Comparison of treatment planning by carbon ion radiotherapy and by intensity-modulated radiotherapy for prostatic adenocarcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the potential benefit of carbon ion radiotherapy (C-ion RT) through comparison with photon intensity-modulated radiotherapy (IMRT) in dose distribution for prostatic adenocarcinoma.</p><p><b>METHODS</b>In randomly selected 5 patients, treatment planning of C-ion RT (4 coplanar beams) and IMRT (7 coplanar fields) were worked out by computer working station. In order to make a meaningful comparison, it was defined that the 95% isodose surface had to cover 100% of the PTV in each plan; all dose was given as normalized dose with the definition of the minimum dose of the PTV being equal to 95% of prescribed dose. Dose-volume histograms (DVHs) of the tumor and organ-at-risks (OARs) were calculated. Volume irradiated more than or equal to some specified doses, conformity index ( CI) , and inhomogeneity coefficient (IC) of each treatment plan was compared, respectively.</p><p><b>RESULTS</b>With C-ion RT, the mean irradiated volumes (in %) of the rectum were significantly smaller than that with IMRT except for 95% dose level, and C-ion RT could provide complete protection to the posterior rectal wall. In addition, C-ion RT could also remarkably reduce the dose to the bladder, femoral heads and non-target normal tissues at each dose level. Dose conformation and homogeneity in the target volume of C-ion RT were better than that in IMRT (mean CI50%, 3.36 vs. 5.04, mean CI95%, 1.20 vs. 1.46, mean IC, 0.03 vs. 0.12).</p><p><b>CONCLUSION</b>Compared with IMRT, C-ion RT can obtain better dose distribution, and may reduce tumor recurrence and radiation-induced complications in prostatic adenocarcinoma.</p>

Oral Leukoplakia Related to Malignant Transformation / Oral Science International

Oral leukoplakia and its malignant transformation are reviewed in this article. Oral leukoplakia is defined as a predominantly white lesion of the oral mucosa that can not be characterized as any other definable lesion; however, the lesion must be confirmed histopathologically by biopsy in order to discuss malignant transformation of oral leukoplakia. Malignant transformation rates of oral leukoplakia range from 0.13 to 17.5%, while the rates of five-year cumulative malignant transformation range from 1.2 to 14.5%. Some reports found a high incidence of malignant transformation in older patients. Chewing tobacco and smoking are distinct risk factors particularly among males in certain countries; however, other countries have noted that females or non-smokers may be at risk of malignant transformation. HPV has been detected in oral dysplasia lesions and cancer in non-smokers. Conflicting reports have been presented regarding the malignant transformation of oral leukoplakia with epithelial dysplasia; however, we and some authors believe that epithelial dysplasia is an important factor in the malignant transformation of oral leukoplakia. The majority of researchers showed non-homogenous leukoplakia as a risk factor, although different terms have been used to describe these lesions. There may be several routes to malignant transformation of oral leukoplakia, including transformations induced by carcinogenesis due to betel quid chewing or smoking, or by HPV infection. While no definite treatment modalities for oral leukoplakia have been established, we suggest surgical therapy with an adequate safety-margin and well-timed evaluation as an appropriate treatment in preventing malignant transformation.

Analysis of Bilateral Neck Metastasis of Tongue Cancer / Oral Science International

To estimate the prognosis of bilateral cervical metastases from tongue carcinoma, we studied twelve patients (24-72 years old) who underwent neck dissections at our hospital to judge whether we should have performed radical treatment or not for those patients of tongue carcinoma who had bilateral metastatic nodes.The five-year survival rate of bilateral neck metastasis patients was 58% (the Kaplan-Meier method). On the other hand, the five-year survival rate of patients with only unilateral neck metastases of squamous cell carcinoma of the tongue was 56%. Thus, there was no statistical significant difference in survival rate.We conclude that even if a patient has metastatic lymph nodes on both sides of the neck, radical therapy should be done.