The prediction of late rectal complications following the treatment of uterine cervical cancer by high-dose-rate brachytherapy

Genetic markers of late radiation toxicity in the era of image-guided radiotherapy: lower toxicity rates reduce the predictive value of γ-H2AX foci decay ratio in patients undergoing pelvic radiotherapy

BACKGROUND

A predictive assay for late radiation toxicity would allow more personalized treatment planning, reducing the burden of toxicity for the more sensitive minority, and improving the therapeutic index for the majority. In a previous study in prostate cancer patients, the γ-H2AX foci decay ratio (γ-FDR) was the strongest predictor of late radiation toxicity. The current study aimed to validate this finding in a more varied group of patients with pelvic cancer. Additionally, the potential correlation between the γ-FDR and patient-reported outcomes was investigated.

METHODS

Prostate and gynecological cancer patients with ≥ 24 months of follow-up were included in the current analysis. Toxicity was evaluated by physician (CTCAE version 4) and patient (EORTC questionnaires). γ-FDRs were determined in ex vivo irradiated lymphocytes. Correlation between γ-FDR and toxicity was assessed using both linear and logistic regression analyses. The highest toxicity grade recorded during follow-up was used. The association between global quality of life and γ-FDR was tested by comparing the change in quality of life over time in patients with γ-FDR < or ≥ 3.41, a previously established threshold.

RESULTS

Eighty-eight patients were included. Physician-assessed and patient-reported cumulative grade ≥ 2 toxicity was 25% and 29%, respectively; which is much lower than in the previous cohort (i.e., 51% CTCAE grade ≥ 2). Patients with toxicity exhibited less favorable dose-volume parameters. In men, these parameters showed significant improvement compared to the previous cohort. The proportion of patients with a low γ-FDR increased with severity of toxicity, but this trend was not statistically significant. In addition, a γ-FDR < 3.41 was not correlated with the development of moderate to severe toxicity. Post-treatment decline in global quality of life was minimal, and similar for patients with γ-FDR < or ≥ 3.41.

CONCLUSIONS

In the present study, the γ-H2AX foci decay ratio could not be validated as a predictor of late radiation toxicity in patients with pelvic cancer. Improved radiotherapy techniques with smaller irradiated bladder and bowel volumes have probably resulted in less toxicities. Future studies on genetic markers of toxicity should be powered on these lower incidences. We further recommend taking persistency, next to severity, into consideration.

The Clinical Course of the Late Toxicity of Definitive Radiotherapy in Cervical Cancer

Background and Objectives: This study aimed to investigate the clinical course and characteristics of late toxicity over time following the completion of definitive radiotherapy (RT) in patients with cervical cancer. Materials and Methods: We retrospectively reviewed the medical records of 60 patients with cervical cancer who underwent pelvic external beam radiotherapy followed by intracavitary brachytherapy. Late toxicity was assessed for the lower gastrointestinal (GI) tract and bladder organ at 6, 12, 24, 36, and >36 months post-RT. We examined the onset and prevalence of late toxicity at each time point. Clinical remission and interventions for managing late toxicity were also investigated. Results: The peak onset of lower GI toxicity occurred 12 months after RT completion, with a median symptom duration of 9.9 months (range, 0.1-26.3 months), and exhibited its highest prevalence rate of 15.5% at 24 months post-RT. Most GI toxicities developed and resolved within three years post-RT, with a prevalence rate of 8.1% at three years, followed by a decreasing trend. Bladder toxicity first peaked at 24 months post-RT and continued to occur beyond 36 months, showing the re-increasing pattern in the prevalence rate after 36 months (23.5%). In terms of clinical remission, 66.7% of lower GI toxicities (12 of 18 patients) and 60% of bladder toxicities (9 of 15 patients) achieved complete remission by the last follow-up date. Conclusions: Late toxicities of the GI and bladder following definitive RT in cervical cancer are partially reversible and exhibit distinct patterns of onset and prevalence over time. A systematic follow-up strategy should be established for the early detection and timely intervention of late toxicity by understanding these clinical courses.

The impact of socioeconomic deprivation on mortality in cervical cancer patients in Cornwall (England)

OBJECTIVES

To assess the association between risk factors, including socioeconomic deprivation, and mortality, recurrence and chemo- or radiation toxicity in cervical cancer patients.

METHODS

Retrospective study of cervical cancer patients diagnosed between January 2007 and July 2018. Patient characteristics and mortality data, including recurrence, were assessed, together with socioeconomic deprivation measures evaluated using the English Indices of Multiple Deprivation. Markov multi-state models were used to model mortality and recurrence, and logistic regression models were used to model chemo- or radiation toxicity.

RESULTS

Included were 243 women with a median age of 49 years. A total of 57 patients died (23%), of which 41 due to cervical cancer, and 21 (9%) had recurrent disease. Hazard ratios (HR) showed no evidence of association between socioeconomic deprivation and cancer-specific hazard of mortality from diagnosis or recurrence, hazard of mortality due to other causes or hazard of cancer recurrence. Furthermore, there was no evidence of association between socioeconomic deprivation and chemo- or radiation toxicity (bowel, bladder or vaginal stenosis).

CONCLUSIONS

No associations were found between socioeconomic deprivation and cancer mortality or recurrence in cervical cancer patients in the population of Cornwall. In addition, no association was found between socioeconomic deprivation and chemo- or radiation toxicity.

Toxicities and Recurrences after Co-60 High-Dose-Rate Brachytherapy for Cervical Cancer in a Tertiary Government Hospital in the Philippines

Introduction Despite the rising popularity of high-dose-rate (HDR) brachytherapy and use of Co-60 in the country, local data on brachytherapy outcomes are lacking. The study reviewed the incidence of toxicities and recurrences in patients with cervical cancer treated with Co-60 intracavitary HDR brachytherapy in a tertiary government hospital in the Philippines.

Methods Records of patients with cervical cancer who completed external beam radiotherapy (EBRT) and brachytherapy from 2016 to 2018 were reviewed. Patient-related (age, smoking history, body mass index, histology, stage, mass size) and treatment-related (overall treatment time [OTT], EBRT machine used, brachytherapy fractionation, dose prior to midline shielding/central tumor dose [CTD]) parameters were analyzed for possible associations with the incidence of toxicities and recurrences.

Results One hundred and sixty-three patients were identified and reviewed for baseline characteristics. Patients who had inadequate follow-up (<90 days) were excluded in the analysis of outcomes. Among the remaining 132 patients, median follow-up duration was 389 days. Gastrointestinal (GI) and genitourinary (GU) toxicities were present in 19.7% (n = 26) and 1.5% (n = 2), respectively. Recurrence was noted in 31.8% (n = 42). The most commonly involved sites of locoregional and distant recurrence was the uterocervix (n = 16, 59.3%) and para-aortics (n = 42, 31.8%), respectively. CTD was significantly associated with toxicities (p = 0.03), while OTT was borderline significantly associated with recurrence (p = 0.06).

Conclusion We present outcomes of GI and GU toxicities, and locoregional and distant recurrences after chemoradiation and Co-60 HDR brachytherapy in a tertiary government hospital in the Philippines. Our study suggests that CTD was significantly associated with incidence of toxicities, while OTT was weakly associated with recurrence. Interventions should be made to control these factors, especially in high-volume, low-resource cancer centers.

A Dosimetric Analysis of the Rectal Doses in Intracavitary Brachytherapy of Carcinoma Cervix: A Prospective Study from a Single Institute

Introduction:

Carcinoma cervix is a common gynecologic malignancy in India and is treated with radical chemoradiation where intracavitary brachytherapy (ICR) is an integral part. In ICR of cervix, the two-dimensional (2D) point-based dosimetry cervix is the most common method used in high-volume centers with rectal dose calculation at modified ICRU rectal point with rectal wire placement. The rectal dose measurement using this method underestimates the dose to the rectum, and rectal dose also varies with the type of applicator used. The aim of our study is to compare the rectal dose calculated by ICRU 38 method versus rectal dose calculated by the rectal wire method using Henschke applicator.

Materials and Methods:

This is a single-institute, dosimetric comparison study done prospectively. Fifty patients were planned for ICR after 2D orthogonal radiograph-based, computer planning by iridium 192 high-dose rate remote afterloading technique after placing the appropriate Henschke applicator. The vaginal packing was done using sterile gauze with contrast material for defining the ICRU 38 rectal point, and a rectal wire was placed for the modified ICRU rectal point. Rectal doses were calculated by both the methods and compared.

Results:

The modified ICRU rectal point recorded a lower rectal dose (mean of 25%) compared to ICRU 38 rectal point in the study patients. There were ten patients (20%) with either too much or too little contrast material which made the visualization of the rectal point and radiation planning difficult. P value by paired t-test method was 0.0001, which was statistically significant.

Conclusion:

The modified ICRU rectal point is easier to visualize than ICRU 38 method (100% vs. 80%) for dosimetry, but it underestimates the rectal doses when compared to ICRU 38 rectal point. There needs to be a correction factor applied (25% in our study for Henschke applicator) when evaluating the rectal doses calculated by rectal wire method, to reduce the rectal toxicity.

Treatment-Related Radiation Toxicity Among Cervical Cancer Patients

Objective

The purpose of this study is to identify incidence of and factors associated with severe late toxicity in women treated with radiation for cervical cancer.

Materials and Methods

All patients with cervical cancer treated with radiation as primary or adjuvant therapy from 2005 to 2017 in a single academic institution were included. Records were reviewed for demographic information, Charlson Comorbidity Index, treatment details, toxicities, and outcomes. Patients with and those without severe late gastrointestinal toxicity (SLGIT), severe late genitourinary toxicity (SLGUT), or any SLGIT or SLGUT, defined as any toxicity (AT), were compared. Overall survival and progression-free survival were also compared.

Results

Of 179 patients identified, 21.2% had AT, 17.3% had SLGIT, and 10% had SLGUT. Estimated AT rate at 3 years was 24.2%. The mean duration of follow-up was 37 months (range, 3–146 months). Most patients (84.1%) received 3-dimensional conformal therapy, and 15.9% received intensity-modulated radiation therapy. Factors associated with AT were lower body mass index (24.9 vs 28.3, P = 0.043), white race (63.2% vs 44%, P = 0.035), and active tobacco smoking during treatment (59.5% vs 40.2%, P = 0.036). Any toxicity was not associated with 3-dimensional versus intensity-modulated radiation therapy planning, low-dose versus high-dose–rate brachytherapy or time to complete radiation treatment. Higher total cumulative radiation dose to clinical target volume was associated with SLGIT. Progression-free survival and overall survival were similar among patients with AT compared to those without toxicity.

Conclusions

In patients with cervical cancer, radiation toxicity is correlated with lower body mass index, white race, and smoking. Despite technologic advances in radiotherapy planning and delivery, toxicity remains high and interventions to reduce the burden of treatment are needed.

Clinical analysis of speculum-based vaginal packing for high-dose-rate intracavitary tandem and ovoid brachytherapy in cervical cancer

Purpose

Intra-vaginal packing is used to fix the applicator and displace organs at risk (OAR) during high-dose-rate intracavitary tandem and ovoid brachytherapy (HDR-ICB). We retain the speculum from applicator placement as a dual-function bladder and rectum retractor during treatment. Our objective is to review salient techniques for OAR displacement, share our packing technique, and determine the reduction in dose to OAR and inter-fraction variability of dose to OAR, associated with speculum-based vaginal packing (SBVP) in comparison to conventional gauze packing during HDR-ICB.

Material and methods

We reviewed HDR-ICB treatment plans for 45 patients, including 10 who underwent both conventional gauze packing and SBVP. Due to institutional inter-provider practice differences, patients non-selectively received either packing procedure. Packing was performed under conscious sedation, followed by cone beam computed tomography used for dosimetric planning. Maximum absolute and percent-of-prescription dose to the International Commission of Radiation Units bladder and rectal points in addition to D_0.1cc, D_1.0cc, and D_2.0cc volumes of the bladder and rectum were analyzed and compared for each packing method using an independent sample t-test.

Results

Of the 179 fractions included, 73% and 27% used SBVP and gauze packing, respectively. For patients prescribed 6 Gy to point A, SBVP was associated with reduced mean D_0.1cc bladder dose, inter-fraction variability in D_0.1cc bladder dose by 9.3% (p = 0.026) and 9.0%, respectively, and statistically equivalent rectal D_0.1cc, D_1.0cc, and D_2.0cc. Patients prescribed 5.5 Gy or 5 Gy to point A after dose optimization, were less likely to benefit from SBVP. In the intra-patient comparison, 80% of patients had reduction in at least one rectum or bladder parameter.

Conclusions

In patients with conducive anatomy, SBVP is a cost-efficient packing method that is associated with improved bladder sparing and comparable rectal sparing relative to gauze packing during HDR-ICB without general anesthesia.

Socioeconomic status as an independent risk factor for severe late bowel toxicity after primary radiotherapy for cervical cancer

OBJECTIVE

To evaluate the frequency of and risk factors for severe late bowel toxicity after curative radiotherapy in women treated for locally advanced cervical cancer.

METHODS

Included were 515 women treated for locally advanced cervical cancer with primary radiotherapy with curative intent from 1992 to 2013. Bowel toxicity was graded according to the Common Terminology Criteria for Adverse Events. Associations between risk factors and severe late bowel toxicity were assessed using Cox proportional hazards regression models.

RESULTS

Median follow-up was 78months. Fifty-nine patients developed severe late bowel toxicity. The actuarial 3-year and 5-year severe late bowel toxicity rates were both 13%. In the multivariable analysis, factors significantly associated with severe late bowel toxicity were: smoking (HR 2.59 [1.48-4.55]), severe acute bowel toxicity (HR 2.46 [1.24-4.49]), previous major abdominal surgery (HR 2.35 [1.20-4.60]), hypertension (HR 2.33 [1.23-4.40]), parametrial boost (HR 2.18 [1.10-4.33]), low socioeconomic status (HR 2.05 [1.17-3.59]) and low BMI (HR 0.93 [0.88-0.99]). First symptoms of severe late bowel toxicity were reported after a median follow-up of 9months, but occurred up to 10years after end of treatment. Only one third of the patients with severe late bowel toxicity were referred to a gastroenterologist.

CONCLUSIONS

Severe late bowel toxicity is a frequent complication of definitive radiotherapy for cervical cancer. Several independent risk factors were found which warrant further research. A standardized and structured approach in the early diagnostics and management of bowel toxicity is needed.

Rectal separation using hydroxypropyl methylcellulose in intracavitary brachytherapy of cervical cancer: an innovative approach

PURPOSE

This study was initiated to prove feasibility of hydrogel application in recto-vaginal space in intracavitary brachytherapy (ICBT) of cervical cancer in order to reduce rectal toxicity.

MATERIAL AND METHODS

In a case of stage IIB cervical cancer, after external beam radiotherapy (EBRT), we planned ICBT 7 Gy × 3 fractions. In 1^st fraction (Plan 1), due to narrow separation between rectum and cervix (0.18 cm), only 5 Gy was delivered at point A (with high-risk clinical target volume [HR-CTV] D₉₀ 5.94 Gy, intermediate risk clinical target volume [IR-CTV] D₉₀ 4.54 Gy, rectum D_2cc 5.72 Gy, bladder D_2cc 5.52 Gy, and sigmoid colon 5.82 Gy). In 2^nd fraction (Plan 2), interstitial brachytherapy (ISBT) was attempted. For the prescription of 5 Gy, we get dose levels almost similar to the 1^st insertion: HR-CTV D₉₀ (6.7 Gy), IR-CTV D₉₀ (3.06 Gy), bladder D_2cc (5.7 Gy), rectum D_2cc (4.8 Gy), sigmoid colon D_2cc (1.3 Gy) (separation = 0.23 cm). During 3^rd fraction (Plan 3), prior doing interstitial insertion, we instilled 50 cc of hydroxypropyl methylcellulose (Viscomet^®) up to the tip of recto-vaginal septum. A repeat computed tomography (CT) scan was done 4 hours after Plan 3 treatment and it was re-planned (Plan 4) to find out migration of hydrogel if any and its dosimetric impact.

RESULTS

9 Gy was delivered to point A with a separation of 1.1 cm in Plan 3 (with HR-CTV D₉₀ 16.4 Gy, IR-CTV D₉₀ 11.3 Gy, rectum D_2cc 3.6 Gy, bladder D_2cc 6.9 Gy, and sigmoid colon 2.2 Gy). We achieved an optimum cumulative EQD₂ dose (HR-CTV D₉₀ 98.4 Gy, IR-CTV D₉₀ 76.1 Gy, rectum D_2cc 67.7 Gy, bladder D_2cc 73.2 Gy, and sigmoid colon 59.3 Gy). Hydrogel volume was decreased in Plan 4 without a major dosimetric changes.

CONCLUSIONS

Hydrogel instillation is a useful tool for recto-vaginal separation during cervical cancer brachytherapy. It increases therapeutic ratio without any adverse event.

Prospective comparison of rectal dose reduction during intracavitary brachytherapy for cervical cancer using three rectal retraction techniques

PURPOSE

To compare three rectal retraction methods on dose to organs at risk, focusing on rectal dose, in cervix cancer patients treated with high-dose-rate intracavitary brachytherapy.

METHODS AND MATERIALS

A prospective study was conducted on patients with cervical carcinoma treated with chemoradiotherapy, including external beam radiation and four fractions of high-dose-rate intracavitary brachytherapy prescribed to Point A using a ring and tandem applicator under conscious sedation. Rectal retraction methods included: a rectal retractor blade (RR), vaginal gauze packing (VP), and a tandem Foley balloon (FB). All three methods were used in all patients. The RR was used first, and the following applications were randomly assigned to VP or FB. CT planning was used to calculate D2cc for rectum, sigmoid, small bowel, and bladder. The Wilcoxon signed rank test was used to determine if the median dose differences between methods were statistically significant.

RESULTS

In these 11 patients, median dose (min, max) in cGy to the rectum using RR, FB, and VP was 131 (102, 165), 199 (124, 243), and 218 (149, 299), respectively. The RR demonstrated lower median intrapatient doses to rectum compared with FB and VP (-55 cGy; p = 0.014 and -76 cGy; p = 0.004, respectively). The RR also resulted in lower sigmoid doses. No differences in dose were observed between the VP and FB methods.

CONCLUSION

The rectal retractor significantly reduced the dose to rectum and sigmoid compared with FP and VP. In patients treated under conscious sedation, the RR method provides the best rectal sparing. There were no significant differences in dose observed between the FB and VP techniques.

Rectal and bladder dose reduction with the addition of intravaginal balloons to vaginal packing in intracavitary brachytherapy for cervical cancer

PURPOSE

The use of intravaginal Foley balloons in addition to conventional packing during high-dose-rate (HDR) tandem and ovoids intracavitary brachytherapy (ICBT) is a means to improve displacement of organs at risk, thus reducing dose-dependent complications. The goal of this project was to determine the reduction in dose achieved to the bladder and rectum with intravaginal Foley balloons with CT-based planning and to share our packing technique.

METHODS AND MATERIALS

One hundred and six HDR-ICBT procedures performed for 38 patients were analyzed for this report. An uninflated Foley balloon was inserted into the vagina above and below the tandem flange separately and secured in place with vaginal packing. CT images were then obtained with both inflated and deflated Foley balloons. Plan optimization occurred and dose volume histogram data were generated for the bladder and rectum. Maximum dose to 0.1, 1.0, and 2.0 cm(3) volumes for the rectum and bladder were analyzed and compared between inflated and deflated balloons using parametric statistical analysis.

RESULTS

Inflation of intravaginal balloons allowed significant reduction of dose to the bladder and rectum. Amount of reduction was dependent on the anatomy of the patient and the placement of the balloons. Displacement of the organs at risk by the balloons allowed an average of 7.2% reduction in dose to the bladder (D0.1 cm(3)) and 9.3% to the rectum (D0.1 cm(3)) with a maximum reduction of 41% and 43%, respectively.

CONCLUSIONS

For patients undergoing HDR-ICBT, a significant dose reduction to the bladder and rectum could be achieved with further displacement of these structures using intravaginal Foley balloons in addition to conventional vaginal packing.

Cost-effectiveness of radical hysterectomy with adjuvant radiotherapy versus radical radiotherapy for FIGO stage IIB cervical cancer

OBJECTIVE

Recent literature reports that radical hysterectomy followed by adjuvant radiotherapy has comparable progression-free survival and overall survival compared to radical radiotherapy for International Federation of Gynecology and Obstetrics stage IIB cervical cancer. Now, we evaluate the cost-effectiveness (CE) of these two treatment regimens.

PRIMARY AND SECONDARY OUTCOME MEASURES

A decision-tree model was constructed comparing CE between treatment arms using the published studies for overall survival rates and treatment-related toxicity rates for 5 years. The cost data were obtained from the hospital system of the First Affiliated Hospital of Xi'an Jiaotong University. Effectiveness was measured as quality-adjusted life year (QALY). Treatment arms were compared with regard to costs and life expectancy using incremental CE ratio, and the results were presented using costs per QALY.

RESULTS

The mean cost was $10,872 for radical hysterectomy followed by adjuvant radiotherapy versus $5,702 for radical radiotherapy. The incremental CE ratio for surgery-based treatment compared to radiotherapy-based treatment was -$76,453 per QALY.

CONCLUSION

Radical radiotherapy would be a cost-effective method for FIGO stage IIB cervical cancer and would be favored in settings where resources are limited.

HDR Brachytherapy Dose Distribution is Influenced by the Metal Material of the Applicator

Applicators containing metal have been widely used in recent years when applying brachytherapy to patients with cervical cancer. However, the high dose rate (HDR) treatment-planning system (TPS) that is currently used in brachytherapy still assumes that the treatment environment constitutes a homogeneous water medium and does not include a dose correction for the metal material of the applicator. The primary purpose of this study was to evaluate the HDR ¹⁹²Ir dose distribution in cervical cancer patients when performing brachytherapy using a metal-containing applicator. Thermoluminescent dosimeter (TLD) measurements and Monte Carlo N-Particle eXtended (MCNPX) code were used to explore the doses to the rectum and bladder when using a Henschke applicator containing metal during brachytherapy. When the applicator was assumed to be present, the absolute dose difference between the TLD measurement and MCNPX simulation values was within approximately 5%. A comparison of the MCNPX simulation and TPS calculation values revealed that the TPS overestimated the International Commission of Radiation Units and Measurement (ICRU) rectum and bladder reference doses by 57.78% and 49.59%, respectively. We therefore suggest that the TPS should be modified to account for the shielding effects of the applicator to ensure the accuracy of the delivered doses.

Severe gastrointestinal complications in the era of image-guided high-dose-rate intracavitary brachytherapy for cervical cancer

PURPOSE

The purposes of this analysis are to report a modern series of severe gastrointestinal toxic effects after definitive chemoradiotherapy in the treatment of locally advanced cervical cancer at our institution and to review the existing literature on factors that contribute to toxic effects and preventive strategies and management.

METHODS

Our institution's cervical cancer cohort was evaluated for patients with late grade 3 to 4 gastrointestinal toxic effects who were retrospectively reviewed for clinical or dosimetric parameters that could have contributed to late toxic effects. A review of the published literature was performed to identify factors associated with late toxic effects, prophylactic agents, and corrective therapy.

FINDINGS

Five of 85 patients were identified as having late grade 3 to 4 gastrointestinal toxic effects with a median follow-up of 13.3 months. Two of 5 patients developed late grade 3 toxic effects, and 3 of 5 developed late grade 4 toxic effects. Three of the 5 patients reviewed ultimately required permanent colostomies. Cumulative median dose (in equivalent dose in 2-Gy fractions) of clinical target volume to the hottest 90% was 107.2 Gy, rectal dose to the hottest 2 cc (D2cc) was 81.7 Gy, sigmoid D2cc was 61.7 Gy, and bladder D2cc was 79.5 Gy. No patient had evidence of disease recurrence in the pelvis. One patient developed oligometastatic disease in the suprarenal gland and was successfully salvaged with adrenalectomy.

IMPLICATIONS

Despite its risk of toxic effects, intracavitary brachytherapy remains a critical component of the treatment of locally advanced cervical cancer. Even with modern radiotherapy planning and delivery techniques, extra attention is warranted to continue to strive for optimal outcomes.

Comparisons between the KKU-model and conventional rectal tubes as markers for checking rectal doses during intracavitary brachytherapy of cervical cancer

BACKGROUND

To compare the KKU-model rectal tube (KKU-tube) and the conventional rectal tube (CRT) for checking rectal doses during high-dose-rate intracavitary brachytherapy (HDR-ICBT) of cervical cancer.

MATERIALS AND METHODS

Between February 2010 and January 2011, thirty -two patients with cervical cancer were enrolled and treated with external beam radiotherapy (EBRT) and intracavitary brachytherapy (ICBT). The KKU-tube and CRT were applied intrarectally in the same patients at alternate sessions as references for calculation of rectal doses during ICBT. The gold standard references of rectum anatomical markers which are most proximal to radiation sources were anterior rectal walls (ARW) adjacent to the uterine cervix demonstrated by barium sulfate suspension enema. The calculated rectal doses derived from actual anterior rectal walls, CRT and the anterior surfaces of the KKU-tubes were compared by using the paired t-test. The pain caused by insertion of each type of rectal tube was assessed by the visual analogue scale (VAS).

RESULTS

The mean dose of CRT was lower than the mean dose of ARW (Dmean0-Dmean1) by 80.55±47.33 cGy (p-value<0.05). The mean dose of the KKU-tube was lower than the mean dose of ARW (Dmean0-Dmean2) by 30.82±24.20 cGy (p-value<0.05). The mean dose difference [(Dmean0-Dmean1)-(Dmean0-Dmean2)] was 49.72±51.60 cGy, which was statistically significant between 42.32 cGy -57.13 cGy with the t-value of 13.24 (p-value<0.05). The maximum rectal dose by using CRT was higher than the KKU-tube as much as 75.26 cGy and statistically significant with the t-score of 7.55 (p-value<0.05). The mean doses at the anterior rectal wall while using the CRTs and the KKU-tubes were not significantly different (p-value=0.09). The mean pain score during insertion of the CRT was significantly higher than the KKU-tube by a t-score of 6.15 (p-value<0.05) CONCLUSIONS: The KKU-model rectal tube was found to be an easily producible, applicable and reliable instrument as a reference for evaluating the rectal dose during ICBT of cervical cancer without negative effects on the patients.

The association of rectal equivalent dose in 2 Gy fractions (EQD2) to late rectal toxicity in locally advanced cervical cancer patients who were evaluated by rectosigmoidoscopy in Faculty of Medicine, Chiang Mai University

Purpose

To evaluate association between equivalent dose in 2 Gy (EQD2) to rectal point dose and gastrointestinal toxicity from whole pelvic radiotherapy (WPRT) and intracavitary brachytherapy (ICBT) in cervical cancer patients who were evaluated by rectosigmoidoscopy in Faculty of Medicine, Chiang Mai University.

Materials and Methods

Retrospective study was designed for the patients with locally advanced cervical cancer, treated by radical radiotherapy from 2004 to 2009 and were evaluated by rectosigmoidoscopy. The cumulative doses of WPRT and ICBT to the maximally rectal point were calculated to the EQD2 and evaluated the association of toxicities.

Results

Thirty-nine patients were evaluated for late rectal toxicity. The mean cumulative dose in term of EQD2 to rectum was 64.2 Gy. Grade 1 toxicities were the most common findings. According to endoscopic exam, the most common toxicities were congested mucosa (36 patients) and telangiectasia (32 patients). In evaluation between rectal dose in EQD2 and toxicities, no association of cumulative rectal dose to rectal toxicity, except the association of cumulative rectal dose in EQD2 >65 Gy to late effects of normal tissue (LENT-SOMA) scale ≥ grade 2 (p = 0.022; odds ratio, 5.312; 95% confidence interval, 1.269-22.244).

Conclusion

The cumulative rectal dose in EQD2 >65 Gy have association with ≥ grade 2 LENT-SOMA scale.

Brachytherapy in the treatment of cervical cancer: a review

Dramatic advances have been made in brachytherapy for cervical cancer. Radiation treatment planning has evolved from two-dimensional to three-dimensional, incorporating magnetic resonance imaging and/or computed tomography into the treatment paradigm. This allows for better delineation and coverage of the tumor, as well as improved avoidance of surrounding organs. Consequently, advanced brachytherapy can achieve very high rates of local control with a reduction in morbidity, compared with historic approaches. This review provides an overview of state-of-the-art gynecologic brachytherapy, with a focus on recent advances and their implications for women with cervical cancer.

Radical hysterectomy with adjuvant radiotherapy versus radical radiotherapy for FIGO stage IIB cervical cancer

BACKGROUND

The goal of this study was to compare treatment outcomes for Federation of Gynecology and Obstetrics (FIGO) stage IIB cervical carcinoma patients receiving radical surgery followed by adjuvant postoperative radiotherapy versus radical radiotherapy.

METHODS

Medical records of FIGO stage IIB cervical cancer patients treated between July 2008 and December 2011 were retrospectively reviewed. A total of 148 patients underwent radical hysterectomy with pelvic lymph node dissection followed by adjuvant radiotherapy (surgery-based group). These patients were compared with 290 patients that received radical radiotherapy alone (RT-based group). Recurrence rates, progression-free survival (PFS), overall survival (OS), local control rates, and treatment-related complications were compared for these two groups.

RESULTS

Similar rates of recurrence (16.89% vs. 12.41%, p = 0.200), PFS (log-rank, p = 0.211), OS (log-rank, p = 0.347), and local control rates (log-rank, p = 0.668) were observed for the surgery-based group and the RT-based group, respectively. Moreover, the incidence of acute grade 3-4 gastrointestinal reactions and late grade 3-4 lower limb lymphedema were significantly higher for the surgery-based group versus the RT-based group. Cox multivariate analyses found no significant difference in survival outcome between the two groups, and tumor diameter and histopathology were identified as significant prognostic factors for OS.

CONCLUSIONS

Radical radiotherapy was associated with fewer treatment-related complications and achieved comparable survival outcomes for patients with FIGO stage IIB cervical cancer compared to radical hysterectomy followed by postoperative radiotherapy.

Comparative analysis of rectal dose parameters in image-guided high-dose-rate brachytherapy for cervical cancer with and without a rectal retractor

PURPOSE

The objective of this study was to determine if use of a rectal retractor (RR) in high-dose-rate intracavitary brachytherapy for cervical cancer reduces rectal dose parameters.

METHODS AND MATERIALS

We reviewed data obtained from patients treated with intracavitary brachytherapy for cervical cancer with and without an RR. Treatment plans for each brachytherapy fraction were separated into two groups; R group with use of an RR and P group with use of vaginal packing. Dose-volume parameters for high-risk clinical target volume (HR-CTV), rectum, sigmoid, small bowel, and vaginal surface were collected for each fraction. Rectal D2cc and International Commission on Radiation Units & Measurements (ICRU) rectal point doses were compared between groups using Student's t tests. Predictors of higher rectal D2cc were determined by univariate and multivariate regression analyses.

RESULTS

Four hundred sixty-three brachytherapy fractions from 114 patients were used for analysis, 377 fractions with a RR (R group) and 86 with vaginal packing only (P group). Both groups were similar except for slightly higher mean HR-CTV and mean bladder volume in P group. Both mean ICRU rectal point dose (241.1 vs. 269.9 cGy, p = 0.006) and rectal D2cc (240.6 vs. 283.6 cGy, p < 0.001) were significantly higher in P group. Point A dose, HR-CTV, stage, and use of an RR were significant predictors of rectal D2cc on multivariate analysis.

CONCLUSIONS

Our data show that use of an RR leads to lower rectal dose parameters compared with vaginal packing. Further study is needed to determine if this will lead to less long-term toxicity.

A prospective observational study with dose volume parameters predicting rectosigmoidoscopic findings and late rectosigmoid bleeding in patients with uterine cervical cancer treated by definitive radiotherapy

Purpose

We assessed the value of dose-volumetric parameters predicting rectosigmoid mucosal changes (RMC) and late rectosigmoid complications (LRC).

Methods

Between January 2004 and February 2006, 77 patients with stage IB-IIIB cervical cancer underwent external beam radiotherapy and computed tomography (CT)-based intracavitary irradiation. Total dose to the rectal point and several dose-volumetric parameters for rectosigmoid colon (D_20cc, D_15cc, D_10cc, D_5cc, D_2cc, D_1cc, and D_{0.1cc ,} defined as the minimal doses received by the highest irradiated volumes of 20, 15, 10, 5, 2, 1, and 0.1 cc, respectively), were calculated using the equivalent dose in 2 Gy fractions (α/β = 3, Gy₃). The RMC and LRC were graded by rectosigmoidoscopy and Radiation Therapy Oncology Group criteria every 6 months, respectively.

Results

Of 77 patients, 27 (35.1%) patients developed RMC ≥ score 3 and 22 (28.6 %) patients developed LRC ≥ grade 2. There was a positive correlation between RMC score and LRC grade (r = 0.728, p < 0.001). In multivariate analyses, D_5cc, among the dose-volumetric parameters, was significant parameter for the risks of RMC ≥ score 3 and LRC ≥ grade 2 (p < 0.05).

Conclusions

D_5cc may be a more reliable estimate than other dose-volumetric parameters for predicting the risk of RMC ≥ score 3 and LRC ≥ grade 2 in CT-based brachytherapy.

High-precision MRI-guided adaptive brachytherapy for cervical carcinoma

Over the past 20 years advances in radiological technology have led to dramatic changes in cervical cancer management. External beam radiotherapy has evolved radically as a result of these changes. More recently, though, three-dimensional (3D) image guidance and volume-based prescribing has been adopted into cervical cancer brachytherapy. This overview covers the science and technology behind magnetic resonance imaging (MRI)-guided adaptive brachytherapy and explains why it is now considered the new international standard of care.

Effect of socio-economic factors on delayed access to health care among Chinese cervical cancer patients with late rectal complications after radiotherapy

OBJECTIVES

To determine the effect of socio-economic status (SES) on delayed access to medical treatment by Chinese cervical cancer patients who suffered from late rectal sequelae (LRS) after external beam radiation therapy (EBRT) and intracavitary brachytherapy.

METHODS

Patients diagnosed with LRS were interviewed for their SES, factors including age, residing district, religion, marital status, income, education, insurance and patient delay (the time interval from the onset of symptoms to the first medical consultation) and other factors such as weight, symptom duration and disease stage at diagnosis.

RESULTS

One hundred and twenty nine patients were interviewed. Seventy-one patients (55%) sought medical treatment within three months after the first symptom being recognized and fifty-eight patients (45%) delayed their medical treatment over 3 months. The study shows that age ≥ 55 (OR=12.1; 95% CI: 3.3-43.9), lower education (OR=4.6; 95% CI: 2.0-10.4 for women with primary school education or illiterate), low annual household income (OR=2.3; 95% CI: 1.2-5.1) and widow/divorce (OR=0.1; 95% CI: 0.01-0.07) were the high risk factors for delayed reporting. Patients with bleeding or bleeding plus other symptoms (61.2%) were more likely to seek treatment within three months, compared to patients with other symptoms only (38.8%) (p=0.002). Additionally, delayed reporting was found to be significantly associated with the late stage of late rectal sequelae (LRS) (p=0.000) and the patients with 55 years or older (p=0.000).

CONCLUSIONS

Delayed reporting and late-stage presentation of late rectal sequelae are more prevalent among Chinese cervical cancer patients with 55 years or older, low education, poor marital status, or poor financial status. Effective social support and educational programs should be implemented to encourage these patients to seek medical treatment as soon as possible.

Can point doses predict volumetric dose to rectum and bladder: a CT-based planning study in high dose rate intracavitary brachytherapy of cervical carcinoma?

OBJECTIVE

Point doses, as defined by the International Commission on Radiation Units and Measurements (ICRU), are classically used to evaluate doses to the rectum and bladder in high dose rate intracavitary brachytherapy (HDR-ICBT) in cervical cancer. Several studies have shown good correlation between the ICRU point doses and the volumetric doses to these organs. In the present study we attempted to evaluate whether this correlation could be used to predict the volumetric doses to these organs.

METHODS

A total of 150 HDR-ICBT insertions performed between December 2006 and June 2008 were randomly divided into two groups. Group A (n=50) was used to derive the correlation between the point and volumetric doses using regression analysis. This was tested in Group B (n=100) insertions using studentised residuals and Bland-Altman plots.

RESULTS

Significant correlations were obtained for all volumetric doses and ICRU point doses for rectum and bladder in Group A insertions. The strongest correlation was found for the dose to 2 cc volumes (D(2cc)). The correlation coefficients for bladder and rectal D(2cc) versus the respective ICRU point doses were 0.82 and 0.77, respectively (p<0.001). Statistical validation of equations generated in Group B showed mean studentised residual values of 0.001 and 0.000 for the bladder and rectum. However, Bland-Altman analysis showed that the error range for these equations for bladder and rectum were ±64% and ±41% of the point A dose, respectively, which makes these equations unreliable for clinical use.

CONCLUSION

Volumetric imaging is essential to obtain proper information about volumetric doses.

Dose effect relationship for late side effects of the rectum and urinary bladder in magnetic resonance image-guided adaptive cervix cancer brachytherapy

PURPOSE

To establish dose-response relationships for late side effects of the rectum and bladder in cervix cancer patients after magnetic resonance image-guided adaptive brachytherapy (IGABT).

METHODS AND MATERIALS

A cohort of 141 patients was treated with 45 to 50.4 Gy with or without cisplatin plus 4 fractions of 7 Gy IGABT. Doses for the most exposed 2, 1, and 0.1-cm(3) (D(2 cc), D(1 cc), D(0.1 cc)) volumes of the rectum and bladder were converted into the equivalent dose in 2 Gy fractions (EQD2), using a linear quadratic model (α/β = 3 Gy). Late side effects were prospectively assessed (using late effects in normal tissues subjective, objective, management and analytic [LENT SOMA]) scales. Dose-response relationships were determined by logit analyses.

RESULTS

Eleven patients developed rectal side effects, and 23 patients had urinary side effects. A significant dose effect was found for all rectal dose-volume histogram (DVH) parameters for patients with side effect grades of 1 to 4 but was only significant for D(2 cc) and D(1 cc) for grades ≥ 2. The ED10 values for D(2 cc) were 73 Gy for grades 1 to 4 and 78 Gy for grades 2 to 4 rectal morbidity. For bladder side effects, a significant dose effect was shown for all DVH parameters for complication grades ≥ 2; the respective ED10 was 101 Gy.

CONCLUSIONS

Well-defined dose-response curves could be established for D(2 cc) in the rectum and the urinary bladder.

3D CT-based high-dose-rate brachytherapy for cervical cancer: clinical impact on late rectal bleeding and local control

BACKGROUND AND PURPOSE

To identify the impact of 3D CT-based high-dose-rate intracavitary radiotherapy (ICR) on late rectal bleeding (LRB) and local control (LC) in patients with cervical cancer.

MATERIAL AND METHODS

The outcomes of 97 consecutive patients treated with 3D CT-based ICR (3D-ICR) were compared with those of 133 consecutive historical patients with conventional 2D brachytherapy planning (2D-ICR). The median follow-up periods were 41 and 56 months for the 3D and 2D groups, respectively.

RESULTS

The overall rectal bleeding rate was similar between the groups (42% for 3D-ICR vs. 44% for 2D-ICR); however, the incidence of severe LRB was higher in the 2D-ICR group than in the 3D-ICR group (13% vs. 2%, respectively; p=0.02). In multivariate analysis, the factors associated with severe LRB were tumor >4 cm (12% vs. 3%) and 2D-ICR (10% vs. 2%). The LC rates were 97% and 91% for 3D-ICR and 2D-ICR, respectively (p=0.14); the progression-free survival rate was 80% for both groups. A significant difference in the LC rates between the two groups was observed in patients with larger tumor sizes with the tumor diameter of over 4 cm (98% vs. 81% by 3D-ICR vs. 2D-ICR, respectively; p=0.02).

CONCLUSIONS

The implementation of 3D-ICR in radiotherapy for cervical cancer can reduce the incidence of severe LRB and may improve the LC rate.

Dose-volume histogram parameters and late side effects in magnetic resonance image-guided adaptive cervical cancer brachytherapy

PURPOSE

To evaluate the predictive value of dose-volume histogram (DVH) parameters for late side effects of the rectum, sigmoid colon, and bladder in image-guided brachytherapy for cervix cancer patients.

METHODS AND MATERIALS

A total of 141 patients received external-beam radiotherapy and image-guided brachytherapy with or without chemotherapy. The DVH parameters for the most exposed 2, 1, and 0.1 cm(3) (D(2cc), D(1cc), and D(0.1cc)) of the rectum, sigmoid, and bladder, as well as International Commission on Radiation Units and Measurements point doses (D(ICRU)) were computed. Total doses were converted to equivalent doses in 2 Gy by applying the linear-quadratic model (α/β = 3 Gy). Late side effects were prospectively assessed using the Late Effects in Normal Tissues-Subjective, Objective, Management and Analytic score. The following patient groups were defined: Group 1: no side effects (Grade 0); Group 2: side effects (Grade 1-4); Group 3: minor side effects (Grade 0-1); and Group 4: major side effects (Grade 2-4).

RESULTS

The median follow-up was 51 months. The overall 5-year actuarial side effect rates were 12% for rectum, 3% for sigmoid, and 23% for bladder. The mean total D(2cc) were 65 ± 12 Gy for rectum, 62 ± 12 Gy for sigmoid, and 95 ± 22 Gy for bladder. For rectum, statistically significant differences were observed between Groups 1 and 2 in all DVH parameters and D(ICRU). Between Groups 3 and 4, no difference was observed for D(0.1cc). For sigmoid, significant differences were observed for D(2cc) and D(1cc), but not for D(0.1cc) in all groups. For bladder, significant differences were observed for all DVH parameters only comparing Groups 3 and 4. No differences were observed for D(ICRU).

CONCLUSIONS

The parameters D(2cc) and D(1cc) have a good predictive value for rectal toxicity. For sigmoid, no prediction could be postulated because of limited data. In bladder, DVH parameters were predictive only for major toxicity.

Late effects after radiotherapy for locally advanced cervical cancer: comparison of two brachytherapy schedules and effect of dose delivered weekly

PURPOSE

To compare the severe late effects (Grade 3 or greater) for two groups of cervical cancer patients treated with the same external beam radiotherapy and two high-dose-rate intracavitary brachytherapy regimens and to investigate the influence of the dose delivered each week.

METHODS AND MATERIALS

For 120 patients, intracavitary brachytherapy was delivered with 33.6 Gy in eight fractions to Point A (HD group), and for 119, intracavitary brachytherapy was delivered with 29.4 Gy in seven fractions to Point A (LD group). The cumulative incidence of severe gastrointestinal and genitourinary late effects were calculated for both dose groups using Kaplan-Meier survival analysis. This method was also used to explore whether the number of weeks with different dose levels could predict the cumulative incidence of late effects.

RESULTS

The actuarial rate of developing severe gastrointestinal morbidity at 7 years was 10.7% and 8.3% for HD and LD groups, respectively. The rate for genitourinary morbidity was 6.6% for the HD group and 5.0% for the LD group, respectively. No significant difference was found between the two groups. The analyses showed that a marginally significant increase occurred in severe gastrointestinal complications as the number of weeks with a physical dose >20 Gy increased in the HD group (p = .047).

CONCLUSION

To establish dose-response relationships for late complications, three-dimensional imaging and dose-volume histogram parameters are needed. We found some indications that 20 Gy/wk is an upper tolerance level when the dose to the International Commission on Radiation Units and Measurements rectum point is 81 Gy(alpha/beta=3) (isoeffective [equivalent] dose of 2-Gy fractions). However, additional investigations using three-dimensional data are needed.

Lack of the dose-rate effect of 192Ir source activity on pelvic control and late complications after high-dose-rate brachytherapy for cervical cancer

This study aimed to assess the dose-rate effect of (192)Ir source activity on pelvic control and late complications following high-dose-rate intracavitary brachytherapy (HDRICB) for cervical cancer patients. Two hundred and twelve patients were enrolled in this study. They were treated with external beam radiotherapy to the pelvis, after which HDRICB was performed using (192)Ir remote after-loading at 1-week intervals for 4 or 5 sessions. Source activity was defined as the average of source activity in each HDRICB session. Dose-rate effect was analyzed after stratification of stage and biologically effective dose (BED). The 5-year pelvic relapse-free survival was 88% for all patients. Forty-two patients developed late rectal complications (13 grade 1, 23 grade 2, 6 grade 3-4). Twenty-seven patients had grade 2 and higher late bladder complications (14 grade 2, 13 grade 3-4). There was no dose-rate effect on pelvic control or complications when source activity was stratified. Multivariate analysis demonstrated a high risk of grade 2 and higher rectal sequelae in patients whose rectal BED >or= 110 Gy(3) (p = 0.039, hazard ratio 2.05). The high risk factors for grade 2 and higher bladder complications were a bladder BED >or= 100 Gy(3) (p = 0.03, hazard ratio 4.37). This study demonstrated no dose-rate effect of (192)Ir source in HDRICB for cervical cancer in terms of pelvic control or radiation injuries. Careful monitoring of the BED values for rectum and bladder is a scrutinizing factor for minimizing late sequelae.

Factors for predicting rectal dose of high-dose-rate intracavitary brachytherapy after pelvic irradiation in patients with cervical cancer: a retrospective study with radiography-based dosimetry

PURPOSE

To evaluate the predictive factors for rectal dose of the first fraction of high-dose-rate intracavitary brachytherapy (HDR-ICBT) in patients with cervical cancer.

METHODS AND MATERIALS

From March 1993 through February 2008, 946 patients undergoing pelvic irradiation and HDR-ICBT were analyzed. Examination under anesthesia (EUA) at the first implantation of the applicator was usually performed in the early period. Rectal point was determined radiographically according to the 38th Report of the International Commission of Radiation Units and Measurements (ICRU). The ICRU rectal dose (PRD) as a percentage of point A dose was calculated; multiple linear regression models were used to predict PRD.

RESULTS

Factors influencing successful rectal dose calculation were EUA (p < 0.001) and absence of diabetes (p = 0.047). Age (p < 0.001), body weight (p = 0.002), diabetes (p = 0.020), and EUA (p < 0.001) were independent factors for the PRD. The predictive equation derived from the regression model was PRD (%) = 57.002 + 0.443 x age (years) - 0.257 x body weight (kg) + 6.028 x diabetes (no: 0; yes: 1) - 8.325 x EUA (no: 0; yes: 1)

CONCLUSION

Rectal dose at the first fraction of HDR-ICBT is positively influenced by age and diabetes, and negatively correlated with EUA and body weight. A small fraction size at point A may be considered in patients with a potentially high rectal dose to reduce the biologically effective dose if the ICRU rectal dose has not been immediately obtained in the first fraction of HDR-ICBT.

Correlation of dose-volume parameters, endoscopic and clinical rectal side effects in cervix cancer patients treated with definitive radiotherapy including MRI-based brachytherapy

PURPOSE

Correlation of dosimetric parameters for MRI-based 3D treatment planning with rectoscopic findings and clinical rectal side effects.

METHODS AND MATERIALS

Rectosigmoidoscopy and rectal morbidity assessment were performed on 35 cervical cancer patients treated with external beam radiotherapy (EBRT) and HDR-intracavitary brachytherapy (ICB). The total doses, normalised to 2 Gy fractions (EQD2, alpha/beta=3 Gy), in 0.1, 1.0 and 2.0 cm(3) (D(0.1 cc), D(1 cc), D(2 cc)) of rectum were determined by summation of EBRT and ICB plans. Correlation analysis between clinical symptoms (LENT/SOMA) and rectoscopic changes (Vienna Rectoscopy Score, VRS) was performed. For dose-response analyses, the logit model was applied.

RESULTS

Mean follow-up was 18 months. LENT/SOMA score was 1 in 4 patients, 2 in 8 patients, 4 in 1 patient. Telangiectasia was found in 26 patients (74%), five of them had ulceration corresponding to the 0.1 cm(3) volume (anterior wall). Mean values D(0.1 cc), D(1 cc), and D(2 cc) were 81+/-13, 70+/-9 and 66+/-8 Gy, respectively. The ED50 values for VRS > or = 3 and for LENT/SOMA > or = 2 significantly increased with decreasing volumes. D(2 cc) was higher in patients with VRS > or = 3 compared to VRS<3 (72+/-6 vs 62+/-7 Gy; p<0.001) and in symptomatic vs asymptomatic patients (72+/-6 vs 63+/-8 Gy; p<0.001). VRS correlated with the LENT/SOMA score.

CONCLUSIONS

Rectosigmoidoscopy is sensitive in detecting mucosal changes, independent of clinical symptoms. The localization of these changes corresponds to the high dose volumes as defined by imaging. The development of mucosal and clinical changes in the rectum follows a clear dose-effect and volume-effect. DVH parameters could be established.

Radiotherapy and hyperthermia for treatment of primary locally advanced cervix cancer: results in 378 patients

PURPOSE

To report response rate, pelvic tumor control, survival, and late toxicity after treatment with combined radiotherapy and hyperthermia (RHT) for patients with locally advanced cervical carcinoma (LACC) and compare the results with other published series.

METHODS AND MATERIALS

From 1996 to 2005, a total of 378 patients with LACC (International Federation of Gynecology and Obstetrics Stage IB2-IVA) were treated with RHT. External beam radiotherapy (RT) was applied to 46-50.4 Gy and combined with brachytherapy. The hyperthermia (HT) was prescribed once weekly. Primary end points were complete response (CR) and local control. Secondary end points were overall survival, disease-specific survival, and late toxicity. Patient, tumor, and treatment characteristics predictive for the end points were identified in univariate and multivariate analyses.

RESULTS

Overall, a CR was achieved in 77% of patients. At 5 years, local control, disease-specific survival, and incidence of late toxicity Common Terminology Criteria for Adverse Events Grade 3 or higher were 53%, 47%, and 12%, respectively. In multivariate analysis, number of HT treatments emerged as a predictor of outcome in addition to commonly identified prognostic factors.

CONCLUSIONS

The CR, local control, and survival rates are similar to previously observed results of RHT in the randomized Dutch Deep Hyperthermia Trial. Reported treatment results for currently applied combined treatment modalities (i.e., RT with chemotherapy and/or HT) do not permit definite conclusions about which combination is superior. The present results confirm previously shown beneficial effects from adding HT to RT and justify the application of RHT as first-line treatment in patients with LACC as an alternative to chemoradiation.

Prospective clinical trial of bladder filling and three-dimensional dosimetry in high-dose-rate vaginal cuff brachytherapy

PURPOSE

To investigate the effect of bladder filling on dosimetry and to determine the best bladder dosimetric parameter for vaginal cuff brachytherapy.

METHODS AND MATERIALS

In this prospective clinical trial, a total of 20 women underwent vaginal cylinder high-dose-rate brachytherapy. The bladder was full for Fraction 2 and empty for Fraction 3. Dose-volume histogram and dose-surface histogram values were generated for the bladder, rectum, and urethra. The midline maximal bladder point (MBP) and the midline maximal rectal point were recorded. Paired t tests, Pearson correlations, and regression analyses were performed.

RESULTS

The volume and surface area of the irradiated bladder were significantly smaller when the bladder was empty than when full. Of the several dose-volume histogram and dose-surface histogram parameters evaluated, the bladder maximal dose received by 2 cm(3) of tissue, volume of bladder receiving >/=50% of the dose, volume of bladder receiving >/=70% of the dose, and surface area of bladder receiving >/=50% of the dose significantly predicted for the difference between the empty vs. full filling state. The volume of bladder receiving >/=70% of the dose and the maximal dose received by 2 cm(3) of tissue correlated significantly with the MBP. Bladder filling did not alter the volume or surface area of the rectum irradiated. However, an empty bladder did result in the nearest point of bowel being significantly closer to the vaginal cylinder than when the bladder was full.

CONCLUSIONS

Patients undergoing vaginal cuff brachytherapy treated with an empty bladder have a lower bladder dose than those treated with a full bladder. The MBP correlated well with the volumetric assessments of bladder dose and provided a noninvasive method for reporting the MBP dose using three-dimensional imaging. The MBP can therefore be used as a surrogate for complex dosimetry in the clinic.

Late Rectal Complications Evaluated by Computed Tomography–Based Dose Calculations in Patients With Cervical Carcinoma Undergoing High-Dose-Rate Brachytherapy

PURPOSE

To investigate the efficacy of dose calculations at the computed tomography (CT)-based rectal point (CTRP) as a predictive factor for late rectal complications in patients with cervical carcinoma who were treated with a combination of high-dose-rate intracavitary brachytherapy and external beam radiotherapy.

METHODS AND MATERIALS

Ninety-two patients with uterine cervical carcinoma undergoing definitive radiotherapy alone were retrospectively analyzed. The median follow-up time for all patients was 32 months (range, 13-60 months). The cumulative biologically effective dose (BED) was calculated at the rectal reference point as defined by the International Commission on Radiation Units and Measurements Report 38 (BED(RP)) and at the CTRP (BED(CTRP)). Late rectal complications were recorded according to the Radiation Therapy Oncology Group grading system.

RESULTS

The late rectal complications were distributed as follows: Grade 0, 68 patients (74%); Grade 1, 20 patients (22%); Grade 2, 4 patients (4%). Univariate analysis showed that BED(RP), BED(CTRP), RP dose/point A dose ratio, and CTRP dose/point A dose ratio were significantly correlated with late rectal complications (p < 0.05). On multivariate analysis, patients with a rectal BED(CTRP) >/=140 Gy(3) presented with significantly greater frequency of rectal complications (p = 0.031).

CONCLUSIONS

The present results suggest that BED(CTRP) is a useful predictive factor for late rectal complications.

Computed Tomography-Based High-Dose-Rate Intracavitary Brachytherapy for Uterine Cervical Cancer: Preliminary Demonstration of Correlation Between Dose–Volume Parameters and Rectal Mucosal Changes Observed by Flexible Sigmoidoscopy

PURPOSE

To compare the dose-volume histogram (DVH) parameters obtained by three-dimensional gynecologic brachytherapy planning with the rectosigmoid mucosal changes observed by flexible sigmoidoscopy.

METHODS AND MATERIALS

Between January 2004 and July 2005, 71 patients with International Federation of Gynecology and Obstetrics Stage IB-IIIB uterine cervical cancer underwent computed tomography-based high-dose-rate intracavitary brachytherapy. The total dose (external beam radiotherapy [RT] plus intracavitary brachytherapy) to the International Commission of Radiation Units and Measurements rectal point (ICRU(RP)) and DVH parameters for rectosigmoid colon were calculated using the equivalent dose in 2-Gy fractions (alpha/beta = 3 Gy). Sigmoidoscopy was performed every 6 months after RT, with the 6-scale scoring system used to determine mucosal changes.

RESULTS

The mean values of the DVH parameters and ICRU(RP) were significantly greater in patients with a score of > or =2 than in those with a score <2 at 12 months after RT (ICRU(RP), 71 Gy(alpha/beta3) vs. 66 Gy(alpha/beta3), p = 0.02; D(0.1cc), 93 Gy(alpha/beta3) vs. 85 Gy(alpha/beta3), p = 0.04; D(1cc), 80 Gy(alpha/beta3) vs. 73 Gy(alpha/beta3), p = 0.02; D(2cc), 75 Gy(alpha/beta3) vs. 69 Gy(alpha/beta3), p = 0.02). The probability of a score of > or =2 showed a significant relationship with the DVH parameters and ICRU(RP) (ICRU(RP), p = 0.03; D(0.1cc), p = 0.05; D(1cc), p = 0.02; D(2cc), p = 0.02).

CONCLUSION

Our preliminary data have shown that DVH values of the rectosigmoid colon obtained by computed tomography-based three-dimensional brachytherapy planning are reliable and predictive of score > or =2 rectosigmoid mucosal changes.

A prospective study to assess the bladder distension effects on dosimetry in intracavitary brachytherapy of cervical cancer via computed tomography-assisted techniques

BACKGROUND AND PURPOSE

Intracavitary brachytherapy (ICBT) is as important as external beam radiotherapy (EBRT) for the radical radiotherapy of uterine cervical cancer. The degree of urinary bladder distension during ICBT may affect the dose distribution in the bladder and rectum, to which an overdose may increase the chance of developing treatment-related complications. The purpose of this prospective study was to assess and quantify the impact of bladder distension on dosimetry in ICBT in patients with cervical cancer.

PATIENTS AND METHODS

We recruited 20 patients with cervical cancer during a 12-month period. Inclusion criteria included pathological diagnosis of cervical cancer with IA to IIIB stages, and intact uterus. Patients were evaluated for brachytherapy after EBRT, and eligible individuals (cervical os could be identified clearly) were invited enter to this protocol to receive ICBT. In the first brachytherapy, bladder preparation (evacuation and distension by a Foley catheter) and CT scan were performed soon after the insertion of CT-compatible applicators. Then the bladder wall doses [median dose, maximum dose and dose-volume histograms (DVH)] were calculated via the PLATO computer planning system (Nucletron PLATO-RTS version 2.0). The individual data regarding doses and DVH were collected and compared. Bladder distension may shift the applicator position, and posterior displacement of the applicator system may increase the dose to the rectal wall, so this effect was also evaluated.

RESULTS

All the continuous variables of these 20 patients followed a normal distribution. By paired t-test and multiple linear regression analysis, we found that bladder distension statistically significantly decreased the median bladder wall dose with an average reduction of 48% of the dose of an empty bladder (P<0.001), and the maximum dose did not change; on the other hand, the bladder distension did not have any adverse effects on the rectal wall doses.

CONCLUSIONS

Using CT-assisted three-dimensional techniques to assess the bladder and rectal wall doses is feasible. Bladder distension reduces the median dose in the bladder wall, which may reduce treatment-related complications.

Dosimetric parameters that predict late rectal complications after curative radiotherapy in patients with uterine cervical carcinoma

BACKGROUND

Late rectal complication (LRC) was a major late complication in patients with uterine cervical carcinoma who were treated with a combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary irradiation (HDR-ICR). For the current study, the authors retrospectively evaluated dosimetric parameters that were correlated with LRC > or = Grade 2 in patients with uterine cervical carcinoma who were treated with curative radiotherapy, and they analyzed the appropriate dose estimates to the rectum that were predictive for LRC > or = Grade 2.

METHODS

Between July 1994 and September 2002, 157 patients who were diagnosed with Stage IB-IIIB cervical carcinoma and were treated with definitive radiotherapy were included. EBRT (41.4-66 grays [Gy] in 23-33 fractions) to the whole pelvis was delivered to all patients, with midline shielding performed after a 36-50.4 Gy external dose. HDR-ICR (21-39 Gy in 6-13 fractions to Point A) was administered at a rate of 2 fractions weekly after midline shielding of EBRT. LRC was scored using Radiation Therapy Oncology Group criteria. The total biologically effective dose (BED) at specific points, such as Point A (BED(Point A)), rectal point (BED(RP)), and maximal rectal point (BED(MP)), was determined by a summation of the EBRT and HDR-ICR components, in which the alpha/beta ratio was set to 3. Analyzed parameters included patient age, tumor size, stage, concurrent chemotherapy, ICR fraction size, RP ratio (dose at the rectal point according to the Point A dose), MP ratio (dose at the maximal rectal point according to the Point A dose), EBRT dose, BED(Point A), BED(RP), and BED(MP).

RESULTS

The 5-year actuarial overall rate of LRC > or = Grade 2 in all patients was 18.4%. Univariate analysis showed that the RP ratio, MP ratio, EBRT dose, BED(Point A), BED(RP), and BED(MP) were correlated with LRC > or = Grade 2 (P < 0.05). Multivariate analysis showed that, of all clinical and dosimetric parameters evaluated, only BED(RP) was correlated with LRC > or = Grade 2 (P = 0.009). The 5-year actuarial rate of LRC > or = Grade 2 was 5.4% in patients with a BED(RP) < 125 Gy(3) and 36.1% in patients with a BED(RP) > or = 125 Gy(3) (P < 0.001).

CONCLUSIONS

BED(RP) was a useful dosimetric parameter for predicting the risk of LRC > or = Grade 2 and should be limited to < 125 Gy(3) whenever possible to minimize the risk of LRC > or = Grade 2 in patients with uterine cervical carcinoma who are treated with a combination of EBRT and HDR-ICR. Cancer 2005.

Comparison of low and high dose rate brachytherapy in the treatment of uterine cervix cancer. Retrospective analysis of two sequential series

PURPOSE

This retrospective analysis aims to report on the comparative outcome of cervical cancer patients treated with low dose rate (LDR) and high dose rate (HDR) brachytherapy.

METHODS AND MATERIALS

From 1989 to 1995, 190 patients were treated with low dose rate (LDR) brachytherapy (LDR group) and from 1994 to 2001, 118 patients were treated with high dose rate (HDR) brachytherapy (HDR group). FIGO stage distribution for the LDR group was Stage I: 6.3%; Stage II: 57.4%; and Stage III: 36.3% and for the HDR group Stage I: 9.3%; Stage II: 43.2%; and Stage III: 47.4%. All patients were treated with telecobalt external-beam radiotherapy (EBR). Median doses of LDR brachytherapy at Point A were 40 Gy and 50 Gy for patients treated with 1 and 2 implants, respectively. All patients from the HDR group were treated with 24 Gy in 4 fractions of 6 Gy to Point A. Survival, disease-free survival, local control, and late complications at 5 years, were endpoints compared for both groups.

RESULTS

Median follow-up time for LDR and HDR groups was 70 months (range, 8-127 months) and 33 months (range, 4-117 months), respectively. For all stages combined, overall survival, disease-free survival, and local control at 5 years were better in the LDR group (69% vs. 55%, p = 0.007; 73% vs. 56%, p = 0.002; and 74% vs. 65%; p = 0.04, respectively). For clinical Stages I and II, no differences was seen in overall survival, disease-free survival, and local control at 5 years between the two groups. For clinical Stage III, overall survival and disease-free survival at 5 years were better in the LDR group than in the HDR group (46% vs. 36%, p = 0.04 and 49% vs. 37%, p = 0.03, respectively), and local control was marginally higher in the LDR group than in the HDR group (58% vs. 50%, p = 0.19). The 5-year probability of rectal complications was higher in the LDR group than in the HDR group (16% vs. 8%, p = 0.03) and 5-year probability of small bowel and urinary complications was not statistically different between the the LDR group and the HDR group (4.6% vs. 8.9%, p = 0.17 and 6% vs. 3%, p = 0.13, respectively).

CONCLUSIONS

This comparative series suggests similar outcome for Stages I and II patients treated with either HDR or LDR brachytherapy. Lower overall and disease-free survival and marginally lower local control were observed for Stage III patients treated with HDR brachytherapy. Less late rectal complications were observed in the HDR group patients. These findings were probably the result of the relatively low HDR brachytherapy dose delivered at Point A.

Long-term results of high-dose rate brachytherapy in cervix cancer using a small number of fractions

OBJECTIVES

To evaluate the long-term treatment outcome of patients with carcinoma of the cervix treated with high dose rate brachytherapy (HDRB) using a small number of fractions.

METHODS

Between 1984 and 1997, 282 patients with cervix cancer (stages IB to IVA) were treated with external beam radiotherapy to the whole pelvis (median dose of 45 Gy) and HDRB (median dose of 24 Gy at point A in 3 insertions given weekly). Endpoints assessed were survival, patterns of failure and complications. Multivariate analysis was performed to identify variables predictive for overall survival and local control. Variables investigated were stage, age, overall duration of treatment, HDRB scheduling and total dose to point A.

RESULTS

At a median follow-up of 86.3 months for patients at risk, the 5-, 10- and 15-year overall survival rates are 57%, 52% and 47%, respectively. On multivariate analysis, only stage and age correlated with improved survival. Treatment duration beyond 47 days was associated with poorer overall survival, although it did not reach statistical significance (P = 0.10). Brachytherapy scheduling and BED to point A had no impact on overall survival. Stage and age significantly correlated with pelvic disease control. Duration of therapy, scheduling of the brachytherapy and BED at point A were not individual predictors for overall local control. Overall, gastrointestinal and genitourinary actuarial complication rates were 15% and 8%, respectively.

CONCLUSIONS

In our experience, HDRB using 3 insertions is well tolerated and the results are comparable to HDRB using larger number of fractions and to low dose rate brachytherapy.

Acute diarrhea during pelvic irradiation: is small-bowel volume effect different in gynecologic patients with prior abdomen operation or not?

OBJECTIVE

To evaluate volume effect of small bowel for diarrhea during pelvic irradiation in gynecologic patients with or without prior abdomen operation.

METHODS

From January 1996 through December 2003, 759 patients undergoing 4-field pelvic irradiation for cervical or uterine cancer were analyzed. Whole pelvic (WP), modified whole pelvic (MWP), or lower pelvic (LP) irradiation were delivered initially. According to contrast medium within small bowel in simulation films, we categorized the small-bowel volume of full dose related to WP fields as small-volume and large-volume groups. We recorded the severity of diarrhea until 39.6 Gy/22 fractions of pelvic irradiation. The actuarial rates of overall and moderate to severe diarrhea were compared among different groups.

RESULTS

Significantly more large-volume distribution (85%) was noted in patients >60 years without prior operation (P < 0.001). Large-volume distribution was 53%, 65%, and 82% in post-operative patients with no diarrhea, mild diarrhea, and moderate to severe diarrhea (P = 0.002), respectively. The corresponding rate was 79%, 77%, and 80% in patients without prior abdomen operation (P = 0.869). In multivariate analysis, prior operation with LP fields (P = 0.005) and prior operation with small volume (P = 0.031) were significantly protective factors for overall diarrhea. The latter was also a protective factor for moderate to severe diarrhea (P = 0.026). Prior operation could diminish overall diarrhea in patients without simultaneous large-field (WP or MWP) and large-volume. Large volume was a significant factor of overall (P = 0.014) and moderate to severe (P = 0.004) diarrhea in large-field patients with operation. The volume effect did not exist in those patients without operation.

CONCLUSION

Age and operation can change small-bowel distribution. Prior operation may attenuate diarrhea if irradiated volume of small bowel is small. There is a volume effect in post-operative rather than non-operative patients receiving large-field irradiation. More practical dose-volume evaluation of small bowel may be applied for volume effect in gynecologic patients without prior operation.

Comparative study of reference points by dosimetric analyses for late complications after uniform external radiotherapy and high-dose-rate brachytherapy for cervical cancer

PURPOSE

This study aimed to correlate and compare the predictive values of rectal and bladder reference doses of uniform external beam radiotherapy without shielding and high-dose-rate intracavitary brachytherapy (HDRICB) with late sequelae in patients with uterine cervical cancer.

METHODS AND MATERIALS

Between September 1992 and December 1998, 154 patients who survived more than 12 months after treatment were studied. Initially, they were treated with 10-MV X-rays (44 to 45 Gy/22 to 25 fractions over 4 to 5 weeks) to the whole pelvis, after which HDRICB was performed using (192)Ir remote afterloading at 1-week intervals for 4 weeks. The standard prescribed dose for each HDRICB was 6.0 Gy to point A. Patient- and treatment-related-factors were evaluated for late rectal complications using logistic regression modeling.

RESULTS

The probability of rectal complications showed better correlation of dose-response with increasing total ICRU (International Committee on Radiotherapy Units and Measurements) rectal dose. Multivariate logistic regression demonstrated a high risk of late rectal sequelae in patients who developed rectal complications (p = 0.0001;relative risk, 15.06;95% CI, 2.89 approximately 43.7) and total ICRU rectal dose greater than 16 Gy (p = 0.02;relative risk, 2.07;95% CI, 1.13 approximately 4.55). The high risk factors for bladder complications were seen in patients who developed rectal complications (p = 0.0001;relative risk, 15.2;95% CI, 2.81 approximately 44.9) and total ICRU bladder dose greater than 24 Gy (p = 0.02;relative risk, 8.93;95% CI, 1.79 approximately 33.1).

CONCLUSION

This study demonstrated the predictive value of ICRU rectal and bladder reference dosing in HDRICB for patients receiving uniform external beam radiation therapy without central shielding. Patients who had a total ICRU rectal dose greater than 16 Gy, or a total ICRU bladder dose over 24 Gy, were at risk of late sequelae.

Radiation injury to intestine following hysterectomy and adjuvant radiotherapy for cervical cancer

OBJECTIVE

To evaluate the risk factors for nonrectal radiation-induced intestinal injury (NRRIII) following adjuvant radiotherapy (RT) for cervical cancer using a retrospective review of medical records.

METHODS

From September 1992 to December 1998, 164 patients with uterine cervical cancer that had completed their allocated adjuvant radiotherapy at the Chinese Medical University Hospital were enrolled for NRRIII analysis. The patients were classified into two groups according to the extent of surgery. Group A consisted of 110 patients (International Federation of Gynecology and Obstetrics [FIGO] stage: IB, n = 87; IIA, n = 21; IIB, n = 2) undergoing radical hysterectomy and bilateral pelvic lymph node dissection, while Group B was composed of 54 analogs receiving adjuvant radiotherapy following incident extrafascial hysterectomy. Treatment consisted of external beam radiotherapy (EBRT) and high-dose-rate intravaginal brachytherapy (HDRIVB). Initially, the whole pelvis was treated with 10 MV X-rays. After irradiation (44 Gy in 22 fractions over 4-5 weeks), the field was limited to the true pelvis and a further 10-20 Gy delivered in 5-10 fractions. For 21 patients in group A without pelvic lymph node metastasis or lymphovascular invasion, the radiation field was confined to the lower pelvis, with a prescribed dose of 50-58 Gy delivered over 5-6 weeks. HDRIVB was performed using an Ir-192 remote after-loading technique at 1-week intervals. A total of 159 patients (97%) received two insertions, while 5 had only one. The standard prescribed HDRIVB dose was 7.5 Gy to the vaginal surface. Logistic regression analysis was performed for assessment of the factors associated with NRRIII.

RESULTS

After 38-119 months of follow-up (median, 60), 22 patients (13.4%) developed Radiation Therapy Oncology Group (RTOG) grade 2 or greater NRRIII at a median latency of 18 months (range, 5-48). Four patients were diagnosed as grade 3 complications requiring surgery and three had expired. The independent factors for NRRIII were radical hysterectomy (P = 0.04, relative risk 2.45), lower-pelvic dose >54 Gy (P = 0.0001, relative risk 10.27), and age over 60 years (P = 0.001, relative risk 5.45). The incidence of NRRIII for patients receiving whole and lower-pelvic irradiation was 14.5% and 10.6%, respectively (P = 0.45). Although there was no statistical significance comparing the two external beam irradiation strategies in terms of NRRIII, all four patients with grade 3 NRRIII underwent whole pelvic irradiation.

CONCLUSION

This study identifies three predictive factors for the development of NRRIII following adjuvant radiotherapy for cervical cancer. Limiting the EBRT dose to less than 54 Gy, meticulous patient selection in the elderly, careful planning of the irradiated field, and the constraint of vaginal brachytherapy are four approaches to optimization of postoperative adjuvant radiotherapy.