the radiologist's markings as a guide using a three-dimensional treatment planning system. Separate contours were prepared using only mediastinal window settings and using both mediastinal and lung window settings. The volumes were calculated using the planning system software (series 1). Factors that resulted in interclinician variation were determined, and, after a 3-year interval, 5 of the 6 clinicians redefined the GTVs using a revised protocol aimed at minimizing variation (series 2). RESULTS: For series 1, the interclinician variation in the measurement of volumes ranged from 5%, in the most tightly measured tumor, to 42%, in the most variable, but was, on average, 20%. Statistically significant differences were noted among the clinicians (p = 0.002), that is, some clinicians tended to record relatively small and some relatively large volumes. The reasons for the variation among the oncologists included a tendency to include regions with a low probability of containing tumor, as if the oncologist were contouring a target volume; inclusion of adjacent atelectasis (ignoring the radiologist's outline); and variable treatment of spicules. When the exercise was repeated using the revised protocol (series 2), the degree of interclinician variation was reduced, with a range of 7-22% (average 13%). In series 2, the differences among the clinicians were not statistically significant (p = 0.25). CONCLUSION: Despite major radiologic input, significant variation occurred in the delineation of the three-dimensional GTVs of NSCLC among oncologists. Standardization of the approach with guidelines resulted in a reduction in this variation.

The clinical impact of (18)F-FDG PET in patients with suspected or confirmed recurrence of colorectal cancer: a prospective study.

UNLABELLED: This prospective study aimed to confirm, in a clinical setting, the benefits suggested by earlier retrospective studies of (18)F-FDG PET scanning for the evaluation of patients with suspected recurrence of colorectal cancer. METHODS: The referring oncologist was asked to prospectively assign a treatment plan for 102 consecutive patients being evaluated by (18)F-FDG PET for suspected or confirmed recurrence of colorectal cancer and without evidence of unresectable disease on conventional staging investigations, including CT. This treatment plan was then compared with that based on incremental information supplied by PET. Management changes were validated by follow-up. RESULTS: For 6 patients, the oncologist would not commit to a management plan without access to PET information, and for all these patients, PET correctly guided management. Of the remaining 96 patients, the management plan for 54 (56%) was altered as a direct result of unexpected PET findings. Thus, PET directly influenced management in 60 (59%) of 102 patients. The discrepant PET results could be validated in 57 patients and were correct for both the presence and the extent of malignant disease in 52 (91%) of these patients but were false-positive in 1 patient because of a pelvic abscess and underestimated the extent of metastatic disease in 4 (7%). Relapse was confirmed in 49 (98%) of 50 evaluable patients with positive PET findings. Significantly, planned surgery was abandoned in 26 (60%) of 43 patients because of incremental PET findings. Of the 42 patients for whom management was not changed by PET findings, false-negative PET findings were documented for 5 (4 with metastases < 1 cm), and the PET findings for 1 were presumed to be false-positive because of sarcoidosis. CONCLUSION: This prospective study confirms the high impact, suggested by previous retrospective analyses, of (18)F-FDG PET on management of patients with suspected recurrent colorectal cancer. The major benefit of PET is avoidance of inappropriate local therapies by documentation of widespread disease.

CNS listeriosis confused with leptomeningeal carcinomatosis in a patient with a malignant insulinoma.

We describe a case of presumed listeria monocytogenes rhomboencephalitis, which was initially confused with leptomeningeal carcinomatosis in a patient with a malignant carcinoid tumor. Long-term corticosteroid treatment and immunosuppression caused by malignancy predisposed the patient to developing listeriosis. The clinical and radiologic features of this illustrative case are described. Listeriosis is an important treatable differential diagnosis in patients with malignancy presenting with neurologic signs.

Estimation of tumor volume in cervical cancer by magnetic resonance imaging.

In 32 patients with stage 1 or 2 cervical cancer, preoperative magnetic resonance imaging (MRI) images were compared with corresponding linear measurements made on fresh histopathology specimens. Their clinical tumor diameters recorded as a part of Federation of International Gynecologists and Obstetricians (FIGO) staging were also correlated with the MRI-derived tumor volumes. The locations of neoplastic lesions within the cervix and uterus were identified accurately by MRI as verified in subsequent histopathology examinations. The examination under anesthesia (EUA) diameter (tumor size) was not related to the MRI-derived tumor diameter. Pathologic tumor diameter correlated well with the corresponding diameter in T2-weighted MRI. Tumor volume as measured by MRI was an accurate representation of the local extent of the disease and can be used as an objective measure of cervical cancer at the primary site. Substituting MRI-derived volume in place of clinical tumor diameter in the FIGO staging system will help refine its prognostic significance in patients with both operable and nonoperable cervical cancer.