[Energy characteristics and examination of the dose correction of each element type in small size radiophotoluminescence glass dosimetry element system]

We studied energy characteristics and examined dose correction when using a radiophotoluminescence glass dosimeter (GD). There are two types of GD. One type of GD is called GD-352, which consists of a glass element and Sn filter. Another type of GD is called GD-302, which has no additional filter. Energy characteristics of these two types of GDs were investigated using a diagnostic X-ray energy range. The equation is as follows: Cf (correction factor) = average of GD measured value/air kerma. The compensation formula for estimating air kerma with each X-ray energy was determined from an approximation formula based on the ratio between GD system reading and air kerma with a specific X-ray energy. From compensation results obtained using the formula, the error for air kerma using GD-352 was approximately 0%, and the error using GD-302 was about 1.0%.

Clinical Implications of a Novel, Iron-containing Fiducial Marker in Radiotherapy for Liver Tumors: An Initial Experience

A 0.5%-iron-containing fiducial marker, Gold AnchorTM (Naslund Medical AB, Huddinge, Sweden), has been recently developed. Herein, we report our initial experiences with the clinical use of the Gold AnchorTM (GA) in radiotherapy for liver tumors. Data of four consecutive patients with liver tumors, including two liver metastases and two hepatocellular carcinomas, were retrospectively analyzed. The GA was percutaneously placed under local anesthesia, close to the tumor. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (MRI) was performed after the placement of the GA. Radiotherapy was designed using the volumetric modulated arc therapy technique. All procedures for placement of the GA were successfully performed with no complications. The GA exhibited various forms in the liver in the four patients. All of the GAs were well-detected on MRI, planned computed tomography (CT), and cone-beam CT. Additionally, the tadpole-like shape of the GA showed better detectability than the uptake of lipiodol emulsion and could be used for three-dimensional correlation during setup in daily image-guided radiotherapy. GA was a useful tool in image registration of radiotherapy with a high applicability. Additionally, the tadpole-like shape can be recommended for liver radiotherapy. Our findings suggest that the GA will indeed be useful in clinical practice.

Neoadjuvant Modified Short-Course Radiotherapy Followed by Delayed Surgery for Locally Advanced Rectal Cancer

This study aimed to assess the clinical outcomes and predictive factors of neoadjuvant modified short-course radiotherapy (mSC-RT) for locally advanced rectal cancer (LARC). Data from 97 patients undergoing mSC-RT followed by radical surgery for LARC were retrospectively analyzed. A 2.5 Gy dose twice daily up to a total dose of 25 Gy in 10 fractions was administered through mSC-RT, and this was delivered with oral chemotherapy in 95 (97.9%) patients. Radical surgery was performed 6 (range, 3-13) weeks after mSC-RT. The median follow-up among surviving patients was 43 (8-86) months. All patients completed neoadjuvant radiotherapy with no acute toxicity grade ≥ 3. Three- and five-year local control rates were 96.3% and 96.3%, respectively. Three- and five-year overall survival (OS) rates were 92.7% and 79.8%, respectively. Univariate analyses revealed that poor OS was associated with no concurrent administration of capecitabine, C-reactive-protein-to-albumin ratio ≥ 0.053, carcinoembryonic antigen ≥ 3.4 ng/mL, and neutrophil-to-lymphocyte ratio (NLR) ≥ 1.83 (P = 0.045, 0.001, 0.041, and 0.001, respectively). Multivariate analyses indicated that NLR ≥ 1.83 was independently associated with poor OS (p = 0.018). mSC-RT followed by delayed surgery for LARC was deemed feasible and resulted in good clinical outcomes, whereas poor OS was associated with high NLR.

Neoadjuvant Modified Short-course Radiotherapy for Stage IV Rectal Cancer

BACKGROUND/AIM

This study aimed to assess the clinical outcomes of neoadjuvant modified short-course radiotherapy (mSC-RT) for rectal metastatic adenocarcinoma.

PATIENTS AND METHODS

Data from 14 patients who underwent mSC-RT followed by surgery for primary tumors were retrospectively analyzed. Twelve patients received systemic chemotherapy for 18 weeks. A 2.5 Gy dose twice daily, up to a total dose of 25 Gy in 10 fractions, over 5 consecutive days was administered through mSC-RT. Surgery for primary tumor was performed five weeks (range=3-7 weeks) after mSC-RT. Nine patients underwent adjuvant chemotherapy. The median follow-up was 38.5 months.

RESULTS

No patients developed grade ≥3 toxicities before surgery. Three patients developed local failures and 10 died during the follow-up period. The 1-, and 3-year local control rates were 91.7% and 71.3%, respectively. The median overall survival (OS) was 45.1 months. The 1-, and 3-year OS rates were 85.7% and 56.3%, respectively. Patients with stage IVA showed significantly better OS than those with stage IVB disease.

CONCLUSION

mSC-RT followed by delayed surgery was well-tolerated and led to good local control in patients with rectal metastatic adenocarcinoma. mSC-RT could be a treatment option for patients with rectal metastatic adenocarcinoma as it is less likely to lead to cessation of systemic chemotherapy.