Target volume motion during anal cancer image guided radiotherapy using cone-beam computed tomography

OBJECTIVE

Literature regarding image-guidance and interfractional motion of the anal canal (AC) during anal cancer radiotherapy is sparse. This study investigates interfractional AC motion during anal cancer radiotherapy.

METHODS

Bone matched cone beam CT (CBCT) images were acquired for 20 patients receiving anal cancer radiotherapy allowing population systematic and random error calculations. 12 were selected to investigate interfractional AC motion. Primary anal gross tumour volume and clinical target volume (CTVa) were contoured on each CBCT. CBCT CTVa volumes were compared to planning CTVa. CBCT CTVa volumes were combined into a CBCT-CTVa envelope for each patient. Maximum distortion between each orthogonal border of the planning CTVa and CBCT-CTVa envelope was measured. Frequency, volume and location of CBCT-CTVa envelope beyond the planning target volume (PTVa) was analysed.

RESULTS

Population systematic and random errors were 1 and 3 mm respectively. 112 CBCTs were analysed in the interfractional motion study. CTVa varied between each imaging session particularly T location patients of anorectal origin. CTVa border expansions ≥ 1 cm were seen inferiorly, anteriorly, posteriorly and left direction. The CBCT-CTVa envelope fell beyond the PTVa ≥ 50% imaging sessions (n = 5). Of these CBCT CTVa distortions beyond PTVa, 44% and 32% were in the upper and lower thirds of PTVa respectively.

CONCLUSION

The AC is susceptible to volume changes and shape deformations. Care must be taken when calculating or considering reducing the PTV margin to the anus. Advances in knowledge: Within a limited field of research, this study provides further knowledge of how the AC deforms during anal cancer radiotherapy.

Systemic chemotherapy (CT) as salvage treatment for locally advanced rectal cancer (LARC) patients (pts) who fail to respond to neoadjuvant chemoradiotherapy (CRT)

709

Background: International guidelines suggest that RT dose escalation, intraoperative RT or brachytherapy could be considered for LARC pts with positive resection margins, pT4 or unresectable tumours after standard neoadjuvant CRT. However, data to support these approaches are scarce. The potential of systemic CT as salvage treatment after failure of neoadjuvant CRT for LARC has never been explored. We conducted a single-centre, retrospective analysis to address this question. Methods: Pts with newly diagnosed rectal adenocarcinoma who were deemed inoperable or candidates for extensive (i.e. beyond total mesorectal excision, TME) surgery after completion of long-course RT and received salvage systemic CT were included. The primary objective was to estimate the proportion of pts who became potentially suitable for TME after CT. Secondary objectives included the proportion of pts who ultimately underwent TME and survival outcomes. Results: 45 pts (2001-2015) met the study inclusion criteria (39 candidates for extensive surgery and 6 with unresectable tumours). Previous RT was given concurrently with CT in 43 cases (median dose: 54.0 Gy; range: 34.0-55.8). Salvage oxaliplatin-based and irinotecan-based CT was administered in 40 (88.9%) and 5 (11.1%) cases, respectively. 8 pts (17.8%) became suitable for TME based on the MRI after CT, 10 (22.2%) ultimately underwent TME with clear margins and 2 (4.4%) were managed with a watch & wait approach following radiological clinical complete response. Additionally, 13 pts had a beyond-TME surgery with curative intent. 3-year progression-free survival and 5-year overall survival in the entire population were 30.0% (95% CI: 15.0-46.0) and 44.0% (95% CI: 26.0-61.0), respectively. For the curatively resected and watch & wait pts these figures were 52.0% (95% CI: 27.0-73.0) and 67.0% (95% CI: 40.0-84.0), respectively. Conclusions: Systemic CT may be an effective salvage strategy for LARC pts who fail to respond to long-course CRT and are inoperable or candidates for beyond-TME surgery. According to our study, 1 out of 4 pts may become resectable or being spared from an extensive surgery after systemic CT.

Proposed genitalia contouring guidelines in anal cancer intensity-modulated radiotherapy

OBJECTIVE

Intensity-modulated radiotherapy (IMRT) for anal canal carcinoma (ACC) is associated with favourable toxicity outcomes. Side effects include sexual dysfunction, skin desquamation, pain and fibrosis to perineum and genitalia region. The genitalia are situated anterior to the primary ACC between two inguinal regions providing a challenging structure to avoid. Techniques improving outcomes require robust, consistent genitalia contouring to ensure standardization and production of fully optimized IMRT plans. Official recommendations for genitalia contouring are lacking. We describe a potential genitalia contouring atlas for ACC radiotherapy.

METHODS

Following a review of genitalia CT anatomy, a contouring atlas was generated for male and female patients positioned prone and supine. Particular attention was paid to the reproducibility of the genitalia contour in all planes.

RESULTS

Male and female genitalia positioned prone and supine are described and represented visually through a contouring atlas. Contoured areas in males include penis and scrotum, and in females include clitoris, labia majora and minora. The muscles, bone, prostate, vagina, cervix and uterus should be excluded. The genitalia contour extends laterally to inguinal creases and includes areas of fat and skin anterior to the symphysis pubis for both genders.

CONCLUSION

This atlas provides descriptive and visual guidance enabling more consistent genitalia delineation for both genders when prone and supine. The atlas can be used for other sites requiring radiotherapy planning.

ADVANCES IN KNOWLEDGE

This atlas presents visual contouring guidance for genitalia in ACC radiotherapy for the first time. Contouring methods provide reproducible genitalia contours that allow the provision of accurate dose toxicity data in future studies.

Prognostic effect of a single nucleotide polymorphism (SNP) in MIR608 in patients with high-risk locally advanced rectal cancer (LARC): Results of the EXPERT-C trial

581

Background: An association between rs4919510, a SNP of mir-608, and prognosis of patients with colorectal cancer has been reported. However, no studies have analysed the role of this SNP in LARC. We conducted a pharmacogenomic analysis of rs4919510 in EXPERT-C, a randomised phase II trial of neoadjuvant CAPOX followed by chemoradiotherapy, surgery and adjuvant CAPOX ± cetuximab in high-risk LARC. Methods: SNP analysis was performed on DNA extracted from tumour tissue. Kaplan-Meier method and Cox regression analysis were used to calculate survival estimates and compare treatment arms. Results: A total of 155/164 (94.5%) patients had tumours assessable for rs4919510 genotyping. 95 (61.3%) were homozygous for CC, 55 (35.5%) heterozygous (CG) and 5 (3.2%) homozygous for GG with no deviation from the Hardy-Weinberg equilibrium (p=0.379). Genotypes were evenly distributed in the two treatment groups and no association with baseline clinico-pathological characteristics or tumour molecular status (including RAS) was observed. Complete response did not differ according to the tumour genotype in the entire population (14.7% for CC, 13.3% for CG/GG) and was not influenced by treatment (12.0% for CC and 14.3% for CG/GG in CAPOX, 17.8% for CC and 12.5% for CG/GG in CAPOX-C) (all p values>0.05). Median follow-up was 64.9 months. In the CAPOX arm the 5-yr PFS and OS rates were 54.6% and 60.7% for CC and 82.0% and 82.1% for CG/GG, respectively (HR PFS 0.13, 95% CI: 0.12-0.83, p=0.02, HR OS 0.38, 95% CI: 0.14-1.01, p=0.05). In the CAPOX-C arm the same survival figures were 73.2% and 82.2% for CC and 64.6% and 73.1% for CG/GG (HR PFS 1.38, 95% CI: 0.61-3.13, p=0.44, HR OS 1.34, 95% CI: 0.52-3.48, p=0.55). An interaction was found between study treatment and rs4919510 genotype for both PFS (p=0.02) and OS (p=0.07). Conclusions: This is the first study investigating rs4919510 in LARC. We found that the CC genotype was associated with worse prognosis compared to the CG/GG genotype in patients treated with chemotherapy alone but not in those treated with cetuximab. The addition of cetuximab to chemotherapy may mitigate the unfavourable prognostic associated with the CC genotype.

RAS mutations in EXPERT-C, a randomized phase II trial of neoadjuvant capecitabine and oxaliplatin (CAPOX) and chemoradiotherapy (CRT) with or without cetuximab (C) in MRI-defined, high-risk rectal cancer (RC)

489

Background: Studies indicate that RAS mutations beyond KRAS exons 2-3 may predict anti-EGFRs benefit. EXPERT-C was a randomized phase II trial of neoadjuvant CAPOX and CRT ± C in MRI-defined, high-risk RC. We have previously shown that adding C in KRAS (exons 2-3)/BRAF wild type (WT) patients did not improve complete response (CR) and was associated with a non-significant improvement in progression-free survival (PFS) (HR 0.62, p=0.23) and overall survival (OS) (HR 0.56, p=0.20). The aim of this study was to analyse the impact of RAS mutations on the outcome of C-treated patients in this trial. Methods: Between October 2005 and July 2008, 164 eligible patients were randomly assigned to 4 cycles of CAPOX followed by CRT, surgery, and 4 cycles of adjuvant CAPOX (n=81) or the same regimen plus C (CAPOX-C, n=83). KRAS (exons 2-3) and NRAS (exon 3) mutations were prospectively analysed. Of 90 KRAS/NRAS WT patients, 84 were retrospectively analysed for additional KRAS (exon 4) and NRAS (exons 2/4) mutations by using bi-directional Sanger sequencing. The effect of C on CR, PFS, and OS in patients with RAS WT tumors was analyzed. PFS and OS were estimated with the Kaplan-Meier method and treatment arms compared using a log-rank analysis. Results: Eleven (13%) of 84 patients initially classified as KRAS/NRAS WT were found to have tumours harbouring a mutation in KRAS exon 4 (11%) or NRAS exons 2/4 (2%). Overall, after this retrospective mutation analysis, 78/149 (52%) assessable patients were RAS WT (CAPOX, n=40; CAPOX-C, n=38). After a median follow-up of 63.8 months, in line with the initial analysis, the addition of C in the group of RAS WT patients, was associated with numerically higher, but not statistically significant, rates of CR (15.8% vs. 7.5%, p=0.31), 5-year PFS (78.4% vs. 67.5%, p=0.17) and 5-year OS (83.8% vs. 70%, p=0.20). Conclusions: Although the results of our analysis are potentially affected by the small numbers, in our locally advanced RC population the status of RAS did not appear to significantly improve the selection of patients who may benefit from the use of an anti-EGFR therapy.

Relationship of RAS and TP53 predictive value for cetuximab (C) benefit: Results of the EXPERT-C trial

447

Background: We previously reported that TP53 status may predict C benefit in patients with locally advanced rectal cancer treated with neoadjuvant chemotherapy and chemoradiotherapy (CRT) and this effect appeared to be independent of KRAS. Recent studies indicate that NRAS mutations and KRAS mutations beyond exons 2-3 may also preclude benefit from anti-EGFRs. We analyzed whether the predictive value of TP53 in EXPERT-C was independent of RAS. Methods: 164 patients received 4 cycles of CAPOX followed by CRT, surgery, and 4 cycles of adjuvant CAPOX (n=81) or the same regimen plus C (CAPOX-C, n=83) and were analyzed for KRAS (exons 2-3) and NRAS (exon 3). TP53 mutations (exons 4-9) were screened for by CE-SSCA. KRAS (exon 4) and NRAS (exons 2 and 4) mutations were screened for by bi-directional Sanger sequencing. Progression-free survival (PFS) and overall survival (OS) were estimated with Kaplan-Meier methods and log-rank analysis was used to compare the treatment arms. The interaction between treatment and TP53 was adjusted for prognostic variables and RAS in a multivariate model. Results: 75/144 (52%) eligible patients had a TP53 mutation. 81/86 patients with known KRAS (exons 2-3) and NRAS (exon 3) wild-type (WT) status were analyzed for the remaining RAS mutations. Of these, 11 (13%) had tumours with mutation in KRAS exon 4 (11%) or NRAS exons 2/4 (2%). Overall, 75/144 (52%) patients were RAS WT (CAPOX, n=39; CAPOX-C, n=36). After a median follow-up of 65 months, no difference in PFS (HR 1.21, p=0.59) and OS (HR 0.97, p=0.94) was observed between TP53 mutant patients treated with CAPOX or CAPOX-C. In TP53 WT patients, the addition of C was associated with a statistically significant improvement in PFS (HR 0.23, p=0.02) and OS (HR 0.16, p=0.02). A significant interaction between TP53 status and C effect was found (PFS, p=0.029; OS, p=0.036). In multivariate analyses, this interaction remained significant even after adjusting for RAS status (PFS, p=0.026; OS, p=0.033). Conclusions: In EXPERT-C, the value of TP53 as predictive biomarker for C benefit was independent of RAS. The value of monoallelic vs. biallelic TP53 inactivation will be presented at the meeting.

Magnetic resonance imaging defined mucinous rectal carcinoma is an independent imaging biomarker for poor prognosis and poor response to preoperative chemoradiotherapy

INTRODUCTION

Mucinous adenocarcinomas represent a potentially poor prognostic subgroup identifiable by imaging. We compared outcomes between magnetic resonance imaging (MRI) detected rectal mucinous carcinoma and adenocarcinomas. The diagnostic performance of MRI compared with initial biopsy in detecting mucinous adenocarcinoma was also assessed.

METHODS

The proportion of patients downstaged in the mrMucinous and adenocarcinoma groups was compared. Cox proportional hazard models were used to test independence of mucinous status and baseline MRI and clinical variables on survival. Differences in survival for mucinous versus non-mucinous tumours were tested for significance using the Mantel-Cox log rank test.

RESULTS

60/330 (18%) patients were correctly diagnosed with mucinous rectal cancer based on pre treatment MRI compared with 15/330 (5%) on initial biopsy (diagnostic odds ratio=4.67, p<0.05). All 60 (100%) patients undergoing surgery for mrMucinous tumours were confirmed as such on final histopathology. Significantly fewer mrMucinous tumours showed ypT downstaging when compared with non-mucinous tumours (14/60 (23%) versus 111/270 (40%), p=0.01). Three-year survival outcomes for patients for MRI detected mucinous tumours were significantly worse: disease free survival (DFS) was 48% versus 71%, p=0.006 and OS was 69% versus 79% p=0.04. MRI Mucin was an independent variable for poor DFS (hazard ratios (HR)) 0.58 95% Confidence interval (CI) 0.38-0.89).

CONCLUSIONS

MRI diagnosis of mucinous adenocarcinoma is diagnostically superior to preoperative biopsy and occurs in up to 20% of rectal cancer patients. It is an independent imaging biomarker for response to preoperative chemoradiotherapy (CRT) and prognosis. MRI documentation of mucinous status will enable future pursuit of treatment strategies in this poor prognostic subgroup.

Chemoradiotherapy response in recurrent rectal cancer

The efficacy of response to preoperative chemoradiotherapy (CRT) in recurrent versus primary rectal cancer has not been investigated. We compared radiological downsizing between primary and recurrent rectal cancers following CRT and determined the optimal size reduction threshold for response validated by survival outcomes. The proportional change in tumor length for primary and recurrent rectal cancers following CRT was compared using the independent sample t-test. Overall survival (OS) was calculated using the Kaplan–Meier product limit method and differences between survival for tumor size reduction thresholds of 30% (response evaluation criteria in solid tumors [RECIST]), 40%, and 50% after CRT in primary and recurrent rectal cancer groups. A total of 385 patients undergoing CRT were analyzed, 99 with recurrent rectal cancer and 286 with primary rectal cancer. The mean proportional reduction in maximum craniocaudal length was significantly higher for primary rectal tumors (33%) compared with recurrent rectal cancer (11%) (P < 0.01). There was no difference in OS for either primary or recurrent rectal cancer when ≤30% or ≤40% definitions were used. However, for both primary and recurrent tumors, significant differences in median 3-year OS were observed when a RECIST cut-off of 50% was used. OS was 99% versus 77% in primary and 100% versus 42% in recurrent rectal cancer (P = 0.002 and P = 0.03, respectively). Only patients that demonstrated >50% size reduction showed a survival benefit. Recurrent rectal cancer appears radioresistant compared with primary tumors for tumor size after CRT. Further investigation into improving/intensifying chemotherapy and radiotherapy for locally recurrent rectal cancer is justified.

The impact of TP53 mutation on high-risk rectal cancer patients treated within the EXPERT-C trial, a randomized phase II study of neoadjuvant oxaliplatin/capecitabine (CAPOX) and chemoradiation (CRT) with or without cetuximab

e14088

Background: The EXPERT-C trial randomised 165 patients into neoadjuvant CAPOX and CRT ± cetuximab and demonstrated a significant increase in radiological response (RR) and overall survival (OS) with cetuximab in KRAS/BRAF wild type (WT) rectal cancer (Dewdney et al JCO in press). TP53 mutation has been associated with worse CRT response and survival in rectal cancer and could lead to stimulation of PI3K signalling pathway, thus potential resistance to cetuximab. This analysis evaluates the impact of TP53 mutation in the EXPERT-C trial. Methods: FFPE tissue from biopsy (n=102) and resection specimens (n=99) were analysed for TP53 mutations (exons 5-8) using a multiplex PCR method followed by direct sequencing. If discordant results were encountered on paired biopsy and resection samples, analyses were repeated. Results: 53/102 (52%) biopsy and 24/99 (24%) resection samples harboured TP53 mutation, most commonly missense in exons 5 and 7. The vast majority had single TP53 mutations, only 4/53 biopsy and 1/24 resection samples had 2 mutations. 21/55 (38%) paired samples demonstrated discordant TP53 mutation status. In both all-treated and KRAS WT populations, presence of TP53 mutation had no impact on RR to neoadjuvant chemotherapy or CRT, regardless of treatment arm. A trend towards worse progression-free (PFS) (HR: 2.68; 95% CI: 0.85 - 8.43; p=0.08) and OS (HR: 4.04; 95% CI: 0.86 - 19.11; p=0.056) was observed in patients with TP53 mutation when treated with cetuximab, independent of the KRAS status. Conclusions: TP53 mutations were common in high-risk rectal cancer patients, the lower mutation rate in the resection samples was potentially due to lower tumour volume post CRT. The presence of a TP53 mutation at baseline had no impact on RR to treatment, however a trend towards worse PFS and OS was observed with the addition of cetuximab, consistent with the perceived biology.

Primary staging and response assessment postchemoradiotherapy in rectal cancer

SUMMARY Initial assessment of newly diagnosed patients with rectal cancer includes clinical examination, colonoscopy, pelvic MRI and CT scan of the thorax, abdomen and pelvis. Radiological staging can objectively evaluate both surgical and biological prognostic features of rectal cancer. MRI has emerged to be the most useful preoperative prognostic staging tool and it can predict the risk of tumor involvement of surgical circumferential resection margin. An agreed definition of favorable tumor response to chemoradiotherapy is controversial. The importance of detecting and assessing good versus poor responders to chemoradiotherapy is of increasing relevance. MRI has been found to be useful in assessing tumor response postchemoradiotherapy, especially the assessment of potential circumferential resection margin and magnetic resonance tumor regression grade. These imaging markers predict survival outcomes for good and poor responders and provide an opportunity for clinicians to offer additional neoadjuvant and adjuvant treatments to reduce local or distance failure for the poor responders.

Use of MRI-defined tumor distance from the anal verge to predict tumor response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer

573

Background: Neoadjuvant Chemoradiotherapy (CRT) and surgical resection is the current standard management for patients with locally advanced rectal cancer (i.e. T3 or 4 N0/1 M0) (LARC). Tumour predictive factors for response to CRT in rectal cancer remain controversial. Staging investigations are not standardised and MRI has not been used consistently to approach this. The aim of this study is to investigate whether tumour distance from anal verge, as measured on MRI, is a predictive factor for response to CRT in LARC.

Methods: This is a retrospective study. Patients with LARC or low T2 N0/1 M0 rectal cancer (i.e. ≤ 5cm from anal verge measured by MRI) treated with preoperative CRT in 2003- 2009 were included. Pelvic MRIs acquired before CRT and no less than 4 weeks post CRT were reviewed. Patients with ypT0-2 in the resected specimen were classified as responders because ypT0-2 has been shown with significant OS and DFS benefit (Valentini V et al. Int J Radiat Oncol Biol Phys. 2002; 53(3): 664-74). Downstage of mrT2 low rectal cancer was defined as ypT0-1 post CRT. Univariate binary logistic regression (UBLR) was used to analyse the predictor associated between responders and non-responders to CRT treated in the same period of time.

Results: 281 patients with LARC who underwent CRT were included in the study. 96% patients in this study had T3/T4 LARC and 4% had T2 low rectal cancer. 114 (41%) were responders as defined above, 167 (59%) were non-responders to CRT. The mean MRI defined tumour distance from anal verge was significantly less in responders (6.4cm [Confidence Intervals (CI) = 5.7 -7.1]) when compared with non-responders (7.9cm [CI =7.3 – 8.6]) (P<0.05).

Conclusions: The UBLR analysis from our study indicated that an MRI measured tumour distance of ≤ 5cm from the anal verge independently predicted higher tumour downstaging rate (p < 0.001) to CRT in LARC. Further investigation is recommended regarding tumour downstaging and sphincter preserving surgical resection rate in low rectal cancer post neoadjuvant CRT.

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Does phase I radiotherapy dose of 30.6Gy in 17 fractions provide adequate microscopic nodal disease control in squamous cell carcinoma of the anus?

588

Background: Definitive chemoradiation has been established as the standard of care for patients with squamous cell carcinoma of the anus. The ACT II study recommends 30.6Gy in 17 fractions for Phase I to the lower pelvis with a superior border 2 cm above the inferior aspect of the sacro-illiac joints, then a Phase II boost of 19.8Gy in 11 fractions to the tumor and involved nodes. Our goal was to retrospectively evaluate patterns of failure in the volumes that received microscopic dose 30.6Gy.

Methods: Between January 2002 and December 2008, 106 patients with non-metastatic squamous cell carcinoma of the anus were treated with definitive chemoradiation. 81 (76.45%) of these patients received Phase I dose of 30.6Gy.The tumor stage was Tx or T1 in 18 % , T2 in 36% , T3 in 29%, and T4 in 12% of patients. The nodal stage was N0 in 57%, N1 in 13%, N2 in 14% and N3 in 11% of patients. The median radiotherapy dose was 50.4 Gy (range 50.4Gy -60 Gy). Concurrent chemotherapy was given with 5-fluorouracil (5-FU) and cisplatin in 12%, 5-FU and mitomycin C in 34%, capecitabine and mitomycin C in 38% and other regimens in 8% of patients. The median follow-up interval was 43 months (range 3.2 - 112.9 months).

Results: A total of 21 patients (19.8%) experienced persistent or progressive disease during follow up. Out of this total, 16 patients received 30.6Gy in Phase I. Of these, 5 patients (4.7%) had persistent disease at the end of chemo-radiation, 4 patients (3.7%) relapsed in the anal region, 2 patients (2.4%) relapsed in the 30.6Gy area and 5 patients (6.2%) developed metastases. 8 patients with local recurrence/persistent disease underwent salvage surgery. Estimated 3 year rates for locoregional control and overall survival were 78% and 82% respectively.

Conclusions: The majority of locoregional failures involve the anus and mesorectum, while nodal recurrence occurs rarely supporting the use of 30.6Gy for microscopic nodal disease control. This makes the case for dose escalation of primary tumours in Phase II. Placing the superior border of the radiotherapy field at 2 cm above inferior sacroiliac joints for phase I could potentially spare bone marrow and small bowel toxicity with minimal risk of nodal relapse.

Cone beam CT verification for oesophageal cancer - impact of volume selected for image registration

PURPOSE

Oesophageal cancers are difficult to visualise on volumetric imaging and reliable surrogate are needed for accurate tumour registration. The aim of this investigation is to evaluate the effect of a user defined volume with automated registration techniques using commercially available software with the on-board volumetric imaging for treatment verification of oesophageal cancer and determine the optimum location of this volume.

MATERIAL AND METHODS

In 20 patients four 'clipbox'(C) volumes were defined: C-planning target volume (PTV), C-carina, C-vertebrae, C-thorax. The set-up corrections (translational and rotational) for C-PTV were compared to the corrections using C-carina, C-vertebrae and C-thorax.

RESULTS

Six hundred and eight registrations were performed. The best concordance in set-up corrections was found in the superior/inferior direction between C-PTV and C-carina (76%). In the right/left and anterior/posterior direction, better agreement was found between C-PTV and C-thorax with 80% and 76% agreement, respectively. Automatic 'bone' registration using C-vertebrae failed in 28% of scans. The correlation ratio between C-PTV and C-carina (n = 4) for mid-oesophageal tumours was 0.88, 0.79, and 0.95 in the right/left, superior/inferior and anterior/posterior directions, respectively.

CONCLUSION

The defined volume for matching is important for oesophageal tumours. The alignment 'clipbox' and registration method selected can affect the displacements obtained. This may best be determined by tumour location and highlights the need to diversify protocols within one tumour treatment site. Further analysis is required to validate carina as a tumour surrogate for mid-oesophageal tumours.

Volumetric modulated arc therapy planning for distal oesophageal malignancies

OBJECTIVES

Volumetric modulated arc therapy (VMAT) is a novel form of intensity-modulated radiation therapy that allows the radiation dose to be delivered in a single gantry rotation using conformal or modulated fields. The capability of VMAT to reduce heart and cord dose, while maintaining lung receiving 20 Gy <20%, was evaluated for chemoradiation for oesophageal cancer.

METHODS

An optimised forward-planned four-field arrangement was compared with inverse-planned coplanar VMAT arcs with 35 control points for 10 patients with lower gastro-oesophageal tumours prescribed 54 Gy in 30 fractions. Conformal (cARC) and intensity-modulated (VMATi) arcs were considered. Plans were assessed and compared using the planning target volume (PTV) irradiated to 95% of the prescription dose (V95), volumes of lung irradiated to 20 Gy (V20), heart irradiated to 30 Gy (V30), spinal cord maximum dose and van't Riet conformation number (CN). The monitor units per fraction and delivery time were recorded for a single representative plan.

RESULTS

VMATi provided a significant reduction in the heart V30 (31% vs 55%; p=0.02) with better CN (0.72 vs 0.65; p=0.01) than the conformal plan. The treatment delivery was 1 min 28 s for VMAT compared with 3 min 15 s.

CONCLUSION

For similar PTV coverage, VMATi delivers a lower dose to organs at risk than conformal plans in a shorter time, and this has warranted clinical implementation.

Set-up errors in radiotherapy for oesophageal cancers--is electronic portal imaging or conebeam more accurate?

PURPOSE

To compare kV computed tomography (CBCT) with electronic portal imaging (EPI) and evaluate set-up variations in the anterior-posterior (AP), right-left (LR) and cranio-caudal (CC) directions and rotational variations: pitch, roll, and yaw, for oesophageal cancer patients treated with radical radiotherapy.

METHODS AND MATERIALS

Twenty patients with locally advanced oesophageal cancer treated with chemoradiation were consented for this prospective ethics approved protocol. Patients were positioned using skin marks/tattoos, kV-CBCT scans (XVI) and EPI's were performed prior to treatment and registered to the planning CT scans and digitally reconstructed radiographs, respectively. XVI data was used to adjust patient setups before treatment delivery. A total of 122 EPI pairs and 207 CBCT scans were analysed. The systematic and random errors were calculated.

RESULTS

The systematic and random errors (mm) for XVI were 1.3, 1.7, 1.4 and 2.6, 3.9, 2.0 in RL, CC and AP direction, respectively, with EPI of similar magnitude. There was no correlation between the 2 modalities of imaging as 31.7% of all image pairs were discordant >3 mm and 12.5% >5 mm. XVI identified rotations >3° in 44 images.

CONCLUSIONS

EPI results in different position correction for verification of radiotherapy in oesophageal malignancies when compared with CBCT. CBCT verification offers adequate 3D volumetric image quality to improve the accuracy of treatment delivery for oesophageal malignancies in radiotherapy and should be used for image guidance.

The effect of treatment position, prone or supine, on dose-volume histograms for pelvic radiotherapy in patients with rectal cancer

Patients undergoing radiotherapy for rectal cancer are generally treated in a prone position, with a full bladder, to reduce the volume of normal bowel in the high-dose volume. This position is difficult to maintain, and is not consistently reproducible. This study evaluates the volume of bowel and dose received in the prone and supine positions in patients undergoing pre-operative rectal cancer chemoradiation. Using CT planning, 19 consecutive patients with rectal cancer with a full bladder underwent CT scanning first in the prone position and then immediately afterwards in the supine position. The planning target volume was outlined for the prone position and transcribed to the supine scan using pre-set criteria. The bladder and small bowel were outlined in both positions. Radiotherapy was planned using three-dimensional conformal planning, and treatment was delivered using three fields with multileaf collimators in two phases: phase I, pelvis 45 Gy/25 fractions; and phase II, tumour 9 Gy/five fractions. For both positions, the volume of bowel receiving doses in 5 Gy increments from 5-45 Gy was calculated using dose-volume histograms. At 5 Gy and 10 Gy dose levels, a significantly higher volume of bowel was irradiated in the supine position (p<0.001). At 15 Gy, it was marginally significant (p = 0.018). From 20-45 Gy, there was no significant difference in the volume of bowel irradiated with each 5 Gy increment. This study demonstrates that the volume of bowel irradiated at doses associated with bowel toxicity in concurrent chemoradiation is not significantly higher in the supine position. This position could be adopted for patients undergoing pre-operative rectal cancer chemoradiation.

MR vs CT imaging: low rectal cancer tumour delineation for three-dimensional conformal radiotherapy

Modern three-dimentional radiotherapy is based upon CT. For rectal cancer, this relies upon target definition on CT, which is not the optimal imaging modality. The major limitation of CT is its low inherent contrast resolution. Targets defined by MRI could facilitate smaller, more accurate, tumour volumes than CT. Our study reviewed imaging and planning data for 10 patients with locally advanced low rectal cancer (defined as < 6 cm from the anal verge on digital examination). Tumour volume and location were compared for sagittal pre-treatment MRI and planning CT. CT consistently overestimated all tumour radiological parameters. Estimates of tumour volume, tumour length and height of proximal tumour from the anal verge were larger on planning CT than on MRI (p < 0.05). Tumour volumes defined on MRI are smaller, shorter and more distal from the anal sphincter than CT-based volumes. For radiotherapy planning, this may result in smaller treatment volumes, which could lead to a reduction in dose to organs at risk and facilitate dose escalation.

Non-operative treatment after neoadjuvant chemoradiotherapy for rectal cancer

The past decade has seen pronounced changes in the treatment of locally advanced rectal cancer. Historically, the standard of care involved surgery followed by adjuvant radiotherapy or chemoradiotherapy. More recently, the emergence of neo-adjuvant chemoradiotherapy has fundamentally changed the management of patients with locally advanced disease. In clinical trials, pathological complete responses of up to 25% have raised the question as to whether surgery can be avoided in a select cohort of patients. A trial of omission of surgery for selected patients with complete response after preoperative chemoradiotherapy has shown favourable long-term results. In this article, we outline emerging factors for achieving pathological complete response, non-operative strategies to date, methods for prediction of response to chemoradiotherapy, and future directions with the addition of MRI as a radiological guide to complete response.

Intensity-modulated radiotherapy in patients with locally advanced rectal cancer reduces volume of bowel treated to high dose levels

PURPOSE

To investigate the potential for intensity-modulated radiotherapy (IMRT) to spare the bowel in rectal tumors.

METHODS AND MATERIALS

The targets (pelvic nodal and rectal volumes), bowel, and bladder were outlined in 5 patients. All had conventional, three-dimensional conformal RT and forward-planned multisegment three-field IMRT plans compared with inverse-planned simultaneous integrated boost nine-field equally spaced IMRT plans. Equally spaced seven-field and five-field and five-field, customized, segmented IMRT plans were also evaluated.

RESULTS

Ninety-five percent of the prescribed dose covered at least 95% of both planning target volumes using all but the conventional plan (mean primary and pelvic planning target volume receiving 95% of the prescribed dose was 32.8 +/- 13.7 Gy and 23.7 +/- 4.87 Gy, respectively), reflecting a significant lack of coverage. The three-field forward planned IMRT plans reduced the volume of bowel irradiated to 45 Gy and 50 Gy by 26% +/- 16% and 42% +/- 27% compared with three-dimensional conformal RT. Additional reductions to 69 +/- 51 cm(3) to 45 Gy and 20 +/- 21 cm(3) to 50 Gy were obtained with the nine-field equally spaced IMRT plans-64% +/- 11% and 64% +/- 20% reductions compared with three-dimensional conformal RT. Reducing the number of beams and customizing the angles for the five-field equally spaced IMRT plan did not significantly reduce bowel sparing.

CONCLUSION

The bowel volume irradiated to 45 Gy and 50 Gy was significantly reduced with IMRT, which could potentially lead to less bowel toxicity. Reducing the number of beams did not reduce bowel sparing and the five-field customized segmented IMRT plan is a reasonable technique to be tested in clinical trials.

Consent for Investigating and Treating Adults with Cancer

The importance of the consenting process, as a key activity in patient care, has been recognised by the Department of Health with the production of a policy aimed at ensuring patient focused national standards. Cancer treatments are complex and multi-disciplinary encompassing difficult issues around outcomes and toxicity. This article looks at the process within the UK Cancer network and addresses some of the situations which occur in clinical practice. Examples of difficult scenarios are given to illustrate the application of the basic principles.

Impact of radiotherapy parameters on outcome in the International Society of Paediatric Oncology/United Kingdom Children's Cancer Study Group PNET-3 study of preradiotherapy chemotherapy for M0-M1 medulloblastoma

PURPOSE

To analyze the impact of radiotherapy (RT) parameters on outcome in a randomized study of pre-RT chemotherapy for M0-M1 medulloblastoma.

METHODS AND MATERIALS

Patients were randomized to RT alone or RT preceded by chemotherapy with vincristine, etoposide, carboplatin, and cyclophosphamide. RT consisted of craniospinal RT, 35 Gy in 21 fractions, followed by a posterior fossa (PF) boost of 20 Gy in 12 fractions. The accuracy of cribriform fossa, skull base, and PF field placement was assessed.

RESULTS

Between 1992 and 2000, 217 patients were randomized, of whom 179 were eligible for analysis. At a median follow-up of 5.4 years, the 3- and 5-year overall survival rate was 79.5% and 70.7%, respectively. The 3- and 5-year event-free survival (EFS) rate was 71.6% and 67.0%, respectively. EFS was significantly better for the chemotherapy plus RT group (3-year EFS rate 78.5% vs. 64.8%, p = 0.0366). Overall survival and EFS were significantly better for patients completing RT within 50 days compared with those taking >50 days to complete RT (3-year overall survival rate 84.1% vs. 70.9%, p = 0.0356, 3-year EFS rate 78.5% vs. 53.7%, p = 0.0092). Multivariate analysis identified the use of chemotherapy (p = 0.0248) and RT duration (p = 0.0100) as predictive of better EFS. Planning films were reviewed for 131 (74.4%) of 176 patients. Sixty-five (49.6%) had no targeting deviations and 58 (44.3%) had one or more deviations. PF recurrence occurred in 11 (34.4%) of 32 with a PF targeting deviation compared with 13 (16.3%) of 80 without (p = 0.043). No statistically significant impact of other targeting deviations on recurrence risk or EFS were found.

CONCLUSION

The results of this study have confirmed the importance of the duration of RT for medulloblastoma. Also, attention to detail when planning RT is important, as illustrated in the case of PF field placement.

Can the Irradiated Uterus Sustain a Pregnancy? A Literature Review

A significant number of adult pre- menopausal women are offered pelvic radical radiotherapy as part of the management of their malignancy. Advances in human reproductive research are making pregnancy a possibility for these women, but ovarian function, however, is not the only requirement for establishing and maintaining a pregnancy that will result in the delivery of a normal infant. The processes of implantation, fetal and placental development and labour require normal cervical structure and function. Radiation induces acute and late changes in the uterus that have a permanent impact. This article aims to summarise the published data on this complex subject. To date, the majority of reports of successful pregnancies refer to women who had hemi-pelvis or abdominal irradiation suggesting that partial volume irradiation of the uterus may not preclude pregnancy. However, with the current available information, women receiving a radical dose of radiotherapy to the whole uterus are very unlikely to have a successful pregnancy even if ovarian function is maintained. Systematic studies and, in particular, studies looking at modern radiotherapy techniques are required, as well as a register of pregnancies and outcomes to be able to provide answers for this group of patients.

Molecular pharmacology of cancer therapy in human colorectal cancer by gene expression profiling

Global gene expression profiling has potential for elucidating the complex cellular effects and mechanisms of action of novel targeted anticancer agents or existing chemotherapeutics for which the precise molecular mechanism of action may be unclear. In this study, decreased expression of genes required for RNA and protein synthesis, and for metabolism were detected in rectal cancer biopsies taken from patients during a 5-fluorouracil infusion. Our observations demonstrate that this approach is feasible and can detect responses that may have otherwise been missed by conventional methods. The results suggested new mechanism-based combination treatments for colorectal cancer and demonstrated that expression profiling could provide valuable information on the molecular pharmacology of established and novel drugs.

Adjuvant therapy in pancreatic cancer: historical and current perspectives

The results from pancreatic ductal adenocarcinoma appear to be improving with increased resection rates and reduced postoperative mortality reported by specialist pancreatic cancer teams. Developments with medical oncological treatments have been difficult, however, due to the fundamentally aggressive biological nature of pancreatic cancer and its resistance to chemotherapy coupled with a relative dearth of randomised controlled trials. The European Study Group for Pancreatic Cancer (ESPAC)-1 trial recruited nearly 600 patients and is the largest trial in pancreatic cancer. The results demonstrated that the current best adjuvant treatment is chemotherapy using bolus 5-fluorouracil with folinic acid. The median survival of patients randomly assigned to chemoradiotherapy was 15.5 months and is comparable with many other studies, but the median survival in the chemotherapy arm was 19.7 months and is as good or superior to multimodality treatments including intra-operative radiotherapy, adjuvant chemoradiotherapy and neo-adjuvant therapies. The use of adjuvant 5-fluorouracil with folinic acid may be supplanted by gemcitabine but requires confirmation by ongoing clinical trials, notably ESPAC-3, which plans to recruit 990 patients from Europe, Canada and Australasia. Major trials such as ESPAC-1 and ESPAC-3 have set new standards for the development of adjuvant treatment and it is now clear that such treatment in this field has the potential to significantly improve both patient survival and quality of life after curative resection.

Results of a randomized study of preradiation chemotherapy versus radiotherapy alone for nonmetastatic medulloblastoma: The International Society of Paediatric Oncology/United Kingdom Children's Cancer Study Group PNET-3 Study

PURPOSE

To determine whether preradiotherapy (RT) chemotherapy would improve outcome for Chang stage M0-1 medulloblastoma when compared with RT alone. Chemotherapy comprised vincristine 1.5 mg/m2 weekly for 10 weeks and four cycles of etoposide 100 mg/m2 daily for 3 days, and carboplatin 500 mg/m2 daily for 2 days alternating with cyclophosphamide 1.5 g/m2.

PATIENTS AND METHODS

Patients aged 3 to 16 years inclusive were randomly assigned to receive 35 Gy craniospinal RT with a 20 Gy posterior fossa boost, or chemotherapy followed by RT.

RESULTS

Of 217 patients randomly assigned to treatment, 179 were eligible for analysis (chemotherapy + RT, 90 patients; RT alone, 89 patients). Median age was 7.67 years, and median follow-up was 5.40 years. Overall survival (OS) at 3 and 5 years was 79.5% and 70.7%, respectively. Event-free survival (EFS) at 3 and 5 years was 71.6% and 67.0%, respectively. EFS was significantly better for chemotherapy and RT (P =.0366), with EFS of 78.5% at 3 years and 74.2% at 5 years compared with 64.8% at 3 years and 59.8% at 5 years for RT alone. There was no statistically significant difference in 3-year and 5-year OS between the two arms (P =.0928). Multivariate analysis identified use of chemotherapy (P =.0248) and time to complete RT (P =.0100) as having significant effect on EFS.

CONCLUSION

This is the first large multicenter randomized study to demonstrate improved EFS for chemotherapy compared with RT alone. It is anticipated that this regimen could reduce ototoxicity and nephrotoxicity compared with cisplatin-containing schedules. The importance of avoiding interruptions to RT has been confirmed.

Non-invasive methods of assessing angiogenesis and their value in predicting response to treatment in colorectal cancer

BACKGROUND

Tumour neoangiogenesis can be assessed non-invasively by measuring angiogenic cytokine concentrations in peripheral circulation and by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The aim of this study was to assess whether these methods can predict and monitor response to treatment in patients with rectal cancer treated with preoperative chemoradiotherapy.

METHODS

Serum and plasma vascular endothelial growth factor levels were measured in 31 patients with T3/T4 rectal cancers before quantitating tumour permeability (ln Ktrans) by DCE-MRI. Sixteen patients receiving preoperative chemoradiotherapy had serial vascular endothelial growth factor (VEGF) and DCE-MRI measurements. Response to treatment was assessed using World Health Organization criteria.

RESULTS

Serum VEGF and ln Ktrans correlated before treatment (r = 0.48, P = 0.01). Responsive tumours (n = 8) had higher pretreatment permeability values than non-responsive tumours (n = 8) (mean ln Ktrans - 0.46 and - 0.72 respectively; P = 0.03). Compared with pretreatment values, responsive tumours showed a marked reduction in permeability at the end of treatment (mean ln Ktrans - 0.46 and - 0.86 respectively; P = 0.04). Pretreatment serum VEGF levels were not statistically different between the two groups.

CONCLUSION

Rectal tumours with higher permeability at presentation appear to respond better to chemoradiotherapy than those of lower permeability. This may allow preselection of appropriate tumours for these regimens, with patients with low-permeability tumours being considered for alternative therapies.

A comparison of conformal and intensity-modulated techniques for oesophageal radiotherapy

BACKGROUND AND PURPOSE

To investigate the potential of intensity-modulated radiotherapy (IMRT) to reduce lung irradiation in the treatment of oesophageal carcinoma with radical radiotherapy.

MATERIALS AND METHODS

A treatment planning study was performed to compare two-phase conformal radiotherapy (CFRT) with IMRT in five patients. The CFRT plans consisted of anterior, posterior and bilateral posterior oblique fields, while the IMRT plans consisted of either nine equispaced fields (9F), or four fields (4F) with orientations equal to the CFRT plans. IMRT plans with seven, five or three equispaced fields were also investigated in one patient. Treatment plans were compared using dose-volume histograms and normal tissue complication probabilities.

RESULTS

The 9F IMRT plan was unable to improve on the homogeneity of dose to the planning target volume (PTV), compared with the CFRT plan (dose range, 16.9+/-4.5 (1 SD) vs. 12.4+/-3.9%; P=0.06). Similarly, the 9F IMRT plan was unable to reduce the mean lung dose (11.7+/-3.2 vs. 11.0+/-2.9 Gy; P=0.2). Similar results were obtained for seven, five and three equispaced fields in the single patient studied. The 4F IMRT plan provided comparable PTV dose homogeneity with the CFRT plan (11.8+/-3.3 vs. 12.4+/-3.9%; P=0.6), with reduced mean lung dose (9.5+/-2.3 vs 11.0+/-2.9 Gy; P=0.001).

CONCLUSIONS

IMRT using nine equispaced fields provided no improvement over CFRT. This was because the larger number of fields in the IMRT plan distributed a low dose over the entire lung. In contrast, IMRT using four fields equal to the CFRT fields offered an improvement in lung sparing. Thus, IMRT with a few carefully chosen field directions may lead to a modest reduction in pneumonitis, or allow tumour dose escalation within the currently accepted lung toxicity.

A quantitative treatment planning study evaluating the potential of dose escalation in conformal radiotherapy of the oesophagus

BACKGROUND AND PURPOSE

This study aims to evaluate the reduction in radiation dose to normal thoracic structures through the use of conformal radiotherapy techniques in the treatment of oesophageal cancer, and to quantify the resultant potential for dose escalation.

MATERIALS AND METHODS

Three different CT-derived treatment plans were created and compared for each of ten patients. A two-phase treatment with conventional straight-edged fields and standard blocks (CV2), a two-phase conformal plan (CF2), and a three-phase conformal plan where the third phase was delivered to the gross tumour only (CF3), were considered for each patient. Escalated dose levels were determined for techniques CF2 and CF3, which by virtue of the conformal field shaping, did not increase the mean lung dose. The resulting increase in tumour control probability (TCP) was estimated.

RESULTS

A two-phase conformal technique (CF2) reduced the volume of lung irradiated to 18 Gy from 19.7+/-11.8 (1 SD) to 17.1+/-12.3% (P=0.004), and reduced the normal tissue complication probability (NTCP) from 2.4+/-4.0 to 0.7+/-1.6% (P=0.02) for a standard prescribed dose of 55 Gy. Consequently, technique CF2 permitted a target dose of 59.1+/-3.2 Gy without increasing the mean lung dose. Technique CF3 facilitated a prescribed dose of 60.7+/-4.3 Gy to the target, the additional 5 Gy increasing the TCP from 53. 1+/-5.5 to 68.9+/-4.1%. When the spinal cord tolerance was raised from 45 to 48 Gy, technique CF3 allowed 63.6+/-4.l Gy to be delivered to the target, thereby increasing the TCP to 78.1+/-3.2%.

CONCLUSIONS

Conformal radiotherapy techniques offer the potential for a 5-10 Gy escalation in dose delivered to the oesophagus, without increasing the mean lung dose. This is expected to increase local tumour control by 15-25%.

Proton magnetic resonance spectroscopy ((1)H-MRS) of the brain following high-dose methotrexate treatment for childhood cancer

BACKGROUND

To avoid the late sequelae associated with cranial radiation therapy in childhood, intermediate- or high-dose intravenous methotrexate (HDMTX) has found increasing application as a means of preventing the development of overt central nervous system disease in childhood acute leukaemia. However, acute and chronic neurotoxicity has been described following HDMTX therapy, and the long-term intellectual outcome in children treated in this way is inadequately documented. Proton magnetic resonance spectroscopy ((1)H-MRS) of the brain is a noninvasive, quantitative way of assessing aspects of cerebral metabolism, which has not previously been applied to the study of children undergoing central nervous system directed therapy.

PROCEDURE

To evaluate the potential role of (1)H-MRS in the investigation of related neurotoxicity, 11 children who had received HDMTX (cumulative dose 6-96 g/m(2)) underwent localised (1)H-MRS, magnetic resonance imaging. Neuropsychological assessments were performed on the children who had more than 1 year of follow-up time since last methotrexate treatment. Control (1)H-MRS studies on 11 adult and 6 young volunteers were undertaken. Eight patients had spectra of adequate quality. Comparisons between (1)H-MRS metabolite ratios and normal controls were made.

RESULTS

Patients had a low choline/water ratio compared to controls (P < 0.01). No differences between patient and control NAA/water, Cr/water, Naa/Cr, and Cho/Cr ratios were seen. Overall, 3 patients had abnormal white matter changes on MRI. The mean IQ of the patients (104.1) was in the normal range.

CONCLUSIONS

It is postulated that choline depletion in the brains of these patients may reflect subclinical disturbances of myelin metabolism as a result of methotrexate therapy and may represent a possible avenue of treatment in patients with clinical chronic methotrexate-related neurotoxicity.

Magnetic resonance spectroscopy in the evaluation of neurotoxicity following cranial irradiation for childhood cancer

In order to evaluate the role of proton MR spectroscopy (1H-MRS) in the diagnosis and assessment of long-term radiation-related neurotoxicity, 14 children who had received cranial irradiation for the treatment of childhood leukaemia (n = 6) or brain tumours (n = 8) underwent 1H-MRS, MRI and neuropsychological assessment. Short-term effects at 2 months following treatment were studied in a further three patients. MRI abnormalities were observed in nine patients. No statistically significant differences between patients and controls (n = 17) were seen in any of the calculated 1H-MRS metabolite ratios, in any of the three patient groups. On multivariate logistic regression analysis there was a correlation between the choline/water ratio and a low IQ. It is concluded that any systematic radiation-induced changes in the 1H MRS metabolites must be below the detection threshold of this study.

Local radiotherapy for alveolar air leak

Images

Knowledge and perception regarding radiotherapy and radiation in patients receiving radiotherapy: a qualitative study

This study aimed to acquire information about the knowledge patients have about radiation and radiotherapy, and the sources and impact of this knowledge. Data collection was by semi-structured interviews with 30 randomly selected adult patients conducted during the first half of a course of radiotherapy. Data analysis used three major themes: language, understanding and sources of knowledge. Few interviewees had any idea of the physical characteristics of radiation treatment, or they found it difficult to explain. Knowledge about radiation use, other than for medical purposes, most commonly concerned the atom bomb. Patients understood radiotherapy in terms of its action on cancer. Almost all offered a sensible description of why radiotherapy was being used to treat their cancer. Most talked about radiation attacking their cancer in some way and many worried about its damaging effect. A third gave detailed information about what they had become aware of through the written press, or radio or television. The message taken from press reports was largely negative.

Acute toxicity in pelvic radiotherapy; a randomised trial of conformal versus conventional treatment

BACKGROUND

A prospective, randomized clinical trial to assess the effect of reducing the volume of irradiated normal tissue on acute reactions in pelvic radiotherapy accured 266 evaluable patients between 1988 and 1993.

PURPOSE

This is the definitive analysis to assess the differences between the conformal and conventional arms of the trial.

MATERIALS AND METHODS

In both arms, patients were treated with 6 MV X-rays using a 3-field technique (in all but 5 cases) consisting of an anterior and two wedged lateral or posterior oblique fields; in the conventional arm, rectangular fields were employed, whereas in the conformal arm, the fields were shaped with customized blocks drawn according to the beam's-eye-view of the target volume. The most common dosage was 64 Gy in 2-Gy fractions 5 times a week, although a subgroup (of ca. bladder patients) were treated with 30-36 Gy in once-a-week 6 Gy fractions. Each patients completed a comprehensive acute toxicity scoring questionnaire concentrating on bowel and bladder problems, tiredness and nausea, before the start of treatment, weekly during and for 3 weeks after the end of treatment and then monthly for a further 2 months. compliance was excellent.

RESULTS

There were no differences between the patients in the two arms with respect to age, gender, tumour type (52% prostate, 41% bladder, 5% rectum, 2% other) fractionation/dosage, anterior field size, weight, or baseline symptoms. Substantial differences in normal-tissue volumes (rectum, bladder, etc.) were achieved: median high-dose volume (HDV) of 689 cm3 for the conformal technique versus 792 cm3 for the conventional. A clear pattern of an increase in symptoms during RT, followed by a decrease after RT, was observed for the patient group as a whole. However, a very extensive analysis has not revealed any (statistically) significant differences between the two arms in level of symptoms, nor in medication prescribed. The disparity between our findings and those of other, non-randomized studies is discussed.

CONCLUSIONS

The data on late effects must be collected and analyzed before any definite conclusions can be drawn on the benefits of conformal therapy in the pelvis.

Radiotherapy and adjuvant chemotherapy for childhood medulloblastoma. The Royal Marsden Hospital experience

PURPOSE

We reviewed the outcome of children with medulloblastoma treated from 1970 to 1985 with combined radiotherapy and chemotherapy.

PATIENTS AND METHODS

Fifty-seven children with a median age of 8 years (range 1 to 16 years) at diagnosis were analyzed regarding survival, site and time of recurrence, treatment toxicity, prognostic factors and performance status.

RESULTS

The overall 5- and 10-year-survival was 66% and 54%, respectively. Patients with subarachnoid metastases or positive cerebrospinal fluid cytology (M1-3) had a shorter survival compared with those without it (p < 0.1). Furthermore, survival appeared to improve with the addition of lomustine (CCNU) to vincristine chemotherapy with a 5-year-survival of 70% versus 31% (relative risk 3.4, 95% confidence interval 1.4 to 8.1) although it should be noted that these were consecutive not randomized patients treated. Of the 52 patients achieving remission, 17 relapsed either in primary (2), spine (5) or a combination of these (10). Two patients developed bone metastases without central nervous system recurrence. Performance status measured crudely appeared to be good in long-term survivors. Of 31 patients that survived for long-term follow-up and had their performance evaluated, 28 had no or minor residual neurological signs and the remaining 3 were disabled.

CONCLUSION

Combined modality treatment for medulloblastoma in childhood was able to cure 54% of patients with a good performance status in the majority of survivors.

Early communicative behavior in young children receiving cochlear implants: factor analysis of turn-taking and gaze orientation

Early communicative behaviors in young children can be analyzed quantitatively from recordings of interactions between the child and a known adult. Our previous work has shown that the development of such behaviors differs markedly between profoundly deaf young children 1) able to make proficient use of hearing aids or having cochlear implants and 2) unable to make proficient use of hearing aids. The former take turns mainly by vocalization, whereas the latter take turns mainly by gesture. The present study set out to examine whether these contrasts in behavior demonstrated between groups are also observable within a group of young children having cochlear implants, and to examine their development over the first year of implantation. In the 20 children with complete data at the 12-month interval, two clear factors were identified that explained 72% of the variance. These can be labeled as 1) vocal-auditory turn-taking and 2) gaze orientation. All measures of communicative behavior, other than autonomy, showed significant development over the 12 months following implantation, although the observed increase in eye contact was small. No differences could be demonstrated between children with congenital and acquired deafness. It is concluded that the technique based on video analysis is sensitive to changes in early communicative behavior in the year after implantation. Deviations from the expected pattern may indicate inappropriate processor adjustment, device malfunction, or inadequate support.

Cellular sensitivity and low dose-rate recovery in Fanconi anaemia fibroblasts

Fanconi anaemia (FA) is a rare inherited condition characterized by developmental abnormalities and progressive bone marrow failure, which requires bone marrow transplantation for successful treatment. This involves the use of alkylating agents and total body or thoraco-abdominal irradiation. Both chemical clastogens and irradiation cause increased chromosome damage in FA cells compared with controls. In some studies FA fibroblasts have been found to be more radiosensitive than normal. From these data it has been inferred that patients with FA might be more sensitive than normal to radiotherapy. However, increased radiosensitivity of FA fibroblasts has not been a uniform finding. The radiosensitivity of fibroblasts from two FA patients was studied at high and low dose-rate (LDR), and their sensitivity compared with normal strains. Both FA strains fell at the sensitive end of the range, but both demonstrated marked dose-rate sparing, with D0.01 recovery factors of 1.23 and 1.27, similar to the normal strains. These recovery factors are inconsistent with the suggestion that FA patients are recovery deficient. The data indicate that at least some FA strains are capable of LDR recovery, and imply that these patients would probably have a clinical benefit from fractionated or low dose-rate total body irradiation.

Video analysis: a method of assessing changes in preverbal and early linguistic communication after cochlear implantation

As the age of cochlear implantation in children decreases, there is an increasing need for methods to monitor the preverbal and early linguistic development of children fitted with these devices. One method that has been used successfully to monitor children wearing acoustic amplifying hearing aids entails the video recording over time of child-adult interactions in a conversational setting, and the subsequent methodical analysis of various aspects of the interaction. These aspects include eye contact, turn taking, autonomy, and auditory processing. The same method has been applied to children wearing the Nucleus 22-electrode cochlear implant system. An overview is given of the video analysis results for a group of 10 children studied from a period before implantation up to one year postimplantation. The results illustrate group changes in the various measures due to the provision of auditory information by the cochlear implant, plus the scatter of individual data. It is concluded that early indications of progress over time generally predict the level of functioning achieved at 12 months postimplantation. The method provides essential objective information, which enables discrete changes in behavior to be monitored realistically. Two case studies are presented to illustrate the application of the video analysis method to obtain information for clinical management of children with cochlear implants.

The Royal Marsden Hospital pelvic radiotherapy trial: technical aspects and quality assurance

Planning and quality control procedures are described for a randomised trial designed to measure the effect on normal tissue toxicity of reducing the volume of normal tissue irradiated through the introduction of Beams-Eye-View designed customised blocks. Consideration is given to the accuracy with which blocks can be designed and to the potential application of multi-leaf collimator technology.