Chylous ascites after whole-abdomen irradiation for gynecologic malignancy

From November 1981 through December 1987, 207 patients received whole-abdomen irradiation (WAI) for gynecologic malignancies at the Mayo Clinic. In seven (3%) of these patients, chylous ascites subsequently developed; one additional patient with chylous ascites after WAI for a gynecologic malignancy was referred to us from another institution. In these eight patients, irradiation was done either adjuvantly (five patients) or as salvage therapy after chemotherapy failure (three patients). Chylous ascites was confirmed by laboratory analysis in six cases and was presumed based on the clinical course in two cases. Mean cumulative radiation doses were 2,925 and 5,122 cGy to the abdomen and pelvis, respectively, with para-aortic boosts administered in six cases to a mean cumulative dose of approximately 4,200 cGy. The mean time from completion of WAI to development of ascites was 12 months (range, 6 to 18 months). In six patients, therapy was conservative-observation and diuretics. Two other patients required multiple paracenteses for relief of abdominal distention. Parenteral nutrition was given to two patients who had associated radiation enteritis. The ascites resolved in all eight cases at a mean of 18 months (range, 8 to 30 months) after development. At a mean follow-up of 57 months after initial diagnosis and 16 months after resolution of the ascites, seven patients are without evidence of disease and one patient died of recurrent carcinoma. Distinguishing this clinical entity from recurrent carcinoma is important because of its benign course and its resolution with conservative management.     

宫颈癌九野均分与角度优化IMRT计划剂量学比较

目的 比较宫颈癌术后患者9个野均分和角度优化的IMRT计划靶区和OAR剂量学参数差异。方法 对 12例宫颈癌术后患者CT图像分别设计9个野均分IMRT计划和利用角度优化产生9个野IMRT计划。评估靶区及OAR剂量分布并配对t检验差异。结果 射野角度优化与均分IMRT计划相比,PTV的 V_95%、V_105%、V_110%分别为99.31%∶99.42%(P=0.020)、60.54%∶47.92%(P=0.013)、7.14%∶0.37%(P=0.000);D_max、D_mean分别为56.62 Gy∶55.47 Gy (P=0.000)、53.29 Gy∶52.72 Gy (P=0.000);CI、HI分别为0.85∶0.89(P=0.000)、0.10∶0.13(P=0.000);膀胱 V₄₀增加约4.7%(P=0.013),直肠 D₄₀增加约0.5 Gy (P=0.004),小肠 V₄₀升高约0.6%(P=0.015)、D_max增加1.4 Gy (P=0.000),骨髓 D_mean均升高约1.3 Gy (P=0.000),马尾神经 D_{0.1 cm³}增加2.0 Gy (P=0.000)。结论 9个野均分IMRT计划质量明显优于通过射野角度优化的IMRT计划。     

Randomized trial comparing cisplatin with radioactive phosphorus or whole-abdomen irradiation as adjuvant treatment of ovarian cancer.

In this study, 347 patients with epithelial ovarian cancer without residual tumor after primary laparotomy, were assigned randomly to receive either intraperitoneal instillation of radioactive phosphorus (32P) or six courses of cisplatin (50 mg/m2). Patients randomized to receive 32P with extensive intraperitoneal adhesions were treated with whole-abdomen irradiation instead of 32P (n = 28). The median follow-up was 62 months. Crude and disease-free survival were similar in all groups. Late bowel complications occurred more often in patients treated with 32P compared with the cisplatin group. The estimated 5-year crude survival rate was as high as 95% in patients with borderline or well-differentiated tumors in Stage I. It is suggested that these patients can be treated adequately by operation alone. Patients with moderately or poorly differentiated cancers in Stage I disease had a 5-year crude survival rate of 75%. In these patients, the relapse risk was high enough to warrant postoperative treatment. The efficacy of adjuvant treatment in this subgroup of patients can only be established in a prospective randomized study comparing postoperative adjuvant treatment with a no-treatment arm. Because of the high number of late bowel complications after 32P treatment, it was recommended that cisplatin be used as standard adjuvant treatment for subsequent controlled studies.     

Craniospinal irradiation with spinal IMRT to improve target homogeneity

PURPOSE: To report a new technique for the spinal component of craniospinal irradiation (CSI) in the supine position, to describe a verification procedure for this method, and to compare this technique with conventional plans. METHODS AND MATERIALS: Twelve patients were treated between 1998 and 2006 with CSI using a novel technique. Sixteen children were treated with a conventional field arrangement. All patients were followed for outcomes and toxicity. CSI was delivered using a posteroanterior (PA) intensity-modulated radiation therapy (IMRT) spinal field matched to conventional, opposed lateral cranial fields. Treatment plans were generated for each patient using the IMRT technique and a standard PA field technique. The resulting dosimetry was compared to determine target homogeneity, maximum dose to normal tissues, and total monitor units delivered. RESULTS: Evaluation of the spinal IMRT technique compared with a standard PA technique reveals a 7% reduction in the target volume receiving > or =110% of the prescribed dose and an 8% increase in the target volume receiving > or =95% of the prescribed dose. Although target homogeneity was improved, the maximum dose delivered in the paraspinal muscles was increased by approximately 8.5% with spinal IMRT compared to the PA technique. Follow-up evaluations revealed no unexpected toxicity associated with the IMRT technique. CONCLUSIONS: A new technique of spine IMRT is presented in combination with a quality assurance method. This method improves target dose uniformity compared to the conventional CSI technique. Longer follow-up will be required to determine any benefit with regard to toxicity and disease control.     

Hybrid IMRT plans--concurrently treating conventional and IMRT beams for improved breast irradiation and reduced planning time

PURPOSE: To evaluate a hybrid intensity modulated radiation therapy (IMRT) technique as a class solution for treatment of the intact breast. METHODS AND MATERIALS: The following five plan techniques were compared for 10 breast patients using dose-volume histogram analysis: conventional wedged-field tangents (Tangents), forward-planned field-within-a-field tangents (FIF), IMRT-only tangents (IMRT tangents), conventional open plus IMRT tangents (4-field hybrid), and conventional open plus IMRT tangents with 2 anterior oblique IMRT beams (6-field hybrid). RESULTS: The 4-field hybrid and FIF achieved dose distributions better than Tangents and IMRT tangents. The volume of tissue outside the planning target volume receiving > or =110% of prescribed dose was largest for IMRT tangents (average 158 cc) and least for 6-field hybrid (average 1 cc); the FIF and 4-field hybrid were comparable (average 15 cc). Heart volume > or =30 Gy averaged 13 cc for all techniques, except Tangents, for which it was 32 cc. Average total lung volume > or =20 Gy was 7% for all. Contralateral breast doses were < 3% for all. Planning time for hybrid techniques was significantly less than for conventional FIF technique. CONCLUSIONS: The 4-field hybrid technique is a viable class solution. The 6-field hybrid technique creates the most conformal dose distribution at the expense of more normal tissue receiving low dose.     

Esophagus sparing with IMRT in lung tumor irradiation: an EUD-based optimization technique

PURPOSE: The aim of this study was to evaluate (1) the use of generalized equivalent uniform dose (gEUD) to optimize dose escalation of lung tumors when the esophagus overlaps the planning target volume (PTV) and (2) the potential benefit of further dose escalation in only the part of the PTV that does not overlap the esophagus. METHODS AND MATERIALS: The treatment-planning computed tomography (CT) scans of patients with primary lung tumors located in different regions of the left and right lung were used for the optimization of beamlet intensity modulated radiation therapy (IMRT) plans. In all cases, the PTV overlapped part of the esophagus. The dose in the PTV was maximized according to 7 different primary cost functions: 2 plans that made use of mean dose (MD) (the reference plan, in which the 95% isodose surface covered the PTV and a second plan that had no constraint on the minimum isodose), 3 plans based on maximizing gEUD for the whole PTV with ever increasing assumptions for tumor aggressiveness, and 2 plans that used different gEUD values in 2 simultaneous, overlapping target volumes (the whole PTV and the PTV minus esophagus). Beam arrangements and NTCP-based costlets for the organs at risk (OARs) were kept identical to the original conformal plan for each case. Regardless of optimization method, the relative ranking of the resulting plans was evaluated in terms of the absence of cold spots within the PTV and the final gEUD computed for the whole PTV. RESULTS: Because the MD-optimized plans lacked a constraint on minimum PTV coverage, they resulted in cold spots that affected approximately 5% of the PTV volume. When optimizing over the whole PTV volume, gEUD-optimized plans resulted in higher equivalent uniform PTV doses than did the reference plan while still maintaining normal-tissue constraints. However, only under the assumption of extremely aggressive tumors could cold spots in the PTV be avoided. Generally, high-level overall results are obtained when optimization in the whole PTV is also associated with a second simultaneous optimization in the PTV minus overlapping portions of the esophagus. CONCLUSIONS: Intensity modulated radiation therapy optimizations that utilize gEUD-based cost functions for the PTV and NTCP-based constraints for the OARs result in increased doses to large portions of the PTV in cases where the PTV overlaps the esophagus, while still maintaining (and confining to the overlap region) minimum dose coverage equivalent to the homogeneous PTV optimization cases.     

Comparison of electron IMRT to helical photon IMRT and conventional photon irradiation for treatment of breast and chest wall tumours

Background and purpose

Conventional irradiation of breast and chest wall tumours may cause high doses in underlying organs. Intensity-modulated radiation therapy (IMRT) with photons achieves high conformity between treated and tumour volume but is associated with considerable low-dose effects which may induce secondary malignancies. We compare treatment plans of electron IMRT to helical photon IMRT and conventional irradiation.

Material and methods

Treatment planning for three patients (breast, chest wall plus lymph nodes, sarcoma of medial chest wall/sternum) was performed using XiO 4.3.3 (CMS) for conventional photon irradiation, Hi-Art 2.2.2.05 (TomoTherapy) for helical photon IMRT, and a self-designed programme for electron IMRT.

Results

The techniques resulted in similar mean and maximum target doses. Target coverage by the 95%-isodose was best with tomotherapy. Mean ipsilateral lung doses were similar with all techniques. Electron IMRT achieved best sparing of heart, and contralateral breast. Compared with photon IMRT, electron IMRT allowed better sparing of contralateral lung and total healthy tissue.

Conclusions

Electron IMRT is superior to conventional irradiation, as it allows satisfying target coverage and avoids high doses in underlying organs. Its advantage over photon IMRT is better sparing of most organs at risk (low-dose effects) which reduces the risk of radiation-induced malignancies.     

基于仰卧位全脑全脊髓无缝整体调强技术可行性研究

目的 探讨基于仰卧位情况下开展全脑全脊髓无缝整体调强技术的可行性和安全性。方法 患者在仰卧位下使用头部面膜加体部真空垫固定组合,根据患者身高使用固定间距(20~25 cm)的3个中心坐标。3个中心计划共13个野,在衔接部射野重叠2~3 cm左右,采用固定钨门,逆向优化的方式进行整体计算。对3个等中心和两个射野重叠处靶区分别进行平面剂量通过率及绝对点剂量验证分析。治疗前对3个中心一次性摆位后进行3个中心CBCT扫描,分别得出3个中心在同一坐标系中左右、头脚、前后方向上的误差,并作整体分析。结果 28例患者颈、胸、腹射野等中心点、颈胸射野衔接点、胸腹射野衔接点的平面剂量γ百分通过率和点剂量百分剂量偏差平均分别为99.36%、99.60%、99.75%、94.77%、95.09%和1.56%、-1.56%、0.52%、-0.76%、-1.68%。28例患者共进行162组图像引导放疗,获得486次各中心CBCT图像的摆位偏差,其中颈、胸、腹各中心左右,头脚,前后方向的平均偏差分别为0.17、0.10、0.02 mm,0.06、0.04、0.46 mm,0.19、0.26、0.41 mm。结论 基于仰卧位全脑全脊髓无缝整体调强技术安全可行,值得临床推广。     

Intensity modulated radiation therapy (IMRT) reduces the dose to the contralateral breast when compared to conventional tangential fields for primary breast irradiation

Summary Purpose To determine the dose received by the contralateral breast during primary breast irradiation using IMRT compared to conventional tangential field techniques. Methods and materials Between March 2003 and March 2004, 83 patients with breast carcinoma were treated using 6, 10, or mixed 6/18 MV photons (65 with tangential IMRT technique and 18 with 3-dimensional technique using tangential fields with wedges) for primary breast irradiation following breast-conserving surgery. Paired thermoluminescent dosimeters (TLDs) were placed on each patient’s contralateral breast, 4 and 8 cm from the center of the medial border of the tangential field. The TLDs were left on the patient during a single fraction and then measured 24 h afterwards. Results The mean dose delivered with photons to the primary breast for all patients was 4999 cGy (SD=52) with a mean single fraction dose of 199 cGy (SD=8). The mean percent of the prescribed dose to the contralateral breast measured at the 4- and 8-cm positions were 7.19% (SD=2.28) and 4.63% (SD=2.12), respectively, for patients treated with IMRT compared to 11.22% (SD=2.73) and 10.70% (SD=3.44), respectively, for the patients treated with conventional tangential field techniques. This represented a 36% and 57% reduction at the 4 and 8-cm contralateral positions, respectively, in the mean dose to the contralateral breast using IMRT compared to 3-D technique which was statistically significant (p<0.0005, <0.0005, respectively). Conclusion Primary breast irradiation with tangential IMRT technique significantly reduces the dose to the contralateral breast compared to conventional tangential field techniques. *Presented in part of the 46th Annual Meeting of the American Society for Therapeutic Radiology and Oncology, Atlanta, GA, October 2004.     

Dosimetric comparison of left-sided whole breast irradiation with 3DCRT, forward-planned IMRT, inverse-planned IMRT, helical tomotherapy, and topotherapy

Background and purpose

To compare left-sided whole breast conventional and intensity-modulated radiotherapy (IMRT) treatment planning techniques.

Materials and methods

Treatment plans were created for 10 consecutive patients. Three-dimensional conformal radiotherapy (3DCRT), forward-planned IMRT (for-IMRT), and inverse-planned IMRT (inv-IMRT) used two tangent beams. For-IMRT utilized up to four segments per beam. For helical tomotherapy (HT) plans, beamlet entrance and/or exit to critical structures was blocked. Topotherapy plans, which used static gantry angles with simultaneous couch translation and inverse-planned intensity modulation, used two tangent beams. Plans were normalized to 50 Gy to 95% of the retracted PTV.

Results

Target max doses were reduced with for-IMRT compared to 3DCRT, which were further reduced with HT, topotherapy, and inv-IMRT. HT resulted in lowest heart and ipsilateral lung max doses, but had higher mean doses. Inv-IMRT and topotherapy reduced ipsilateral lung mean and max doses compared to 3DCRT and for-IMRT.

Conclusions

All modalities evaluated provide adequate coverage of the intact breast. HT, topotherapy, and inv-IMRT can reduce high doses to the target and normal tissues, although HT results in increased low doses to large volume of normal tissue. For-IMRT improves target homogeneity compared with 3DCRT, but to a lesser degree than the inverse-planned modalities.     

Retinoblastoma with cerebrospinal fluid metastasis treated with orbital and craniospinal irradiation using IMRT

A 4-year-old male child presented with history of leucocoria, photophobia, and progressive visual deterioration in the left eye. Clinical examination and computed tomography revealed a unilateral retinoblastoma involving the left globe. He underwent enucleation of the left eye and was referred for adjuvant radiotherapy in view of optic nerve infiltration up to the line of resection. However, he did not report for treatment and presented six months later with a recurrent mass in the left orbit with intracranial extension. Cerebrospinal fluid (CSF) cytology was positive for malignant retinoblastoma cells. He received multiagent chemotherapy with vincristine, carboplatin, and etoposide along with intrathecal methotrexate. Although the recurrent orbital mass reduced significantly with chemotherapy, malignant cells persisted in the CSF. He was subsequently treated using intensity modulated radiation therapy (IMRT) to treat the left orbital mass along with craniospinal axis irradiation. Computed tomography done at three and nine months after completion of radiotherapy showed complete disappearance of orbital tumor. CSF cytology also showed no evidence of malignant cells.     

Five-field IMRT class solutions and dosimetric planning guidelines for implementing accelerated partial breast irradiation

Purpose

A comprehensive set of planning guidelines was developed to aid in achieving reproducible dosimetric results for external beam accelerated partial breast irradiation (APBI). The methodology for the development of class solutions for dosimetric planning of the APBI technique, including dose constraint recommendations, is presented for target coverage and conformity as well as normal tissues.

Multibeam inverse intensity-modulated radiotherapy (IMRT) for whole breast irradiation: a single center experience in China

Purpose

To present the clinical experience in our cancer center with multibeam inverse intensity-modulated radiotherapy (IMRT) for early stage breast cancer (BC) patients with whole breast irradiation (WBI).

Methods

We retrospectively analyzed 622 patients with Stage 0 to III BC treated from 2008 to 2011 with wide local excision and WBI, using an inverse IMRT technique. All of the patients were prescribed a total dose of 50 Gy to the whole breast in 2-Gy fractions, followed by a tumor bed boost of 10 Gy in 5 fractions using an electron beam.

Results

Of all of the patients, 132 (21.2%) received whole breast plus regional lymph node (RLN) irradiation. 438 of 622 patients had records of acute skin toxicity based on common terminology criteria (CTC) for adverse events. Two hundred eighty (64%) patients had Grade 0/1 toxicity, 153 (35%) had Grade 2 and only 4 patients experienced grade 3 toxicity. Seventy patients (16%) had moist desquamation. Univariate analysis revealed that breast planning target volume was the only predictive factor for Grade ≥2 acute dermatitis (P = 0.002). After 4 years, 170 patients reported cosmetic results by self-assessment, of whom 151 (89%) patients reported good/excellent cosmetic results, and 17 (11%) patients reported fair assessments. For invasive cancer, the four-year rate of freedom from locoregional recurrence survival was 98.3%. Regarding carcinoma in situ, no patients experienced recurrence.

Conclusion

BC patients who underwent conservative surgery followed by inverse IMRT plan exhibited acceptable acute toxicities and clinical outcomes. Longer follow-up is needed.     

乳腺癌保乳术后螺旋断层治疗技术的剂量学研究

目的 研究乳腺癌保乳术后患者应用固定野调强放疗(FF-IMRT)和螺旋断层治疗(HT)计划的剂量学差异。方法 选择10例左侧乳腺癌保乳术后IMRT患者,CT模拟定位、勾画靶区及危及器官,对同一CT图像设计FF-IMRT计划和HT计划。配对t检验两种计划靶区及危及器官剂量分布及照射时间差异。结果 与FF-IMRT计划相比,HT计划的100%PTV覆盖度增加(P=0.000),105%PTV覆盖度降低(P=0.000),平均剂量(D_mean)降低(P=0.002),均匀指数(HI)、适形指数(CI)增加(P=0.001、0.023)。HT计划的患侧肺剂量体积V₅、V₁₀、V₂₀、V₃₀、V₄₀、D_mean分别降低28%、30%、35%、46%、61%、32%(P=0.000),双肺的分别降低30%、28%、34%、46%、62%、26%(P=0.000),心脏的和最大剂量(D_max)分别降低57%、59%、71%、82%、91%、45%和12%(P=0.000~0.002),健侧乳腺D_mean、D_max分别增加0.9、3.0 Gy (P=0.000、0.000),健侧肺的分别增加0.42、2.70 Gy (P=0.000、0.000)。HT计划照射时间明显高于FF-IMRT计划(11.98 min:5.96 min,P=0.000)。结论 左侧如乳腺癌HT计划的靶区均匀性和适形度均优于FF-IMRT计划,危及器官可获得等同于或优于FF-IMRT计划的剂量分布,可作为新照射方式用于乳腺癌保乳术后患者。     

A method to improve target dose homogeneity of craniospinal irradiation using dynamic split field IMRT

Purpose

Craniospinal irradiation (CSI) is technically very challenging and field edge matching is needed because of the mechanical limitations of standard linear accelerators. We assessed the feasibility of intensity-modulated radiotherapy (IMRT) in CSI to overcome the standard feathering and dose inhomogeneities associated with the standard feathering technique in the junction areas.

Materials and methods

The use of IMRT in CSI was studied with five patients CT scanned in the supine position. Isocentric treatment plans of three dimensional conventional radiotherapy (3D-CRT) and split field IMRT (sfIMRT) with dynamic intrafractional feathering were created with the same field setup and the resulted dose distributions were compared. The effect of treatment inaccuracy was simulated with an intentional shift of ±3 mm with both treatment plans. Dosimetric verification of the sfIMRT treatment plan was performed with radiographic films placed in a phantom.

Results

The sfIMRT treatment plans resulted in a better dose coverage and uniformity in the target volume. The ±3 mm shift had only a minor effect on the dose distribution of the sfIMRT treatment plan whereas with the 3D-CRT the shift resulted in an error of ±38% of the calculated dose in the spinal cord. The measured dose distribution of the sfIMRT treatment plan correlated well with the calculations.

Conclusions

Improved dose homogeneity in the target volume was achieved with the sfIMRT compared to the conventional 3D-CRT treatment plan. With the sfIMRT technique only a single treatment plan is required to deliver the total treatment dose and the resulting dose distribution is also less volatile for technical uncertainties of the treatment.     

Predictors of acute bowel toxicity in patients treated with IMRT whole pelvis irradiation after prostatectomy

Purpose/objective

Whole pelvis irradiation with IMRT (WPRT-IMRT) after prostatectomy is efficient in reducing acute toxicity: however, a number of patients still experience moderate acute bowel toxicity.

Materials and methods

Ninety-six patients treated with WPRT-IMRT after prostatectomy with adjuvant or salvage intent were analysed. A number of parameters were individually recovered, including the DVHs of the intestinal cavity outside PTV and of the loops referred to both the WPRT phase and the whole treatment. Correlation between clinical-dosimetric parameters and acute bowel toxicity was investigated by logistic analyses. Best predictive cut-off values for continuous variables were assessed by ROC curves.

Results

15/96 (15.6%) Patients experienced grade 2 toxicity (no grade 3). Best dose-volume predictors were the fraction of loops receiving more than 45, 50 and 55 Gy (respectively, V45TL ? 50 cc, V50TL ? 13 cc, V55TL ? 3 cc; p-values ranging from 0.005 to 0.027). Age, GU acute toxicity, rectal acute toxicity and time between prostatectomy and IMRT were also predictors of acute bowel toxicity. Multivariate analysis showed that the most predictive independent parameters were age (OR: 1.13; 95%CI: 1.02-1.25; p = 0.021) and V50TL (?13 cc, OR: 8.2; 95%CI: 1.7-40; p = 0.009).

Conclusions

The risk of moderate acute uGI toxicity during WPRT-IMRT for post-operatively treated patients increases with age; the risk is substantially reduced in patients with small overlap between PTV and loops.