Endometrial carcinoma: high dose-rate brachytherapy in combination with external irradiation; a multivariate analysis of relapses

Câncer do Endométrio: Tratamento Adjuvante Pélvico apenas com Radioterapia Externa após Cirurgia sem Linfadenectomia

A incidência mediana de câncer endometrial no Brasil é de 6 casos novos/cem mil mulheres/ ano. A radioterapia tem sido usada como tratamento adjuvante pré ou pós cirurgia, com ou sem braquiterapia. Há consenso de que os casos estadiados como II e III pela FIGO recebam irradiação pélvica, com ou sem braquiterapia. Entretanto, 75% dos casos são estádios I. Por isso há subgrupos prognósticos que dependem da profundidade de invasão do miométrio e do grau histológico do tumor. Tumores em estádio I com invasão profunda do miométrio e/ou alto grau têm também sido tratados com irradiação. A adição de braquiterapia vaginal após a radioterapia externa resulta em melhor controle de falha pélvica? Esta é uma pergunta não resolvida. Desde 1990 temos feito apenas radioterapia externa nos casos de câncer do endométrio que têm indicação de irradiação adjuvante, sem braquiterapia. A cirurgia básica destes casos têm sido histerectomia abdominal total + salpingo-ooforectomia bilateral sem dissecção de rotina dos linfonodos pélvicos. Foram revistas retrospectivamente 61 destes casos tratados no nosso serviço, com 4 campos pélvicos. Cobalto, dose total entre 45Gy-50,4Gy em 25 a 28 frações. Seguimento mediano de 33 meses mostrou um único caso de falha em vagina, 6/61 casos de pacientes que morreram e apenas um caso de complicação intestinal moderada. Estes resultados se assemelham com outros da literatura que não usam a braquiterapia de rotina após a irradiação externa na pelve.

The role for vaginal cuff brachytherapy boost after external beam radiation therapy in endometrial cancer

PURPOSE

To evaluate the role and technique of a vaginal cuff brachytherapy (VB) boost to adjuvant external beam (EB) radiation for endometrial cancer through a systematic review.

METHODS AND MATERIALS

Relevant trials were identified through a systematic search of the literature.

RESULTS

A total of 21 prospective and retrospective studies which had a patient cohort undergoing EB + VB was identified to evaluate for rates of vaginal and pelvic recurrences, overall survival, and toxicity. Additional database studies were utilized to demonstrate differences in local control and overall survival between EB and EB + VB.

CONCLUSIONS

While there is limited prospective evidence to guide the use of a VB boost after EB, the evidence suggests that patients with a higher risk of a vaginal recurrence such as those with cervical stromal involvement in select Stage III patients may derive local control and survival benefits from a VB boost. Additional individual risk factors such as grade, histology, extent of invasion, margin status, age, and the use of lower doses of EB should be considered when deciding when to add a VB boost.

Role of vaginal brachytherapy boost following adjuvant external beam radiotherapy in cervical cancer: Turkish Society for Radiation Oncology Gynecologic Group Study (TROD 04-002)

OBJECTIVE

There are a limited number of studies supporting vaginal brachytherapy boost to external beam radiotherapy in the adjuvant treatment of cervical cancer. The aim of this study was to assess the impact of the addition of vaginal brachytherapy boost to adjuvant external beam radiotherapy on oncological outcomes and toxicity in patients with cervical cancer.

METHODS

Patients treated with post-operative external beam radiotherapy ± chemotherapy ± vaginal brachytherapy between January 2001 and January 2019 were retrospectively evaluated. The treatment outcomes and prognostic factors were analyzed in patients treated with external beam radiotherapy with or without vaginal brachytherapy.

RESULTS

A total of 480 patients were included in the analysis. The median age was 51 years (range 42-60). At least two intermediate risk factors were observed in 51% of patients, while 49% had at least one high-risk factor. The patients in the external beam radiotherapy + vaginal brachytherapy group had worse prognostic factors than the external beam radiotherapy alone group. With a median follow-up time of 56 months (range 33-90), the 5-year overall survival rate was 82%. There was no difference in 5-year overall survival (87% vs 79%, p=0.11), recurrence-free survival (74% vs 71%, p=0.49), local recurrence-free survival (78% vs 76%, p=0.16), and distant metastasis-free survival (85% vs 76%, p=0.09) rates between treatment groups. There was no benefit of addition of vaginal brachytherapy to external beam radiotherapy in patients with positive surgical margins. In multivariate analysis, stage (overall survival and local recurrence-free survival), tumor histology (recurrence-free survival, local recurrence-free survival and distant metastasis-free survival), parametrial invasion (recurrence-free survival and distant metastasis-free survival), lymphovascular space invasion (recurrence-free survival), and lymph node metastasis (distant metastasis-free survival) were found as negative prognostic factors.

CONCLUSION

Adding vaginal brachytherapy boost to external beam radiotherapy did not provide any benefit in local control or survival in patients with cervical cancer.

Postoperative Radiotherapy and Surgery in Stage I Endometrial Carcinoma: A 10-Year Experience

Background

Data from the literature show that the incidence of pelvic recurrences in poor prognosis endometrial carcinoma is significantly reduced by combined surgery and radiotherapy compared to surgery alone.

Methods

In this paper we analyze the results of the combined treatment surgery plus adjuvant irradiation in patients with endometrial carcinoma with regard to survival, site of progression, and toxicity. The surgical treatment consisted of total abdominal hysterectomy and bilateral salpingo-oophorectomy. Pelvic and para-aortic node dissection was performed.

Results

The overall 5-year survival was 88%. Three patients had local failure. Ten patients with local control of disease had distant metastases and 2 had local and distant recurrences.

Conclusions

Our experience confirms the data of the literature. Postoperative irradiation is a safe and well tolerated treatment which can achieve good local control in high-risk stage I endometrial carcinoma. The control of distant metastases remains an open issue.

American Brachytherapy Task Group Report: Adjuvant vaginal brachytherapy for early-stage endometrial cancer: A comprehensive review

This article aims to review the risk stratification of endometrial cancer, treatment rationale, outcomes, treatment planning, and treatment recommendations of vaginal brachytherapy (VBT) in the postoperative management of endometrial cancer patients. The authors performed a thorough review of the literature and reference pertinent articles pertaining to the aims of this review. Adjuvant VBT for early-stage endometrial cancer patients results in very low rates of vaginal recurrence (0-3.1%) with low rates of late toxicity which are primarily vaginal in nature. Post-Operative Radiation Therapy in Endometrial Cancer 2 (PORTEC-2) supports that VBT results in noninferior rates of vaginal recurrence compared to external beam radiotherapy for the treatment of high-intermediate risk patients. VBT as a boost after external beam radiotherapy, in combination with chemotherapy, and for high-risk histologies have shown excellent results as well though randomized data do not exist supporting VBT boost. There are many different applicators, dose-fractionation schedules, and treatment planning techniques which all result in favorable clinical outcomes and low rates of toxicity. Recommendations have been published by the American Brachytherapy Society and the American Society of Radiation Oncology to help guide practitioners in the use of VBT. Data support that patients and physicians prefer joint decision making regarding the use of VBT, and patients often desire additional treatment for a marginal benefit in risk of recurrence. Discussions regarding adjuvant therapy for endometrial cancer are best performed in a multidisciplinary setting, and patients should be counseled properly regarding the risks and benefits of adjuvant therapy.

High dose rate brachytherapy: its clinical applications and treatment guidelines

Brachytherapy has the advantage of delivering a high dose to the tumor while sparing the surrounding normal tissues. With proper case selection and delivery technique, high-dose-rate (HDR) brachytherapy has great promise, because it eliminates radiation exposure, allows short treatment times, and can be performed on an outpatient basis. Additionally, use of a single-stepping source, allows optimization of dose distribution by varying the dwell time at each dwell position. However, when HDR brachytherapy is used, the treatments must be executed carefully, because the short treatment times do not allow any time for correction of errors, and mistakes can result in harm to patients. Hence, it is very important that all personnel involved in HDR brachytherapy be well trained and be constantly alert. It is expected that the use of HDR brachytherapy will greatly expand over the next decade and that refinements will occur primarily in the integration of imaging (computed tomography, magnetic resonance imaging, intraoperative ultrasonography) and optimization of dose distribution. It is anticipated that better tumor localization and normal tissue definition will help to optimize dose distribution to the tumor and reduce normal tissue exposure. The development of well-controlled randomized trials addressing issues of efficacy, toxicity, quality of life, and costs-versus-benefits will ultimately define the role of HDR brachytherapy in the therapeutic armamentarium.

[Preoperative brachytherapy for clinical stage I and II endometrial carcinoma: results from a series of 780 patients with a 10-year follow-up]

AIMS OF THE STUDY

Retrospective analysis of patients treated by preoperative brachytherapy for endometrial carcinoma.

PATIENTS AND METHODS

From 1973 to 1994, 780 consecutive patients with a clinical stage I-II endometrial carcinoma were treated with brachytherapy followed by surgery and pelvic irradiation if necessary. Tumour was staged according to 1979 UICC classification. There were 462 T1a, 257 T1b, and 61 T2, 62% were well differentiated. Brachytherapy consisted in one low dose rate endocavitary application. Sixty grays were delivered on the reference isodose. Surgery consisted in a TAH/BSO (Piver II) and was performed 6 weeks later. Nodal pelvic irradiation was indicated in case of unfavourable pathological prognostic factors.

RESULTS

Median follow up was 122 months. Five year survival rates were: 84% for overall survival, 86% for survival without recurrence, 92.8% for local control, and 3.8% for late complications. Pronostic factors were age, stage, differentiation, grade and postoperative extension. Multivariate analysis showed only age, differentiation and postoperative extension to be independent prognostic factors.

CONCLUSION

If for stage 1, initial surgery has now replaced preoperative brachytherapy in most cases because it allows to identify initial prognostic factors, preoperative brachytherapy remains the most interesting option for stage 2 endometrial carcinomas.

[Brachytherapy of endometrial cancers]

Endometrial adenocarcinomas rank third as tumoral sites en France. The tumors are confined to the uterus in 80% of the cases. Brachytherapy has a large place in the therapeutic strategy. The gold standard treatment remains extrafascial hysterectomy with bilateral annexiectomy and bilateral internal iliac lymph node dissection. However, after surgery alone, the rate of locoregional relapses reaches 4-20%, which is reduced to 0-5% after postoperative brachytherapy of the vaginal cuff. This postoperative brachytherapy is delivered as outpatients treatment, by 3 or 4 fractions, at high dose rate. The uterovaginal preoperative brachytherapy remains well adapted to the tumors which involve the uterine cervix. Patients presenting a localized tumor but not operable for general reasons (< 10%) can be treated with success by exclusive irradiation, which associates a pelvic irradiation followed by an uterovaginal brachytherapy. A high local control of about 80-90% is obtained, a little lower than surgery, with a higher risk of late complications. Last but not least, local relapses in the vaginal cuff, or in the perimeatic area, can be treated by interstitial salvage brachytherapy, associated if possible with external beam irradiation. The local control is reached in half of the patients, but metastatic dissemination is frequent. We conclude that brachytherapy has a major role in the treatment of endometrial adenocarcinomas, in combination with surgery, or with external beam irradiation for not operable patients or in case of local relapses. It should use new technologies now available including computerized afterloaders and 3D dose calculation.

The influence of applicator angle on dosimetry in vaginal vault brachytherapy

In vaginal vault brachytherapy, the critical normal tissues are bladder and rectum; doses to these tissues may be affected by the position of a single line applicator placed in the vagina. Dosimetry with the applicator lying at its "natural" angle in the vagina with the patient in the lithotomy position has been compared with the applicator held horizontal as defined by a spirit level in 30 consecutive patients. A mean change in angle of 19.7 degrees was found. This resulted in a mean decrease in ICRU (International Commission of Radiation Units and Measurements) rectal point dose when the applicator is horizontal of 12.9%, equivalent to a mean absolute dose reduction of 1.3 Gy for a prescription dose of 5.5 Gy at 5 mm depth. An increase in mean dose to the ICRU bladder point when the applicator is horizontal of 13.3%, equivalent to an absolute mean dose increase of 0.5 Gy per fraction for the same prescription dose, was also found. On the basis of these findings, it is recommended that vaginal vault brachytherapy is performed with a single line source held in the "corrected" horizontal position to reduce bowel dose as this is the most sensitive critical normal tissue.

Gynecologic brachytherapy-II: Intravaginal brachytherapy for carcinoma of the endometrium

Brachytherapy plays a significant role in the management of endometrial cancer. In the adjuvant setting, based on pathologic risk factors, intravaginal brachytherapy alone, external radiation therapy alone, or a combination of the two is recommended. For patients who are medically inoperable, brachytherapy with or without external beam therapy is the mainstay of treatment. In recurrent disease, to achieve improved local regional control interstitial and/or intravaginal brachytherapy is used as a boost. This article will highlight the indications and technical aspects of postoperative intravaginal brachytherapy, which is the most common application of brachytherapy in endometrial cancer.

Postoperative irradiation in endometrial cancer: still a matter of controversy

Although endometrial cancer is the most common female malignancy, evidence-based uniform guidelines for postoperative therapy have not been established. The most logical management is adjuvant irradiation tailored to the extent of surgery, the tumour grade, depth of myometrial invasion, degree of lymph node involvement and age of the patient. Currently, the only widely accepted treatment recommendations are no further therapy in low-risk patients who underwent extensive surgical staging, and external beam radiotherapy (EBRT) in high-risk patients. Most authors recommend postoperative application of only one radiotherapy modality: either brachytherapy (BRT) or EBRT, as their routine combination does not clearly improve the outcome but does increase the risk of late complications. A combination of BRT and EBRT should however be considered in patients with stage II disease, for infiltration of the lower uterine segment, vaginal involvement, positive or close surgical margins, capillary space involvement or unfavourable histology. Two recent randomized studies including mostly intermediate-risk patients managed with either extensive surgical staging or total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH&BSO) with or without postoperative EBRT, showed better local control but no survival benefit from adjuvant irradiation. Two ongoing Gynecologic Oncology Group (GOG) studies compare adjuvant chemotherapy with pelvic or abdominal irradiation in patients with high risk of local relapse. The role of adjuvant radiotherapy (EBRT with or without BRT) in high-risk patients as well as the value of lymphadenectomy in patients fit for such surgery is being addressed in a trial co-ordinated by the Medical Research Council. Future studies are warranted to define whether any irradiation should be employed in intermediate-risk patients and which radiotherapy modality should be used in high-risk node-negative patients with stage I tumours (stage Ib grade 3 and all stage Ic). Other issues which should be addressed in future studies include the extent of surgery, the role of systemic therapies, the relevance of novel biologic prognostic factors, salvage therapies after recurrence, cost-benefit analysis and quality of life.

The American Brachytherapy Society recommendations for high-dose-rate brachytherapy for carcinoma of the endometrium

PURPOSE

To develop recommendations for use of high-dose-rate (HDR) brachytherapy in patients with endometrial cancer.

METHODS

A panel of members of the American Brachytherapy Society (ABS) performed a literature review, supplemented their clinical experience, and formulated recommendations for endometrial HDR brachytherapy.

RESULTS

The ABS endorses the National Comprehensive Cancer Network (NCCN) guidelines for indications for radiation therapy for patients with endometrial cancer and the guidelines on HDR quality assurance of the American Association on Physicists in Medicine (AAPM). The ABS made specific recommendations for HDR applicator selection, insertion techniques, target volume definition, dose fractionation, and specifications for postoperative adjuvant vaginal cuff therapy, for vaginal recurrences, and for medically inoperable primary endometrial cancer patients. The ABS recommends that applicator selection should be based on patient and target volume geometry. The dose prescription point should be clearly specified. The treatment plan should be optimized to conform to the target volume whenever possible while recognizing the limitations of computer optimization. Suggested doses were tabulated for treatment with HDR alone, and in combination with external beam radiation therapy (EBRT), when applicable. For intravaginal brachytherapy, the largest diameter applicator should be selected to ensure close mucosal apposition. Doses should be reported both at the vaginal surface and at 0.5-cm depth irrespective of the dose prescription point. For vaginal recurrences, intracavitary brachytherapy should be restricted to patients with nonbulky (< 0.5-cm thick) disease. Patients with bulky (> 0.5-cm thick) recurrences should be treated with interstitial techniques. For medically inoperable patients, an appropriate applicator that will allow adequate irradiation of the entire uterus should be selected.

CONCLUSION

Recommendations are made for HDR brachytherapy for endometrial cancer. Practitioners and cooperative groups are encouraged to use these recommendations to formulate their treatment and dose reporting policies. This will lead to meaningful comparisons of reports from different institutions and lead to advances and appropriate use of HDR.

Recurrent endometrial cancer after surgery alone: results of salvage radiotherapy

PURPOSE

Postoperative irradiation of endometrial cancer patients decreases the risk of local recurrence but is associated with a number of long-term sequelae. In a proportion of patients, no immediate postoperative radiotherapy is applied and this treatment is introduced only at relapse. The aim of our study was to assess the long-term results of salvage radiotherapy in previously nonirradiated endometrial cancer patients who developed local recurrence, and to evaluate the impact of patient- and treatment-related factors on treatment efficacy.

METHODS AND MATERIALS

We performed a detailed retrospective analysis of 73 endometrial cancer patients given radiotherapy for local recurrence after the initial surgery only. The mean age at diagnosis of the recurrence was 63 years (range, 39-78 years). Median time to recurrence was 11 months (range, 1-19 months). All recurrences were staged with the use of Perez modification of the International Federation of Gynecology and Obstetrics (FIGO) staging system for primary vaginal carcinoma. There were five (7%) Stage I patients, 43 (59%) Stage II patients, and 25 (34%) Stage III patients. Forty-four patients (60%) received both external beam irradiation (EBRT) and endovaginal brachytherapy (BRT), 17 (23%) received only BRT, and 12 (17%) received only EBRT. The mean total physical radiation dose was 75.9 Gy (range, 8-130 Gy), and the mean normalized total dose (NTD) calculated on the base of the linear-quadratic model was 86.6 Gy (range, 8.5-171.9 Gy). Median follow-up for alive patients was 8.8 years (range, 3-21 years). The impact of patient-, tumor-, and therapy-related factors on the treatment outcome was evaluated with the use of uni- and multivariate analyses.

RESULTS

Three- and 5-year overall survival rates were 33% and 25%, respectively. In the univariate analysis, lower stage of recurrent disease (p < 0.0005), combined EBRT and BRT (p = 0.027), higher total radiation dose (p = 0.031), and higher NTD (p = 0.006) were significantly correlated with better survival. In the multivariate analysis, only stage of recurrent disease (p < 0.005) and high total dose (p = 0.047) were independently correlated with better survival. Lower FIGO stage of recurrence (p = 0.023) and higher total dose (p = 0.005) were also independently correlated with longer time to progression, whereas higher radiotherapy dose was the only factor correlated with better local control (p = 0.029).

CONCLUSIONS

The efficacy of salvage radiotherapy in endometrial cancer patients with local failure after previous surgery is limited. Factors determining treatment outcome include advancement of the tumor at relapse and radiotherapy dose.

Vaginal vault brachytherapy: the effect of varying bladder volumes on normal tissue dosimetry

This study was designed to assess the impact of bladder volume on dosimetry to critical normal structures in vaginal vault brachytherapy using a single line source vaginal applicator. 30 consecutive patients undergoing vaginal vault brachytherapy were studied by CT scanning with the applicator in situ and the bladder empty and then with the bladder containing either 35 ml of water (10 patients), 70 ml of water (10 patients) or 100 ml of water (10 patients). The scans were then analysed with isodose distributions overlayed to determine changes in dosimetry. No effect on bladder dose was seen with increasing volume compared with the empty bladder; however, there was a reduction in amount of small bowel within the high dose treatment region as bladder volume increased. With 100 ml bladder volume, the reduction reached 57.5% compared with the empty bladder. We conclude that vaginal vault brachytherapy should be undertaken with a bladder volume of at least 100 ml, which will considerably reduce the amount of small bowel in the irradiation volume with no increase in bladder dose.

Post-operative high dose rate brachytherapy in patients with low to intermediate risk endometrial cancer

BACKGROUND AND PURPOSE

This paper investigates the outcome using different dose/fractionation schedules in high dose rate (HDR) post-operative vaginal vault radiotherapy in patients with low to intermediate risk endometrial cancer.

MATERIALS AND METHODS

The world literature was reviewed and thirteen series were analyzed representing 1800 cases.

RESULTS

A total of 12 vaginal vault recurrences were identified representing an overall vaginal control rate of 99.3%. A wide range of dose fractionation schedules and techniques have been reported. In order to analyze a dose response relationship for tumor control and complications, the biologically effective doses to the tumor and late responding tissues were calculated using the linear quadratic model. A threshold was identified for complications, but not vaginal control. While dose fractionation schedules that delivered a biologically effective dose to the late responding tissues in excess of 100 Gy(3) (LQED=60 Gy) predicted for late complications, dose fractionation schedules that delivered a modest dose to the vaginal surface (50 Gy(10) or LQED=30 Gy) appeared tumoricidal with vaginal control rates of at least 98%.

CONCLUSIONS

By using convenient, modest dose fractionation schedules, HDR vaginal vault - brachytherapy yields very high local control and extremely low morbidity rates.

High-dose-rate postoperative vaginal cuff irradiation alone for stage IB and IC endometrial cancer

PURPOSE

To evaluate the effectiveness of postoperative high-dose-rate (HDR) vaginal cuff irradiation alone (1500 cGy in 3 fractions) in patients with Stage Ib and Ic endometrial cancer.

METHODS AND MATERIALS

This is a retrospective review of 102 patients with Stage Ib and Ic endometrial cancer treated with a hysterectomy and postoperative HDR intracavitary therapy alone during the period of 1/1/90-12/31/96. Each patient received 1500 cGy in 3 weekly treatments, dosed to a depth of 0.5 cm. Pathologic features such as depth of invasion, tumor grade, lower uterine segment (LUS) involvement, and lymphvascular invasion (LVI) were evaluated for their impact on recommended postoperative treatment. All survival curves were generated utilizing Kaplan-Meier methods and all statistical comparisons were via a Wilcoxon rank sum test.

RESULTS

The 5-year actuarial overall survival (OS) is 84% and the 5-year disease-free survival (DFS) is 93%. Locoregional disease control (pelvic control) was excellent with 97% of the patients free of pelvic disease at 5 years. Of the three pelvic failures only one was in the vaginal cuff. LVI, LUS involvement, Grade 3 and/or outer third myometrial involvement were identified in 41 patients. Thirty-one of these patients underwent a lymphadenectomy and there were two regional failures within this increased-risk group.

CONCLUSIONS

We obtained an excellent level of locoregional control with minimal morbidity and minimal time commitment for treatment with vaginal HDR brachytherapy alone. Our dose per fraction and total dose is lower than most reported series and there is no apparent loss in locoregional control. In addition, intermediate-risk patients and patients with an increased risk of recurrence (Grade 3, outer third myometrial involvement, LVI, LUS) may be treated with cuff irradiation alone, after surgical staging and a negative lymphadenectomy.

Surgery followed by radiotherapy in endometrial cancer: analysis of survival and patterns of failure

We performed a retrospective evaluation of survival and patterns of failure in 317 consecutive endometrial cancer patients treated between 1974 and 1991 with surgery and adjuvant radiotherapy. Two hundred and forty seven patients (78%) had FIGO stage I disease, 30 (9%) - stage II, 35 (11%) - stage III and 5 (2%) - stage IV. Both low dose rate brachytherapy (BRT) and external beam radiation (EBRT) were applied in 247 patients (78%), only BRT in 49 (15%), and only EBRT in 21 (7%). Median follow-up was 7.3 years. Five-year overall survival was 75%, and five-year disease free survival was 81%. Both overall and disease free survival rates were correlated with stage (P = 0.001 and P = 0.000, respectively). Recurrence occurred in 70 patients (22%): 11 (3.5%) in the pelvis, 51 (16%) outside the pelvis and 6 (2%) both in- and outside the pelvis. Independent risk factors for local recurrence included older age (P = 0.03) and variant histologic subtypes (P = 0.039), whereas independent risk factors for distant spread were stage (P = 0.000) and older age (P = 0.011). Normalized Total Dose (the sum of EBRT and BRT doses, based on linear-quadratic equation), type of radiotherapy regimen, overall radiotherapy time and surgery-to-radiotherapy interval did not correlate with the risk of relapse. Severe early and late radiotherapy complications were observed in 21 (7%) and 35 patients (11%), respectively. In view of the relatively low risk of exclusive pelvic recurrences and the high rate of severe late radiotherapy complications, indications for postoperative radiotherapy and its scheme should be verified. A relatively high rate of extrapelvic recurrences calls for effective systemic adjuvants to surgery. Further definition of high risk patients is warranted in order to tailor postoperative therapy to the prognostic factors and to increase the therapeutic index of management of endometrial cancer.

Cost minimization analysis of high-dose-rate versus low-dose-rate brachytherapy in endometrial cancer. Gynecology Tumor Group

PURPOSE

Endometrial cancer is a common, usually curable malignancy whose treatment frequently involves low-dose-rate (LDR) or high-dose-rate (HDR) brachytherapy. These treatments involve substantial resource commitments and this is increasingly important. This paper presents a cost minimization analysis of HDR versus LDR brachytherapy in the treatment of endometrial cancer.

METHODS AND MATERIALS

The perspective of the analysis is that of the payor, in this case the Ministry of Health. One course of LDR treatment is compared to two courses of HDR treatment. The two alternatives are considered to be comparable with respect to local control, survival, and toxicities. Labor, overhead, and capital costs are accounted for and carefully measured. A 5% inflation rate is used where applicable. A univariate sensitivity analysis is performed.

RESULTS

The HDR regime is 22% less expensive compared to the LDR regime. This is $991.66 per patient or, based on the current workload of this department (30 patients per year) over the useful lifetime of the after loader, $297,498 over 10 years in 1997 dollars.

CONCLUSION

HDR brachytherapy minimizes costs in the treatment of endometrial cancer relative to LDR brachytherapy. These results may be used by other centers to make rational decisions regarding brachytherapy equipment replacement or acquisition.

Postoperative radiotherapy for endometrial carcinoma. Stage I. Wide variation in referral patterns but no effect on long-term survival in a retrospective study in the southeast Netherlands

The aim of this study was to assess the referral pattern and the impact on long-term survival of postoperative radiotherapy in patients with adenocarcinoma of the endometrium stage I. This was a retrospective study performed in a regional cancer registry which covers a population of approximately 1,000,000 persons. All 724 patients registered between 1975 and 1992 in the Comprehensive Cancer Centre South, Eastern Section, The Netherlands, were analysed. All patients had received surgery as primary treatment which was performed in one of the seven community hospitals of the region. Radiotherapy was given in one regional department. All pathology reports were checked for data on tumour differentiation and myometrial invasion. Almost half the patients (45%) were referred for postoperative radiotherapy. The depth of myometrial invasion and the degree of tumour differentiation were the main factors (P < 0.0001) influencing referral for postoperative radiotherapy. The referral pattern varied between the different hospitals, but became more similar during 1985-1988, to diverge again in recent years. In patients younger than 60 years, the depth of myometrial invasion was significantly (P = 0.01) correlated with survival. In patients older than 60 years, tumour differentiation (P = 0.05) and age (P < 0.001) were correlated with survival, but not the depth of myometrial invasion. After adjustment for known prognostic factors, a survival benefit of postoperative radiotherapy could not be established. The studied group had an excess death rate over the normal Dutch female population. This excess death rate did not decrease during follow-up, as even after 10 years an excess death rate was found. A prospective randomised trial is ongoing in The Netherlands.

[Low-dose postoperative vaginal brachytherapy of adenocarcinoma of the endometrium]

PURPOSE

Surgery is the primary treatment for endometrial carcinoma. Methods of complementary treatment are still debated, with the potential association of external radiotherapy and/or brachytherapy before or after surgery. This study was aimed at evaluating local control and complications rates in a series of patients treated by hysterectomy followed by postoperative vaginal low-dose rate brachytherapy (BT) combined with pelvic irradiation in case of poor prognosis factors.

PATIENTS AND METHODS

From 1978 to 1993, 101 patients were treated at the Centre Alexis-Vautrin, France according to this scheme. Forty five had deep myometrial invasion, and thirteen cervical involvement. Fifty patients received pelvic irradiation (median dose 46 Gy) combined with BT (dose 14 Gy, median volume 127 cm3); 51 patients had BT alone (dose 60 Gy, median volume 71 cm3).

RESULTS

The 5-year overall survival rate was 83% and the local control rate 97% with a median follow-up of 7 years. Multivariate analysis showed two factors of bad prognosis, i.e., deep myometrial invasion and cervical involvement. Three severe complications occurred in two patients for whom the treated volume was larger than the theoretical target volume. Eleven patients developed metastases.

CONCLUSION

Results obtained from this series are comparable with those of previous studies, particularly in regard to pre-operative BT. The complication rate is also satisfactory and depends on the irradiation precision and the definition of the target volume.

Pelvic control following external beam radiation for surgical stage I endometrial adenocarcinoma

PURPOSE

To determine if postoperative external pelvic radiation (EBRT), without vaginal brachytherapy, is sufficient to prevent vaginal cuff and pelvic recurrences in patients with surgical Stage I endometrial adenocarcinoma (ACA).

METHODS AND MATERIALS

The records of 122 patients with surgical Stage I endometrial cancer were reviewed. There were 87 patients with ACA who received EBRT alone and are the subject of this study. Their radiation records were reviewed. All patients underwent exploration, total abdominal hysterectomy, and bilateral salpingo-oophorectomy (TAH BSO), and pelvic and paraaortic lymph node sampling. They were staged according to the FIGO 1988 surgical staging system recommendations. Postoperatively, pelvic EBRT was administered by megavoltage equipment using four fields, to a total dose of 45 to 50.4 Gy. Actuarial survival and disease free survival were calculated according to Kaplan-Meier Method.

RESULTS

Twenty-seven patients with Stage IA Grade 1 or 2 ACA with less than one-third myometrial invasion, who did not receive EBRT, and eight patients with histology other than adenocarcinoma (i.e., serous papillary, mucinous, etc.) were not included in the study. For the remaining 87 patients who are in the study group, the median follow-up was 52 months (range: 12-82 months). The 5-year overall survival for these 87 patients was 92%, with a disease-free survival of 83%. There were no tumor recurrences in the upper vagina or in the pelvis. Two patients developed small bowel obstruction (no surgery required), and one patient developed chronic enteritis.

CONCLUSION

Adjuvant external pelvic radiation, without vaginal brachytherapy, prevents pelvic and vaginal cuff recurrences in surgical Stage I endometrial ACA.

Postoperative vaginal cuff irradiation using high dose rate remote afterloading: a phase II clinical protocol

PURPOSE

In September 1989, a postoperative Phase II high dose rate (HDR) brachytherapy protocol was started for International Federation of Gynecology and Obstetrics (FIGO) Stage I endometrial adenocarcinoma. This review reports the overall survival, local control, and complication rates for the initial 63 patients treated in this Phase II study.

METHODS AND MATERIALS

High dose rate brachytherapy was delivered using an Iridium-192 HDR remote afterloader. Sixty-three patients were entered into the Phase II protocol, each receiving two vaginal cuff treatments 1 week apart (range 4-12 days) with vaginal ovoids (diameter 2.0-3.0 cm). No patient received adjuvant external beam radiation. A dose of 32.4 Gy in two fractions was prescribed to the ovoid surface in 63 patients. The first three patients treated at our institution received 15, 16.2, and 29 Gy, respectively, to determine acute effects.

RESULTS

At a median follow-up of 1.6 years (range 0.75-4.3 years) no patient has developed a vaginal cuff recurrence. One regional recurrence (1.6%) occurred at 1.2 years at the pelvic side wall. This patient is alive and without evidence of disease 7 months after completion of salvage irradiation, which resulted in the only vaginal stenosis (1.6%). Fourteen patients (22%) experienced vaginal apex fibrosis by physical exam, which was clinically symptomatic in four patients. Two patients reported stress incontinence; however, these symptoms were noted prior to their HDR therapy. One patient died 2.4 years after HDR therapy due to cardiovascular disease without evidence of cancer at autopsy.

CONCLUSION

Preliminary results of our phase II HDR vaginal cuff protocol for postoperative FIGO Stage IA, Grade 3 or Stage IB, Grade 1-2 patients demonstrate that 32.4 Gy in two fractions is well tolerated by the vaginal cuff mucosa. Local control appears comparable to our prior experience and others with low dose rate (LDR) brachytherapy. Additional patient accrual and further follow-up will better determine the late morbidity, local control, and overall survival of these patients.

Comparison of high dose-rate and low dose-rate dose distributions for vaginal cylinders

PURPOSE

The identification of appropriate high dose-rate parameters required to produce a "uniform" dose distribution on the surface of a vaginal cylinder. The high dose-rate dose distribution is then compared to the traditional low dose-rate dose distributions obtained with Burnett cylinders.

METHODS AND MATERIALS

Dose distributions were calculated for 2, 3, and 3.5 cm diameter Burnett cylinders with and without crossing sources. Three models for the high dose-rate cylinders were developed and compared. High dose-rate dose distributions were calculated for 2, 3, and 3.5 cm diameter cylinders with and without anisotropic corrections for various dose specification points.

RESULTS

Low dose-rate distributions are not uniform over the surface of the applicator. The exact distribution depends upon cylinder diameter and upon the exact source loading. High dose rate dose distributions can be configured to provide for a "uniform" dose on the surface, if an apex dose specification point is used together with dose specification points on the surface of the applicator opposite each dwell position.

CONCLUSIONS

The conversion of low dose rate techniques to high dose rate techniques for vaginal cylinders involves an appreciation of the details of dose distributions of both approaches. The comparison between traditional low dose-rate distributions and high dose-rate distributions shows that, unlike the low dose-rate distributions, a relatively uniform high dose-rate distribution can be obtained independent of cylinder diameter. The clinical significance of the differences in the low dose-rate and high dose-rate dose distributions remains to be determined by long-term follow up of patients treated with high dose-rate techniques.

Consensus guidelines for high dose rate remote brachytherapy in cervical, endometrial, and endobronchial tumors. Clinical Research Committee, American Endocurietherapy Society

PURPOSE

A large number of medical centers have recently instituted the use of High Dose-Rate Afterloading Brachytherapy (HDRAB). There is wide variation in treatment regimens, techniques, and dosimetry being used and there are no national standard protocols or guidelines for optimal therapy.

METHODS AND MATERIALS

The Clinical Research Committee (CRC) of the American Endocurietherapy Society (AES) met to formulate consensus guidelines for HDRAB in cervical, endometrial, and endobronchial tumors.

CONCLUSION

Each center is encouraged to follow a consistent treatment policy in a controlled fashion with complete documentation of treatment parameters and outcome including efficacy and morbidity. Until further clinical data becomes available, the linear quadratic model can be used as a guideline to formulate a new HDR regimen exercising caution when changing from a Low Dose Rate (LDR) to a HDRAB regimen. The treatments should be fractionated as much as practical to minimize long term morbidity. As more clinical data becomes available, the guidelines will mature and be updated by the Clinical Research Committee of the AES.

Radioresponsiveness of human glioma, sarcoma, and breast cancer spheroids depends on tumor differentiation

PURPOSE

Differences in the intrinsic radiosensitivity within and between different tumor classes have been noticed for human tumor cell lines using the clonogenic assay. By far, most of the cell lines studied up to now were derived from poorly differentiated tumors. In this study, the influence of tumor differentiation on the radiation doses necessary to control 50% of small oxic spheroids (SCD50) was determined. Evidence of a distinct dependence of radioresponsiveness on tumor progression provides a background for an investigation of the underlying mechanisms.

METHODS AND MATERIALS

Spheroids were aggregated from 1000-1500 cells in agarose coated 24 multi-well plates. Their diameters ranged from 156 to 405 microns, depending on the cell line. Spheroids were irradiated with graded 60Co single doses using spheroid control as end point and a minimum follow-up period of 3 months.

RESULTS

Cell lines from three low grade gliomas and 10 malignant gliomas were studied in the spheroid control assay. The group mean SCD50 values were 6.1 +/- 1.6 Gy and 13.1 +/- 3.3 Gy, respectively. Four cell lines from grade 2 soft tissue sarcomas had a mean SCD50 value of 6.2 +/- 0.5 Gy and one undifferentiated sarcoma line of 11.0 Gy. Three well-differentiated breast cancer lines expressed the cell adhesion molecule E-cadherin, had an epithelioid morphology in monolayer culture, were estrogen receptor positive or contact inhibited in multicellular spheroids. Two undifferentiated breast cancer lines had a fibroblastoid morphology and were marker negative. The mean SCD50 value of the former was 10.5 +/- 1.0 Gy while that of the undifferentiated lines was 14.8 +/- 2.8 Gy. Analysis of variance revealed a significant effect of the tumor type as well as the grade of dedifferentiation on the SCD50 after irradiation with one fraction or 2Gy/fraction. The surviving fractions at 2 Gy (SF2), obtained from the spheroid control rates after different fractionation schedules by approximation of the linear quadratic model assuming Poisson statistics were significantly dependent on tumor type (p = 0.001, ANOVA F-test) but not on tumor differentiation (p = 0.27). The alpha/beta ratios did not depend on tumor type (p = 0.08, ANOVA F-Test) but significantly increased with the grade of tumor cell dedifferentiation (p = 0.03).

CONCLUSION

The spheroid model is suitable for measuring the radioresponsiveness of differentiated cell lines with very low colony forming efficiencies. Tumor cell differentiation is an important factor for the radioresponsiveness and recovery capacity of human tumor cells.

Endometrial carcinoma: does the addition of intracavitary vault caesium to external beam therapy postoperatively result in improved control or increased morbidity?

A retrospective analysis of treatment for endometrial carcinoma is reported here. From 1987 to 1989, 138 patients were referred to the oncology department following total abdominal hysterectomy and bilateral salpingo-oophorectomy for endometrial cancer. Forty-seven patients were not prescribed postoperative radiotherapy; 31 had Stage I well differentiated adenocarcinoma with minimal myometrial invasion, while the remaining 16 patients were considered unfit for postoperative radiotherapy. There were no instances of local relapse amongst the 31 patients with minimal myometrial invasion. The remaining 91 patients all received external beam irradiation to the pelvis and, according to the preference of the individual therapist, 51 were prescribed additional intracavitary vault caesium-137. Patients receiving postoperative radiotherapy were analysed according to whether or not they received additional intracavitary vault caesium. The two groups were also analysed for incidence of vaginal vault recurrence and treatment related morbidity. In the group receiving additional intracavitary treatment more patients had Stage II or III disease (P < 0.05), and had greater depth of myometrial invasion (P < 0.05). Vaginal vault recurrence was not observed in patients receiving intracavitary therapy in addition to external beam therapy. Four patients (10%) receiving external beam therapy alone developed vaginal vault recurrence. The incidence of Kottmeier-Perez grade 2 or 3 bowel toxicity following treatment was significantly higher in those patients receiving combined treatment (18% vs. 2.5%; P = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)