Tumor Volume Shrinkage Research Articles

Is FDG-PET scan in patients with early stage Hodgkin lymphoma of any value in the implementation of the involved-node radiotherapy concept and dose painting?

Background and purpose To evaluate the input of FDG-PET data in the implementation of the involved-node radiotherapy concept and dose painting. Materials and methods Patients with early-stage Hodgkin lymphoma treated with combined modality treatments. First, patients underwent a PET/CT before chemotherapy in the treatment position using a head and shoulder immobilization mask. Second, all patients had a CT simulation for treatment planning. The CT simulation was coregistered with the prechemotherapy CT and FDG-PET scan. All prechemotherapy volumes were superimposed on the CT simulation. The initially involved lymph node areas to be irradiated were delineated on the CT simulation scan. Chemotherapy-induced shrinkage rates of the tumor masses visible on CT scan and on FDG-PET were determined and compared. Results Before chemotherapy, FDG-PET-avid areas represented 25% of the total volume on CT. After chemotherapy, the influence of initial FDG-PET data on the delineation of involved-node radiotherapy fields was significant and was due to the fact that in 36% of the patients, FDG-PET helped pinpoint lymph nodes that were undetected on CT. After chemotherapy, the rates of tumor volume shrinkage on CT and FDG-PET were similar. This finding suggests similar chemosensitivity for FDG-PET-avid and non-avid areas. There was no correlation between initial FDG-PET-avid volumes and the clinical outcome. Conclusion Prechemotherapy FDG-PET data are essential for correctly implementing the involved-node radiotherapy concept but seem to be of minimal value for applying the concept of dose painting.

SIGNIFICANT TUMOR VOLUME REDUCTION OF MENINGIOMAS AFTER STEREOTACTIC RADIOTHERAPY

Stereotactic radiosurgery (SRS) is well established in the treatment of cranial base meningiomas. Fractionated stereotactic radiotherapy (SRT) offers an additional treatment option. Data for radiological regression differ, ranging from 13 to 61%. Therefore, the aims of this prospective study were to quantitatively analyze tumor volume (TV) shrinkage and to calculate determining factors. Eighty-four patients were examined under equal conditions before and after SRT. Fat-saturated axial T1-weighted contrast-enhanced magnetic resonance imaging scans with 1- to 3-mm slice thickness were used. After image fusion, TV was drawn in each slice to analyze TV shrinkage three-dimensionally by the planning system. Mean TV had shrunk by 33% at 24 months (P = 0.02) and by 36% at 36 months (P = 0.0007) after SRT. With regard to half-year intervals, TV reduction decreased continuously towards a steady state (P < 0.0001). Younger age (P = 0.001) and smaller TV (P = 0.01) are determining factors. There was no correlation between TV reduction, prescribed dose, histological classification, sex, or previous operations. Meningiomas shrink significantly after SRT. TV shrinkage declines towards a steady state, which is not yet defined. Younger age and smaller TV are determining factors. Previous operations, sex, prescribed dose, or histological subtypes do not affect TV shrinkage. Eighteen to 24 months after irradiation, when symptoms are clinically stable, is the best time for the first magnetic resonance imaging scans evaluating tumor control and shrinkage.

Review of Radiosurgery of Pineal Parenchymal Tumors. Long Survival Following 125-Iodine Brachytherapy of Pineoblastomas in 2 Cases

The aim of the present work is to report the volumetric changes of tumor in two pineoblastoma patients treated with stereotactic interstitial irradiation and to present a review on radiosurgery of pineal parenchymal tumors. Two of our patients with pineoblastoma were treated with CT and image-fusion guided 125-iodine brachytherapy. The tumor volumes were determined with outlined contours on planning and control CT/MRI images and were compared. Until January 2006, there were 61- and 58-month follow-up periods in the two cases. 56 and 53 months after irradiation the MRI images showed significant tumor shrinkage. In case 1 tumor volume was 0.76 cm (3) on the last control MRI image, compared to the 2.87 cm (3) at the time of interstitial irradiation, which means 73% shrinkage. In case 2, tumor volume measured with the last control MRI examination was 0.29 cm (3), which represents 77% shrinkage of the original tumor volume. In both Cases 1 and 2, PET examinations using (11)C-methionine showed no active tumor mass 56 and 53 months following brachytherapy. Two successful treatments of pineoblastoma are reported. The interstitial irradiation of the tumors decreased their volumes significantly. The CT and image fusion-guided 125-iodine stereotactic brachytherapy can be planned well dosimetrically and is surgically precise.

Tumor Volume Shrinkage after SRT

Introduction: Fractionated stereotactic radiotherapy (SRT) is well established in the treatment of skull base meningiomas. Local tumor control is excellent (overall survival and the progression-free survival rates for 5 years: 92.9% and 96.9%, respectively). During follow-up 1/3 of the patients developed a radiological regression. We examined 94 patients prospectively in both departments to analyze quantitatively the tumor volume (TV) shrinkage.

Therapeutic Efficacy of DTI-015 using Diffusion Magnetic Resonance Imaging as an Early Surrogate Marker

To investigate diffusion weighted magnetic resonance imaging as a quantitative surrogate marker for evaluating the therapy-induced cellular changes in an orthotopic experimental glioma model, tumors were treated with direct intratumoral administration of DTI-015, a solution of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) in 100% EtOH. Intracerebral 9L tumors were induced in Fischer 344 rats, and three treatment groups were established: DTI-015, EtOH, and sham. Two groups of rats received intratumoral injection of either 67 mg/mL BCNU in EtOH or EtOH alone at 50% of the tumor volume up to a maximum of 30 mul under stereotactic guidance. Diffusion magnetic resonance images were acquired before treatment and after treatment at 1, 24, 48, and 72 hours and then 3 times per week thereafter. Tumor cell viability was examined using multislice diffusion weighted magnetic resonance imaging with diffusion weighted transverse magnetic resonance images and histogram plots of each tumor quantified over time. Control animals (EtOH- or sham-treated animals) showed mean apparent diffusion coefficients (ADCs) that remained essentially unchanged over the experimental time course. In contrast, rats treated with DTI-015 showed a significant increase in ADC relative to the pretreatment within 24 hours, which further increased over time, followed by a significant therapeutic response as evidenced by subsequent tumor volume shrinkage, development of a cystic region, and enhanced animal survival. Finally, not only were ADC measurements predictive of differences between treatment groups, but they also yielded spatial and temporal data regarding the efficacy of treatment within individual treated animals that could be used to guide subsequent therapy.

MR imaging assessment of irregular shrinkage of tumor morphology and volume in cervical cancer during radiation therapy

Objective: To study the clinical significance of the morphological and volume changes in cervical cancer during an ongoing course of radiation therapy (RT) using MR imaging. Methods: Serial MR imaging examinations were performed in 60 advanced cervical cancer patients. MR imaging was obtained at the start of RT, at 20–25 Gy (2–2.5 weeks of RT), at 45–50 Gy (4–5 weeks of RT), and 1–2 month post-RT. Tumor morphology was classified qualitatively as well-defined (round/oval with a well-demarcated smooth margin) vs. lobulated vs. irregular and tumor volume was assessed in each serial MR examination independently by ROI volumetry and diameter volumetry. ROI volumetry was traced on the computer workstation with a trackball in each sagittal T2-weighted image and calculated by the summation of all tumor areas in each slice and multiplication by the slice profile. Diameter volumetry was to measure the largest three orthogonal tumor diameters in each orthogonal measurement plane and calculate as an ellipsoid formula (V=d1×d2×d3×π/6). Serial tumor volume was compared between the two measurement methods. Results: The proportion of lobulated and irregular tumors increased early during RT and declined lately post-RT (68% pre-RT, 80% at 2–2.5 weeks of RT, 72% at 4–5 weeks of RT, 33% post-RT). Accordingly, ROI volumetry and diameter volumetry correlated well pre-RT (r1=0.89) and post-RT (r4=0.80), but poorly during RT (r2=0.17 at 2–2.5 weeks of RT, r3=0.69 at 4–5 weeks of RT). Conclusions: Cervical cancers regress in a non-uniform fashion during RT and undergo increasingly irregular shrinkage. Measurement with ROI volumetry techniques, which can optimally measure irregular volumes, provides better assessment of radiation response during treatment than diameter volumetry.

Irregular shrinkage of tumor volume in cervical cancer during radiation therapy and its impact on the assessment method of response using magnetic resonance imaging

Purpose: To determine temporal changes of tumor irregularity in cervical cancer during/after radiation therapy (RT) and their impact on the method of tumor volume measurement (simple diameter-based measurement vs. quantitative 3-D volumetry) for response assessment during/after RT.

Pergolide as primary therapy for macroprolactinomas.

The objective of this study is to determine whether pergolide therapy is an effective modality for the de novo treatment of patients with macroprolactinomas. Twenty-two consecutive patients with macroprolactinomas were included in the study and followed prospectively. These included 16 men and 6 women in whom pregnancy was not of concern. Pergolide was administered once or twice a day depending on the patient's preference. Ten patients received 0.1 mg daily as a maintenance regimen and in the others the daily dose ranged from 0.05 to 0.5 mg. Eight patients reported minor but tolerable side effects. One patient had to be switched to cabergoline because of intolerable nausea. After a mean of 12 months (range, 3-36), mean PRL levels declined from 3,135 ng/ml (range, 126-31,513) to 50 ng/ml (3-573), representing a mean PRL suppression of 88% (range, 0-99). PRL levels became normal in 15 patients and decreased to 25-40 ng/ml in 3 others. The mean tumor volume shrinkage was 25% or greater in 19 patients (86%), 50% or greater in 17 patients (77%), and 75% or greater in 10 patients (45%). Visual abnormalities were reversible after pergolide therapy in all but 1 of 12 patients with initially abnormal formal visual testing. Two out of 4 premenopausal women did not normalize PRL levels and had persistent oligomenorrhea. Testosterone was low in 14 men at presentation and normalized in 3 with pergolide therapy. We conclude that pergolide is a safe, inexpensive, and generally well-tolerated dopamine agonist for the treatment of macroprolactinomas in men and women in whom pregnancy is not of concern. In these specific populations, pergolide may become the first-line therapy for treatment of macroprolactinomas.

Variation of post-treatment H-MRSI choline intensity in pediatric gliomas.

Pediatric brain gliomas are not always amenable for complete surgical excision, therefore adjuvant treatment for a large tumor mass is often required. As tumor volume shrinkage may not be a reliable method for assessing response to treatment, information about the tumor growth potential is desirable for an adequate follow-up of the patients. Choline (Cho) signal intensity, determined by proton magnetic resonance spectroscopy imaging (H-MRSI), has proved to be a reliable indicator of the metabolic activity and of tumor progression in various intracranial tumors. In this study we have sought to determine if H-MRSI can be of use in monitoring the response of pediatric gliomas to different forms of therapy. We performed pretreatment and post-treatment H-MRSI in 10 children with biopsed or partially excised brain gliomas. The follow-up period ranged between 6 and 40 months. A total of 38 H-MRSI were performed. All the patients had chemotherapy or radiotherapy. As an indicator of tumor activity we utilized the ratio between tumor/brain Cho signal intensity. Treatment response was evaluated as a function of tumor volume and clinical outcome. In 6 patients whose tumor volume decreased or remained stable we observed that the Cho ratio decreased (p < 0.01) after treatment and remained low during longitudinal follow-up. In the 4 patients whose tumors progressed the Cho ratio increased after treatment. These observations suggest that serial H-MRSI can provide valuable information regarding the response to therapy in pediatric gliomas and therefore be of use in the follow-up of these neoplasms of childhood.