In vivo whole body dosimetry measurement technique of total body irradiation: a 12-year retrospective study result from one institute in Thailand.

OBJECTIVE: The main problem of total body irradiation (TBI) is how to maintain radiation dose homogeneity throughout the body during a treatment course. The simple set up treatment with non-complicated in vivo dosimetry measurement technique is the ideal method to solve this problem. For this reason, the authors have reported the results of in vivo dosimetry measurement method to prove the reliability of dose distribution from the authors' TBI technique. MATERIAL AND METHOD: The authors reviewed the data of dose measurement record from 53 patients' treatment files to report the uniformity of absorbed in vivo dose distribution throughout the whole body from TBI with semiconductor detectors and ionization chamber with the accepted homogeneity within +/- 10% of the prescribed dose. The result was reported in the term of mean and standard deviation of absorbed dose difference from the prescribed dose. RESULTS: The uniformity of radiation dose distribution throughout the whole body of all patients calculated from semiconductors was accepted with mean difference value of -3.2 +/- 2.5% from the prescribed dose and the difference of mean absorbed dose value at midline point between semiconductor and ionization chamber was 4 +/- 3.3%. CONCLUSION: This TBI dosimetry measurement technique has been proved to exhibit the reliability of dose homogeneity throughout the whole body within the accepted value. This could be applied for use at any institute that has some limitation in resources and small treatment room.

Vascular endothelial growth factor a and proliferation marker in prediction of lymph node metastasis in oral and pharyngeal squamous cell carcinoma.

OBJECTIVE: To explore the effect of Ki-67 and vascular endothelial growth factor A (VEGF-A) expression on the risks of advanced T category (T3,4) and positive lymph node involvement (N+) in oral and pharyngeal squamous cell carcinoma (SCC) compared with laryngeal SCC. DESIGN: Immunohistochemical analysis of prospectively recruited patients. SETTING: University-affiliated hospital. PATIENTS: A total of 147 previously untreated patients with different stages of SCC in the oral cavity, pharynx, and larynx. MAIN OUTCOME MEASURES: Relative risks of T3,4 tumor and N+, a risk ratio comparing risks under high vs low marker expression. RESULTS: A significant association of Ki-67 and VEGF-A expression with tumor T category was observed for oral and pharyngeal SCC and for laryngeal SCC (P < or = .006). Regarding nodal status, Ki-67 expression was a significant risk factor for N+ in all tumors (P < or = .009), whereas VEGF-A expression was related to N+ in oral and pharyngeal SCC only (P < .03). Analytically, Ki-67 expression alone in oral and pharyngeal SCC was associated with a relative risk of N+ of 3.83 (95% confidence interval, 1.22-11.99; P = .009), and additional expression of VEGF-A raised the value to 6.12 (2.09-17.93; P < .001). Moreover, the combined expression of both markers was 3.25 times more effective in predicting N+ for T1,2 tumor compared with T3,4 tumor. CONCLUSIONS: Proliferative status was a common risk factor for N+ in all of the tumors in this series. Exploitation of VEGF-A in lymph node metastasis in addition to proliferation by oral and pharyngeal SCC but not by laryngeal SCC explains the clinical aggressiveness of oral and pharyngeal SCC, especially the early lymphatic invasion. In the management of cervical lymph nodes, combined expression of Ki-67 and VEGF-A may help identify patients at risk for occult metastases. This study suggests anti-VEGF-A therapy, an additional intervention to the classic antiproliferative regimen, for preventing lymphatic progression of oral and pharyngeal SCC.

Fractionated stereotactic radiotherapy in residual or recurrent nasopharyngeal carcinoma.

The aim of this study was to evaluate results of fractionated stereotactic radiotherapy (FSRT) in patients with residual or recurrent nasopharyngeal carcinoma (NPC) in terms of local progression-free (LPFS) and overall survival (OS) rate and complications after treatment. There were 32 residual or recurrent NPC patients treated with FSRT using linac-based radiosurgery system. Time from the previous radiotherapy to FSRT was 1-165 months (median, 15). Two patients were treated for the second and one for the third recurrence. Thirteen patients (40.6%) also received chemotherapy with FSRT. Tumor volume ranged from 6.2-215 cc (median, 44.4). Average FSRT dose was 17-59.4 Gy (median, 34.6) in 4-25 fractions (median,6) in 1-5.5 weeks (median, 3). Median follow-up time was 25.5(3-67) months. LPFS rate at 1 and 3 years after FSRT was 67.8% and 37.9%. OS rate at 1 and 3 years was 89.7% and 71.2%. If all patients who had tumor progression with no further follow-up were assumed dead, the OS rate at 1 and 3 years would be 75.0% and 37.9%. Univariate analysis showed better local tumor control in patients with tumor volume

Preoperative chemoradiotherapy in locally advanced rectal cancer: Ramathibodi experience.

A retrospective study of the preoperative chemoradiotherapy in locally advanced rectal cancer performed at Ramathibodi Hospital. The median age of twelve patients was 52 years. The tumor locations (upper-, mid-, lower rectum) were 25%, 50% and 25%, respectively. Eleven patients had clinical stage 111 disease. All received concurrent 5-FU-based chemoradiotherapy followed by surgery (if resectable) and chemotherapy. The most common toxicity of preoperative treatment was gr. 1-2 diarrhea (58.3%). The response rate was 41.7%. Five patients (41.7%) underwent sphincter-sparing surgery. Four patients underwent AP resection. Twenty-five percent achieved pathological complete response. Pathological downstaging occurred in 33.3%. The remaining three patients had unresectable disease. With the median follow up of 13 months, five patients had progressive disease and one has expired. The local failure rate was 16.7%. The one-year recurrence-free survival was 75%. The authors conclude that preoperative chemoradiotherapy is an effective treatment with favorable outcome in locally advanced rectal cancer.

Fractionated stereotactic radiotherapy for bilateral vestibular schwannomas associated with neurofibromatosis type 2: early experiences in Ramathibodi Hospital.

PURPOSE: To evaluate the rates of tumor control and useful hearing preservation in patients with bilateral vestibular schwannomas (VSs) associated with neurofibromatosis type 2 (NF-2) treated with fractionated stereotactic radiotherapy (FSRT). MATERIAL AND METHOD: From August 1998--December 2002 there were 5 patients with NF-2 who underwent FSRT (Linac-based system) for bilateral CP angle tumors. Median age was 28 (18-47) years. Median tumor volume was 5.4 (2.2-9.4) cc. Eight lesions received a marginal dose of 44.2-59.9 (median = 46.2) Gy in 25-33 fractions. The other 2 lesions received 4.4 and 4.9 Gy/fraction for 6 fractions in 3 and 2 weeks. Median follow-up was 19 (14-44) months. RESULTS: Radiographic and clinical tumor control rate was 90%. One lesion progressed at 7 months after FSRT and was completely resected Of the 5 lesions with Gardner-Robertson class I-II hearing before FSRT 2 (40%) retained useful hearing at the last follow-up. One patient had left facial spasm at 10 months after FSRT which gradually improved. No patient had facial palsy, facial numbness or pain. CONCLUSIONS: FSRT provided good tumor control and hearing preservation rate in NF-2 patients with minimal morbidity. However, a longer follow-up is needed to evaluate long term results.