Elective clinical target volumes for conformal therapy in anorectal cancer: a radiation therapy oncology group consensus panel contouring atlas

Volumetric modulated arc therapy (VMAT) in the combined modality treatment of anal cancer patients

OBJECTIVE

To report clinical and dosimetric outcomes of a consecutive series of patients with anal cancer treated with volumetric-modulated arc therapy (VMAT) concomitant to chemotherapy (CT).

METHODS

A cohort of 39 patients underwent VMAT employing a schedule consisting of 50.4 Gy/28 fractions to the gross tumour volume (GTV) and 42 Gy/28 fractions to the elective nodal volumes for patients with cT2N0 disease. Patients with cT3-T4/N0-N3 tumours were prescribed 54 Gy/30 fractions to the GTV and 50.4 Gy/30 fractions to the gross nodal volumes if sized ≤3 cm or 54 Gy/30 fractions if > 3 cm. Elective nodal regions were given 45 Gy/30 fractions. CT was administered concurrently following Nigro's regimen. The primary end point was acute toxicity. Secondary end points were colostomy-free survival (CFS), disease-free survival (DFS), cancer-specific survival (CSS) and overall survival (OS). Dosimetric data are also provided.

RESULTS

Median follow-up was 21 months. Maximum acute toxicities were: dermatologic-G3: 18%; gastrointestinal-G3: 5%; genitourinary-G3: 2%; anaemia-G2: 7%; leukopenia-G3: 28%; G4: 8%; neutropenia-G3: 13%; G4: 18%; thrombocytopenia-G3: 11%; and G4: 2%. The actuarial 2-year CFS was 77.9% [95% confidence interval (CI): 54-90.4%]. Actuarial 2-year OS and CSS were 85.2% (95% CI: 60.1-95.1%), while DFS was 75.1% (95% CI: 52.4.7-88.1%).

CONCLUSION

Our clinical results support the use of VMAT as a safe and effective intensity-modulated radiotherapy (IMRT) option in the combined modality treatment of anal cancer, with consistent dosimetry, mild toxicity and promising sphincter preservation and survival rates.

ADVANCES IN KNOWLEDGE

IMRT is a standard of care for patients with anal cancer, and VMAT is a robust technical solution in this setting.

Squamous-cell carcinoma of the anus: progress in radiotherapy treatment

Chemoradiotherapy is the standard-of-care treatment of squamous-cell carcinoma of the anus (SCCA), and this has not changed in decades. Radiation doses of 50-60 Gy, as used in many phase III trials, result in substantial late morbidities and fail to control larger and node-positive tumours. Technological advances in radiation therapy are improving patient outcomes and quality of life, and should be applied to patients with SCCA. Modern techniques such as intensity-modulated radiotherapy (IMRT), rotational IMRT, image-guided radiotherapy using cone-beam CT, and stereotactic techniques have enabled smaller margins and highly conformal plans, resulting in decreased radiation doses to the organs at risk and ensuring a shorter overall treatment time. In this Perspectives article, the use of novel approaches to target delineation, optimized radiotherapy techniques, adaptive radiotherapy, dose-escalation with external-beam radiotherapy (EBRT) or brachytherapy, and the potential for modified fractionation are discussed in the context of SCCA.

Comparison of investigator-delineated gross tumor volumes and quality assurance in pancreatic cancer: Analysis of the pretrial benchmark case for the SCALOP trial

BACKGROUND AND PURPOSE

To evaluate the variation in investigator-delineated volumes and assess plans from the radiotherapy trial quality assurance (RTTQA) program of SCALOP, a phase II trial in locally advanced pancreatic cancer.

MATERIALS AND METHODS

Participating investigators (n=25) outlined a pre-trial benchmark case as per RT protocol, and the accuracy of investigators' GTV (iGTV) and PTV (iPTV) was evaluated, against the trials team-defined gold standard GTV (gsGTV) and PTV (gsPTV), using both qualitative and geometric analyses. The median Jaccard Conformity Index (JCI) and Geographical Miss Index (GMI) were calculated. Participating RT centers also submitted a radiotherapy plan for this benchmark case, which was centrally reviewed against protocol-defined constraints.

RESULTS

Twenty-five investigator-defined contours were evaluated. The median JCI and GMI of iGTVs were 0.57 (IQR: 0.51-0.65) and 0.26 (IQR: 0.15-0.40). For iPTVs, these were 0.75 (IQR: 0.71-0.79) and 0.14 (IQR: 0.11-0.22) respectively. Qualitative analysis showed largest variation at the tumor edges and failure to recognize a peri-pancreatic lymph node. There were no major protocol deviations in RT planning, but three minor PTV coverage deviations were identified. .

CONCLUSIONS

SCALOP demonstrated considerable variation in iGTV delineation. RTTQA workshops and real-time central review of delineations are needed in future trials.

Rectal Radiotherapy--Intensity-modulated Radiotherapy Delivery, Delineation and Doses

The use of intensity-modulated radiotherapy in rectal cancer is attractive in that it may reduce acute and late toxicities and potentially facilitate dose escalation. Intensity-modulated radiotherapy probably has a role in selected patients, but further investigation is required to identify the parameters for selection. Delineation of specific nodal groups allows maximal sparing of bladder and small bowel. In locally advanced tumours a simultaneous integrated boost allows dose escalation incorporating hypofractionation and a shorter overall treatment time. However, due to a sparsity of data on late toxicity in doses ≥ 60 Gy, doses at this level should be used with caution, ideally within prospective trials. Future studies investigating dose escalation must ascertain late toxicity as well as local control, as both can significantly affect quality of life and without both, the risk-benefit ratio cannot be calculated.

Trends in incidence and survival for anal cancer in New South Wales, Australia, 1972-2009

INTRODUCTION

Little is known about the incidence and survival of anal cancer in New South Wales (NSW), Australia, as anal cancer cases are often grouped together with other colorectal cancers in descriptive epidemiological analyses.

METHODS

We studied patterns and trends in the incidence and survival of people diagnosed with anal cancer in NSW, Australia, 1972-2009 (n=2724). We also predicted anal cancer incidence in NSW during 2010-2032. Given the human papilloma virus-associated aetiology for most anal cancers, we quantified these changes over time in incidence and survival by histological subtype: anal squamous cell carcinoma (ASCC); and anal adenocarcinoma (AAC).

RESULTS

There was a linear increase in incident anal cancer cases in NSW with an average annual percentage change (AAPC) of 1.6 (95% CI 1.1-2.0) such that, in combination with age-period-cohort modelling, we predict there will be 198 cases of anal cancer in the 2032 calendar year (95% CI 169-236). Almost all of these anal cancer cases are projected to be ASCC (94%). Survival improved over time regardless of histological subtype. However, five-year relative survival was substantially higher for people with ASCC (70% (95% CI 66-74%)) compared to AAC (51% (95% CI 43-59%)), a 37% difference. Survival was also greater for women (69% (95% CI 64-73%)) with ASCC compared to men (55% (95% CI 50-60%)). It was not possible to estimate survival by stage at diagnosis particularly given that 8% of all cases were recorded as having distant stage and 22% had missing stage data.

INTERPRETATION

Aetiological explanations, namely exposure to oncogenic types of human papillomavirus, along with demographic changes most likely explain the actual and projected increase in ASCC case numbers. Survival differences by gender and histological subtype point to areas where further research is warranted to improve treatment and outcomes for all anal cancer patients.

Dosimetric planning study for the prevention of anal complications after post-operative whole pelvic radiotherapy in cervical cancer patients with hemorrhoids

OBJECTIVE

Radiation-induced anal toxicity can be induced by low radiation doses in patients with haemorrhoids. The object of this study was to determine the dosimetric benefits of different whole pelvic radiotherapy (WPRT) techniques in terms of dose delivered to the anal canal in post-operative patients with cervical cancer.

METHODS

The planning CT images of 10 patients with cervical cancer undergoing postoperative radiotherapy were used for comparison of three different plans. All patients had been treated using the conventional box technique WPRT (CV-WPRT), and we tried low-margin-modified WPRT (LM-WPRT), three-dimensional conformal techniques WPRT (CF-WPRT) and intensity-modulated WPRT (IM-WPRT) planning for dosimetric comparison of the anal canal, retrospectively.

RESULTS

Mean anal canal doses of the IM-WPRT were significantly lower (p < 0.05) than those of CV-WPRT, LM-WPRT and CF-WPRT, and V10, V20, V30 and V40 to the anal canal were also significantly lower for IM-WPRT (p < 0.05). The proportion of planning target volumes (PTVs) that received ≥98% of the prescribed dose for all plans was >99%, and the proportion that received ≥108% of the prescribed dose for IM-WPRT was <2%. Volumes of bladders and rectums that received ≥30 or ≥40 Gy were significantly lower for IM-WPRT than for three of the four-field WPRT plans (p = 0.000).

CONCLUSION

IM-WPRT can significantly reduce radiation dose delivered to the anal canal and does not compromise PTV coverage. In patients with haemorrhoids, IM-WPRT may be of value for the prevention of anal complications.

ADVANCES IN KNOWLEDGE

Although tolerance of the anal canal tends to be ignored in patients undergoing post-operative WPRT, patients with haemorrhoids may suffer complications at low radiation doses. The present study shows IM-WPRT can be meaningful in these patients.

[Recommendations for the management of cancers of the anal canal]

Anal canal carcinomas remain rare, but their management has improved recently. The PET-CT is now used as a standard at the first diagnosis and after relapses. The introduction of intensity-modulated irradiation techniques makes it possible to better conform the pelviperineal and inguinal volumes, improving the homogeneity of the irradiation while sparing some pelvic structures, thus reducing acute and late effects. Nevertheless, the conversion from 3D to intensity-modulated radiotherapy needs a specific and careful approach, mainly for the management of the perineal region, where relapses and complications occur. Last but not least, new chemotherapy associations are studied for metastatic disease.

NRG Oncology Radiation Therapy Oncology Group 0822: A Phase 2 Study of Preoperative Chemoradiation Therapy Using Intensity Modulated Radiation Therapy in Combination With Capecitabine and Oxaliplatin for Patients With Locally Advanced Rectal Cancer

PURPOSE

To evaluate the rate of gastrointestinal (GI) toxicity of neoadjuvant chemoradiation with capecitabine, oxaliplatin, and intensity modulated radiation therapy (IMRT) in cT3-4 rectal cancer.

METHODS AND MATERIALS

Patients with localized, nonmetastatic T3 or T4 rectal cancer <12 cm from the anal verge were enrolled in a prospective, multi-institutional, single-arm study of preoperative chemoradiation. Patients received 45 Gy with IMRT in 25 fractions, followed by a 3-dimensional conformal boost of 5.4 Gy in 3 fractions with concurrent capecitabine/oxaliplatin (CAPOX). Surgery was performed 4 to 8 weeks after the completion of therapy. Patients were recommended to receive FOLFOX chemotherapy after surgery. The primary endpoint of the study was acute grade 2 to 5 GI toxicity. Seventy-one patients provided 80% probability to detect at least a 12% reduction in the specified GI toxicity with the treatment of CAPOX and IMRT, at a significance level of .10 (1-sided).

RESULTS

Seventy-nine patients were accrued, of whom 68 were evaluable. Sixty-one patients (89.7%) had cT3 disease, and 37 (54.4%) had cN (+) disease. Postoperative chemotherapy was given to 42 of 68 patients. Fifty-eight patients had target contours drawn per protocol, 5 patients with acceptable variation, and 5 patients with unacceptable variations. Thirty-five patients (51.5%) experienced grade ≥ 2 GI toxicity, 12 patients (17.6%) experienced grade 3 or 4 diarrhea, and pCR was achieved in 10 patients (14.7%). With a median follow-up time of 3.98 years, the 4-year rate of locoregional failure was 7.4% (95% confidence interval [CI]: 1.0%-13.7%). The 4-year rates of OS and DFS were 82.9% (95% CI: 70.1%-90.6%) and 60.6% (95% CI: 47.5%-71.4%), respectively.

CONCLUSION

The use of IMRT in neoadjuvant chemoradiation for rectal cancer did not reduce the rate of GI toxicity.

Role of Radiotherapy and Newer Techniques in the Treatment of GI Cancers

The role of radiotherapy in multidisciplinary treatment of GI malignancies is well established. Recent advances in imaging as well as radiotherapy planning and delivery techniques have made it possible to target tumors more accurately while sparing normal tissues. Intensity-modulated radiotherapy is an advanced method of delivering radiation using cutting-edge technology to manipulate beams of radiation. The role of intensity-modulated radiotherapy is growing for many GI malignancies, such as cancers of the stomach, pancreas, esophagus, liver, and anus. Stereotactic body radiotherapy is an emerging treatment option for some GI tumors such as locally advanced pancreatic cancer and primary or metastatic tumors of the liver. Stereotactic body radiotherapy requires a high degree of confidence in tumor location and subcentimeter accuracy of the delivered dose. New image-guided techniques have been developed to overcome setup uncertainties at the time of treatment, including real-time imaging on the linear accelerator. Modern imaging techniques have also allowed for more accurate pretreatment staging and delineation of the primary tumor and involved sites. In particular, magnetic resonance imaging and positron emission tomography scans can be particularly useful in radiotherapy planning and assessing treatment response. Molecular biomarkers are being investigated as predictors of response to radiotherapy with the intent of ultimately moving toward using genomic and proteomic determinants of therapeutic strategies. The role of all of these new approaches in the radiotherapeutic management of GI cancers and the evolving role of radiotherapy in these tumor sites will be highlighted in this review.

Predictors of acute toxicities during definitive chemoradiation using intensity-modulated radiotherapy for anal squamous cell carcinoma

PURPOSE

To identify clinical and dosimetric factors associated with acute hematologic and gastrointestinal (GI) toxicities during definitive therapy using intensity-modulated radiotherapy (IMRT) for anal squamous cell carcinoma (ASCC).

MATERIALS AND METHODS

We retrospectively analyzed 108 ASCC patients treated with IMRT. Clinical information included age, gender, stage, concurrent chemotherapy, mitomycin (MMC) chemotherapy and weekly hematologic and GI toxicity during IMRT. From contours of the bony pelvis and bowel, dose-volume parameters were extracted. Logistic regression models were used to test associations between toxicities and clinical or dosimetric predictors.

RESULTS

The median age was 59 years, 81 patients were women and 84 patients received concurrent MMC and 5-fluorouracil (5FU). On multivariate analysis (MVA), the model most predictive of Grade 2 + anemia included the maximum bony pelvis dose (Dmax), female gender, and T stage [p = 0.035, cross validation area under the curve (cvAUC) = 0.66]. The strongest model of Grade 2 + leukopenia included V10 (percentage of pelvic bone volume receiving ≥ 10 Gy) and number of MMC cycles (p = 0.276, cvAUC = 0.57). The model including MMC cycle number and T stage correlated best with Grade 2 + neutropenia (p = 0.306, cvAUC = 0.57). The model predictive of combined Grade 2 + hematologic toxicity (HT) included V10 and T stage (p = 0.016, cvAUC = 0.66). A model including VA45 (absolute bowel volume receiving ≥ 45 Gy) and MOH5 (mean dose to hottest 5% of bowel volume) best predicted diarrhea (p = 0.517, cvAUC = 0.56).

CONCLUSION

Dosimetric constraints to the pelvic bones should be integrated into IMRT planning to reduce toxicity, potentially reducing treatment interruptions and improving disease outcomes in ASCC. Specifically, our results indicate that Dmax should be confined to ≤ 57 Gy to minimize anemia and that V10 should be restricted to ≤ 87% to reduce incidence of all HT.

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.

Intensity-modulated radiation therapy with simultaneous integrated boost combined with concurrent chemotherapy for the treatment of anal cancer patients: 4-year results of a consecutive case series

PURPOSE

To report the 4-year outcomes of a consecutive series of anal cancer patients treated with concurrent chemo-radiation delivered with intensity-modulated radiotherapy (IMRT), employing a simultaneous integrated boost (SIB) approach.

METHODS

A consecutive series of 54 patients was enrolled between 2007 and 2013. Treatment schedule consisted of 50.4 Gy/28 fractions (1.8 Gy daily) to the gross tumor volume, while the elective nodal volumes were prescribed 42 Gy/28 fractions (1.5 Gy/daily) for patients having a cT2N0 disease. Patients with cT3-T4/N0-N3 tumors were prescribed 54 (T3) or 60 (T4) Gy/30 fractions (1.8-2 Gy daily) to the gross tumor volume; gross nodal volumes were prescribed 50.4 Gy/30 fr (1.68 Gy daily) if sized ≤ 3 cm or 54 Gy/30 fr (1.8 Gy daily) if > 3 cm; elective nodal regions were given 45 Gy/30 fractions (1.5 Gy daily). Chemotherapy was administered concurrently according to the Nigro's regimen. Primary endpoint was colostomy-free survival (CFS). Secondary endpoints were local control (LC), disease-free survival (DFS), cancer-specific survival (CSS), overall survival (OS), and toxicity profile.

RESULTS

Median follow up was 32.6 months (range 12-84). The actuarial probability of being alive at 4 years without a colostomy (CFS) was 68.9% (95% CI: 50.3%-84.7%). Actuarial 4-year OS, CSS, DFS, and LC were 77.7% (95% CI: 60.7-88.1%), 81.5% (95% CI: 64%-91%), 65.5% (95% CI: 47.7%-78.5%), and 84.6% (95% CI: 71.6%-92%). Actuarial 4-year metastasis-free survival was 74.4% (95% CI: 55.5%-86.2%). Maximum detected acute toxicities were as follows: dermatologic -G3: 13%; GI-G3: 8%; GU-G3: 2%; anemia-G3: 2%; neutropenia-G3:11%; G4: 2%; thrombocytopenia- G3:2%. Four-year G2 chronic toxicity rates were 2.5% (95% CI: 3.6-16.4) for GU, 14.4% (95% CI: 7.1-28) for GI, 3.9% (95% CI: 1%-14.5%) for skin, and 4.2% (95% CI: 1.1-15.9) for genitalia.

CONCLUSIONS

Our study shows the feasibility of IMRT in the combined modality treatment of anal cancer, with comparable results to the literature with respect to LC, sphincter preservation and survival. Acute toxicity is lower if compared to series employing standard techniques. Our results support the use of IMRT on a routine basis for the treatment of anal cancer.

Interstitial pulsed-dose-rate brachytherapy for the treatment of squamous cell anal carcinoma: A retrospective single institution analysis

OBJECTIVE

To examine the outcome of patients receiving interstitial pulsed-dose-rate brachytherapy (PDR-BT) after pelvic radiation therapy for treatment of an anal squamous cell carcinoma.

METHODS AND MATERIALS

Twenty-one patients were identified: 13, six, and two with stages I, II, and III tumors, respectively. After receiving received pelvic irradiation +/- concurrent chemotherapy, patients were delivered a PDR-BT boost to the residual tumor, with intention to deliver a minimal total dose of 60 Gy. The greatest dimension of residual tumor at the time of brachytherapy procedure was 12.5 mm (range: 0-20 mm). Brachytherapy implantation was performed according to the Paris system, only one plane implant being used.

RESULTS

Median dose delivered through BT was 20 Gy (range: 10-30 Gy). Median number of pulses was 48 (range: 20-80 pulses). Median treated volume was 9 cm(3) (range: 5-16 cm(3)). Median dose per pulse was 40 cGy (range: 37.5-50 cGy). No Grade 3 or more acute toxicity was reported. No Grade 3 or more delayed toxicity was seen among 18 patients with more than 6 months follow-up. Median followup was 47 months (range: 6-73 months). Twenty patients (95%) were alive at last follow-up. Tumor relapses were experienced in four patients (19%), including local relapse in three patients (14%).

CONCLUSION

With almost 4 years median followup, this study confirms previous data suggesting that PDR-BT is effective and safe in this indication. Local control rate and toxicity were in the range of what was seen with continuous low-dose-rate BT.

Helical Tomotherapy for the Treatment of Anal Canal Cancer: A Dosimetric Comparison with 3D Conformal Radiotherapy

Aims and Background

The standard treatment of anal canal cancer (ACC) is combined chemotherapy and radiation therapy (RT), which is complex because of the shape of the target volumes and the need to minimize the irradiation of normal pelvic structures. In this study we compared the dosimetric results of helical tomotherapy (HT) plans with traditional 3D conformal RT (3DRT) plans for the treatment of ACC.

Methods and Study Design

Twelve patients (median age 57 years, range 38–83; F/M 8/4) treated with HT and concurrent chemotherapy for locally advanced ACC were selected. All had histologically confirmed squamous-cell carcinoma. A clinical target volume including the tumor and pelvic and inguinal lymph nodes was treated with HT to a total dose of 36 Gy in 1.8-Gy daily fractions. Then a sequential boost of 23.4 Gy in 1.8-Gy daily fractions (total dose 59.4 Gy) was delivered to the tumor and involved nodes. For all 12 patients, 3DRT plans were generated for comparison. Treatment plans were evaluated by means of standard dose-volume histograms. Dose coverage of the planning target volumes (PTVs), homogeneity index (HI), and mean doses to organs at risk (OARs) were compared.

Results

The coverage of PTV was comparable between the two treatment plans. HI was better in the HT vs. 3DRT plans (1.25 and 3.57, respectively; p<0.0001). HT plans resulted in better sparing of OARs (p<0.0001).

Conclusions

HT showed superior target dose conformality and significant sparing of pelvic structures compared with 3DRT. Further investigation should determine if these dosimetric improvements will improve clinical outcomes regarding locoregional control, survival, and treatment-related acute and late morbidity.

Pencil-beam scanning proton therapy for anal cancer: a dosimetric comparison with intensity-modulated radiotherapy

BACKGROUND

Concurrent chemoradiotherapy cures most patients with anal squamous cell carcinoma at the cost of significant treatment-related toxicities. Intensity-modulated radiotherapy (IMRT) reduces side effects compared to older techniques, but whether proton beam therapy (PBT) offers additional advantages is unclear.

MATERIAL AND METHODS

Eight patients treated with PBT for anal cancer were chosen for this study. We conducted detailed plan comparisons between pencil-beam scanning PBT via two posterior oblique fields and seven-field IMRT. Cumulative dose-volume histograms were analyzed by Wilcoxon signed-rank test, and plan delivery robustness was assessed via verification computed tomography (CT) scans obtained during treatment.

RESULTS

Compared to IMRT, PBT reduced low dose radiation (≤ 30 Gy) to the small bowel, total pelvic bone marrow, external genitalia, femoral heads, and bladder (all p < 0.05) without compromising target coverage. For PBT versus IMRT, mean small bowel volume receiving ≥ 15 Gy (V15) was 81 versus 151 cm(3), mean external genitalia V20 was 14 versus 40%, and mean total pelvic bone marrow V15 was 66 versus 83% (all p = 0.008). The lumbosacral bone marrow dose was higher with PBT due to beam geometry. PBT was delivered with ≤ 1.3% interfraction deviation in the dose received by 98% of the clinical target volumes.

CONCLUSION

Pencil-beam scanning PBT is clinically feasible and can be robustly delivered for anal cancer patients. Compared with IMRT, PBT reduces low dose radiation to important organs at risk in this population. While the clinical benefit of these differences remains to be shown, existing data suggest that limiting low dose to the small bowel and pelvic bone marrow may reduce treatment toxicity.

CAPIRI-IMRT: a phase II study of concurrent capecitabine and irinotecan with intensity-modulated radiation therapy for the treatment of recurrent rectal cancer

BACKGROUND

This study investigated the local effect and acute toxicity of irinotecan and capecitabine with concurrent intensity-modulated radiation therapy (IMRT) for the treatment of recurrent rectal cancer without prior pelvic irradiation.

METHODS

Seventy-one patients diagnosed with recurrent rectal cancer who did not previously receive pelvic irradiation were treated in our hospital from October 2009 to July 2012. Radiotherapy was delivered to the pelvis, and IMRT of 45 Gy (1.8 Gy per fraction), followed by a boost of 10 Gy to 16 Gy (2 Gy per fraction), was delivered to the recurrent sites. The concurrent chemotherapy regimen was 50 mg/m(2) irinotecan weekly and 625 mg/m(2) capecitabine twice daily (Mon-Fri). Radical surgery was recommended for medically fit patients without extra-pelvic metastases. The patients were followed up every 3 months. Tumor response was evaluated using CT/MRIs according to the RECIST criteria or postoperative pathological findings. NCI-CTC 3.0 was used to score the toxicities.

RESULTS

Forty-eight patients (67.6%) had confirmed recurrent rectal cancer without extra pelvic metastases, and 23 patients (32.4%) had extra pelvic metastases. Fourteen patients (19.7%) underwent radical resections (R0) post-chemoradiation. A pathologic complete response was observed in 7 of 14 patients. A clinical complete response was observed in 4 patients (5.6%), and a partial response was observed in 22 patients (31.0%). Only 5 patients (7.0%) showed progressive disease during or shortly after treatment. Of 53 symptomatic patients, clinical complete and partial symptom relief with chemoradiation was achieved in 56.6% and 32.1% of patients, respectively. Only 2 patients (2.8%) experienced grade 4 leukopenia. The most common grade 3 toxicity was diarrhea (16 [22.5%] patients). The median follow-up was 31 months. The cumulative local progression-free survival rate was 74.2% and 33.9% at 1 and 3 years after chemoradiation, respectively. The cumulative total survival rate was 80.1% and 36.5% at 1 and 3 years after chemoradiation, respectively.

CONCLUSIONS

This study revealed that concurrent irinotecan and capecitabine with IMRT significantly relieves local symptoms and exhibits promising efficacy with manageable toxicities in recurrent rectal cancer without prior pelvic irradiation. Improving the rate of R0 resections will be investigated in a future study.

Anal cancer: ESMO-ESSO-ESTRO clinical practice guidelines for diagnosis, treatment and follow-up

Squamous cell carcinoma of the anus (SCCA) is a rare cancer but its incidence is increasing throughout the world, and is particularly high in the human immunodeficiency virus positive (HIV+) population. A multidisciplinary approach is mandatory (involving radiation therapists, medical oncologists, surgeons, radiologists and pathologists). SCCA usually spreads in a loco-regional manner within and outside the anal canal. Lymph node involvement at diagnosis is observed in 30%-40% of cases while systemic spread is uncommon with distant extrapelvic metastases recorded in 5%-8% at onset, and rates of metastatic progression after primary treatment between 10 and 20%. SCCA is strongly associated with human papilloma virus (HPV, types 16-18) infection. The primary aim of treatment is to achieve cure with loco-regional control and preservation of anal function, with the best possible quality of life. Treatment dramatically differs from adenocarcinomas of the lower rectum. Combinations of 5FU-based chemoradiation and other cytotoxic agents (mitomycin C) have been established as the standard of care, leading to complete tumour regression in 80%-90% of patients with locoregional failures in the region of 15%. There is an accepted role for surgical salvage. Assessment and treatment should be carried out in specialised centres treating a high number of patients as early as possible in the clinical diagnosis. To date, the limited evidence from only 6 randomised trials [1,2,3,4,5,6,7], the rarity of the cancer, and the different behaviour/natural history depending on the predominant site of origin, (the anal margin, anal canal or above the dentate line) provide scanty direction for any individual oncologist. Here we aim to provide guidelines which can assist medical, radiation and surgical oncologists in the practical management of this unusual cancer.

The Role of FDG-PET in the Initial Staging and Response Assessment of Anal Cancer: A Systematic Review and Meta-analysis

PURPOSE

The aim of this systematic review and meta-analysis was to compare the role of FDG-positron emission tomography (PET) or PET/computed tomography (CT) with conventional imaging in the detection of primary and nodal disease in anal cancer, and to assess the impact of PET or PET/CT on the management of anal cancer.

METHODS

A systematic review of the literature was performed. Eligible studies included those comparing PET or PET/CT with conventional imaging in the staging of histologically confirmed anal squamous cell carcinoma (SCC), or studies that performed PET or PET/CT imaging to assess response following treatment.

RESULTS

Twelve studies met the inclusion criteria. For the detection of primary disease, CT and PET had a sensitivity of 60 % (95 % confidence interval [CI] 45.5-75.2) and 99 % (95 % CI 96-100), respectively. Compared with conventional imaging, PET upstaged 15 % (95 % CI 10-21) and downstaged 15 % (95 % CI 10-20) of nodal disease. This led to a change in nodal staging in 28 % of patients (95 % CI 18-38). When only studies performing contemporary PET/CT were considered, the rate of nodal upstaging was 21 % (95 % CI 13-30) and the TNM stage was altered in 41 % of patients. Following chemoradiotherapy, 78 % (95 % CI 65-88) of patients had a complete response on PET.

CONCLUSION

Compared with conventional imaging, PET or PET/CT alters the nodal status in a sufficient number of cases to justify its routine use in the staging of patients with anal SCC.

Locally advanced gastroesophageal junction tumor: a treatment dilemma

Over the last several decades, the incidence of adenocarcinoma of the gastroesophageal junction (GEJ) has been increasing in developed countries. Although complete surgical resection remains the cornerstone of treatment for resectable disease, long-term outcomes are poor and recurrence rates are high with surgery alone in patients presenting with locally advanced disease. Multimodal therapy has been shown to improve survival; however, the optimal therapeutic approach remains controversial, and practices vary across the world. Preoperative chemoradiotherapy is generally used in the U.S., whereas perioperative chemotherapy without radiation is favored in most European countries. In this review, we discuss why the treatment of locally advanced GEJ tumors remains controversial, examine the evidence for various multimodal approaches, discuss their respective pros and cons, evaluate the role of radiation therapy, highlight some ongoing and planned clinical trials, and suggest areas that need further research.

Nonoperative management of squamous-cell carcinoma of the rectum

BACKGROUND

Radiochemotherapy without surgical resection has become the treatment of choice for anal squamous-cell carcinoma. The optimal treatment for rectal squamous-cell carcinoma is not well established.

OBJECTIVE

The purpose of this work was to assess the efficacy of nonoperative strategies in the management of primary rectal squamous-cell carcinoma.

DESIGN

We retrospectively reviewed data from all of the patients with documented rectal squamous-cell carcinoma who were treated with conservative strategies in a single institution. Concomitant radiochemotherapy was proposed to all except 1 patient. The remaining patient was treated by radiotherapy alone given his impaired functional status. All of the patients were treated with conformal or intensity-modulated radiation therapy. Surgical resection was reserved for persistent disease or relapse.

SETTING

This study was conducted in a single tertiary institution.

MAIN OUTCOME MEASURES

After a mean follow-up of 56 months, 2 patients experienced relapse and no patients died.

RESULTS

Eleven patients were included in the series. The clinical response to radiotherapy was complete for 7 patients. The remaining 4 patients underwent salvage surgery. The pathologic response was incomplete for 2 of the 4 patients. One recurrence occurred outside the field of radiotherapy and was successfully treated by radiotherapy. The second was a local recurrence, which occurred on a patient who was treated with radiotherapy alone.

LIMITATIONS

The number of patients included in this retrospective series was limited because of the rarity of the disease. Patients were treated with nonhomogeneous conservative strategies because of modification in the therapeutic strategy for anal squamous-cell carcinoma and of the adaptation of the treatment to patient comorbidities and functional status.

CONCLUSIONS

This series demonstrates that good results can be obtained by using a rectum-conserving strategy. Close follow-up should be maintained, with the use of salvage surgery reserved only for persistent disease or relapse (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A155).

Clinical results and toxicity for short-course preoperative radiotherapy and total mesorectal excision in rectal cancer patients

Short-course preoperative radiotherapy (SCPRT) is an alternative method to chemoirradiation for patients with Stage II and III rectal cancer when no downsizing is needed, but there is still widespread reluctance to use this method because of fear of side effects from high-fraction doses. This paper reports on a single institution patient cohort of operated rectal cancer patients after SCPRT, evaluated for chronic adverse effects, local control, progression-free survival and overall survival. Altogether, 257 patients were treated with SCPRT and surgery including total mesorectal excision (92% total mesorectal excision = TME) between 2002 and 2009. Local control and survival were analyzed. Chronic adverse effects for 154 patients without local relapse were evaluated according to the NCI-CTCAE version 4.0 classification, with a median follow-up of 48 months. We found a 5-year disease-free survival (DFS) and overall survival (OS) of 71%. The 5-year estimated local control (LC) rate was 94%. A positive resection margin was found in 4% of the patients and was significantly correlated with decreased DFS, OS and LC. Chronic adverse effects were reported by 58% of the patients, of which 10% were Grade 3 toxicities. The most frequent Grade 2 toxicity was stool incontinence (13%). Sexual dysfunction was found in 36% of the patients (31% Grade 1 or 2, and only 5% Grade 3). SCPRT combined with TME produced excellent LC rates together with a low rate of high-grade chronic adverse effects.

Five-year outcomes of preoperative chemoradiation for rectal carcinoma in Saudi population: single-institutional experience

OBJECTIVES

Preoperative chemoradiation (CRT) followed by surgery is the standard treatment for locally advanced rectal cancer (LARC). The outcomes of preoperative CRT in Saudi patients with LARC have not been widely studied. The study reports long-term outcomes after preoperative CRT followed by curative surgery in Saudi patients with LARC.

DESIGN AND SETTINGS

A retrospective, single-institutional study performed in the tertiary care oncology center in Saudi Arabia.

MATERIALS AND METHODS

A total of 154 out of 204 patients with LARC were treated with preoperative CRT and followed by surgery at the oncology center between September 2005 and November 2012. Data regarding the response rates, toxicity profile, locoregional control (LRC), distant metastasis control (DMC), overall survival (OS), and disease-free survival (DFS) rates were analyzed.

RESULTS

The median age of the study population was 56.6 years (range: 26-89). Predominant clinical stages were IIA (70 patients; 45.4%) and IIIB (49 patients; 31.8%). Majority of patients (79.8%) underwent a complete total mesorectal excision (TME). Complete pathological response (ypT0N0) was seen in 26 patients (16.8%). At 5 years, locoregional recurrence (LR) was reported in 12 patients (7.8%), and distant metastases were noted in 33 patients (21.4%). The 5-year cumulative LRC, DMC, OS, and DFS rates were 91%, 71.3%, 78%, and 64.8%, respectively. Stage, nodal status, circumferential margins, ypT0N0, and adjuvant chemotherapy were found to be important prognostic factors for DFS.

CONCLUSION

The results of preoperative CRT followed by surgery and adjuvant chemotherapy in Saudi population are comparable with international data.

Is elective inguinal radiotherapy necessary for locally advanced rectal adenocarcinoma invading anal canal?

Background

We investigated whether routine elective irradiation of a clinically negative inguinal node (IGN) is necessary for patients with locally advanced distal rectal cancer and anal canal invasion (ACI).

Methods

We reviewed retrospectively 1,246 patients with locally advanced rectal adenocarcinoma managed using preoperative or postoperative chemoradiotherapy and radical surgery between 2001 and 2011. The patients’ IGN was clinically negative at presentation and IGN irradiation was not performed. ACI was defined as the lower edge of the tumor being within 3 cm of the anal verge. Patients were divided into two groups, those with ACI (n = 189, 15.2%) and without ACI (n = 1,057, 84.8%).

Results

The follow-up period was a median of 66 months (range, 3–142 months). Among the 1,246 patients, 10 developed IGN recurrence; 7 with ACI and 3 without ACI. The actuarial IGN recurrence rate at 5 years was 0.7%; 3.5% and 0.2% in patients with and without ACI, respectively (p < 0.001). Isolated IGN recurrence occurred in three patients, all of whom had ACI tumors. These three patients received curative intent local treatments, and one was alive with no evidence of disease 10 years after IGN recurrence. Salvage treatments in the other two patients controlled successfully the IGN recurrence for >5 years, but they developed second malignancy or pelvic and distant recurrences. Seven patients with non-isolated IGN recurrence died of disease at 5–22 months after IGN recurrence.

Conclusion

The low IGN recurrence rate even with ACI and the feasibility of salvage of isolated IGN recurrence indicated that routine elective IGN irradiation is not necessary for rectal cancer with ACI.

Intensity-modulated radiation therapy with concurrent chemotherapy for anal cancer: outcomes and toxicity

OBJECTIVES

To evaluate toxicity, local control, and survival in anal cancer patients treated with intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy.

METHODS

Sixty-five patients were treated at a single institution with IMRT and concurrent chemotherapy for localized squamous cell carcinoma of the anal canal. Radiotherapy was delivered with a simultaneous integrated boost technique, with dose based on the T stage. The median dose to the primary tumor and pelvis were 54 Gy (range, 50 to 58.8 Gy) and 45 Gy (range, 40.5 to 50.4 Gy), respectively. The most common concurrent chemotherapy regimens were 5-fluorouracil and cisplatin (75%), capecitabine and oxaliplatin (11%), and 5-fluorouracil and mitomycin C (5%).

RESULTS

The percentage of patients with Tx, T1, T2, T3, and T4 disease were 8%, 17%, 49%, 15%, and 11%, respectively. The percentage of patients with N0, N1, N2, and N3 disease were 46%, 17%, 9%, and 28%, respectively. Ninety-one percent of patients completed treatment without a break. Grade 3 gastrointestinal toxicity occurred in 9%, and moist desquamation beyond the perianal area occurred in 17%. The use of a vaginal dilator during simulation and treatment seemed to lower the rates of acute skin and late sexual toxicity. With a median follow-up of 19 months, the 2-year local and distant control rates were both 93%. The 2-year overall and disease-free survival rates were 96% and 86%, respectively.

CONCLUSIONS

Concurrent chemotherapy and IMRT was well tolerated, and was associated with low rates of acute and late toxicity and excellent local control, disease-free survival, and overall survival.

PET-based radiation therapy planning

In this review, we review the literature on the use of PET in radiation treatment planning, with an emphasis on describing our institutional methodology (where applicable). This discussion is intended to provide other radiation oncologists with methodological details on the use of PET imaging for treatment planning in radiation oncology, or other oncologists with an introduction to the use of PET in planning radiation therapy.

Radiation therapy of anal canal cancer: from conformal therapy to volumetric modulated arc therapy

BACKGROUND

To appraise the role of volumetric modulated arc (RapidArc, RA) in the treatment of anal canal carcinoma (ACC).

METHODS

A retrospective analysis has been conducted on 36 patients treated with RA since 2009 comparing outcome against a group of 28 patients treated with conformal therapy (CRT). RA treatments were prescribed with SIB technique with 59.4 Gy to the primary tumor and nodes and 49.5 Gy to the elective nodes. CRT was sequentially delivered with 45 Gy to the pelvic target and a boost of 14.4 Gy to the primary tumor.

RESULTS

Median age of patients was 65 yrs for RA (59 yrs for CRT); 90% had Stage II-III (93% in the CRT group). No statistically significant differences were observed concerning survival or control. 5 yrs disease specific survival was 85.7% and 81.2%, loco-regional control was of 78.1% and 82.1% for RA and CRT respectively. RA treatments lead to lower incidence of higher grade of toxicity events (all retrospectively retrieved from charts as worse events). Grade 2-3 toxicity, compared to CRT, reduced from 89% to 68% for GI, from 39% to 33% for GU and from 82% to 75% for the skin. Late toxicity was as follows: 5/36 (14%) and 3/36 (8%) patients had G1 or G2 GI toxicity in the RA group (1/28 (4%) and 4/28 (14%) in the CRT group). GU late toxicity was observed only in 4/28 (14%) patients of the CRT group: 3/28 (11%) had G2 and 1/28 (4%) had G1.

CONCLUSIONS

RA treatments of ACC patients proved to be equally effective than CRT but it was associated to a reduction of toxicity.

[Sexual functions after treatment for rectal cancer: impact of doses in autonomic pelvic nerves]

PURPOSE

Prospective evaluation of sexual function after treatment of rectal cancer and identification of predictive factors.

PATIENTS AND METHODS

Thirty-three patients were treated with curative intent by chemoradiation and surgery for localized rectal adenocarcinoma. Sexual toxicity was assessed four times (before treatment and at 2, 6 and 12 months) using validated questionnaires: QLQ C30 and EORTC CR38 for all, simplified IIEF for men and FSFI for women. A correlation was sought between the toxicity and clinical and dosimetric parameters by Fisher and Mann-Whitney tests.

RESULTS

In men, erections and sexual satisfaction decreased significantly from the acute phase and then stabilized (respective scores of 84.5 and 86/100 in the initial phase, 66 and 70.4 at the end of radiotherapy, 70 and 70 at 6 months and 68.5 and 70 at 12 months). For women, the changes were not significant. This study confirms some risk factors for sexual toxicity already mentioned (original function, age, tumor volume) and highlights new (dose to the seminal vesicles and above all, doses to pelvic autonomic plexus).

CONCLUSION

Sexual effects of combined treatment of rectal cancer have only recently been described but remain undervalued and poorly understood. The impact of the autonomic pelvic plexus doses is a completely new data that could be extended in the development of intensity-modulated radiotherapy.

Interstitial high-dose rate brachytherapy as boost for anal canal cancer

AIM

To assess clinical outcomes of patients treated with a high-dose rate brachytherapy boost for anal canal cancer (ACC).

METHODS

From August 2005 to February 2013, 28 patients presenting an ACC treated by split-course external beam radiotherapy (EBRT) and HDR brachytherapy with or without chemotherapy in a French regional cancer center in Nice were retrospectively analyzed.

RESULTS

Median age was 60.6 years [34 - 83], 25 patients presented a squamous cell carcinoma and 3 an adenocarcinoma; 21 received chemotherapy. Median dose of EBRT was 45 Gy [43.2 - 52]. Median dose of HDR brachytherapy was 12 Gy [10 - 15] with a median duration of 2 days. Median overall treatment time was 63 days and median delay between EBRT and brachytherapy was 20 days. Two-year local relapse free, metastatic free, disease free and overall survivals were 83%, 81.9%, 71.8% and 87.7% respectively. Acute toxicities were frequent but not severe with mostly grade 1 toxicities: 37% of genito-urinary, 40.7% of gastro-intestinal and 3.7% of cutaneous toxicities. Late toxicities were mainly G1 (43.1%) and G2 (22%). Two-year colostomy-free survival was 75.1%, one patient had a definitive sphincter amputation.

CONCLUSION

High-dose rate brachytherapy for anal canal carcinoma as boost represents a feasible technique compared to low or pulsed-dose rate brachytherapy. This technique remains an excellent approach to precisely boost the tumor in reducing the overall treatment time.

VMAT planning study in rectal cancer patients

Background

To compare the dosimetric differences among fixed field intensity-modulated radiation therapy (IMRT), single-arc volumetric-modulated arc therapy (SA-VMAT) and double-arc volumetric-modulated arc therapy (DA-VMAT) plans in rectal cancer.

Method

Fifteen patients with rectal cancer previously treated with IMRT in our institution were selected for this study. For each patient, three plans were generated with the planning CT scan: one using a fixed beam IMRT, and two plans using the VMAT technique: SA-VMAT and DA-VMAT. Dose prescription to the PTV was 50 Gy in 2 Gy per fraction. Dose volume histograms (DVH) for the target volume and the organs at risk (small bowel, bladder, femoral heads and healthy tissue) were compared for these different techniques. Monitor units (MU) and delivery treatment time were also reported.

Results

DA-VMAT achieved the highest minimum planning target volume (PTV) dose and the lowest maximal dose, resulting in the most homogeneous PTV dose distribution. DA-VMAT also yielded the best CI, although the difference was not statistically significant. Between SA-VMAT and IMRT, the target dose coverage was largely comparable; however, SA-VMAT was able to achieve a better V95 and V107. VMAT showed to be inferior to IMRT in terms of organ at risk sparing, especially for the small bowel. Compared with IMRT, DA-VMAT increased the V15 of small bowel nearly 55 cc. The MU and treatment delivery time were significantly reduced by the use of VMAT techniques.

Conclusion

VMAT is a new radiation technique that combines the ability to achieve highly conformal dose distributions with highly efficient treatment delivery. Considering the inferior role of normal tissue sparing, especially for small bowel, VMAT need further investigation in rectal cancer treatment.

IMRT, RapidArc® and conformal radiotherapy in the treatment of tumours of the anal canal

Purpose

To compare dosimetric results of the use of RapidArc® with simultaneous integrated boost, sliding window intensity-modulated radiotherapy (IMRT) with simultaneous integrated boost, and conformal radiotherapy with sequential boost in the management of anal canal cancer.

Methods

Two patients with squamous cell cancer of the anal canal with compromised inguinal nodes were included. The simulation was performed in the supine position with a customized Vac-Lok™ immobilizer. Treatment volumes and organs at risk were defined in accordance with international recommendations. Dosimetric comparisons were made in the target volume by means of tumour conformity, coverage, and homogeneity indexes; in healthy organs, integral doses were compared.

Results

A similar planning target volume coverage was achieved with the three techniques. The two IMRT techniques demonstrated benefits in doses received by healthy organs compared to the conformal radiotherapy. RapidArc® showed reduction in the execution time and monitor units required for treatment compared with sliding window IMRT.

Conclusions

The IMRT showed coverage and tumour conformity indexes similar to those of conformal radiotherapy with better dosimetric results in the organs at risk, which should translate into a better toxicity profile. RapidArc® demonstrated benefits over the sliding window IMRT, which makes treatment more comfortable for the patient with less uncertainty about intrafraction motion and a reduced potential for radiation-induced tumours.

Prospective evaluation of acute toxicity and quality of life after IMRT and concurrent chemotherapy for anal canal and perianal cancer

PURPOSE

A prospective cohort study was conducted to evaluate toxicity, quality of life (QOL), and clinical outcomes in patients treated with intensity modulated radiation therapy (IMRT) and concurrent chemotherapy for anal and perianal cancer.

METHODS AND MATERIALS

From June 2008 to November 2010, patients with anal or perianal cancer treated with IMRT were eligible. Radiation dose was 27 Gy in 15 fractions to 36 Gy in 20 fractions for elective targets and 45 Gy in 25 fractions to 63 Gy in 35 fractions for gross targets using standardized, institutional guidelines, with no planned treatment breaks. The chemotherapy regimen was 5-fluorouracil and mitomycin C. Toxicity was graded with the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3. QOL was assessed with the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 and CR29 questionnaires. Correlations between dosimetric parameters and both physician-graded toxicities and patient-reported outcomes were evaluated by polyserial correlation.

RESULTS

Fifty-eight patients were enrolled. The median follow-up time was 34 months; the median age was 56 years; 52% of patients were female; and 19% were human immunodeficiency virus-positive. Stage I, II, III, and IV disease was found in 9%, 57%, 26%, and 9% of patients, respectively. Twenty-six patients (45%) required a treatment break because of acute toxicity, mainly dermatitis (23/26). Acute grade 3 + toxicities included skin 46%, hematologic 38%, gastrointestinal 9%, and genitourinary 0. The 2-year overall survival (OS), disease-free survival (DFS), colostomy-free survival (CFS), and cumulative locoregional failure (LRF) rates were 90%, 77%, 84%, and 16%, respectively. The global QOL/health status, skin, defecation, and pain scores were significantly worse at the end of treatment than at baseline, but they returned to baseline 3 months after treatment. Social functioning and appetite scores were significantly better at 12 months than at baseline. Multiple dose-volume parameters correlated moderately with diarrhea, skin, and hematologic toxicity scores.

CONCLUSION

IMRT reduces acute grade 3 + hematologic and gastrointestinal toxicities compared with reports from non-IMRT series, without compromising locoregional control. The reported QOL scores most relevant to acute toxicities returned to baseline by 3 months after treatment.

Evaluating QUANTEC Small Bowel Dose-Volume Guidelines for Rectal Cancer Patients Treated Using a Couch Top Inclined Belly Board

PURPOSE

The goal of this work was to analyse small bowel (SB) dose-volume following the Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) guidelines for rectal cancer patients treated using a couch top inclined belly board (iBB). As part of this, the consistency in SB displacement was evaluated using on-treatment cone-beam computed tomographic (CBCT) imaging.

METHODS

Twenty-four patients with rectal cancer were treated on a commercially available iBB. All patients went through the standard radiochemotherapy protocol in either a pre- or postoperative setup. All patients underwent weekly CBCT imaging during the course of radiation treatment. The planning computed tomographic data sets were used to analyze the quality of SB displacement, and the CBCT data sets were used to assess the reproducibility in SB displacement during treatment. The SB dose volume was evaluated and compared with QUANTEC-recommended dose limitations. Similarly, the impact of body mass index on dose volume and SB displacement was evaluated.

RESULTS

The SB displacement was assessed respectively as "good" and "very good" by both independent evaluating radiation oncologists. The consistency of SB displacement through the course of radiation treatment was scored as "excellent" for 22 of 24 and 23 of 24 patients by both radiation oncologists, respectively. The QUANTEC recommendation was met for all patients without bowel adhesions; however, the most benefit was observed for patients with body mass index > 23 kg/m².

CONCLUSIONS

Our study has shown that QUANTEC recommendations for SB dose during rectal cancer treatment can easily be met by treating patients on a couch top iBB. This technique is robust and produces consistent SB displacement.

Nanotechnology in radiation oncology

Nanotechnology, the manipulation of matter on atomic and molecular scales, is a relatively new branch of science. It has already made a significant impact on clinical medicine, especially in oncology. Nanomaterial has several characteristics that are ideal for oncology applications, including preferential accumulation in tumors, low distribution in normal tissues, biodistribution, pharmacokinetics, and clearance, that differ from those of small molecules. Because these properties are also well suited for applications in radiation oncology, nanomaterials have been used in many different areas of radiation oncology for imaging and treatment planning, as well as for radiosensitization to improve the therapeutic ratio. In this article, we review the unique properties of nanomaterials that are favorable for oncology applications and examine the various applications of nanotechnology in radiation oncology. We also discuss the future directions of nanotechnology within the context of radiation oncology.

Technical aspects of radiation therapy for anal cancer

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

Consequences of anorectal cancer atlas implementation in the cooperative group setting: radiobiologic analysis of a prospective randomized in silico target delineation study

PURPOSE

The aim of this study is to ascertain the subsequent radiobiological impact of using a consensus guideline target volume delineation atlas.

MATERIALS AND METHODS

Using a representative case and target volume delineation instructions derived from a proposed IMRT rectal cancer clinical trial, gross tumor volume (GTV) and clinical/planning target volumes (CTV/PTV) were contoured by 13 physician observers (Phase 1). The observers were then randomly assigned to follow (atlas) or not-follow (control) a consensus guideline/atlas for anorectal cancers, and instructed to re-contour the same case (Phase 2).

RESULTS

The atlas group was found to have increased tumor control probability (TCP) after the atlas intervention for both the CTV (p<0.0001) and PTV1 (p=0.0011) with decreasing normal tissue complication probability (NTCP) for small intestine, while the control group did not. Additionally, the atlas group had reduced variance in TCP for all target volumes and reduced variance in NTCP for the bowel. In Phase 2, the atlas group had increased TCP relative to the control for CTV (p=0.03).

CONCLUSIONS

Visual atlas and consensus treatment guideline usage in the development of rectal cancer IMRT treatment plans reduced the inter-observer radiobiological variation, with clinically relevant TCP alteration for CTV and PTV volumes.

Dosimetric coverage of the external anal sphincter by 3-dimensional conformal fields in rectal cancer patients receiving neoadjuvant chemoradiation: implications for the concept of sphincter-preserving radiation therapy

Background. We evaluated the anatomic location of the external anal sphincter (EAS) to pelvic bony landmarks related to 3-dimensional conformal radiotherapy (3DRT) and studied the dosimetric coverage of the EAS in patients undergoing neoadjuvant chemoradiation for rectal cancer. Methods. Sixty-four consecutive rectal cancer patients treated with neoadjuvant chemoradiation were included. All patients were treated in a prone position on a bellyboard by 3DRT. The inferior border of the RT fields was at least 3–5 cm inferior to the gross tumorous volume (GTV) or at the inferior border of the obturator foramen (IBOF), whichever was more inferior. The EAS was contoured and dose distributions were determined using dose-volume histograms. Results. In 53 out of 64 cases (82.8%), the EAS was completely inferior to the IBOF. In the remaining 11 cases, the EAS was either overlapping the IBOF (10 cases; 15.6%) or completely superior to the IBOF (1 case; 1.7%). The average mean dose delivered to the EAS was 2795 cGy. Lower mean doses were delivered to the EAS when the center of the EAS was located more distant from the GTV. Conclusions. Meticulous planning to define the inferior border of the RT field is recommended to avoid irradiating the EAS.

Chemoradiotherapy for anal cancer: clinical trials past, present and future

SUMMARY

Anal cancer is a rare cancer whose incidence is increasing in the UK. It is associated with human papilloma virus infection and smoking and is more common in women and immunosuppressed individuals, including those with transplants and HIV infection. The current standard of care is chemoradiotherapy (CRT) to the pelvis with surgery reserved for patients where CRT is contraindicated or as salvage treatment for residual disease or recurrence post-CRT. Radiotherapy combined with mitomycin-C and 5-fluorouracil has emerged as the standard of care following a series of six well-conducted Phase III trials. Trials have shown no benefit for cisplatin-based combination regimens either concurrently, adjuvantly or neoadjuvantly.