Comparision of four different dose specification methods for high-dose-rate intracavitary radiation for treatment of cervical cancer

Vaginal dose-surface maps in cervical cancer brachytherapy: Methodology and preliminary results on correlation with morbidity

PURPOSE

The purpose of the study was to develop a methodology for vaginal dose-surface maps (DSMs) in patients with cervix cancer and to investigate dose-surface histogram metrics as predictors for vaginal stenosis (St) and mucositis (Muc).

METHODS AND MATERIALS

Thirty-one patients with locally advanced cervix cancer with no vaginal St/Muc (CTCAE-v3) G ≥ 2 at baseline were analyzed. Patients were divided in four morbidity groups: 15 with St/Muc G0/1, 6 with St G ≥ 2, 4 with St/Muc G ≥ 2, and 6 with Muc G ≥ 2. Patients received external beam radiotherapy and 4-fraction intracavitary/interstitial high-dose-rate brachytherapy using tandem and ovoids. DSMs were generated from inner/outer vaginal surfaces. DSMs of external beam radiotherapy and brachytherapy (Gy EQD2₃) were added based on a system of homologous points, to generate cumulative DSMs. Dose-surface histogram/dose-volume histogram parameters, location of high/intermediate-dose regions, rectovaginal reference point, vaginal lateral 5 mm point doses, and vagina/implant dimensions were investigated for St and Muc prediction. Average/difference DSMs and one-way analysis of variance were used to compare between groups.

RESULTS

Best predictors of stenosis were D_15-25cm2 and upper-vagina S_65-120Gy(%). Cutoffs of ∼90 Gy EQD2₃ for D_20cm2 and ∼80% for S_65Gy to top 3 cm inner vaginal surface suitably discriminated for stenosis. Spatial dose location on average/difference DSMs showed significantly higher doses (by > 20 Gy, p < 0.001) over longer parts of the dorsolateral vagina and higher rectovaginal reference point doses for any G ≥ 2 morbidity, over the whole circumference of the upper vagina for G ≥ 2 stenosis. Dose-volume histogram parameters were dependent on vaginal wall thickness. An increase of wall thickness from 2 to 4 mm resulted in an increase of D_2cm3 (D_4cm3) of 16% (32%).

CONCLUSIONS

A novel method was developed to generate vaginal DSMs and spatial-dose metrics. DSMs were found to correlate with vaginal stenosis. The findings of this study are promising and should be further validated on a larger patient cohort, treated with different applicators.

Vaginal dose de-escalation in image guided adaptive brachytherapy for locally advanced cervical cancer

PURPOSE

Vaginal stenosis is a major problem following radiotherapy in cervical cancer. We investigated a new dose planning strategy for vaginal dose de-escalation (VDD).

MATERIALS AND METHODS

Fifty consecutive locally advanced cervical cancer patients without lower or middle vaginal involvement at diagnosis from 3 institutions were analysed. External beam radiotherapy was combined with MRI-guided brachytherapy. VDD was obtained by decreasing dwell times in ovoid/ring and increasing dwell times in tandem/needles. The aim was to maintain the target dose (D90 of HR-CTV⩾85Gy EQD2) while reducing the dose to the surface of the vagina to <140% of the physical fractional brachytherapy dose corresponding to a total EQD2 of 85Gy.

RESULTS

The mean vaginal loading (ovoid/ring) was reduced from 51% to 33% of the total loading with VDD, which significantly reduced the dose to the vaginal dose points (p<0.001) without compromising the target dose. The dose to the ICRU recto-vaginal point was reduced by a mean of 4±4Gy EQD2 (p<0.001), while doses to bladder and rectum (D_2cm³) were reduced by 2±2Gy and 3±2Gy, respectively (p<0.001).

CONCLUSIONS

VDD significantly reduces dose to the upper vagina which is expected to result in reduction of vaginal stenosis.

Short-term clinical outcome and dosimetric comparison of tandem and ring versus tandem and ovoids intracavitary applicators

Purpose

To compare the short-term toxicity and dosimetry of tandem and ring (TR), and tandem and ovoid (TO) applicators in treatment of gynecologic malignancy.

Material and methods

Following pelvic external beam radiation therapy (EBRT), a total of 52 computed tomography-based plans from 13 patients with cervical cancer (FIGO IB2-IIIB) were evaluated for HDR brachytherapy. Prescription was 7 Gy to the ICRU point A for four weekly fractions. Gastrointestinal and genitourinary toxicities were evaluated. Clinical target volume (CTV) and organs at risk were delineated on CT scans. Bladder, rectum, and sigmoid mean doses and D_2cc were calculated. Treatment time and irradiated tissue volume were compared. Percent of CTV receiving 100% (CTV_100%) of the prescribed dose as well as the percent of the prescription dose covering 90% of the CTV (D₉₀) were evaluated.

Results

Gastrointestinal and genitourinary toxicities were not different between TO and TR applicators. No significant differences in the dose to the right and left point A, or the left point B were observed. TO delivered a higher dose to right point B. Organs at risk doses were similar between the two applicators, except mean rectal dose was lower for TO applicator. Overall, TO treats a larger tissue volume than TR. Mean treatment time was shorter for TR. Tumor coverage (D₉₀ and CTV_100%) was equivalent between TO and TR applicators.

Conclusion

Although TO treats a larger tissue volume than TR, short-term toxicities and tumor coverage are similar. Long-term clinical outcomes will be elucidated with longer follow up period.

Tolerance of the vaginal vault to high-dose rate brachytherapy and concomitant chemo-pelvic irradiation: Long-term perspective

AIM/BACKGROUND

We sought to determine the tolerance level and complication rates of the vaginal vault to combined high-dose-rate intra-cavitary brachytherapy with concomitant chemo-radiotherapy.

PATIENTS AND METHODS

A retrospective review of medical records of all the patients who received definitive chemo-radiotherapy for cervical cancer between 1998 and 2002 was undertaken. The records were reviewed for doses and for radiation-associated early and late sequelae of the vagina, rectum and bladder. Cumulative biological effective dose was calculated for two reference vaginal surface points.

RESULTS

Fifty patients were included. Average age at diagnosis was 54 years. Median follow-up was 59 months. There were no recorded instances of acute grade IV toxicity. Maximal high-dose-rate vaginal surface dose (upper central point) was 103 Gy, and maximal brachytherapy lateral surface dose was 70 Gy. Maximal cumulative biological effective dose for the lateral surface reference point was 465.5 Gy3, and the maximal cumulative biological effective dose for the superior reference point was 878.6 Gy3. There were no cases of vaginal necrosis or fistulas, and no cases of grade IV late vaginal, rectal or bladder toxicity. No correlation was found between the maximal vaginal surface dose and vaginal, rectal or bladder toxicity.

CONCLUSIONS

The maximal surface HDR brachytherapy dose of 103 Gy and the maximal cBED of 878.6 Gy3 were not associated with fistula or necrosis or other grade 3-4 vaginal complications. Concomitant chemo-radiotherapy, including pelvic radiotherapy and high-dose-rate intracavitary brachytherapy, is relatively safe for cervical cancer patients.

Does inadequate Point-A dose warrant treatment plan modifications in CT-image-based cervix high dose-rate brachytherapy planning? A dosimetric perspective

Background and purpose

To investigate whether inadequate dose to Point-A necessitates treatment plan changes in a time of computed tomography (CT)-image-guided brachytherapy treatment planning for cervix cancer.

Materials and methods

A total of 125 tandem and ovoid insertions from 25 cervix patients treated were reviewed. CT-image-based treatment planning was carried out for each insertion. Point-A is identified and the dose documented; however, dose optimisation in each plan was based on covering target while limiting critical organ doses (PlanTarget). No attempts were made to equate prescription and Point-A dose. For each insertion, a second hypothetical treatment plan was generated by prescribing dose to Point-A (PlanPoint-A). Plans were inter-compared using dose–volume histogram analyses.

Results

A total of 250 treatment plans were analysed. For the study population, the median cumulative dose at Point-A was 80 Gy (range 70–95) for PlanTarget compared with 84·25 Gy for PlanPoint-A. Bladder and rectal doses were higher for PlanPoint-A compared with PlanTarget (p < 0·0001). Target D90 did not correlate with Point-A dose (p = 0·60).

Conclusions

Depending on applicator geometry, tumour size and patient anatomy, Point-A dose may vary in magnitude compared with prescription dose. Treatment plan modifications purely based on inadequate Point-A dose are unnecessary, as these may result in higher organ-at-risk doses and not necessarily improve target coverage.

Three-dimensional high dose rate intracavitary image-guided brachytherapy for the treatment of cervical cancer using a hybrid magnetic resonance imaging/computed tomography approach: feasibility and early results

AIMS

To evaluate the feasibility and outcome of image-guided brachytherapy (IGBT) for treating cervical cancer using magnetic resonance imaging (MRI)-based planning for the first fraction followed by computed tomography (CT)-based planning for subsequent fractions.

MATERIALS AND METHODS

Forty-four patients with cervical cancer were treated with three-dimensional high dose rate IGBT. The brachytherapy dose was 5.0-6.0 Gy × five fractions. All but five patients received concurrent weekly cisplatinum at 40 mg/m(2). All patients received external beam radiotherapy (EBRT) with a median dose of 45Gy over 25 fractions. Total doses for the high-risk clinical target volume (HRCTV) and organs at risk, including the rectum, bladder and sigmoid, from EBRT and brachytherapy were summated and normalised to a biologically equivalent dose of 2Gy per fraction (EQD(2)). At 3 months after therapy, any early response was assessed with positron emission tomography (PET)/CT imaging.

RESULTS

The mean D(90) for the HRCTV was 83.3 (3.0) Gy. The mean 2 cm (3) dose to the bladder, rectum and sigmoid colon organs was 79.7 (5.1), 57.5 (4.4) and 66.8 (5.7) Gy, respectively. All but one (2.3%) patient had a complete response. Follow-up PET/CT was carried out in 41 (93.0%) patients, of whom 38 (92.5%) had a complete response. Of the 38 patients with a complete response on PET/CT, two had local recurrences at 6 and 8 months, respectively. Actuarial 2 year local control, disease-specific and overall survival rates were 88, 85 and 86%, respectively.

CONCLUSION

This is the first report of three-dimensional high dose rate IGBT for the treatment of cervical cancer using a hybrid MRI/CT approach. Early results have shown the feasibility of this approach with excellent local control. Additional studies are needed to assess long-term outcomes of local control and associated morbidities.

Dosimetric analysis of 3D image-guided HDR brachytherapy planning for the treatment of cervical cancer: is point A-based dose prescription still valid in image-guided brachytherapy?

The purpose of this study was to analyze the dosimetric outcome of 3D image-guided high-dose-rate (HDR) brachytherapy planning for cervical cancer treatment and compare dose coverage of high-risk clinical target volume (HRCTV) to traditional Point A dose. Thirty-two patients with stage IA2-IIIB cervical cancer were treated using computed tomography/magnetic resonance imaging-based image-guided HDR brachytherapy (IGBT). Brachytherapy dose prescription was 5.0-6.0 Gy per fraction for a total 5 fractions. The HRCTV and organs at risk (OARs) were delineated following the GYN GEC/ESTRO guidelines. Total doses for HRCTV, OARs, Point A, and Point T from external beam radiotherapy and brachytherapy were summated and normalized to a biologically equivalent dose of 2 Gy per fraction (EQD2). The total planned D90 for HRCTV was 80-85 Gy, whereas the dose to 2 mL of bladder, rectum, and sigmoid was limited to 85 Gy, 75 Gy, and 75 Gy, respectively. The mean D90 and its standard deviation for HRCTV was 83.2 ± 4.3 Gy. This is significantly higher (p < 0.0001) than the mean value of the dose to Point A (78.6 ± 4.4 Gy). The dose levels of the OARs were within acceptable limits for most patients. The mean dose to 2 mL of bladder was 78.0 ± 6.2 Gy, whereas the mean dose to rectum and sigmoid were 57.2 ± 4.4 Gy and 66.9 ± 6.1 Gy, respectively. Image-based 3D brachytherapy provides adequate dose coverage to HRCTV, with acceptable dose to OARs in most patients. Dose to Point A was found to be significantly lower than the D90 for HRCTV calculated using the image-based technique. Paradigm shift from 2D point dose dosimetry to IGBT in HDR cervical cancer treatment needs advanced concept of evaluation in dosimetry with clinical outcome data about whether this approach improves local control and/or decreases toxicities.

Potential of dose optimisation in MRI-based PDR brachytherapy of cervix carcinoma

BACKGROUND AND PURPOSE

In this study on PDR treatment planning of utero-vaginal carcinoma, we analysed the dosimetry of traditional X-ray based plans as it presents on MR images. The potential gain of MRI-based dose optimisation was assessed.

PATIENTS AND METHODS

Sixteen patients boosted with PDR brachytherapy after external beam therapy were included. The clinical X-ray based plans were projected on MR images. The GTV, HR-CTV and IR-CTV were retrospectively contoured, as well as the bladder, rectum and sigmoid colon. The dose in the critical organs and target coverage was investigated. In a second phase, the plans were manually optimised using the MR information. The objectives were to lower the dose in the critical organs (<or= 85 Gy(alphabeta3) for bladder, <or= 75 Gy(alphabeta3) for rectum and sigmoid colon) and to increase the HR-CTV dose to D90 >or= 85 Gy(alphabeta10).

RESULTS

In the X-ray based plans, D(2cc) in bladder and sigmoid colon exceeded the tolerance doses in 10/16 and 7/16 patients, respectively. Coverage of the IR-CTV with the 60 Gy(alphabeta10) was acceptable. D90 of the HR-CTV was below 85 Gy(alphabeta10) in 13 out of 16 patients. After optimisation, the dose constraints in the OAR were not exceeded anymore in any patient. The average D(2cc) dose reduction was 7+/-6 Gy(alphabeta3) in the bladder and 7+/-4 Gy(alphabeta3) in the sigmoid colon for those patients in which the dose constraint was initially exceeded. In addition, an average dose increase of 3 Gy(alphabeta10) was accomplished in the HR-CTV.

CONCLUSIONS

MRI-based dose optimisation can play an important role to reduce the dose delivered to the critical organs and to improve target coverage.

Multimodality therapy for locally advanced cervical carcinoma: state of the art and future directions

Globally, cervical cancer is the second most common cause of cancer-related mortality among women causing approximately 234,000 deaths annually among developing countries and killing 40,000 in developed nations. Most of these deaths occur in women with bulky or locally advanced cervical cancer, International Federation of Gynecology and Obstetrics (FIGO) stages IIB through IVA, when lesions are not amenable to high cure rates with surgery or radiation (RT). The standard prescription for RT used to treat locally advanced cervical cancer has been dictated by common practice and patterns of care studies. In contrast, the addition of concomitant chemotherapy to RT has been studied in a number of randomized prospective trials, which are discussed in detail. When added to RT, cisplatin reduces the relative risk of death from cervical carcinoma by approximately 50% by decreasing local/pelvic failure and distant metastases. In 1999, weekly intravenous cisplatin at 40 mg/m2 for 6 weeks in combination with RT was established as a new standard for the treatment of locally advanced cervical carcinoma. More recently, this recommendation has been expanded to include women with FIGO stage IB2 lesions as well as those with bulky stage IIA cancers. This monograph reviews the state of the art in treating locally advanced cervical cancer with combined chemotherapy and RT and discusses clinical and pathologic prognostic factors that impact cure. Quality of life during and after multimodality therapy is considered as well as ongoing clinical trials and future directions.

Uncertainties in assessment of the vaginal dose for intracavitary brachytherapy of cervical cancer using a tandem-ring applicator

PURPOSE

The vagina has not been widely recognized as organ at risk in brachytherapy for cervical cancer. No widely accepted dose parameters are available. This study analyzes the uncertainties in dose reporting for the vaginal wall using tandem-ring applicators.

METHODS AND MATERIALS

Organ wall contours were delineated on axial magnetic resonance (MR) slices to perform dose-volume histogram (DVH) analysis. Different DVH parameters were used in a feasibility study based on 40 magnetic resonance imaging (MRI)-based treatment plans of different cervical cancer patients. Dose to the most irradiated, 0.1 cm(3), 1 cm(3), 2 cm(3), and at defined points on the ring surface and at 5-mm tissue depth were reported. Treatment-planning systems allow different methods of dose point definition. Film dosimetry was used to verify the maximum dose at the surface of the ring applicator in an experimental setup.

RESULTS

Dose reporting for the vagina is extremely sensitive to geometrical uncertainties with variations of 25% for 1 mm shifts. Accurate delineation of the vaginal wall is limited by the finite pixel size of MRI and available treatment-planning systems. No significant correlation was found between dose-point and dose-volume parameters. The DVH parameters were often related to noncontiguous volumes and were not able to detect very different situations of spatial dose distributions inside the vaginal wall. Deviations between measured and calculated doses were up to 21%.

CONCLUSIONS

Reporting either point dose values or DVH parameters for the vaginal wall is based on high inaccuracies because of contouring and geometric positioning. Therefore, the use of prospective dose constraints for individual treatment plans is not to be recommended at present. However, for large patient groups treated within one protocol correlation with vaginal morbidity can be evaluated.

Application of mri for improved local control in complex radiotherapy of cervical cancer

Background: The aim of this study was to analyze the use of magnetic resonance imaging (MRI) as a modern medical imaging technique in radiotherapy with special emphasis on the integration of MRI and a novel technique in brachytherapy to optimize treatment outcome in cervical cancer. Methods: In addition to the CT based shrinking volume conformal teletherapy in 31 patients with locally advanced cervical cancer, MRI examination with a special adjustable applicator at the treatment site was performed for the brachytherapy planning. To avoid excessive doses to the healthy structures during complex cervical radiotherapy isodose curves were calculated upon the information of the MR image and dose distribution was evaluated. Results: The consecutive application of CT and MRI limited the possibility for overdosage of the critical organs and undertreatment of the advanced tumor spread in all cases. The overall response rate for the complex treatment was 74.2% with complete regression in 25.8% of the cases. Based on the exact information of the three dimensional digital data radiation doses could be optimized without increasing the possibility of acute complications rate. Conclusion: The introduction of 3D treatment planning for teletherapy pelvic and boost irradiation of cervical carcinoma as well as for the brachytherapy part of the complex treatment is to be recommended. .

Current controversies in high-dose-rate versus low-dose-rate brachytherapy for cervical cancer

The use of brachytherapy in the treatment of cervical cancer has increased worldwide since its initial introduction over 100 years ago. However, certain aspects of the use of high-dose-rate (HDR) versus low-dose-rate (LDR) brachytherapy continue to be controversial, particularly the role of HDR in FIGO Stage III cervical cancer and the use of HDR with concurrent chemotherapy. This study represents a systematic literature review of prospective and retrospective series of patients with cervical carcinoma treated with external-beam radiation (EBRT) followed by either HDR or LDR radiation. The local control rates, survival rates, and treatment-related complications in patients with Stage III cervical cancer treated with HDR or LDR and those treated with concomitant chemotherapy are examined. Patients with Stage III cervical cancer treated with EBRT and brachytherapy have a local control rate of >50% in most series. Randomized prospective and retrospective studies show overall statistically equivalent local control, overall survival, and complication rates between HDR and LDR. However, LDR may be preferable for large, bulky tumors at the time of brachytherapy. Retrospective studies of HDR and concurrent chemotherapy are limited but have demonstrated toxicity rates similar to those with LDR. Selected patients with Stage III cervical carcinoma who have an adequate response to EBRT and concomitant chemotherapy may be treated with HDR brachytherapy. The existing literature shows no significant increase in complications in patients treated with HDR and concurrent chemotherapy; however, sufficient tumor shrinkage prior to HDR and careful monitoring of the dose to the normal tissues are imperative.

Dose and volume parameters for MRI-based treatment planning in intracavitary brachytherapy for cervical cancer

PURPOSE

Magnetic resonance imaging (MRI)-based treatment planning in intracavitary brachytherapy allows optimization of the dose distribution on a patient-by-patient basis. In addition to traditionally used point dose and volume parameters, dose-volume histogram (DVH) analysis enables further possibilities for prescribing and reporting. This study reports the systematic development of our concept applied in clinical routine.

METHODS AND MATERIALS

A group of 22 patients treated with 93 fractions using a tandem-ring applicator and MRI-based individual treatment planning for each application was analyzed in detail. High-risk clinical target volumes and gross tumor volumes were contoured. The dose to bladder, rectum, and sigma was analyzed according to International Commission of Radiation Units and Measurements (ICRU) Report 38 and DVH parameters (e.g., D(2cc) represents the minimal dose for the most irradiated 2 cm(3)). Total doses, including external beam radiotherapy and the values for each individual brachytherapy fraction, were biologically normalized to conventional 2-Gy fractions (alpha/beta 10 Gy for target, 3 Gy for organs at risk).

RESULTS

The total prescribed dose was about 85 Gy(alphabeta10), which was mainly achieved by 45 Gy external beam radiotherapy plus 4 x 7 Gy brachytherapy (total 84 Gy(alphabeta10)). The mean value was 82 Gy(alphabeta10) for the point A dose (left, right) and 84 cm(3) for the volume of the prescribed dose. The average dose to the clinical target volume was 66 Gy(alphabeta10) for the minimum target dose, 87 Gy(alphabeta10) for the dose received by at least 90% of the volume, with a mean volume treated with at least the prescribed dose of 89%. The mean D(2cc) for the bladder was 83 Gy(alphabeta3), the ICRU point dose was 75 Gy(alphabeta3), and the dose at the ICRU point plus 1.5 cm cranially was 100 Gy(alphabeta3). The average dose to the rectum was 64 Gy(alphabeta3) for D(2cc) and at ICRU point 69 Gy(alphabeta3). The sigma D(2cc) was 63 Gy(alphabeta3).

CONCLUSION

A standard loading pattern should be used as the starting point for MRI-based optimization. Individual changes of active dwell positions and dwell weights are guided by a concept of DVH constraints for target and organs at risk. In our clinical routine, the dose to point A and dose received by at least 90% of the volume for the clinical target volume are both comparable to the prescribed dose. The DVH constraints for organs at risk allow reproducible treatment plans, helping to detect and avoid severe overdosage.

Combination external beam radiotherapy and high-dose-rate intracavitary brachytherapy for uterine cervical cancer: analysis of dose and fractionation schedule

PURPOSE

To determine an appropriate dose and fractionation schedule for a combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) for uterine cervical cancer.

METHODS

Eighty-eight patients with uterine cervical squamous cell carcinoma treated with EBRT and HDR-ICBT were analyzed. Twenty-five patients were classified as early disease (nonbulky Stage I/II, less than 4-cm diameter) and 63 patients as advanced disease (greater than 4 cm diameter or Stage IIIB) according to the American Brachytherapy Society definition. Tumor diameter was measured by MRI. Pelvic EBRT was delivered before applications of ICBT. HDR-ICBT was performed once a week, with a fraction point A dose of 6 Gy. Source loadings corresponded to the Manchester System for uterine cervical cancer. No planned optimization was done. A Henschke-type applicator was mostly used (86%). Median cumulative biologic effective dose (BED) at point A (EBRT + ICBT) was 64.8 Gy(10) (range: 48-76.8 Gy(10)) for early disease, and 76.8 Gy(10) (range: 38.4-86.4 Gy(10)) for advanced disease. Median cumulative BED at ICRU 38 reference points (EBRT + ICBT) was 97.7 Gy(3) (range: 59.1-134.4 Gy(3)) at the rectum, 97.8 Gy(3) (range: 54.6-130.4 Gy(3)) at the bladder, and 324 Gy(3) (range: 185.5-618 Gy(3)) at the vagina. Actuarial pelvic control rate and late complication rate were analyzed according to cumulative dose and calculated BED.

RESULTS

The 3-year actuarial pelvic control rate was 82% for all 88 patients: 96% for those with early disease, and 76% for advanced disease. For pelvic control, no significant dose-response relationship was observed by treatment schedules and cumulative BED at point A for both early and advanced disease. The 3-year actuarial late complication rates (Grade > or =1) were 12% for proctitis, 11% for cystitis, and 14% for enterocolitis. There were significant differences on the incidence of proctitis (p < 0.0001) and enterocolitis (p < 0.0001), but not for cystitis by the treatment schedules and cumulative point A BED. All 4 patients treated with 86.4 Gy(10) at point A suffered both proctitis and enterocolitis. Patients with cumulative BED at rectal point of > or =100 Gy(3) had significantly higher incidence of proctitis (31% vs. 4%, p = 0.013).

CONCLUSIONS

In view of the therapeutic ratio, cumulative BED 70-80 Gy(10) at point A is appropriate for uterine cervical cancer patients treated with a combination of EBRT and HDR-ICBT. Present results and data from other literatures suggested that cumulative BED at the rectal point should be kept below 100-120 Gy(3) to prevent late rectal complication.

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.