A dosimetric analysis of dose escalation using two intensity-modulated radiation therapy techniques in locally advanced pancreatic carcinoma

PURPOSE: To perform an analysis of three-dimensional conformal radiation therapy (3D-CRT), sequential boost intensity-modulated radiation therapy (IMRTs), and integrated boost IMRT (IMRTi) for dose escalation in unresectable pancreatic carcinoma. METHODS AND MATERIALS: Computed tomography images from 15 patients were used. Treatment plans were generated using 3D-CRT, IMRTs, and IMRTi for dose levels of 54, 59.4, and 64.8 Gy. Plans were analyzed for target coverage, doses to liver, kidneys, small bowel, and spinal cord. RESULTS: Three-dimensional-CRT exceeded tolerance to small bowel in 1 of 15 (6.67%) patients at 54 Gy, and 4 of 15 (26.7%) patients at 59.4 and 64.8 Gy. 3D-CRT exceeded spinal cord tolerance in 1 of 15 patients (6.67%) at 59.4 Gy and liver constraints in 1 of 15 patients (6.67%) at 64.8 Gy; no IMRT plans exceeded tissue tolerance. Both IMRT techniques reduced the percentage of total kidney volume receiving 20 Gy (V20), the percentage of small bowel receiving 45 Gy (V45), and the percentage of liver receiving 35 Gy (V35). IMRTi appeared superior to IMRTs in reducing the total kidney V20 (p < 0.0001), right kidney V20 (p < 0.0001), and small bowel V45 (p = 0.02). CONCLUSIONS: Sequential boost IMRT and IMRTi improved the ability to achieve normal tissue dose goals compared with 3D-CRT. IMRTi allowed dose escalation to 64.8 Gy with acceptable normal tissue doses and superior dosimetry compared with 3D-CRT and IMRTs.     

Alternative methods for intensity-modulated radiation therapy inverse planning and dose delivery

A large number of IMRT systems are currently being marketed. Many of these systems appear to be unique, and manufacturers often emphasize design differences as they argue the merits of their particular approach. This paper focuses on highlighting the underlying feature that is intrinsically part of all IMRT systems. On the other hand, major differences often appear at the implementation stage for dose delivery. Such variations are evident because each manufacturer has a unique approach to balancing the issues of treatment time, leakage radiation reaching the patient's total body, aperture approximation of the ideal intensity maps, increasing the angles of approach for the treatment fields, integration of on-line imaging, selection of treatment distance, availability of different photon energies, and overall system complexity (i.e., cost). How these different issues are handled in the process of system design affects the relative advantages and disadvantages that appear in the final product. This paper takes the approach of dividing the various IMRT methods into categories that are divided roughly along the lines of the technique used during dose delivery to approximate the intensity patterns. Other features of each system are included under these sub-sections.     

Technical aspects of radiation therapy for anal cancer

Historically treated with surgery, current practice recommends anal carcinoma to be treated with a combination of chemotherapy and radiation. This review will examine the anatomy, modes of disease spread and recurrence, and evaluate the existing evidence for treatment options for these tumors. An in-depth examination of specific radiation therapy (RT) techniques—such as conventional 3D-conformal RT and intensity-modulated RT—will be discussed along with modern dose constraints. RT field arrangement, patient setup, and recommended gross and clinical target volume (CTV) contours will be considered. Areas in need of further investigation, such as the role in treatment for positron emission tomography (PET) will be explored.     

Intensity modulated radiation therapy with simultaneous integrated boost based dose escalation on neoadjuvant chemoradiation therapy for locally advanced distal esophageal adenocarcinoma

AIM: To evaluate impact of radiation therapy dose escalation through intensity modulated radiation therapy with simultaneous integrated boost (IMRT-SIB). METHODS: We retrospectively reviewed the patients who underwent four-dimensional-based IMRT-SIB-based neoadjuvant chemoradiation protocol. During the concurrent chemoradiation therapy, radiation therapy was through IMRT-SIB delivered in 28 consecutive daily fractions with total radiation doses of 56 Gy to tumor and 5040 Gy dose-painted to clinical tumor volume, with a regimen at the discretion of the treating medical oncologist. This was followed by surgical tumor resection. We analyzed pathological completion response (pCR) rates its relationship with overall survival and event-free survival. RESULTS: Seventeen patients underwent dose escalation with the IMRT-SIB protocol between 2007 and 2014 and their records were available for analysis. Among the IMRT-SIB-treated patients, the toxicity appeared mild, the most common side effects were grade 1-3 esophagitis (46%) and pneumonitis (11.7%). There were no cardiac events. The Ro resection rate was 94% (n = 16), the pCR rate was 47% (n = 8), and the postoperative morbidity was zero. There was one mediastinal failure found, one patient had local failure at the anastomosis site, and the majority of failures were distant in the lung or bone. The 3-year disease-free survival and overall survival rates were 41% (n = 7) and 53% (n = 9), respectively. CONCLUSION: The dose escalation through IMRT-SIB in the chemoradiation regimen seems responsible for down-staging the distal esophageal with well-tolerated complications.     

Radiation dose escalation for localized prostate cancer

BACKGROUND:

In the current study, the effects of dose escalation for localized prostate cancer treatment with intensity‐modulated radiotherapy (IMRT) or permanent transperineal brachytherapy (BRT) in comparison with conventional dose 3‐dimensional conformal radiotherapy (3D‐CRT) were evaluated.

METHODS:

This study included 853 patients; 270 received conventional dose 3D‐CRT, 314 received high‐dose IMRT, 225 received BRT, and 44 received external beam radiotherapy (EBRT) + BRT boost. The median radiation doses were 68.4 grays (Gy) for 3D‐CRT and 75.6 Gy for IMRT. BRT patients received a prescribed dose of 144 Gy with iodine‐125 (I‐125) or 120 Gy with palladium‐103 (Pd‐103), respectively. Patients treated with EBRT + BRT received 45 Gy of EBRT plus a boost of 110 Gy with I‐125 or 90 Gy with Pd‐103. Risk group categories were low risk (T1‐T2 disease, prostate‐specific antigen level ≤10 ng/mL, and a Gleason score ≤6), intermediate risk (increase in value of 1 of the factors), and high risk (increase in value of ≥2 factors).

RESULTS:

With a median follow‐up of 58 months, the 5‐year biochemical control (bNED) rates were 74% for 3D‐CRT, 87% for IMRT, 94% for BRT, and 94% for EBRT + BRT (P <.0001). For the intermediate‐risk group, high‐dose IMRT, BRT, or EBRT + BRT achieved significantly better bNED rates than 3D‐CRT (P <.0001), whereas no improvement was noted for the low‐risk group (P = .22). There was no increase in gastrointestinal (GI) toxicity from high‐dose IMRT compared with conventional dose 3D‐CRT, although there was more grade 2 genitourinary (GU) toxicity (toxicities were graded at the time of each follow‐up visit using a modified Radiation Therapy Oncology Group [RTOG] scale). BRT caused more GU but less GI toxicity, whereas EBRT + BRT caused more late GU and GI toxicity than IMRT or 3D‐CRT.

CONCLUSIONS:

The data from the current study indicate that radiation dose escalation improved the bNED rate for the intermediate‐risk group. IMRT caused less acute and late GU toxicity than BRT or EBRT + BRT. Cancer 2009. © 2009 American Cancer Society.     

Histopathologic tumor response after induction chemotherapy and stereotactic body radiation therapy for borderline resectable pancreatic cancer

Background

While clinical outcomes following induction chemotherapy and stereotactic body radiation therapy (SBRT) have been reported for borderline resectable pancreatic cancer (BRPC) patients, pathologic response has not previously been described.

Methods

This single-institution retrospective review evaluated BRPC patients who completed induction gemcitabine-based chemotherapy followed by SBRT and surgical resection. Each surgical specimen was assigned two tumor regression grades (TRG), one using the College of American Pathologists (CAP) criteria and one using the MD Anderson Cancer Center (MDACC) criteria. Overall survival (OS) and progression free survival (PFS) were correlated to TRG score.

Results

We evaluated 36 patients with a median follow-up of 13.8 months (range, 6.1-24.8 months). The most common induction chemotherapy regimen (82%) was GTX (gemcitabine, docetaxel, capecitabine). A median SBRT dose of 35 Gy (range, 30-40 Gy) in 5 fractions was delivered to the region of vascular involvement. The margin-negative resection rate was 97.2%. Improved response according to MDACC grade trended towards superior PFS (P=061), but not OS. Any neoadjuvant treatment effect according to MDACC scoring (IIa-IV vs. I) was associated with improved OS and PFS (both P=0.019). We found no relationship between CAP score and OS or PFS.

Conclusions

These data suggest that the increased pathologic response after induction chemotherapy and SBRT is correlated with improved survival for BRPC patients.     

A prospective trial of stereotactic body radiation therapy for unresectable pancreatic cancer testing ablative doses

BackgroundWe explored the safety and efficacy of ablative doses of stereotactic body radiation therapy (SBRT) for unresectable pancreatic cancer.MethodsThis phase I/II trial included patients with unresectable pancreatic cancer previously treated with any number of cycles of induction chemotherapy. Patients were enrolled according to a 3+3 dose escalation design at 10, 12.5, and 15 Gy ×3, with subsequent patients at the maximally tolerated dose (MTD). Treatment was delivered to gross tumor delineated with MRI fusion using image-guidance to fiducial markers. Dose-limiting toxicity (DLT) was defined as grade 3+ toxicity within 30 days. Secondary endpoints included late gastrointestinal (GI) toxicity, freedom from local failure (FFLF), and survival.ResultsFifteen patients received a median 10 cycles of chemotherapy. There were no DLTs, and the MTD was 15 Gy ×3. Thirty-day toxicity included grade 2 nausea (46%) and grade 2 diarrhea (7%). Median survival after SBRT was 12.8 months (23 months after diagnosis) and median relapse-free survival was 7 months. At 1-year, FFLF was 80%. Four patients had grade 3+ GI bleeding after 30 days (median 6 months). Grade 3+ GI bleeding was associated with tumor volume (P=0.01), heterogeneity of dose within the planning target volume (PTV) (V120, P=0.03), and duodenal dose (V26–30 Gy, P<0.2).ConclusionsThis aggressive SBRT regimen demonstrated limited 30-day morbidity, a moderate degree of local control, and a moderate risk for late GI bleeding. Further work is necessary to define the most appropriate hypofractionated radiation therapy (RT) regimen in the ablative dose range.     

左侧乳腺癌保乳术后3种放疗技术在同步推量中的剂量学研究

目的 探讨左侧乳腺癌保乳术后半弧容积动态旋转调强(VMAT)放疗、切线弧VMAT放疗和逆向调强放疗(IMRT)3种放疗技术在同步推量中的剂量学差异.方法 选取10例左侧乳腺癌保乳术后患者,使用MONACO 5.1计划系统,分别采用半弧VMAT、切线弧VMAT和IMRT三种放疗技术,处方剂量均为计划靶区(PTV)50 Gy/25 f、计划肿瘤靶区(PGTV)60 Gy/25 f,评估3种计划靶区剂量适形度指数(CI)、均匀性指数(HI)以及周围正常组织器官的受照剂量.结果 半弧VMAT的PGTV靶区CI优于IMRT(P﹤0.05).切线弧VMAT放疗技术较IMRT放疗技术降低了左侧乳腺癌保乳术后患者患侧肺组织V10的照射范围(P=0.04).切线弧VMAT放疗技术较半弧VMAT放疗技术降低了左侧乳腺癌保乳术后患者健侧肺组织V5(P﹤0.001)、V10(P=0.04)、心脏的V10(P=0.01)、Dmean(P=0.01)及健侧乳腺组织V5(P﹤0.01)的剂量范围.而IMRT放疗技术降低了左侧乳腺癌保乳术后患者健侧肺组织V5、V10的剂量范围(P﹤0.05).结论 对于左侧乳腺癌保乳术后患者的同步推量放疗,VMAT放疗技术尤其是半弧VMAT放疗技术具有更好的靶区适形性;切线弧VMAT放疗技术可以降低周围大部分正常组织器官的照射剂量.     

调强放疗联合NP方案同步与序贯治疗中晚期非小细胞肺癌的疗效观察

Objective： To evaluate the clinical effects of concurrent and sequential therapy for middle and advanced stage non-small cell lung cancer （NSCLC） useing IMRT combined with NP regimen chemotherapy. Methods： Eighty patients with middle and advanced stage NSCLC were randomized into two groups. Forty patients were underwent sequential therapy and other 40 patients were underwent concurrent therapy. IMRT was used in radiotherapy and NP regimen of vinorelbine＋cispatin （NP） was used in chemotherapy. Results： （1） The overall response （CR＋PR） rate was 75% in concurrent group and 45% in sequential group （P〈0.05）; （2） The treatment courses were 84 days and 140 days for concurrent group and sequential group respectively （P〈0.05）; （3） One-year survival rate in concurrent group was 72.4% and 52.3% in sequential group respectively; （4） The toxic effects can be tolerable by all of patients. Conclusion： The concurrent chemo-radiotherapy has better overall response, one-year survival rate and shorter treatment course than the sequential chemo-radiotherapy, so it is a better method for the treatment of middle and advanced stage NSCLC, but the long term survival rate will be studied.     

The impact of dose escalation on secondary cancer risk after radiotherapy of prostate cancer

PURPOSE: To estimate secondary cancer risk due to dose escalation in patients treated for prostatic carcinoma with three-dimensional conformal radiotherapy (3D-CRT), intensity-modulated RT (IMRT), and spot-scanned proton RT. METHODS AND MATERIALS: The organ equivalent dose (OED) concept with a linear-exponential, a plateau, and a linear dose-response curve was applied to dose distributions of 23 patients who received RT of prostate cancer. Conformal RT was used in 7 patients, 8 patients received IMRT with 6- and 15-MV photons, and 8 patients were treated with spot-scanned protons. We applied target doses ranging from 70 Gy to 100 Gy. Cancer risk was estimated as a function of target dose and tumor control probability. RESULTS: At a 100-Gy target dose the secondary cancer risk relative to the 3D treatment plan at 70 Gy was +18.4% (15.0% for a plateau model, 22.3% for a linear model) for the 6-MV IMRT plan, +25.3% (17.0%, 14.1%) for the 15-MV IMRT plan, and -40.7% (-41.3%, -40.0%) for the spot-scanned protons. The increasing risk of developing a radiation-associated malignancy after RT with increasing dose was balanced by the enhanced cure rates at a larger dose. CONCLUSIONS: Cancer risk after dose escalation for prostate RT is expected to be equal to or lower than for conventional 3D treatment at 70 Gy, independent of treatment modality or dose-response model. Spot-scanned protons are the treatment of choice for dose escalation because this therapy can halve the risk of secondary cancers.     

The impact of starting dose with or without subsequent dose escalation of liposomal irinotecan on treatment outcomes in patients with metastatic pancreatic ductal adenocarcinoma

Liposomal irinotecan (nal-IRI) plus 5-fluorouracil and leucovorin (5-FU/LV) improves survival in patients with pancreatic ductal adenocarcinoma (PDAC) after progression to gemcitabine-based therapy. Few studies have examined whether the starting dose and dose escalation of nal-IRI in subsequent treatment cycles may influence patient outcomes and toxicity profiles. A total of 667 patients who received nal-IRI + 5-FU/LV for PDAC treatment between August 2018 and November 2020 at nine medical centers in Taiwan were included and retrospectively analyzed. Patients were allocated to the standard starting dose (SD), reduced starting dose (RD) without escalation, and RD with escalation of nal-IRI groups for comparison of survival outcome and safety. Propensity score matching (PSM) was performed to adjust for possible confounding variables. Nal-IRI was prescribed at SD, RD without escalation, and RD with escalation in 465 (69.7%), 147 (22.0), and 55 (8.2%), respectively. RD with escalation patients had significantly longer treatment cycles (6, range 2-25) than SD (5, range 1-42, P<0.001) and RD without escalation patients (4, range 1-26, P<0.001). The median overall survival (OS) of the patients were as follows: SD, 6.2 months (95% confidence interval [CI], 5.7-6.7); RD with escalation, 7.6 months (95% CI, 6.1-9.2); and RD without escalation, 3.6 months (95% CI, 2.6-4.5). After PSM to adjust for potential confounders, RD without escalation patients still had the poorest OS compared to the other two groups (P<0.001), while the OS difference between SD and RD with escalation patients was insignificant (P=0.10). SD patients had higher incidences of ≥ grade 3 neutropenia and febrile neutropenia than the other two groups. Administering nal-IRI at RD followed by dose escalation in subsequent treatment cycles is safe and does not compromise survival outcomes in selected patients with PDAC receiving nal-IRI plus 5-FU/LV.     

Increased organ sparing using shape-based treatment plan optimization for intensity modulated radiation therapy of pancreatic adenocarcinoma

Purpose

To develop a model to assess the quality of an IMRT treatment plan using data of prior patients with pancreatic adenocarcinoma.

Methods

The dose to an organ at risk (OAR) depends in large part on its orientation and distance to the planning target volume (PTV). A database of 33 previously treated patients with pancreatic cancer was queried to find patients with less favorable PTV-OAR configuration than a new case. The minimal achieved dose among the selected patients should also be achievable for the OAR of the new case. This way the achievable doses to the OARs of 25 randomly selected pancreas cancer patients were predicted. The patients were replanned to verify if the predicted dose could be achieved. The new plans were compared to their original clinical plans.

Results

The predicted doses were achieved within 1 and 2 Gy for more than 82% and 94% of the patients, respectively, and were a good approximation of the minimal achievable doses. The improvement after replanning was 1.4 Gy (range 0-4.6 Gy) and 1.7 Gy (range 0-6.3 Gy) for the mean dose to the liver and the kidneys, respectively, without compromising target coverage or increasing radiation dose to the bowel, cord or stomach.

Conclusions

The model could accurately predict the achievable doses, leading to a considerable decrease in dose to the OARs and an increase in treatment planning efficiency.     

Adjuvant radiation therapy for pancreatic cancer: a review of the old and the new

Surgery represents the only potential curative treatment option for patients diagnosed with pancreatic adenocarcinoma. Despite aggressive surgical management for patients deemed to be resectable, rates of local recurrence and/or distant metastases remain high, resulting in poor long-term outcomes. In an effort to reduce recurrence rates and improve survival for patients having undergone resection, adjuvant therapies (ATs) including chemotherapy and chemoradiation therapy (CRT) have been explored. While adjuvant chemotherapy has been shown to consistently improve outcomes, the data regarding adjuvant radiation therapy (RT) is mixed. Although the ability of radiation to improve local control has been demonstrated, it has not always led to improved survival outcomes for patients. Early trials are flawed in their utilization of sub-optimal radiation techniques, limiting their generalizability. Recent and ongoing trials incorporate more optimized RT approaches and seek to clarify its role in treatment strategies. At the same time novel radiation techniques such as intensity modulated RT (IMRT) and stereotactic body RT (SBRT) are under active investigation. It is hoped that these efforts will lead to improved disease-related outcomes while reducing toxicity rates.     

调强放疗联合NP方案同步与序贯治疗中晚期非小细胞肺癌的疗效观察

目的:比较调强放疗联合NP方案同步与序贯治疗中晚期非小细胞肺癌的临床疗效。方法:选择不能手术的中晚期非小细胞肺癌(NSCLC)患者80例,随机分成同步组和序贯组各40例。放疗采用调强放疗,化疗采用NP方案(盖诺 顺铂)。结果:(1)治疗总有效率比较(CR PR):同步组75·0%,序贯组45·0%,两组比较差异有显著性(P<0·05);(2)两组的总治疗时间比较:同步组平均84天,序贯组平均为140天,两组比较差异有显著性(P<0·05);(3)生存率(Kaplan-Meier法)比较:同步组1年生存率为72·4%,序贯组为52·3%,两组比较差异有显著性(P<0·05);(4)两组病人均能耐受治疗中的不良反应。结论:同步组的近期疗效明显优于序贯组,能提高患者的1年生存率,且能缩短住院周期,减轻患者的经济负担,但远期生存率的比较有待进一步观察。     

The impact of dose on parotid salivary recovery in head and neck cancer patients treated with radiation therapy

PURPOSE: A common side effect experienced by head and neck cancer patients after radiation therapy (RT) is impairment of the parotid glands' ability to produce saliva. Our purpose is to investigate the relationship between radiation dose and saliva changes in the 2 years after treatment. METHODS AND MATERIALS: The study population includes 142 patients treated with conformal or intensity-modulated radiotherapy. Saliva flow rates from 266 parotid glands are measured before and 1, 3, 6, 12, 18, and 24 months after treatment. Measurements are collected separately from each gland under both stimulated and unstimulated conditions. Bayesian nonlinear hierarchical models were developed and fit to the data. RESULTS: Parotids receiving higher radiation produce less saliva. The largest reduction is at 1-3 months after RT followed by gradual recovery. When mean doses are lower (e.g., <25 Gy), the model-predicted average stimulated saliva recovers to pretreatment levels at 12 months and exceeds it at 18 and 24 months. For higher doses (e.g., >30 Gy), the stimulated saliva does not return to original levels after 2 years. Without stimulation, at 24 months, the predicted saliva is 86% of pretreatment levels for 25 Gy and <31% for >40 Gy. We do not find evidence to support that the overproduction of stimulated saliva at 18 and 24 months after low dose in 1 parotid gland is the result of low saliva production from the other parotid gland. CONCLUSIONS: Saliva production is affected significantly by radiation, but with doses <25-30 Gy, recovery is substantial and returns to pretreatment levels 2 years after RT.     

Stereotactic body radiation therapy for the treatment of locally recurrent pancreatic cancer after surgical resection

BackgroundTo report on a cohort of radiation-naïve patients with pancreatic cancer who developed isolated local recurrence following surgical resection and were subsequently treated with stereotactic body radiation therapy (SBRT).MethodsPatients with pancreatic cancer who were treated with SBRT for isolated local recurrence after surgical resection were retrospectively reviewed. Clinical outcomes were calculated from completion of SBRT and included overall survival (OS), local progression-free survival (LPFS), distant metastasis-free survival (DMFS), and progression-free survival (PFS). Univariate (UVA) analysis was performed to identify variables associated with clinical outcomes. Kaplan-Meier method was used for survival outcomes. Toxicity was assessed using the Common Terminology Criteria for Adverse Events version 4.0.ResultsFrom September 2012 to November 2018, a total of 19 patients with localized pancreatic cancer were treated with SBRT for isolated local recurrence after initial surgical resection. No patients had prior radiation. The median biologically effective dose (BED₁₀) was 54.8 Gy (range, 37.5–54.8 Gy). Median OS was 17.1 months, with 6-month and 1-year OS rates of 94.4% and 69.6%, respectively. Nine patients (47.4%) developed local failure after SBRT. Pattern of first failure after SBRT was distant in 7 patients (46.7%), local in 5 patients (33.3%), and synchronous distant and local in 3 patients (20.0%). One patient developed local failure after developing distant disease first. Of the 9 local failures, 3 (33.3%) were out-of-field. Median LPFS was 22.2 months, with 6-month and 1-year LPFS rates of 86.9% and 63.2%, respectively. A BED₁₀ <54.8 Gy was associated with inferior LPFS (1-year, 25.0% vs. 80.2%, P<0.009). Median DMFS and PFS were 15.6 months. There was 1 case (5.3 %) of grade 3 gastric perforation. There were no cases of grade 4–5 toxicity events.ConclusionsSBRT for locally recurrent pancreatic cancer after initial curative resection is safe and feasible. A BED₁₀ <54.8 Gy was significantly associated with inferior local control. Further studies investigating dose escalation and optimal treatment volumes in the locally recurrent setting are warranted.     

Evaluation of intra- and inter-fraction movement of the cervix during intensity modulated radiation therapy

Background and purpose

To assess the degree of intra- and inter-fraction cervical motion throughout a course of intensity modulated radiation therapy (IMRT) for cervical cancer patients.

Materials and methods

A retrospective study of 10 women with stage 1B1-3B cervical cancer diagnosed from September 2007 to July 2008 was conducted. All patients were treated with chemoradiation using IMRT followed by intracavitary brachytherapy. Pretreatment, patients had 2 seeds placed at a depth of 10 mm into the cervix. On-Board Imaging (OBI) was used to obtain anterior/posterior (AP) and lateral X-rays before and after each treatment. OBI images were rigidly aligned to baseline digitally reconstructed radiographs (DRRs), and movement of cervical seeds was determined in the lateral, vertical, and AP directions. Mean differences in cervical seed position and standard error of the mean (SEM) were calculated.

Results

A total of 922 images were reviewed, with approximately 90 images per patient. The mean intra-fractional movement in cervical seed position in the lateral, vertical, and AP directions were 1.6 mm (SD ± 2.0), 2.6 mm (SD ± 2.4), and 2.9 mm (SD ± 2.7), respectively, with a range from 0 to 15 mm for each direction. The mean inter-fractional movement in the lateral, vertical, and AP directions were 1.9 mm (SD ± 1.9), 4.1 mm (SD ± 3.2), and 4.2 mm (SD ± 3.5), respectively, with a range from 0 to 18 mm for each direction.

Conclusions

This is the first study to assess intra- and inter-fractional movement of the cervix using daily imaging before and after each fraction. Within and between radiation treatments, cervical motion averages approximately 3 mm in any given direction. However, maximal movement of the cervix can be as far as 18 mm from baseline. This wide range of motion needs to be accounted for when generating planning treatment volumes.     

局限性前列腺癌调强适形放疗联合间歇性内分泌治疗的疗效评价

目的探讨调强适形放射治疗（intensity modulated radiation therapy,IMRT）联合间歇性内分泌治疗（intermittent hormonal therapy,IHT）方法治疗局限性前列腺癌的疗效评价。方法将72例同期局限性前列腺癌患者随机分为两组,分别进行调强适形放射治疗联合间歇性内分泌治疗（37例）和单纯调强适形放射治疗（35例）,分析比较两组患者的临床症状缓解率、前列腺体积变化、血清前列腺特异性抗原（PSA）值改变、肿瘤控制率、放疗不良反应发生率及生存率。结果随访5～118个月,平均56个月,联合治疗组与单纯治疗组比较,临床症状缓解率、前列腺体积差值、血清PSA〈0．2μg/L者所占比例及治疗后1年、3年、5年和8年的PSA无进展生存率差异均有统计学意义（P〈0．05）;治疗后1年、3年两组均无死亡病例,差异无统计学意义,治疗后5年、8年的生存率和早期放疗不良反应发生率两组间差异均有统计学意义（P〈0．05）。结论调强适形放射治疗联合间歇性内分泌治疗方法治疗局限性前列腺癌可明显缓解患者的临床症状,降低血清PSA水平,提高疾病控制率及生存率,降低放疗早期不良反应发生率,疗效优于单纯调强适形放射治疗,是一种安全、有效的治疗措施。