Applicator reconstruction in MRI 3D image-based dose planning of brachytherapy for cervical cancer

Background and purpose

To elaborate a method for applicator reconstruction for MRI-based brachytherapy for cervical cancer.

Materials and methods

Custom-made plastic catheters with a copper sulphate solution were made for insertion in the source channels of MR-CT compatible applicators: plastic and titanium tandem ring applicators, and titanium needles. The applicators were CT and MR scanned in a phantom for accurate 3D assessment of applicator visibility and geometry. A reconstruction method was developed and evaluated in 19 patient MR examinations with ring applicator (plastic: 14, titanium: 5). MR applicator reconstruction uncertainties related to inter-observer variation were evaluated.

Results

The catheters were visible in the plastic applicator on T1-weighted images in phantom and in 14/14 clinical applications. On T2-weighted images, the catheters appeared weaker but still visible in phantom and in 13/14 MR clinical applications. In the titanium applicator, the catheters could not be separated from the artifacts from the applicator itself. However, these artifacts could be used to localize both titanium ring applicator (5/5 clinical applications) and needles (6/6 clinical applications). Standard deviations of inter-observer differences were below 2 mm in all directions.

Conclusion

3D applicator reconstruction based on MR imaging could be performed for plastic and titanium applicators. Plastic applicators proved well to be suited for MRI-based reconstruction. For improved practicability of titanium applicator reconstruction, development of MR applicator markers is essential. Reconstruction of titanium applicator and needles at 1.5 T MR requires geometric evaluations in phantoms before using the applicator in patients.     

Direct reconstruction of the Vienna applicator on MR images

Purpose

To introduce and test a direct reconstruction concept for intracavitary tandem ring applicators in MR image-based brachytherapy treatment planning.

Materials and methods

Optical measurements of transparent ring-phantoms provided the geometric relation between source path and the Vienna ring applicator as visible on MRI. For the manual direct reconstruction method (PLATO), the geometry plotted on a transparency was placed on the screen and rotated to fit with visible ring holes. With the software-integrated reconstruction method (OncentraGYN), the applicator geometry was directly used when placing the visible parts of the applicator in the 3D dataset. Clinical feasibility was tested in 10 clinical insertions. Reconstruction and dose calculation were performed independently on two treatment planning systems (PLATO and OncentraGYN) using MRI alone. DVH parameters for targets and organs at risk were analysed and compared to the clinically used radiograph/MRI registration-based method.

Results

The direct reconstruction concept for both methods was feasible and reduced treatment planning time. Evaluated DVH parameters for plans using direct reconstruction methods differed from clinically used plans (traditional reconstruction) in mean differences ?0.2 Gy for plans with 7 Gy prescribed dose.

Conclusion

If the relation between applicator shape visible on MRI and the source path is defined once, the reconstruction process can be performed by directly placing the applicator in the MRI dataset.     

Applicator reconstruction and applicator shifts in 3D MR-based PDR brachytherapy of cervical cancer

Purpose

To evaluate the methods of applicator reconstruction in 3D MR-based planning for brachytherapy of cervical cancer, and to investigate applicator shifts and changes in DVH parameters during PDR treatment.

Methods

For each application MR scans with applicator in situ were made: three T2-weighted (4.5 mm slices) Turbo Spin Echo (TSE) scans and a balanced Steady State Free Precession scan (1.5 mm). Three observers tested two applicator reconstruction methods: (A) directly on the bSSFP scan and (B) on a resampled combination of the three T2-weighted scans. For 10 patients MR imaging was repeated on the second day of each PDR fraction to determine applicator shifts and changes in DVH parameters.

Results

For both applicator reconstruction methods the interobserver variation for the DVH parameters was comparable (average <1.5% in dose). Differences between the two methods were larger (up to 6.4% for target) and were related to position differences during MR scanning.The average applicator shift relative to the pelvic structures was 5-6 mm into the ventral direction and 3-4 mm cranially. For a single PDR fraction, the average D90 (HR-CTV) on ‘day 2’ was 0.2 (SD 2.0) Gy lower than that for day 1. The average increase in D_2cc (bladder) was 1.0 (SD 3.0) Gy_αβ3 for a single PDR fraction. If the effect of both fractions was combined, for 1 patient a total decrease of D90 of 7 Gy_αβ10 was found, whereas for another patient the total increase in bladder dose was 12 Gy_αβ3.

Conclusions

Applicator reconstruction on MR data is feasible. In the overall accuracy during PDR brachytherapy the reconstruction uncertainty is of minor importance. Applicator and/or organ movement during the course of the PDR fraction produce larger uncertainties.     

Time course of hypothalamic-pituitary deficiency in adults receiving cranial radiotherapy for primary extrasellar brain tumors

Background

No longitudinal data on hypothalamic-pituitary (HP) function are available in patients who had received cranial radiation therapy (CRT) for primary extrasellar brain tumors (PBT).

Purpose

To investigate the effects of CRT on HP function in adults with PBT.

Patients and methods

Twenty-six adults irradiated for PBT and six CRT naive controls were studied. CRT was delivered with 6 MV X-ray by a linear accelerator (2 Gy fraction schedule). Gross Tumor Volume (GTV) excluded the HP region that was contoured on the planning CT. Median dose to the HP region was 41.8 Gy (IQR: 30.7-49.8).

Results

All controls maintained normal HP function. Hypopituitarism developed in 38% of CRT patients (GH deficiency 29%, ACTH 22%, TSH 14%, gonadotropin 4%, no abnormal prolactin level or diabetes insipidus). All HP failures occurred within 32 months after CRT.

Conclusions

Adults undergoing CRT for PBT are at increased risk for HP dysfunction within 3 years from CRT. Endocrine surveillance is recommended also in adults patients exposed to CRT for primary brain tumors distant from HP region.     

Non-invasive modalities for predicting lymph node spread in early stage endometrial cancer?

Background

Lymph node status in EC determines the staging and has important prognostic and therapeutic implications.

Objectives

We have examined the diagnostic value of preoperative and intraoperative non-invasive methods to determine the lymph node status in endometrial cancer, or, indirectly, for identification of patients at increased risk of lymph node involvement.

Search strategy

We conducted a literature search to identify all relevant reports that evaluated lymph node spread in EC.

Selection criteria

Articles were only considered when data of investigational modalities were compared with histopathological findings of the surgical specimens, considered as the gold standard.

Data collection and analysis

When numerous relevant articles were identified for one investigational modality, only series including more than 50 patients were considered.

Main results

Sensitivity of CT and MRI for diagnosis metastatic lymph node is limited. TVS performs as well as MRI in predicting deep myometrial invasion. It is unclear whether intraoperative gross visual examination and frozen section perform better than preoperative methods to predict deep myometrial invasion. There is a limited sensitivity of intraoperative frozen section for predicting poorly differentiated EC.

Conclusion

Accurate non-invasive assessment of lymph node status in patients with EC remains challenging.

Synopsis

Despite imaging advances in the past 20 years, accurate non-invasive assessment of lymph node status in patients with EC remains challenging.     

Incidental findings on brain Magnetic Resonance Imaging in long-term survivors of breast cancer treated with adjuvant chemotherapy

Purpose

Incidental brain findings defined as previously undetected abnormalities of potential clinical relevance that are unexpectedly discovered at brain imaging and are unrelated to the purpose of the examination are common in the general population. Because it is unclear whether the prevalence of incidental findings in breast cancer patients treated with chemotherapy is different to that in the general population, we compared the prevalence in breast cancer survivors treated with chemotherapy to that in a population-based sample of women without a history of any cancer.

Patients and methods

Structural brain MRI (1.5T) was performed in 191 female CMF (Cyclophosphamide, Methotrexate, 5-Fluorouracil) chemotherapy-exposed breast cancer survivors. A reference group of 1590 women without a history of cancer was sampled from a population-based cohort study. All participants were aged 50 to 80 years. Five trained reviewers recorded the brain abnormalities. Two experienced neuro-radiologists reviewed the incidental findings.

Results

The cancer survivors had completed chemotherapy on average 21 years before. Of the 191 subjects, 2.6% had an aneurysm and 3.7% had a meningioma. The prevalence of meningiomas and aneurysms was not different between the groups. The prevalence of pituitary macro adenomas in the breast cancer survivors (1.6%) was higher than that in the reference group (0.1%) (OR = 23.7; 95% CI 2.3-245.8).

Conclusion

Contrary to commonly held opinions, we did not observe an increased prevalence of meningiomas in cancer survivors. Breast cancer survivors previously treated with chemotherapy are more likely to develop pituitary adenomas than persons without a history of cancer and chemotherapy treatment.     

Monte Carlo-based analytical model for small and variable fields delivered by TomoTherapy

Background and purpose

Extend to very small fields the validity of a Monte Carlo (MC) based model of TomoTherapy called TomoPen for future implementation of the dynamic jaws feature for helical TomoTherapy.

Materials and methods

First, the modelling of the electron source was revisited using a new method to measure source obscuration for very small fields (<1 cm). The method consisted in MC simulations simulations and measurements of the central dose in a water phantom for a 10 cm × FW field scanned to deliver a 10 × 10 cm² fluence. FW, the longitudinal field width, was varied from 0.4 to 5 cm. The second part of the work consisted of adapting TomoPen to account for any configuration of the jaws in a fast and efficient way by using routinely only the phase-space file of the largest field (5 cm) and interpolated analytical information of phase-space files of smaller field widths.

Results

For the electron source fine tuning, it was shown that the best results were obtained for a 1.1 mm wide spot. Our single phase-space method showed no significant differences compared to MC simulations of various field widths even though only longitudinal intensity and angular analytical functions were applied to the 5 cm phase-space.

Conclusion

The designed model is able to simulate all jaw openings from the 5 cm field phase-space file by applying a bi-dimensional analytical function accounting for the fluence and the angular distribution in the longitudinal direction.     

Intrafraction motion in patients with cervical cancer: The benefit of soft tissue registration using MRI

Background and purpose

During radiation delivery, target volumes change their position and shape due to intrafraction motion. The extent of these changes and the capability to correct for them will contribute to the benefit of an MRI-accelerator in terms of PTV margin reduction. Therefore, we investigated the primary CTV motion within a typical IMRT delivery time for cervical cancer patients for various correction techniques: no registration, rigid bony anatomy registration, and rigid soft tissue registration.

Materials and methods

Twenty-two patients underwent 2-3 offline MRI exams before and during their radiation treatment. Each MRI exam included four sagittal and four axial MRI scans alternately within 16 min. We addressed the CTV motion by comparing subsequent midsagittal CTV delineations and investigated the correlation with intrafraction bladder filling.

Results

The maximum (residual) motions within 16 min for all points on the CTV contour for 90% of the MRI exams without registration, with rigid bony anatomy registration, and with rigid soft tissue registration were 10.6, 9.9, and 4.0 mm. A significant but weak correlation was found between intrafraction bladder filling and CTV motion.

Conclusions

Considerable intrafraction CTV motion is observed in cervical cancer patients. Intrafraction MRI-guided soft tissue registration using an MRI-accelerator will correct for this motion.     

Validation of functional imaging with pathology for tumor delineation in the prostate

Introduction

A study was performed to validate magnetic resonance (MR) based prostate tumor delineations with pathology.

Material and methods

Five patients with biopsy proven prostate cancer underwent a T2 weighted (T2w), diffusion weighted MRI (DW-MRI) and dynamic contrast-enhanced MRI (DCE-MRI) scan before prostatectomy. Suspicious regions were delineated based on all available MR information. After prostatectomy whole-mount hematoxylin-eosin stained (H&E) sections were made. Tumor tissue was delineated on the H&E stained sections and compared with the MR based delineations. The registration accuracy between the MR images and H&E stained sections was estimated.

Results

A tumor coverage of 44-89% was reached by the MR based tumor delineations. The application of a margin of ∼5 mm to the MR based tumor delineations yielded a tumor coverage of 85-100% in all patients. Errors created during the registration procedure were 2-3 mm, which cannot completely explain the limited tumor coverage.

Conclusions

An accurate tissue processing and registration method was presented (registration error 2-3 mm), which enables the validation of MR based tumor delineations with pathology. Reasonable tumor coverage of about 85% and larger was found when applying a margin of ∼5 mm to the MR based tumor delineations.     

Impact of the prophylactic gastrostomy for unresectable squamous cell head and neck carcinomas treated with radio-chemotherapy on quality of life: Prospective randomized trial

Background and purpose

Concomitant radio-chemotherapy is the gold standard treatment for unresectable head and neck carcinomas. Placement of prophylactic gastrostomy has been proposed to provide adequate nutrition during the therapeutic sequence. The objectives of this study were to assess the impact of prophylactic gastrostomy on the 6-month quality of life, and to determine the factors related to this quality of life.

Materials and methods

Design. randomized, controlled, open study (“systematic percutaneous gastrostomy” versus “no systematic gastrostomy”). Patients. squamous cell head and neck carcinoma (stages III and IV, UICC 1997). Setting. oncological departments of French university teaching hospitals. Treatment. optimal concomitant radio-chemotherapy. Evaluations. T0 baseline evaluation, T1 during the treatment, T2 end of the treatment, and T3 6-month post-inclusion. Primary endpoint. 6-month quality of life (Qol) assessed using SF36, EORTC QLQ-C30, EORTC QLQ H&N35 questionnaires.

Results

The Qol changes from baseline included a decline (T1 and T2) followed by an improvement (T3). Qol at 6 months was significantly higher in the group receiving systematic prophylactic gastrostomy (p = 10⁻³). Higher initial BMI and lower initial Karnofsky index were significant factors related to a higher 6-month Qol.

Conclusions

The study results suggest that prophylactic gastrostomy improves post-treatment quality of life for unresectable head and neck cancer patients, after adjusting for other potential predictive quality of life factors.     

Economic evaluation of four follow-up strategies after curative treatment for breast cancer: results of an RCT

Background

An economic evaluation was performed alongside a randomised controlled trial (ISRCTN 74071417) investigating the cost-effectiveness of nurse-led telephone follow-up instead of hospital visits, and of a short educational group programme (EGP) in the first year after breast cancer treatment.

Method

This economic evaluation (n = 299) compared the one-year costs and the effects of four follow-up strategies: (1) hospital follow-up; (2) nurse-led telephone follow-up; (3) hospital follow-up plus EGP; and (4) nurse-led telephone follow-up plus EGP. Costs were measured using cost diaries and hospital registrations. Quality-adjusted life years (QALYs) were measured using the EQ-5D. Outcomes were expressed in incremental cost-effectiveness ratios (ICERs) and cost-effectiveness acceptability curves.

Results

Hospital follow-up plus EGP yielded most QALYs (0.776), but also incurred the highest mean annual costs (€4914). The ICER of this strategy versus the next best alternative, nurse-led telephone follow-up plus EGP (0.772 QALYs and €3971), amounted to €235.750/QALY. Hospital and telephone follow-up without EGP both incurred higher costs and less QALYs than telephone follow-up plus EGP and were judged inferior. Hospital follow-up plus EGP was not considered cost-effective, therefore, telephone follow-up plus EGP was the preferred strategy. The probability of telephone follow-up plus EGP being cost-effective ranged from 49% to 62% for different QALY threshold values. Secondary and sensitivity analyses showed that results were robust.

Conclusion

Nurse-led telephone follow-up plus EGP seems an appropriate and cost-effective alternative to hospital follow-up for breast cancer patients during their first year after treatment.     

Prognostic factors and oncologic outcome in 146 patients with colorectal peritoneal carcinomatosis treated with cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy: Italian multicenter study S.I.T.I.L.O.

Aim

The present study was specifically designed to assess the major clinical and pathological variables of patients with colorectal peritoneal carcinomatosis in order to investigate whether currently used criteria appropriately select candidates for peritonectomy procedures (cytoreductive surgery) combined with hyperthermic intraperitoneal chemotherapy (HIPEC).

Patients and methods

Preoperative, operative and follow-up data on 146 consecutive patients presenting with peritoneal carcinomatosis of colorectal origin and treated by surgical cytoreduction combined with HIPEC in 5 Italian Hospital and University Centers were prospectively entered in a common database. Univariate and multivariate analyses were used to assess the prognostic value of clinical and pathologic factors.

Results

Over a minimum 24-month follow-up, the overall morbidity rate was 27.4% (mortality rate: 2.7%) and was directly related to the extent of surgery. Peritoneal cancer index (PCI), unfavorable peritoneal sites, synchronous or previously resected liver metastasis and the completeness of cytoreduction, all emerged as independent prognostic factors correlated with survival.

Conclusions

Until research provides more effective criteria for selecting patients based upon the biomolecular features of carcinomatosis, patients should be selected according to the existing independent prognostic variables.     

Robotic system-based fractionated stereotactic radiotherapy in locally recurrent nasopharyngeal carcinoma

Purpose

We reviewed survival, local control, and toxicity in patients with locally recurrent nasopharyngeal carcinoma (NPC) who had been treated with fractionated stereotactic radiotherapy (FSRT).

Materials and methods

Between June 2002 and March 2008, we retrospectively reviewed 35 patients with locally recurrent NPC treated using FSRT with CyberKnife. Gross tumor volumes ranged from 2.6 to 64.0 ml (median, 7.9 ml). Radiation doses were prescribed at the isodose line (75-84% of the maximum dose; median, 80%). The prescribed dose of FSRT ranged from 24 to 45 Gy (median, 33 Gy) in three or five fractions.

Results

The overall survival (OS) rate, local failure-free survival (LFFS) rate, and disease progression-free survival (DPFS) rate at 5 years were 60%, 79%, and 74%, respectively. Twenty-three patients achieved complete response after FSRT. Only T stage at recurrence was an independent prognostic factor for OS and DPFS. Five patients exhibited severe late toxicity (Grade 4 or 5).

Conclusions

With regard to OS and LFFS, our study provided favorable outcomes. The incidence of severe late toxicities was acceptable in our study. FSRT would be considered as the alternative treatment of choice in re-irradiation for locally recurrent NPC.     

MRI before and after external beam intensity-modulated radiotherapy of patients with prostate cancer: The feasibility of monitoring of radiation-induced tissue changes using a dynamic contrast-enhanced inversion-prepared dual-contrast gradient echo sequence

Purpose

To identify and quantify suitable pharmacokinetic MRI parameters for monitoring tissue changes after external beam intensity-modulated radiotherapy of prostate cancer.

Material and methods

Six patients with biopsy-proven prostate cancer (initial PSA, 6.0-81.4 ng/ml) underwent MRI at 1.5 T using a combined endorectal/body phased-array coil and a dynamic contrast-enhanced inversion-prepared dual-contrast gradient echo sequence (T1/T2^∗w; 1.65 s temporal resolution). MRI was performed before and immediately after radiotherapy, at 3 months and at 1 year. Perfusion, blood volume, mean transit time, delay, dispersion, interstitial volume, and extraction coefficient were calculated in prostate cancer and normal prostate for all four time points using a sequential 3-compartment model.

Results

Prostate cancer and normal prostate tissue showed a statistically significant decrease in perfusion (p = 0.006, p = 0.001) and increase in extraction coefficient (p = 0.004, p < 0.001). For prostate cancer, there was also a decrease in vascular volume (p = 0.034). The other parameters investigated showed no statistically significant changes. Statistically significant differences between prostate cancer and normal prostate tissue were only observed before radiotherapy, when prostate cancer showed significantly higher perfusion (1.84 vs. 0.12 ml/cm³ min, p = 0.028) and a smaller extraction coefficient (0.42 vs. 0.64, p = 0.028).

Conclusions

Two pharmacokinetic parameters, perfusion and extraction coefficient, appear to be suitable candidates for monitoring the response to percutaneous intensity-modulated radiotherapy of prostate cancer.     

Comparative study of respiratory motion correction techniques in cone-beam computed tomography

Background and purpose

To validate the clinical usefulness of motion-compensated (MC) cone-beam (CB) computed tomography (CT) for image-guided radiotherapy (IGRT) in comparison to four-dimensional (4D) CBCT and three-dimensional (3D) CBCT.

Material and methods

Forty-eight stereotactic body radiation therapy (SBRT) patients were selected. Each patient had 5-12 long CB acquisitions (4 min) and 1-7 short CB acquisitions (1 min), with a total of 349 and 150 acquisitions, respectively. 3D, 4D and MC CBCT images of every acquisition were reconstructed. Image quality, tumor positioning accuracy and tumor motion amplitude were quantified.

Results

The mean image quality of long short acquisitions, measured using the correlation ratio with the planning CT, was 74%/70%, 67%/47% and 79%/74% for 3D, 4D and MC CBCT, respectively; both 4D and MC CBCT were corrected for respiratory motion artifacts but 4D CBCTs suffered from streak artifacts. Tumor positioning with MC CBCT was significantly closer to 4D CBCT than 3D CBCT (p < 0.0001). Detailed patient analysis showed that motion correction was not required for tumors with less than 1 cm motion amplitude.

Conclusions

4D and MC CBCT both allow accurate tumor position analysis under respiratory motion but 4D CBCT requires longer acquisition time than MC CBCT for adequate image quality. MC CBCT can therefore advantageously replace 4D CBCT in clinical protocols for patients with large motion to improve image quality and reduce acquisition time.     

Influence of body mass index on outcome in advanced colorectal cancer patients receiving chemotherapy with or without targeted therapy

Purpose

Obesity is associated with an increased risk of development and recurrence of colorectal cancer. However, the role of obesity in advanced colorectal cancer (ACC) patients is unknown. We investigated the effect of body mass index (BMI) on overall survival (OS) in ACC patients receiving systemic treatment in two large phase III studies (CAIRO and CAIRO2).

Patients and methods

Treatment data were obtained and analysed from 796 ACC patients who were treated with chemotherapy in the CAIRO study, and from 730 ACC patients who were treated with chemotherapy plus targeted therapy in the CAIRO2 study. Baseline height and weight were used to assign patients to one of the following BMI categories: A (<18.5 kg/m²), B (18.5-24.9 kg/m²), C (25.0-29.9 kg/m²) and D (?30.0 kg/m²).

Results

In 796 patients of the CAIRO study a high BMI was associated with better median OS (8.0, 14.9, 18.4 and 19.5 months for BMI categories A, B, C, and D, respectively; P = 0.001), and was an independent prognostic factor for OS in a multivariate analysis. BMI was not associated with OS in 730 patients who participated in the CAIRO2 study, although a trend was observed.

Conclusions

These results show that BMI is an independent prognostic factor for survival in patients receiving chemotherapy, but not in patients receiving chemotherapy and targeted therapy. The possible decreased efficacy of bevacizumab in obese patients may explain this discrepant result. The role of BMI in patients receiving targeted therapy should be further tested.     

HDR monotherapy for prostate cancer: A simulation study to determine the effect of catheter displacement on target coverage and normal tissue irradiation

Purpose

The aim of this study was to systematically analyse the effect of catheter displacements both on target coverage and normal tissue irradiation in fractionated high dose rate (HDR) prostate brachytherapy, using a simulation study, and to define tolerances for catheter displacement ensuring that both target coverage and normal tissue doses remain clinically acceptable. Besides the effect of total implant displacement, also displacements of catheters belonging to selected template rows only were evaluated in terms of target coverage and normal tissue dose, in order to analyse the change in dose distribution as a function of catheter dwell weight and catheter location.

Material and methods

Five representative implant geometries, with 17 catheters each, were selected. The clinical treatment plan was compared to treatment plans in which an entire implant displacement in caudal direction over 3, 5, 7 and 10 mm was simulated. Besides, treatment plans were simulated considering a displacement of either the central, most ventral or most dorsal catheter rows only, over 5 mm caudally.

Results

Due to displacement of the entire implant the target coverage drops below the tolerance of 93% for all displacements studied. The effect of displacement of the entire implant on organs at risk strongly depended on the patient anatomy; e.g., for 80% of the implant geometries the V₈₀ of the rectum exceeded its tolerance for all displacements. The effect of displacement of catheters belonging to selected template rows depended strongly on the relative weight of each catheter row when considering the target coverage and on its location when considering the dose in the organs at risk.

Conclusion

This study supports the need for a check of the catheter locations before each fraction and correction of deviations of the catheter position exceeding 3 mm.     

Prognostic value of the multidrug resistance transporter ABCG2 gene polymorphisms in Chinese patients with de novo acute leukaemia

Background

Functional polymorphisms of the ABCG2 gene may contribute to individual variability in drug response and the prognosis of patients.

Methods

In the present study, the genetic polymorphisms and expression of ABCG2 were analysed in blasts cells obtained from 184 Chinese patients with de novo acute leukaemia to investigate their possible association with clinical outcomes.

Results

A novel synonymous ABCG2-single nucleotide polymorphism (SNP) at exon 16 (13561218 C/T) and five known SNPs at exon 2 (13608835 G/A), exon 5 (13600044 C/A), intron 10 (13576005 C/T), intron 13 (13564503 C/T) and intron 14 (13563578 A/G) were identified with occurrence rates of 1.1%, 64.1%, 30.4%, 21.2%, 39.7% and 28.8%, respectively. We found that patients with the ABCG2 34GG genotype displayed longer disease free survival (DFS) (P < 0.001) and overall survival (OS) (P < 0.001) than those with the 34GA/AA genotypes. Furthermore, the DFS and OS were significantly diminished in bone marrow transplantation (BMT) patients with the 34GA/AA genotypes relative to those with the 34GG genotype.

Conclusions

These results suggest that these highly prevalent ABCG2 34GA/AA genotypes are associated with poor prognosis of Chinese patients with acute leukaemia and BMT patients.     

Reasons given by patients for participating, or not, in Phase 1 cancer trials

Background

Communication with patients contemplating Phase 1 cancer trial participation can be challenging. Controversy exists as to whether they are provided with sufficient information to give genuinely informed consent. We present data examining the reasons patients gave for trial entry.

Method

Following discussions with oncologists about Phase1 trials, participants completed a 19-item study specific ‘accept or decline measure’ exploring hope, expectations of benefit, altruism, concerns, and general perceptions of the trial information. They also completed 2 standardised questionnaires measuring psychological morbidity and predisposition towards optimism.

Results

Forty patients completed the study questionnaires. Patients were generally optimistic with few concerns about the experimental nature of Phase 1 trials. Most 36/40 (90%) consented to trial entry. Fifty-one percent thought the trial was the only treatment option available. The four main reasons for trial entry were: expectation of some medical benefit (21%); trial the best available option (21%); to maintain hope (15%) and to help with research (13%). Only one patient gave altruism as their main reason for trial participation.

Conclusion

Patients considering Phase 1 trials may be a self-selected group with optimistic expectations of personal benefit driving trial entry rather than altruism. Achieving genuinely informed consent and avoidance of therapeutic misconceptions in such patients may be difficult.     

Tumor volume discrepancies between FDG-PET and MRI for cervical cancer

Purpose

To compare the MRI-defined gross tumor volume (MR-GTV) to the metabolic tumor volume (Metabolic GTV) defined by FDG-PET in patients with cervical cancer.

Materials and methods

Forty seven patients with cervical cancer underwent FDG-PET/CT and MRI simulations. FDG-PET images were acquired with a spatial resolution of 5 mm. MR imaging was performed on a 1.5 Tesla scanner. MR-GTV was contoured on the T2 axial images while Metabolic GTV was auto-contoured using a 40% SUV threshold. Tumor volumes were compared.

Results

Eighteen patients (38.3%) had tumors ?62 cc on MRI. Seventeen patients (36.2%) had tumors ?14 and <62 cc, while 12 patients (25.5%) had tumors <14 cc. 83% of patients in the ?62 cc, 23.5% in the 14-62 cc, and 16.7% in the <14 cc cohort had Grade 3 images as defined by Dimopoulos et al. In the ?62 cc cohort, MR-GTV and Metabolic GTV had a lesion coverage factor of 0.68 (mean MR-GTV_vol 124.1, mean Metabolic GTV_vol 119.9 cc). This fell to 0.51 (32.4, 33.1 cc) for the 14-62 cc, and 0.28 (8.4, 8.7 cc) for the <14 cc cohort. These differences were statistically significant on ANOVA testing (p < 0.001).

Conclusions

MRI provided better visualization of larger tumors than smaller tumors in reference to FDG-PET/CT. FDG-PET/CT visualized tumor volumes different from T2-weighted MRI, especially in tumors <14 cc in regard to location.