乳腺托架固定下全乳调强放疗CBCT测定摆位误差的研究

目的 探讨乳腺癌保乳术后乳腺托架固定下全乳调强放疗的摆位误差和影响因素,明确临床靶体积外扩至计划靶体积的边界。方法 选取肿瘤医院2016-2017年间乳腺癌保乳术后接受全乳大分割调强放疗的患者30例,其中左侧乳腺癌患者15例,右侧乳腺癌患者15例。所有患者均采用乳腺托架体位固定。比较放疗计划系统图像与放射治疗期间锥形束CT的位移,确定摆位误差,并计算临床靶体积外扩至计划靶体积的边界。不同情况的摆位误差比较采用t检验。结果 全组患者共拍摄锥形束CT图像151套,平均每人(5.0±1.3)套。全组患者摆位误差在x、y、z轴的位移分别为(2.2±1.7)、(3.1±2.5)、(3.3±2.3) mm,CTV至PTV外扩边界分别为6.39、10.00、8.57 mm。放疗第1周摆位误差与后续治疗摆位误差在z轴方向有统计学差异[(3.7±2.5) mm和(2.6±1.6) mm,P=0.002],体重指数超重比正常患者在z轴方向摆位误差显著增大[(3.9±2.6) mm和(2.9±2.0) mm,P=0.033]。结论 乳腺癌保乳术后乳腺托架固定行全乳调强放疗时,推荐CTV至PTV的外扩边界为6~10 mm。建议增加放疗第1周的影像验证频率。     

Melanoma margin assessment

Primary cutaneous melanoma is treated by excisional surgery and careful histologic assessment of the specimen margins is a crucial component of pathology reporting. Surgical margins may be assessed by conventional transverse (bread-loaf) vertical sections, by en face vertical sections, or by en face oblique sections. Transverse techniques only sample a small percentage of the surgical margin. En face techniques are technically challenging but allow assessment of close to 100% of the margin. Margin assessment for melanoma removed from chronically sun-damaged skin is difficult. Melanoma in situ shows contiguous melanocyte growth, nesting, or intraepidermal pagetoid spread. Pitfalls include solar melanocytic hyperplasia, solar lentigines, melanocytic hyperplasia secondary to previous biopsy, lichenoid reactions, and invasive melanoma mimicking scar or benign nevus. En face sections can be used to assess margins for melanoma on sun-damaged skin, and evidence suggests that frozen sections may also be employed by experienced clinicians. Immunohistochemistry is a useful ancillary technique, enabling more accurate identification of in situ melanoma within a surgical margin.     

Evaluation of bond strength of various margin ceramics to a zirconia ceramic

OBJECTIVE: This study evaluated the bond strengths of four different margin ceramics based on fluoroapatite and feldspath to a zirconia ceramic. METHODS: Zirconia cores (Zirconzahn) (N=28, n=7/margin ceramic group) were fabricated according to the manufacturers' instructions (diameter: 4mm; thickness: 2mm) and ultrasonically cleaned. Four different margin ceramics (thickness: 5mm) (Cerabien Zr, Noritake; Ceramco PFZ, Ceramco; e.max, Ivoclar Vivadent and Triceram, Dentaurum) were vibrated and condensed in a stainless steel mould and fired onto their zirconia cores. After trying the specimens in the mould for minor adjustments, they were again ultrasonically cleaned and embedded in PMMA. The specimens were stored in distilled water at 37 degrees C for 1 week and shear bond strength (MPa+/-S.D.) tests were performed in a universal testing machine (crosshead speed: 0.5mm/min). Failure modes were recorded under SEM. RESULTS: Significant effect of margin ceramic types were found on the bond strength values (P<0.05). The mean bond strength values of Ceramco margin ceramic to zirconia was significantly lower (25.4+/-4.5MPa) (P<0.05) than those of Cerabien (31.6+/-6.4MPa), e.max (35.9+/-8.4MPa), and Triceram margin ceramic (38.8+/-7.1MPa) systems. CONCLUSIONS: Margin ceramics, compatible with zirconia framework material tested in the present study, exhibited high bond strength values. Variations in thermal expansion coefficients might influence their bond strength values.     

Absence of dysplasia in the excised cervix by a loop electrosurgical excision procedure in the treatment of cervical intraepithelial neoplasia

Objective

Absence of dysplasia in the excised specimen following loop electrosurgical excision procedure (LEEP) for treatment of cervical intraepithelial neoplasia (CIN) 2/3 is an occasional finding of uncertain clinical significance. We evaluated several factors including age, liquid-based Pap (LBP) test, human papillomavirus (HPV) load before treatment, and HPV typing as predictors for absence of dysplasia. Absence of dysplasia in LEEP specimens was analyzed in terms of factors for recurrent disease after LEEP conization

Methods

In total, 192 women (mean age, 39.3±8.4 years; range, 24 to 70 years) with biopsy-proven CIN 2/3 were treated by LEEP conization. Age, LBP test, histological grade, HPV load, and HPV DNA typing were evaluated as possible predictors of the absence of residual dysplasia or recurrent disease.

Results

Of the LEEP specimens, 34 (17.7%) showed no dysplasia in preoperative biopsies from patients with proven CIN 2/3. Low HPV load (<100 relative light units [RLU]) was significantly related to the absence of dysplasia in LEEP specimens, using logistic regression. Margin involvement and high HPV load (≥400 RLU) were significant factors for recurrence.

Conclusion

Absence of dysplasia in LEEP specimens occurred in 17.7% of our specimens. Prediction of the absence of dysplasia in LEEP specimens was associated with low HPV load. Residual/recurrent disease after LEEP was associated with a positive resection margin and high viral load, and was not associated with absence of dysplasia in LEEP specimens. Even if there is no dysplasia in conization specimens, close follow-up for residual/recurrent disease is needed.     

在线千伏级锥形束CT引导前列腺癌调强放疗摆位误差研究

目的 通过千伏级锥形束CT(KV-CBCT)在线测量前列腺癌调强放疗的摆位误差及图像引导后的残余误差,确定前列腺癌患者外照射治疗计划中CTV外放PTV的边界大小.方法 入选7例接受根治性调强放疗的前列腺癌患者,每例患者每周至少行KV-CBCT在线校正治疗体位2次.采用常规皮肤标记激光对位后采集图像,将所获得CBCT与计划CT图像进行灰度自动配准.计算摆位误差并进行在线评价,若摆位误差＞2 mm则调整治疗床进行纠正.纠正后重新采集CBCT图像进行配准,计算残余误差.根据摆位误差和残余误差分别计算纠正前后临床靶体积(CTV)至计划靶体积(PTV)外放边界大小.结果 共获取197幅KV-CBCT图像.7例患者左右、头脚、前后方向系统误差和随机误差分别为3.1和2.1、1.5和1.8、4.2和3.7 mm,外放边界分别为9.3、5.1、13.0 mm.经KV-CBCT引导纠正后左右、头脚、前后方向系统残余误差和随机残余误差分别为1.1和0.9、0.7和1.1、1.1和1.3 mm,外放边界分别为3.4、2.5、3.7 mm.结论 在线KV-CBCT引导放疗技术可减小前列腺癌患者摆位误差、提高摆位精度,CTV外放PTV边界可缩小至3～4 mm.     

Intra-fraction motion of the prostate during treatment with helical tomotherapy

Background and purpose

To measure the geometric uncertainty resulting from intra-fraction motion and intra-observer image matching, for patients having image-guided prostate radiotherapy on TomoTherapy.

Material and methods

All patients had already been selected for prostate radiotherapy on TomoTherapy, with daily MV-CT imaging. The study involved performing an additional MV-CT image at the end of treatment, on 5 occasions during the course of 37 treatments. 54 patients were recruited to the study. A new formula was derived to calculate the PTV margin for intra-fraction motion.

Results

The mean values of the intra-fraction differences were 0.0 mm, 0.5 mm, 0.5 mm and 0.0° for LR, SI, AP and roll, respectively. The corresponding standard deviations were 1.1 mm, 0.8 mm, 0.8 mm and 0.6° for systematic uncertainties (Σ), 1.3 mm, 2.0 mm, 2.2 mm and 0.3° for random uncertainties (σ). This intra-fraction motion requires margins of 2.2 mm in LR, 2.1 mm in SI and 2.1 mm in AP directions. Inclusion of estimates of the effect of rotations and matching errors increases these margins to approximately 4 mm in LR and 5 mm in SI and AP directions.

Conclusions

A new margin recipe has been developed to calculate margins for intra-fraction motion. This recipe is applicable to any measurement technique that is based on the difference between images taken before and after treatment.     

Systematic cavity shaving: Modifications of breast cancer management and long-term local recurrence,a multicentre study

Background

The status of the surgical margins of lumpectomy is one of the most important determinants of local recurrence in breast cancer. Systematically practicing cavity margin resection is debated but may avoid surgical re-excision and allow the diagnosis of multifocality.

Methods

This multicentric retrospective study included 294 patients who underwent conservative management of breast cancer with 2–4 systematic cavity shavings. Clinico-biological characteristics of the patients were collected in order to establish whether surgical management was modified by systematic cavity shaving. Local recurrence rate with a long-term follow up of minimum 4 years was evaluated.

Results

Cavity shaving avoided the need for re-excision in 25% of cases and helped in the diagnosis of multifocality in 8% of cases. Resection volume was not associated with usefulness of the cavity shaving. No predictive factor of positive cavity shaving was found. The rate of local recurrence was 3.7% and appeared in a median time of 3 years and 8 month. Only one quarter of the patients with local recurrence had initially positive lumpectomy margins but negative cavity shaving.

Discussion

Systematic cavity shaving can change surgical management of conservative treatment. No specific target population for useful cavity shaving was found, such that we recommend utilising it systematically.     

Impact of hepatectomy margin on survival following resection of colorectal metastasis: The role of adjuvant therapy and its effects

Introduction

The optimal width of microscopic margin and the use of adjuvant therapy after a positive margin for hepatic resection for colorectal liver metastasis (CRCLM) has not been conclusively determined. The aim of the current study is to evaluate the influence of width of surgical margin and adjunctive therapy upon disease free and overall survival.

Methods

All patients undergoing hepatectomy for CRCLM from 1997 to 2012 were identified from a prospectively maintained, IRB approved database. Patients were divided into four subgroups based on the parenchymal margin: positive, <0.1 cm, 0.1 cm–1 cm, and >1 cm.

Results

A total of 373 patients were included for analysis with a median follow up of 26 months (range 9–103 months) and a median overall survival of 53 months. The resection margin was positive (26 patients median OS 24 months), <0.1 cm (48 patients median OS 36 mon), 0.1 cm–1 cm (82 patients median OS 44 months), and >1 cm (217 patients median OS 64 months). The most common adjunctive therapy was chemotherapy, hepatic arterial therapy, or local. Patients with positive margins also had the shortest disease free survival (DFS), 16 months. The DFS was similar amongst the other margin groups (<0.1 cm: 21 months, 0.1–1 cm: 22 months, >1 cm 25 months). Hepatectomy margin independently influenced survival (p = 0.017) and disease free survival (p = 0.034). Patients with negative margins has similar overall recurrence rates (p = 0.36) and survival rates (p = 0.89).

Conclusions

A positive surgical margin indicates a worse overall biology of disease for patients undergoing hepatectomy for CRCLM, and appropriate multi-disciplinary therapy should be considered in this high risk patient population. Marginal width if a complete resection has been achieved does not adversely effect overall surgical in patients with CRCLM.     

卫生资源配置的经济学思考

鉴于卫生保健领域资源的有限性,人们提出了各种配置卫生资源的方法。但是,对这些方法进行比较的文献却很少见,而且多数决策者对这些方法并不很了解。该文从经济理论方面对现有的一些资源配置方法,如需要评价法、疾病负担法、基本医疗服务法进行了剖析,指出这些方法都存在一个共同的缺憾,即忽视了机会成本和边际理论。文章建议:更多地关注基本经济学原理将有助于优先领域的资源配置。