Treating the vaginal vault in carcinoma of the endometrium using the Buchler afterloading system

Preventing vaginal stenosis after brachytherapy for gynaecological cancer: an overview of Australian practices

Despite advances in brachytherapy techniques in recent years, patients still experience a variety of treatment-related complications. Vaginal stenosis is a recognised toxicity of brachytherapy for the treatment of gynaecological cancer. It can result in long-term sexual dysfunction and painful vaginal examinations; however, it is generally accepted that it may be prevented by regular sexual intercourse or the use of vaginal dilators. The incidence of vaginal stenosis is variably reported in the literature, while preventative strategies and compliance are infrequently described and rarely evaluated. A telephone survey of radiation oncology centres in Australia was undertaken as a quality improvement activity to determine best practice for the use of vaginal dilators for the prevention of vaginal stenosis, by way of identifying similarities of practice. The results revealed a lack of consistency for all variables, including which patients are advised to use vaginal dilators, the time to initiate use, frequency of use, insertion time and duration of use. These findings suggest that current methods for preventing radiation-induced vaginal stenosis warrant formal evaluation in order to establish an evidence base for practice.

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.

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.

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.

Outpatient vaginal cuff brachytherapy for endometrial cancer

Petereit DG, Tannehill SP, Grosen EA, Hartenbach EM, Schink JC. Outpatient vaginal cuff brachytherapy for endometrial cancer. The objective of this study was to determine the efficacy and complications of postoperative high-dose-rate (HDR) vaginal-cuff brachytherapy (VCB) in patients with endometrial carcinoma. Between August 1989 to September 1997, 191 patients were treated postoperatively after a total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH/BSO) with outpatient adjuvant HDR VCB for low-risk endometrial cancer (IB-84%, grade 1 or 2-96%). Patients were treated with 2 HDR fractions, delivered one week apart while under conscious sedation (16.2 Gy X 2 to the vaginal surface). All clinical endpoints were calculated using the Kaplan Meier method. The median time in the brachytherapy suite was 60 min in which no acute complications were observed. The 30-day morbidity and mortality rates were both 0%. With a median follow-up of 38 months (12-82 months), the 4-year survival, relapse-free survival, and vaginal-control rates were 95%, 98%, and 100%, respectively. One patient developed a colo-vaginal fistula at 5 years. Adjuvant HDR VCB in 2 outpatient insertions produced 100% vaginal control rates with minimal morbidity. The advantages of high dose-rate compared to low dose-rate vaginal brachytherapy include patient convenience, markedly shorter treatment times (1 h per insertion), and reduction in the cost and potential morbidity of hospitalization. HDR brachytherapy approach is a cost-effective alternative to either low-dose-rate brachytherapy or whole pelvic radiotherapy in carefully selected patients.

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.

[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.

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.