Anatomic study of the pelvis in carcinoma of the uterine cervix as related to the box technique

The issues regarding postoperative adjuvant therapy and prognostic risk factors for patients with stage I-II cervical cancer: A review

The treatment for most patients with early-stage cervical cancer involves radical hysterectomy and pelvic lymph node dissection, and indications for postoperative adjuvant therapy have been determined by evaluating the prognostic risk factors for recurrence in each case. The aim of this review is to raise and discuss the various issues that have not yet been resolved regarding the prognostic risk factors and postoperative adjuvant therapy. Several clinicopathological factors, such as tumor size, lymphovascular space involvement, deep stromal invasion, parametrial involvement and lymph node metastasis, have been identified to have prognostic significance in early-stage cervical cancer. However, this remains controversial because there is suggested to be substantial heterogeneity among patients after radical hysterectomy and lymphadenectomy and it would be difficult to define the risk groups clearly. This indicates the need to develop more convenient and accurate criteria to define risk groups. According to the currently available evidence, patients in the high-risk group should receive adjuvant concurrent chemoradiotherapy (CCRT) with cisplatin (CDDP) and fluolouracil. However, CCRT with CDDP administered weekly (CCRT-P) has instead been applied in a clinical context worldwide. Whether CCRT-P has a survival benefit compared with radiotherapy (RT) alone is unknown because no randomized phase III trials have been performed for patients in the high-risk group after radical surgery. Patients with high-risk factors have a high incidence of distant metastasis, for whom systemic chemotherapy might be a key to improving overall survival. The pivotal study that investigated the role of RT alone for patients with intermediate-risk factors after hysterectomy is the GOG092 trial. This trial showed a 47% reduction in the risk of recurrence after RT compared with no further treatment (NFT). However, the improvement in overall survival with RT did not reach statistical significance, while patients allocated to the RT group did experience an increase in severe toxicities compared with the NFT group. This could be why many physicians are reluctant to treat patients with this approach, although guidelines recommend RT for patients with intermediate-risk factors. With regard to toxicities, postoperative RT would be problematic because the organs in the pelvis targeted by RT have already been damaged by radical surgery. To reduce the toxicities, intensity-modulated radiotherapy would best be used worldwide. Further improvement in adjuvant therapy will come from enhanced definition of prognostic risk factors, better patient selection, and refinements in both local and systematic therapies.

CT Simulation to Evaluate of Pelvic Lymph Node Coverage in Conventional Radiotherapy Fields Based on Bone and Vessels Landmarks in Prostate Cancer Patients

BACKGROUND

Radiotherapy is the gold standard for treatment of prostrate cancer as it can cover an adequate area of tissues at risk for metastasis.

OBJECTIVES

We evaluated the Pelvic lymph node coverage of conventional radiotherapy fields based on bone and vessels landmarks using computed tomography (CT) simulation in patients with prostate cancer referred to Shohada-e-Tajrish hospital.

PATIENTS AND METHODS

In this cross sectional study, 40 patients with prostate cancer at the Stage T1c to T3b were studied. Pelvic lymph nodes were contoured by using pelvic vessels as surrogate markers. The distances were measured at different points of anterior-posterior (AP) and lateral fields and distances > 5 mm or more between the contoured nodes and the field borders.

RESULTS

Mean and standard deviation of the aortic bifurcation from the superior border was 4.73 ± 1.16 cm, the distance of common iliac bifurcation from the superior border was 1.11 ± 1.25 cm, the mean (SD) distance of right external iliac from the lateral border of AP field was 2.06 ± 0.48 cm and for left external iliac artery was 1.90 ± 0.56 cm. The distance of the external iliac artery from the anterior border of the lateral field was 2.30 ± 0.74 cm. The distance of the external iliac artery from pelvic rim was 0.59 ± 0.59 cm, distance of bifurcation of iliac from sacroiliac joint was 0.82 ± 1.01 cm, the size of the pelvic rim was 12.30 ± 0.64 cm, sacral width was 8.29 ± 1.01 cm, anterior promontory symphysis distance was 12.02 ± 0.92 cm and posterior promontory symphysis distance was 10.98 ± 0.73 cm.

CONCLUSIONS

We observed that conventional radiotherapy using CT simulation based on bone and vessels landmarks provided adequate coverage of pelvic lymph nodes in our patients with prostate cancer.

A practical review of magnetic resonance imaging for the evaluation and management of cervical cancer

Cervical cancer is a leading cause of mortality in women worldwide. Staging and management of cervical cancer has for many years been based on clinical exam and basic imaging such as intravenous pyelogram and x-ray. Unfortunately, despite advances in radiotherapy and the inclusion of chemotherapy in the standard plan for locally advanced disease, local control has been unsatisfactory. This situation has changed only recently with the increasing implementation of magnetic resonance image (MRI)-guided brachytherapy. The purpose of this article is therefore to provide an overview of the benefits of MRI in the evaluation and management of cervical cancer for both external beam radiotherapy and brachytherapy and to provide a practical approach if access to MRI is limited.

Pelvic nodal CTV from L4-L5 or aortic bifurcation? An audit of the patterns of regional failures in cervical cancer patients treated with pelvic radiotherapy

OBJECTIVE

To assess the patterns of recurrence in cervical cancer patients treated with pelvic nodal clinical target volume at L4-L5 junction instead of aortic bifurcation.

METHODS

Records of patients with locally advanced cervical cancer treated with chemo-radiation were reviewed. Patients treated with standard pelvic fields (superior border of the field at L4/L5 junction), without any radiological evidence of regional lymphadenopathy (<10 mm) were included in the study. The level of aortic bifurcation was retrospectively documented on computed tomography. Patterns of recurrences were correlated to the aortic bifurcation and the superior border of the radiation fields (L4/L5).

RESULTS

Aortic bifurcation was above the radiation fields (above L4/5) in 82 of 116 (70.7%) patients. Of the nine patients that recurred above the radiation field, 5 (55%) were above L4/5 failures, i.e. between aortic bifurcation and L4/5, and 4 (45%) had para-aortic failures. On retrospective analysis, 16 patients were found to have subcentimeter lymph nodes and higher nodal failures (7/16) were observed in patients with subcentimeter regional lymph nodes at diagnosis.

CONCLUSIONS

Superior border of nodal clinical target volume should ideally include the aortic bifurcation instead of L4-L5 inter space in patients with locally advanced cervical cancer. Radiotherapy fields need to be defined cautiously in patients with subcentimeter pelvic lymph nodes.

Conventional four field radiotherapy versus computed tomography-based treatment planning in cancer cervix: A dosimetric study

Background:

With advancements in imaging, wide variations in pelvic anatomy have been observed, thus raising doubts about adequate target volume coverage by conventional external radiotherapy fields based on bony landmarks. The present study evaluates the need for integrating computed tomography (CT)-based planning in the treatment of carcinoma cervix.

Aims:

To estimate inadequacies in target volume coverage when using conventional planning based on bony landmarks.

Materials and Methods:

The study consisted of 50 patients. Target volume delineation was done on planning CT scans, according to the guidelines given in literature. The volume of target receiving 95% of prescribed dose (V95) was calculated after superimposing a conventional four field box on digitally reconstructed radiograph. The geographic miss with conventional four field box technique was compared with the CT-based target volume delineation.

Results:

In 48 out of 50 patients, the conventional four field box failed to encompass the target volume. The areas of miss were at the superior and lateral borders of the anterior-posterior fields, and the anterior border of the lateral fields. The median V95 for conventional fields marked with bony landmarks was only 89.4% as compared to 93% for target delineation based on CT contouring.

Conclusions:

Our study shows inadequate target volume coverage with conventional four field box technique. We recommend routine use of CT-based planning for treatment with radiotherapy in carcinoma cervix.

Dosimetric comparison between conventional and conformal radiotherapy for carcinoma cervix: Are we treating the right volumes?

Background and Purpose:

Conventional portals, based on bony anatomy, for external beam radiotherapy for cervical cancer have been repeatedly demonstrated as inadequate. Conversely, with image-based conformal radiotherapy, better target coverage may be offset by the greater toxicities and poorer compliance associated with treating larger volumes. This study was meant to dosimetrically compare conformal and conventional radiotherapy.

Materials and Methods:

Five patients of carcinoma cervix underwent planning CT scan with IV contrast and targets, and organs at risk (OAR) were contoured. Two sets of plans-conventional and conformal were generated for each patient. Field sizes were recorded, and dose volume histograms of both sets of plans were generated and compared on the basis of target coverage and OAR sparing.

Results:

Target coverage was significantly improved with conformal plans though field sizes required were significantly larger. On the other hand, dose homogeneity was not significantly improved. Doses to the OARs (rectum, urinary bladder, and small bowel) were not significantly different across the 2 arms.

Conclusion:

Three-dimensional conformal radiotherapy gives significantly better target coverage, which may translate into better local control and survival. On the other hand, it also requires significantly larger field sizes though doses to the OARs are not significantly increased.

Dose to organs at risk in the upper abdomen in patients treated with extended fields by helical tomotherapy: a dosimetric and clinical preliminary study

Background

The aim of this work was to determine the technical feasibility and safety of extended-field radiotherapy (EF), performed by Helical TomoTherapy, in patients with positive pelvic and/or para-aortic nodes. Dosimetric data were collected and acute and sub-acute toxicities of the upper abdominal organs at risk (OAR) were evaluated.

Methods

Twenty-nine patients suitable for EF irradiation for local disease and/or nodal disease in the pelvic or para-aortic area were treated. The prescription dose was 50.4/54 Gy (1.7-1.8 Gy/fraction) for prophylactic lymph nodes (N-) and 60–70.5 Gy (2–2.35 Gy/fraction) for clinically evident gross disease (N+). Modulation factor (MF), pitch and field width (FW) were chosen to optimize dose distribution and treatment duration. Dose values of PTVs and OAR were analysed. The length of the treatment field, the N + and N- volumes, and treatment duration were reported. To evaluate the safety of treatment, haematological, hepatic, renal and pancreatic functions were assessed before, during and after treatment. The median follow-up time was 17.6 months (range: 6–22 months).

Results

The treatment was well tolerated and all patients but one completed treatment without interruption. Four of the 29 patients experienced G3 haematological acute toxicity (13.8%), but no patient experienced sub-acute grade G3 toxicity. Ten patients experienced G1 and three G2 acute gastrointestinal toxicity (nausea). No sub-acute gastrointestinal or renal toxicity was observed. Only one (3.7%) patient had a persistent slight increase of pancreatic enzymes and two (7.4%) patients a slight increase of hepatic enzymes six months after radiotherapy (G1 toxicity).

Conclusions

With our treatment design and dose regimen, we found that EF treatment by TomoTherapy could be safely and effectively delivered with minimal acute and sub-acute toxicities in the upper abdomen area.

Better survival with three-dimensional conformal radiotherapy than with conventional radiotherapy for cervical cancer: a population-based study

Three-dimensional conformal radiation therapy (3DCRT) has emerged as a preferred treatment for gynecologic malignancies. Yet its superiority to conventional radiotherapy (2-dimensional radiotherapy (2DRT)) for gynecologic malignancies has not been well established. Data from the 2005 to 2010 National Health Insurance Research Database (NHIRD) provided by the National Research Institutes in Taiwan were analyzed to address this issue. Patients were initially diagnosed as having cervical cancer according to the International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) code 180, and this clinical diagnosis was confirmed histopathologically or cytologically. Kaplan-Meier method and Cox proportional hazards regression were used to analyze the reported data. Between January 2005 and December 2010, there were 776 patients with newly diagnosed cervical cancer without metastasis, local recurrence, or surgical treatment before RT and 132 and 644 patients, respectively, who received 2DRT and 3DCRT. After adjustment for age, diabetes mellitus, hypertension, coronary heart disease, hyperlipidemia, side effects, urbanization level, geographic region, and enrollee category in the 5-year follow-up period, the HR was 1.82 (95% CI, 1.16–2.85, P = 0.009). The 5-year survival rate in the 2DRT and 3DCRT groups was 73.0% and 82.3%, P = 0.007, respectively. Cervical cancer patients treated with 3DCRT had better overall survival.

ACR Appropriateness Criteria® role of adjuvant therapy in the management of early stage cervical cancer

OBJECTIVE

The use of adjuvant treatment(s) following initial hysterectomy and retroperitoneal nodal harvesting of patients with clinical stage I and II cervical carcinoma is (are) presently based on the pathological assessment of surgical specimens. This report sought to delineate further the clinical application of potential therapeutic interventions and associated follow-up investigations of this patient cohort.

METHODS

The American College of Radiology (ACR) Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journal and the application of a well-established consensus methodology (modified Delphi) to rate appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

RESULTS

From this process, 5 unique clinical variants were developed. These scenarios pertained to options of adjuvant radiation therapy and chemotherapy, methods of delivery of radiotherapy to optimize target volume coverage while simultaneously minimizing radiation exposure of adjacent healthy organs, and recommendations for patient follow-up care. Group members reached consensus of topic ratings in descending order of importance. A risk assessment breakdown was established to highlight the most likely indications for adjuvant treatment(s).

CONCLUSION

This assembly by the ACR of physicians involved in the management of patients with early stage cervical cancer was able to describe appropriateness criteria to aid other practitioners in selecting reasonable implementation of postoperative therapies and subsequent surveillance studies. These guidelines await further validation and refinement by both current and future prospectively randomized clinical studies regarding this patient population.

Modern Radiotherapy and Cervical Cancer

For most cervical cancers, radiotherapy is the mainstay of treatment. The introduction of concurrent chemotherapy to radiation at the end of the 20th century led to a significant improvement in disease survival. Now, techniques such as intensity-modulated radiotherapy, which allow a high degree of conformity to the tumor, offer the opportunity to further improve outcome by reducing treatment-related toxicity and also to potentially improve local control by an increase in tumor dose.

This review will outline the history and current state of play of cervical radiotherapy.

Ressonância magnética para avaliação dos limites dos campos clássicos de radioterapia em pacientes portadoras de neoplasia maligna de colo uterino

OBJETIVO: Avaliar os limites de campo padronizados para radioterapia de neoplasia maligna de colo uterino com o uso de ressonância magnética e verificar a importância deste exame na redução de possíveis erros de planejamento com técnica convencional. MATERIAIS E MÉTODOS: Foram analisados, retrospectivamente, exames de ressonância magnética do planejamento de 51 pacientes tratadas devido a neoplasia de colo uterino. Os parâmetros estudados foram limites anterior e posterior no corte sagital. RESULTADOS: Observou-se, no corte sagital das ressonâncias magnéticas, que o limite de campo anterior apresentou-se inadequado em 20 (39,2%) pacientes e que houve perda geográfica em 37,3% dos casos no limite posterior. A inadequação de ambos os limites de campo não se relacionou com parâmetros clínicos como idade das pacientes, estadiamento, tipo e grau histológico. CONCLUSÃO: A avaliação dos limites de campo padronizados pela literatura com o uso de ressonância magnética mostrou altos índices de inadequação dos limites do campo lateral, assim como a importância do uso deste exame no planejamento radioterápico de pacientes portadoras de câncer de colo uterino com a finalidade de reduzir a perda geográfica no volume alvo de tratamento.

Evaluation of pelvic lymph node coverage of conventional radiotherapy fields based on bony landmarks in Chinese cervical cancer patients using CT simulation

OBJECTIVE

To evaluate the pelvic lymph node coverage of conventional pelvic fields based on bony landmarks in Chinese patients with cervical cancer by using computed tomography (CT) simulation images to contour pelvic vessels as substitutes for lymph nodes location.

METHODS

A retrospective review of CT simulation images and conventional pelvic radiation planning data sets was performed in 100 patients with cervical cancer at the International Federation of Gynecology and Obstetrics (FIGO) Stage IIB to IIIB in our hospital. Pelvic arteries were contoured on CT simulation images, and the outlines of conventional pelvic fields were drawn as defined by the gynecologic oncology group (GOG) after hiding the contours. The distances between the following vessel contours and field borders were measured: D(1), the superior border of the anterior/posterior (AP) field and the bifurcation of abdominal aorta; D(2), the ipsilateral border of the AP field and the distal end of external iliac artery; and D(3), the anterior border of the lateral (LAT) field and the distal end of the external iliac artery. The distances were recorded as positive values if the measuring point was within the conventional pelvic fields, or they were recorded as negative values. Lymph nodes coverage was considered adequate when D(1)(0 mm, D(2)(17 mm or D(3)(7 mm.

RESULTS

All patients had at least 1 inadequate margin, 97 patients (97.0%) had 2, and 22 patients (22.0%) had all the 3. On the AP field, 95 patients (95%) had the measuring point, the bifurcation of the abdominal aorta, out of the field (D(1)<0 mm), and all the patients had a distance less than 17.0 mm between the distal end of the external iliac artery and ipsilateral border (D(2)<17.0 mm). On the LAT field, 24 patients (24%) had a distance less than 7.0 mm between the distal end of the external iliac artery and anterior border (D(3)<7.0 mm).

CONCLUSION

We observed that conventional pelvic fields based on bony landmarks provided inadequate coverage of pelvic lymph nodes in our patients with cervical cancer. CT simulation may be a feasible technique for planning pelvic fields optimally and individually.

Clinical tumor dimensions may be useful to prevent geographic miss in conventional radiotherapy of uterine cervix cancer-a magnetic resonance imaging-based study

PURPOSE

To evaluate the risk of geographic miss associated with the classic four-field "box" irradiation technique and to define the variables that predict this risk.

MATERIALS AND METHODS

The study population consisted of 80 patients with uterine cervix cancer seen between 2001 and 2006. Median age was 55 years (23-82 years), and 72 (90%) presented with squamous cell carcinoma. Most patients (68.7%) presented with locally advanced disease (IIb or more). Magnetic resonance imaging findings from before treatment were compared with findings from simulation of the conventional four-field "box" technique done with rectal contrast. Study variables included tumor volume; involvement of vagina, parametrium, bladder, or rectum; posterior displacement of the anterior rectal wall; and tumor anteroposterior diameter (APD). Margins were considered adequate when the target volume (primary tumor extension, whole uterine body, and parametrium) was included within the field limits and were at least 1 cm in width.

RESULTS

Field limits were inadequate in 45 (56%) patients: 29 (36%) patients at the anterior and 28 (35%) at the posterior border of the lateral fields. Of these, 12 patients had both anterior and posterior miss, and this risk was observed in all stages of the disease (p = 0.076). Posterior displacement of the anterior rectal wall beyond S2-S3 was significantly correlated with the risk of geographic miss (p = 0.043). Larger tumors (APD 6 cm or above and volume above 50 cm(3)) were also significantly correlated with this risk (p = 0.004 and p = 0.046, respectively).

CONCLUSIONS

Posterior displacement of the anterior rectal wall, tumor APD, and volume can be used as guidance in evaluating the risk of geographic miss.

Conformal and intensity-modulated radiotherapy for cervical cancer

Three-dimensional radiotherapy planning techniques, including conformal radiotherapy and intensity-modulated radiotherapy, have potential for improving outcomes in cervical cancer. Accurate target volume definition is essential in order to maximise normal tissue sparing while minimising the risk of a geographical miss. This reduction in toxicity provides the option of dose escalation, particularly with simultaneous integrated boost intensity-modulated radiotherapy. The evidence for the current use and potential applications of these techniques in the treatment of cervical cancer are discussed.

The use of MRI in planning radiotherapy for gynaecological tumours

Parameters that significantly influence results in radiation treatment of gynaecological malignancies are mainly related to the tumour characteristics and the radiotherapy technique used. High-dose radiotherapy requires accurate localisation of the tumour volume and its relationship to surrounding normal tissues. For many years the standard technique used for irradiation of the pelvic area was the four-field box technique which offered the potential benefit of the lateral fields to shield the rectum and small bowel. However, this conventional technique was designed according to bony landmarks and offered limited information regarding the topography of the tumour and the flexion of the uterus which are influenced by the tumour burden and bladder and rectal filling. CT and MRI enable the visualisation of the cervix, uterus, vagina, iliac vessels and organs at risk, but MRI allows tumour depiction in all planes. In the early 1990s, several studies reported on the value of pelvic MRI in designing the lateral fields of the box technique. They demonstrated that conventional lateral portals would have resulted in a marginal tumour miss and incomplete coverage of the uterine fundus in more than 50% of cases, thus leading to the conclusion that if a box technique is used its design should be based on sagittal MRI. CT-based 3D planning systems are now routinely used in the vast majority of radiotherapy departments. Target volumes and organs at risk are delineated by the physician on each CT slice in order to conform the radiotherapy fields to the tumour volume. For several reasons, such as distortion and lack of electron density which is essential for dose calculation, the implementation of MRI into radiation treatment planning has its limitations. However, MRI can still be used if planning systems integrate tools for CT/MR image registration. There is little experience in the literature for gynaecological malignancies demonstrating that image fusion allows an improvement of the definition of the target and the organ at risk compared to CT alone. Only a few papers in the literature report on the use of CT/MR image registration in planning the external irradiation of gynaecological tumours. Most demonstrate feasibility, but they fail to quantify the improvement for volume definition compared to the use of CT alone. Finally, recent possibilities offered by MRI technology are promising in the area of brachytherapy planning as the full potential of individually defining and evaluating GTV and CTV based on tumour extent and anatomical structures is exploited.

Postoperative radiation therapy for carcinoma of the uterine cervix

Postoperative radiation therapy (PORT) for cervical cancer has been empirically performed for patients with pathologic risk factors for recurrence after surgery. The efficacy of PORT is mainly supported by retrospective studies. Despite convincing evidence demonstrating a reduction in pelvic recurrence rates when PORT is employed, there is no evidence that it eventually improves patient survival. Local recurrence, such as vaginal stump recurrence, is not always fatal if diagnosed earlier. Some patients, unfortunately, may develop distant metastases even after PORT. The positive effects of PORT also may be counterbalanced by increased toxicities that result from combining local therapies. These factors obscure the efficacy of PORT for cervical cancer patients. There has been no consensus on the predictive value of risk factors for recurrence, which renders indication of PORT for early-stage cervical cancer quite variable among institutions. Today, efforts have been made to divide patients into three risk groups based on the combination of risk factors present after radical hysterectomy. In Europe/USA and Japan, however, a fundamental difference exists in the indications for radical surgery, highlighting differences in the concept of PORT; "adjuvant pelvic irradiation for stage IB-IIA patients after complete resection" in Europe/USA and "pelvic irradiation after surgery irrespective of initial clinical stage and surgical margin status" in Japan. Thus, it is questionable whether scientific evidence established in Europe/USA is applicable to Japanese clinical practice. The purpose of this article is to review the role of PORT by interpreting the results of clinical studies.

Valor da ressonância magnética no planejamento radioterápico dos tumores de colo de útero: resultados preliminares

OBJETIVO: Verificar o índice de erros geográficos no planejamento radioterápico convencional de pacientes com carcinoma de colo uterino por meio da ressonância magnética. MATERIAIS E MÉTODOS: Trinta e duas pacientes com diagnóstico histológico de carcinoma espinocelular de colo uterino, com indicação de radioterapia, foram analisadas. Foi realizada ressonância magnética da pelve, sendo essas imagens comparadas aos campos clássicos de radioterapia, técnica de quatro campos em "tijolo". Considerou-se erro geográfico quando o volume alvo não foi englobado pelos campos, com margens mínimas de 1 cm. RESULTADOS: Em 24 pacientes (75%) foi detectada possibilidade de erro geográfico se fossem utilizados os campos convencionais. Em todos os casos o erro foi à custa dos limites anterior (46%) ou posterior (40%) dos campos laterais. CONCLUSÃO: A ressonância magnética evidenciou chance elevada de erro geográfico no planejamento radioterápico convencional na população analisada, tanto nas pacientes com doença em estádios iniciais quanto avançados.

A three-dimensional definition of nodal spaces on the basis of CT images showing enlarged nodes for pelvic radiotherapy

PURPOSE

To demonstrate that margins of each pelvic chain may be derived by verifying the bony and soft tissue structures around abnormal nodes on computed tomography (CT) slices.

METHODS AND MATERIALS

Twenty consecutive patients (16 males, 4 females; mean age, 66 years; range, 43-80 years) with radiologic diagnosis of nodal involvement by histologically proved cervix carcinoma (two), rectum carcinoma (three), prostate carcinoma (four), lymphoma (five), penis carcinoma (one), corpus uteri carcinoma (one), bladder carcinoma (two), cutis tumor (one), and soft-tissue sarcoma (one) were retrospectively reviewed. One hundred CT scans showing 85 enlarged pelvic nodes were reviewed by two radiation oncologists (M.P., S.B.), and two radiologists (C.P., G.A.).

RESULTS

The more proximal structures to each enlarged node or group of nodes were thus recorded in a clockwise direction.

CONCLUSION

According to their frequency and visibility, craniocaudal, anterior, lateral, posterior and medial margins of common iliac, external and internal iliac nodal chains, obturator and pudendal nodes, and deep and superficial inguinal nodes were derived from CT observations.

Use of CT simulation for treatment of cervical cancer to assess the adequacy of lymph node coverage of conventional pelvic fields based on bony landmarks

PURPOSE

To assess the adequacy of nodal coverage of "conventional" pelvic radiation fields for carcinoma of the cervix, with contoured pelvic vessels on simulation computed tomography (CT) as surrogates for lymph node location.

METHODS AND MATERIALS

Pelvic arteries were contoured on non-contrast-enhanced CT simulation images of 43 patients with cervix cancer, FIGO Stages I-III. Vessel contours were hidden, and conventional pelvic fields were outlined: (1) anterior/posterior fields (AP): superior border, L5-S1 interspace; inferior border, obturator foramina; lateral border, 2 centimeters lateral to pelvic brim. (2) Lateral fields (LAT): Anterior border, symphysis pubis; posterior border, S2-S3 interspace. Distances were measured between the following: (1) bifurcation of the common iliac artery and superior border, (2) external iliac artery and lateral border of the AP field, and (3) external iliac artery and anterior border of the LAT field. The distances were considered as "inadequate" if <15 mm, "adequate" if 15-20 mm, and "generous" if >20 mm.

RESULTS

Superiorly, 34 patients (79.1%) had inadequate coverage. On the AP, margins were generous in 19 (44.2%), but inadequate in 9 (20.9%). On the LAT, margins were inadequate in 30 (69.8%) patients. Overall, 41 (95.4%, CI, 84.2%-99.4%) patients had at least 1 inadequate margin, the majority located superiorly. Twenty-four (55.8%; CI, 39.9%-70.9%) patients had at least 1 generous margin, the majority located laterally on the AP field.

CONCLUSION

Conventional pelvic fields based on bony landmarks do not provide optimal lymph node coverage in a substantial proportion of patients and may include excess normal tissue in some. CT simulation with vessel contouring as a surrogate for lymph node localization provides more precise and individualized field delineation.

Conventional, conformal, and intensity-modulated radiation therapy treatment planning of external beam radiotherapy for cervical cancer: The impact of tumor regression

PURPOSE

Investigating the impact of tumor regression on the dose within cervical tumors and surrounding organs, comparing conventional, conformal, and intensity-modulated radiotherapy (IMRT) and the need for repeated treatment planning during irradiation.

METHODS AND MATERIALS

Fourteen patients with cervical cancer underwent magnetic resonance (MR) imaging before treatment and once during treatment, after about 30 Gy. Target volumes and critical organs were delineated. First conventional, conformal, and IMRT plans were generated. To evaluate the impact of tumor regression, we calculated dose-volume histograms for these plans, using the delineations of the intratreatment MR images. Second conformal and IMRT plans were made based on the delineations of the intratreatment MR images. First and second plans were compared.

RESULTS

The average volume receiving 95% of the prescribed dose (43 Gy) by the conventional, conformal, and IMRT plans was, respectively, for the bowel 626 cc, 427 cc, and 232 cc; for the rectum 101 cc, 90 cc, and 60 cc; and for the bladder 89 cc, 70 cc, and 58 cc. The volumes of critical organs at this dose level were significantly reduced using IMRT compared with conventional and conformal planning (p < 0.02 in all cases). After having delivered about 30 Gy external beam radiation therapy, the primary gross tumor volumes decreased on average by 46% (range, 6.1-100%). The target volumes on the intratreatment MR images remained sufficiently covered by the 95% isodose. Second IMRT plans significantly diminished the treated bowel volume, if the primary gross tumor volumes decreased >30 cc.

CONCLUSIONS

Intensity-modulated radiation therapy is superior in sparing of critical organs compared with conventional and conformal treatment, with adequate coverage of the target volumes. Intensity-modulated radiation therapy remains superior after 30 Gy external beam radiation therapy, despite tumor regression and internal organ motion. Repeated IMRT planning can improve the sparing of the bowel and rectum in patients with substantial tumor regression.

Conventional 4-field box radiotherapy technique for cancer cervix: potential for geographic miss without CECT scan-based planning

BACKGROUND

The advantage of 4-field radiation to the pelvis is that the use of lateral portals spares a portion of the small bowel anteriorly and rectum posteriorly. The standard lateral portals defined in textbooks are not always adequate especially in advanced cancer cervix.

METHODS

An analysis was done to determine adequacy of margins of standard lateral pelvic portals with CECT defined tumor volumes. The study included 40 patients of FIGO stage IIB and IIIB treated definitively for cancer cervix between 1998 and 2000. An inadequate margin was defined if the cervical growth and uterus were not encompassed by the 95% isodose.

RESULTS

An inadequate posterior margin was common with bulky disease (P = 0.06) and with retroverted uterus (P = 0.08). Menopausal status, FIGO stage, associated myoma, and age were of no apparent prognostic significance. Bulk retained significant on multivariate analysis. An inadequate anterior margin was common in premenopausal (P = 0.01); anteverted uterus (P = 0.02); associated myoma (P = 0.01); and younger patients (P = 0.03). It was not influenced by bulk or stage. Menopausal status and associated myoma retained significant on multivariate analysis.

CONCLUSION

Without the knowledge of precise tumor volume, the 4-field technique with standard portals is potentially risky as it may under dose the tumor through lateral portals and the standard AP/ PA portals are a safer option.

Clinical and anatomical guidelines in pelvic cancer contouring for radiotherapy treatment planning

BACKGROUND AND PURPOSE

Many observations on potential inadequate coverage of tumour volume at risk in advanced cervical cancer (CC) when conventional radiation fields are used, have further substantiated by investigators using MRI, CT or lymphangiographic imaging. This work tries to obtain three dimensional margins by observing enlarged nodes in CT scans in order to improve pelvic nodal chains clinical target volumes (CTVs) drawing, and by looking for corroborative evidence in the literature for a better delineation of tumour CTV.

METHOD

Eleven consecutive patients (seven males, four females, mean age 62 years, range 43-78) with CT diagnosis of nodal involvement caused by pathologically proved carcinoma of the cervix (n = 2), carcinoma of the rectum (n = 2), carcinoma of the prostate (n = 2), non-Hodgkin lymphoma (n = 2), Hodgkin lymphoma (n = 1), carcinoma of the penis (n = 1) and carcinoma of the corpus uteri (n = 1) were retrospectively reviewed. Sixty CT scans with 67 enlarged pelvic nodes were reviewed in order to record the more proximal structures (muscle, bone, vessels, cutis or subcutis and other organs) to each enlarged node or group of nodes according to the four surfaces (anterior, lateral, posterior and medial) in a clockwise direction.

RESULTS

A summary of the observations of each nodal chain and the number of occurrences of every marginal structure on axial CT slices is presented. Finally, simple guidelines are proposed.

CONCLUSIONS

Tumour CTV should be based on individual tumour anatomy-mainly for lateral beams as it results from sagittal T2 weighted MRI images. Boundaries of pelvic nodes CTVs can be derived from observations of enlarged lymph nodes in CT scans.

Clinical effects in a cohort of cancer patients overexposed during external beam pelvic radiotherapy

PURPOSE

To evaluate the clinical outcome of 28 overexposed cancer patients in a cohort of 153 treated with pelvic irradiation and to correlate the outcome with the doses received.

METHODS AND MATERIALS

Between August 2000 and March 2001, 153 patients were treated at the Instituto Oncológico Nacional of Panama with radiotherapy for cancers of the cervix, uterus, endometrium, prostate, and rectum using conventional techniques. In 56 patients, irradiated with partially blocked teletherapy fields, the treatment times were determined using a treatment planning system that generated isodose distributions. The absorbed doses received by the patients were calculated and the biologically effective doses (BEDs) and 2-Gy equivalent doses derived. The clinical outcome was evaluated using the Radiation Therapy Oncology Group (RTOG) and late effects on normal tissues-subjective, objective, management, analytic scales (LENT/SOMA). The relationships between clinical outcome and dose were investigated and compared with published data.

RESULTS

Of the 56 patients for whom treatment times were generated with the treatment planning system, 28 received some doses per fraction approximately double those prescribed. Using an alpha/beta = 10 Gy, the tumor BED(10) values ranged from 77 to 225 Gy. The rest of the patients received doses within 10% of the prescribed values. Seventeen of the 28 overexposed patients died 35 days to 21 months after treatment; 13 of the fatalities were caused by rectal complications. Survival was longer in those patients who had undergone colostomy. Bladder complications were less enhanced. The nonoverexposed patients with cervical cancer exhibited a greater incidence of treatment failures than generally reported in other centers.

CONCLUSION

This study provides the clinical outcome after high doses of pelvic radiotherapy in a range not previously well documented. For cervical cancer patients receiving both tele- and brachytherapy, some deaths in this overexposure cohort occurred from assumed consequential rectal injury within 2 years, when the BED(10) values exceeded 70-80 Gy. The incidence was asymptotic to 100% fatalities at >150 Gy. This confirmed and extended other data in the literature.

Radiation fields in gynecologic oncology: correlation of soft tissue (surgical) to radiologic landmarks

OBJECTIVES

(1). To determine if radiation fields defined by bony structure landmarks correlate to anatomic boundaries of lymph node dissection marked intraoperatively; and (2). to determine if a patient's body mass index (BMI) correlates with these anatomic or radiographic boundaries.

METHODS

One hundred patients undergoing exploratory laparotomy with pelvic and paraaortic lymph node dissection had three medium hemoclips placed at vascular junctions considered of clinical significance to lymph node dissection: insertion of the left ovarian vein into the renal vein, insertion of the right ovarian vein into the vena cava, inferior mesenteric artery (IMA), bifurcation of the aorta, bifurcation of the common iliacs (bilateral), and the insertion of the deep circumflex vein (DCV) in to the external iliac vein (bilateral). Postoperatively, an abdominal X-ray was obtained. Comparisons were made between these eight major vascular landmarks and radiographic bony landmarks that are used to define radiation field boundaries. The percentage of vascular landmarks that were encompassed or fell outside of traditional radiation fields was determined with a 1-cm margin considered an adequate boundary for radiation. These measurements were also compared to patient BMIs.

RESULTS

Radiation fields defined by traditional bony landmarks would adequately encompass the paraaortic lymph nodes in the majority of patients (91%). For pelvic radiation fields, there was a significant "miss" (39%) of common iliac lymph nodes. Approximately one quarter (26%) of patients would receive inadequate coverage of one or both of the lateral boundaries of pelvic radiation. There was no apparent correlation of BMI to vascular or bony landmarks.

CONCLUSIONS

Radiation fields determined by traditional bony landmarks do not adequately reflect the anatomic (surgical) landmarks associated with the lymphatic drainage of the female reproductive organs. Although the majority of tertiary care centers now use advanced imaging techniques (e.g. computed tomography) to plan their radiation treatments, the historical guidelines of radiographic landmarks are still used in smaller institutions and continue to be referenced in Gynecologic Oncology Group protocols. For centers still using radiographic landmarks, the application of hemoclips with X-ray identification is a low-cost modality that is easily reproducible and may be clinically useful in guiding treatment.

Pelvic insufficiency fractures in postmenopausal woman with advanced cervical cancer treated by radiotherapy

PURPOSE

To assess the predisposing factors and clinical characteristics of pelvic insufficiency fractures (PIF) in postmenopausal women with pelvic irradiation.

MATERIAL AND METHODS

A total 335 postmenopausal patients with cervical cancer of the intact uterus treated with radiation therapy between 1983 and 1998 were reviewed. Total external dose was delivered between 45 and 50.4 Gy with parallel opposed anteroposterior portals. Total brachytherapy dose at point A was delivered between 10 and 36 Gy. PIF were diagnosed by bone scintigraphy and confirmed by computed tomography. The cumulative incidence of symptomatic PIF was estimated by actuarial methods. Potential risk factors (age, weight, type II diabetes, delivery, menopause, total external dose, total brachytherapy dose) were assessed.

RESULTS

Fifty-seven (17.0%) of 335 patients were diagnosed as having PIF. Forty-seven patients were symptomatic and ten were asymptomatic. Parameters carrying a significant association with PIF were body weight 49 kg or below (P=0.044) in stepwise logistic regression analysis. The cumulative incidence of symptomatic PIF at 5 years was 17.9% calculated by the Kaplan-Meier method. A body weight of 49 kg or below and more than three deliveries were identified as having a significant effect on symptomatic PIF in univariate analysis (P=0.021, P=0.003, log-rank test) and Cox life table regression analysis (P=0.038, P=0.013). Five patients required narcotic agents and eight patients required hospital admission.

CONCLUSIONS

We should consider reducing the dose contribution to the sacrum and sacroilac joints, without underdosing the tumor, especially in postmenopausal women with many deliveries or low body weight.

Results of radiation therapy for uterine cervical cancer using high dose rate remote after loading system

In Japan, radiotherapy with high dose rate remote after loading system (HDR-RALS) for intracavitary brachytherapy is the standard treatment for more than 30 years. This report showed the usefulness of HDR-RALS for uterine cervical cancer. From 1980 through 1999, 442 patients with uterine cervical cancers (stage I: 66, stage II: 161, stage III: 165, stage IV: 50) were treated. Radiotherapy was performed both external teletherapy and HDR-RALS. Overall survival rate at 5 years was 60.2%. The 5-year actuarial incidence of all complications was 16.4%. The 5-year actuarial incidence of all complications in cases treated with the sum doses of whole pelvic irradiation (without central shield) and RALS up to 49 Gy, 50 to 59 Gy or larger doses were 7.5%, 11.0% and 25.2%, respectively. Radiation therapy using HDR-RALS was very effective. While the dose of whole pelvic irradiation was increased, the actuarial incidence of all complications was increased.

How iliopelvic lymphoscintigraphy can affect the definition of planning target volume in radiation therapy of pelvic and testicular tumors

PURPOSE

External beam radiation therapy (EBRT) of most intrapelvic and testicular tumors has been generally performed with large fields encompassing both the primary disease and lymphatic drainage. This study was carried out to map the pelvic and periaortic lymphatics by means of iliopelvic lymphoscintigraphy (IPL) in preparation for radiotherapy planning.

METHODS AND MATERIALS

Between January 2000 and October 2001, 70 patients scheduled for EBRT (61 operated on, 52 females, 18 males, mean age 61, range, 24-80), affected with uterine (43), rectal (11), testicular (8), anal (4), penile (2), and vulvar (2) cancers were enrolled in the study. IPL was performed by injection of 99mtechnetium-nanocolloids in the bipedal (70 cases) or bipedal plus perianal (20 cases) sites. The sensitivity of IPL in mapping the lymphatic anatomy was evaluated first. Then three radiation oncologists scored the modifications induced by IPL on the planning target volume (PTV) which had been previously delineated only on the basis of bony landmarks. The original fields were classified "inadequate" if they failed to match the new PTV by more than 1 cm.

RESULTS

IPL sensitivity in showing the inguinal, external iliac, common, and periaortic lymphatics was 100%, 90%, 80%, and 70% in anterior-posterior (A-P) projections, and 100%, 80%, 70%, and 60% in lateral projections respectively. For the presacral and hypogastric ones the sensitivity was 40%. When compared with bony landmarks, IPL changed the delineation of PTV in 24 of 70 A-P P-A fields (34%) and 22 of 58 (38%) lateral fields. Furthermore, 8/12 (67%) lymphadenectomies resulted in being incomplete. No IPL-related toxicity was observed.

CONCLUSION

IPL is a safe, inexpensive (cost: 100 Euros), and effective method to map the lymphatic chains. In the A-P scintigrams these structures were detected in 85% (70-100%) of the patients referred for total pelvis irradiation, and this figure could be higher in subjects not operated on. IPL can also give a reliable evaluation of the lymphadenectomies in order to schedule the proper treatments after surgery. Finally, IPL may change the conventional PTV for pelvic irradiation in about 36% (34-38%) of the cases; therefore, the fields should be tailored more around the lymphatic landmarks than the bony landmarks.

The impact of patient positioning on the adequate coverage of the uterus in the primary irradiation of cervical carcinoma: a prospective analysis using magnetic resonance imaging

BACKGROUND AND PURPOSE

The intention of this prospective study is to assess the influence of different patient positionings and the use of belly boards on the coverage of the uterus by standard radiation fields.

MATERIAL AND METHODS

In 21 women with carcinoma of the uterine cervix magnetic resonance imaging (MRI) scans in prone patient position with and without belly board and computed tomography (CT) scans in supine position were analysed after superimposing standard pelvic box fields. Further, all patients underwent a second MRI field control in prone position with belly board to detect intraindividual variations in the uterus position during treatment.

RESULTS

Standard portals did not completely cover the uterus in supine position in 7/21 (33%), in prone position with belly board in 7/21 (33%) and without belly board in 5/21 (24%). Insufficient uterine coverage was found only in the anteroposterior direction. The mean distance (+/- standard deviation) between the field borders of the lateral portals and the uterus was in supine position anteriorly 3.4 cm (+/-2.2 cm) and posteriorly 1.8 cm (+/-1.3 cm), in prone position with belly board anteriorly 2.2 cm (+/-2.7 cm) and posteriorly 2.6 cm (+/-1.6 cm), prone without belly board anteriorly 3.3 cm (+/-2.4 cm) and posteriorly 1.9 cm (+/-1.1 cm). The difference was statistically significant between supine and prone position with belly board and between prone position with and without belly board. Repeated MRI controls during therapy showed no significant changes compared to the MRIs at the beginning of therapy.

CONCLUSIONS

The use of standard radiation fields results in a high percentage of geographical misfits. Three-dimensional treatment planning is a prerequisite for adequate uterus coverage.

[Radiotherapy for tumors of the uterine cervix. Gross tumor volume and clinical target volume]

Treatment of carcinoma of the uterine cervix needs a multidisciplinary approach. External irradiation and brachytherapy are highly curative because of the tumor radiosensitivity. The main prognostic factors are tumoral volume and nodal involvement. Tumoral extent is evaluated by diagnostic MR imaging, and gynecological exam. Nodal involvement can be assessed, accurately by coelioscopic pelvic node sampling and by imaging modalities such as CT scan. The knowledge of these two factors helps to choose the treatment strategy. The use of imaging (MRI and CT) added to clinical findings allows to design external irradiation fields. 3D treatment planning in external irradiation and brachytherapy is based upon the use of imaging (CT and MRI). It leads to a better knowledge of dose distribution to the target and critical organs and allows more individualized and conformal treatment.

Optimizing radiation treatment for cervical cancer

The technical and radiobiological improvements in the science of radiotherapy, coupled with the use of cisplatin-containing regimens concurrent with radiation therapy, have improved dramatically the cure rate and quality of Life for cervical cancer survivors. Further research is necessary to understand the complex dose distribution of external beam and intracavitary radiation and their relationship to tumor control and complications. With the use of CT-compatible applicators for intracavitary radiation, CT simulation and three-dimensional treatment planning for EBRT, the radiation oncology community should meet this challenge.

[Contribution of imaging in radiotherapy planning in uterine cervix cancers]

External irradiation and brachytherapy are curative in the treatment of carcinoma of the cervix. The aim of radiotherapy is to optimize the irradiation of the target volume and to reduce the dose to critical organs. The use of imaging (computed tomography and magnetic resonance imaging added to clinical findings and standard guidelines) are studied in the treatment planning of external irradiation and brachytherapy in carcinoma of the cervix. Imaging allows an individualized and conformal treatment planning.

Optimizing radiation parameters for cervical cancer

The treatment of cervical cancer has become increasingly sophisticated with evidence-based guidelines generated from randomized trials directing combined modality programs. The radiotherapeutic guidelines have been derived largely from single institutional experiences coupled with data from the Patterns of Care Studies. The design of external-beam fields has improved because of a better understanding of the anatomy of the cervix, uterus, parametrium, and draining lymph nodes from surgical, lymphangiogram, computed tomography scan, and magnetic resonance imaging series. An improvement in survival and local control with dose intensity (a reduction in overall treatment time and increase in overall dose) has been shown for cervical cancer, especially for locally advanced disease, and these series are highlighted. The use of intracavitary radiation, which is technically accurate, dramatically improves outcome and allows for dose intensity. Alternative brachytherapy techniques, such as high-dose-rate, and interstitial, are discussed. Ways to improve the therapeutic ratio for radiation, including biological factors, are reviewed. More research is necessary to understand the complex dose distribution of external-beam and intracavitary brachytherapy and its relationship to tumor control.