High-dose-rate brachytherapy in the treatment of uterine cervix cancer. Analysis of dose effectiveness and late complications

Dose and fractionation regimen for brachytherapy boost in cervical cancer in the US

PURPOSE

Curative-intent radiotherapy for locally advanced and select early stage cervical cancer in the US includes external beam radiotherapy (EBRT) with brachytherapy. Although there are guidelines for brachytherapy dose and fractionation regimens, there are limited data on practice patterns. This study aims to evaluate the contemporary utilization of cervical cancer brachytherapy in the US and its association with patient demographics and facility characteristics.

METHODS

We retrospectively analyzed clinical covariates of cervical cancer patients diagnosed and treated in 2018-2020 with curative-intent radiotherapy from the 2020 National Cancer Database. Associations between patient and institutional factors with the number of brachytherapy fractions were identified with logistic regression. Factors with association (p < 0.10) were then included in a multivariable logistic regression model. All tests were two-sided with significance <0.05 unless specified otherwise.

RESULTS

Among the eligible 2517 patients, 97.3% received HDR or LDR and is further analyzed. More patients received HDR than LDR brachytherapy (98.9% vs 1.1%) and intracavitary than interstitial brachytherapy (86.4% vs 13.6%). The most common number of HDR fractions prescribed were 5 (51.0%), 4 (32.9%), and 3 (8.6%). After adjusting for the other variables in the model, ethnicity, private insurance status, overall insurance status, and facility type were the only factors that were significantly associated with the number of brachytherapy factions (p < 0.0001, p = 0.028, p = 0.001, and p < 0.0001, respectively, n = 2184).

CONCLUSIONS

In the US, various HDR brachytherapy regimens are utilized depending on patient and institutional factors. Future research may optimize cervical cancer brachytherapy by correlating specific dose and fractionation regimens with patient outcomes.

Comparison of Two High Dose Rate Brachytherapy Regimes

Background

Two HDR brachytherapy regimes were compared, 9.5 Gray per fraction for two fractions and 7.5 Gray per fraction for three fractions.

Materials and Methods

A total of 80 patients with histologically evident squamous cell carcinoma cervix were taken in the current research after randomization. Radiotherapy dose delivered was 50 Gray/25#/5 weeks with concomitant chemotherapy with weekly cisplatin 35 mg/m2. Following external chemoradiation, patients were randomized into two arms. In Arm A, 40 patients were given high dose rate (HDR) brachytherapy of weekly 7.5 Gray in three fractions over 3 weeks. In Arm B, 40 patients were given high dose rate (HDR) brachytherapy of weekly 9.5 Gray in two fractions over 2 weeks. BED and LQED had been calculated, and the evaluation of response and consequences was examined.

Results

In Arm A, BED to point A was 99.38 ± 0.00 and EQD2 to point A was 82.81 ± 0.00. In Arm B, BED to point A was 97.05 ± 0.00 and EQD2 to point A was 80.89 ± 0.00. With respect to rectum in Arm A, BED rectum was 108.66 ± 11.43 and EQD2 rectum was 65.07 ± 6.84. In Arm B, BED rectum was 107 ± 10.83 and EQD2 rectum was 64.21 ± 6.49. Similarly in Arm A, BED bladder was 107.86 ± 10.23 and EQD2 bladder was 64.59 ± 6.13. In arm B, BED bladder was 104.14 ± 10.79 and EQD2 bladder was 62.36 ± 6.46.

Conclusion

In a follow-up of 6 months, no statistical significance in terms of local control as well as complications rates in both the arms. Our research demonstrates that two fractions of HDR are comparable with three fractions of HDR.

Complications of intracavitary brachytherapy for gynecologic cancers and their management: A comprehensive review

Intracavitary gynecologic brachytherapy in the form of tandem-based brachytherapy and vaginal cylinder-based brachytherapy represents a fundamental component of the treatment of women with cervical or uterine cancer due to the ability to deliver a therapeutic dose of radiation with sharp dose falloff. This results in highly effective treatment in terms of oncologic outcomes with an overall favorable toxicity profile. Still, complications and side effects of brachytherapy do exist. While advances in brachytherapy techniques have led to a significant decrease in the rates of toxicity, a thorough understanding of the potential complications is crucial to ensuring optimal outcomes for women with gynecologic cancer undergoing brachytherapy. Use of equivalent dose at 2 Gy per fraction (EQD2) models has allowed incorporation of external beam radiotherapy dose to the brachytherapy dose leading to development of consolidated dose constraints for organs-at-risk in the modern era. This manuscript offers a comprehensive review of potential complications associated with intracavitary brachytherapy for gynecologic cancer including predictive factors, mitigation tactics, and management strategies.

The 100 most cited articles in cervical cancer brachytherapy

PURPOSE

This study aimed to identify the 100 most cited research articles on cervical cancer brachytherapy.

METHODS AND MATERIALS

The Institute for Scientific Information Web of Science was used to identify the 100 most cited articles in cervical cancer brachytherapy as of July 5, 2019. The following important information was extracted: journal, year and month, country of region, author, type of article, type of dose rate, type of radionuclide, and image modality for brachytherapy planning.

RESULTS

The 100 most cited articles in cervical cancer brachytherapy were published between 1981 and 2016, and the citations ranged from 858 to 49, which collectively had been cited 11,372 times at the time of searching. The index of citations per year ranged from 63.56 to 1.43. These articles were from 16 countries or regions, with most publications being from the United States (n = 27), followed by Austria (n = 26), Japan (n = 10), France (n = 7), and the Netherlands (n = 7). The International Journal of Radiation Oncology, Biology, Physics produced the most articles (n = 46), followed by Radiotherapy and Oncology (n = 39) and Gynecologic Oncology (n = 5). These articles were categorized as original studies (n = 75), reviews (n = 2), editorials (n = 2), surveys (n = 2), guidelines (n = 3), and recommendations (n = 6). A high dose rate (n = 69) was the most widely used, dose rate followed by a low dose rate (n = 20) and pulsed dose rate (n = 16).

CONCLUSIONS

The bibliometric analysis presents a detailed list of the 100 most cited articles in cervical cancer brachytherapy. This analysis provides an insight into historical developments and enables the important advances in this field to be recognized.

Appropriate Methodology for EBRT and HDR Intracavitary/Interstitial Brachytherapy Dose Composite and Clinical Plan Evaluation for Patients With Cervical Cancer

PURPOSE

This study assessed the appropriateness of full parameter addition (FPA) methods with respect to the 3-dimensional deformable dose composite method for evaluating combined external beam radiation therapy (EBRT) and intracavitary brachytherapy (ICBT).

METHODS AND MATERIALS

A total of 22 patients who received EBRT and high-dose-rate ICBT were retrospectively evaluated. Split-ring and tandem applicators were used for all patients. Additional interstitial needles were used for 5 patients to supplement the implant. Deformable image registrations were performed to deform the secondary EBRT and ICBT planning computed tomography (CT) images onto the reference CT from the third fraction of ICBT. The Dice similarity coefficient was used to evaluate the quality of deformable registration. Doses were transferred to the reference CT, scaled to the equivalent dose in 2-Gy fractions and combined to create the dose composite. Eight dose-accumulation methods were evaluated and compared. D_2cc and D_0.1cc for organs at risk were investigated.

RESULTS

The differences in D_2cc for rectum, bladder, sigmoid, and bowel between the FPA method for whole-pelvis EBRT and ICBT, calculated using an old American Brachytherapy Society worksheet (FPA_E_h + I_old) and deformable composite for EBRT with boosts and ICBT (Def_E + B + I) were -2.19 ± 1.37 Gy_{α/β = 3}, -0.64 ± 1.13 Gy_{α/β = 3}, -2.06 ± 2.71 Gy_{α/β = 3}, and -1.59 ± 0.89 Gy_{α/β = 3}, respectively. The differences in D_2cc for rectum, bladder, sigmoid, and bowel between the new ABS worksheet (FPA_E_h + B + I_abs) and the Def_E + B + I method were 1.21 ± 1.22 Gy _{α/β = 3}, 1.93 ± 1.38 Gy_{α/β = 3}, 0.72 ± 1.12 Gy_{α/β = 3}, and 1.19 ± 1.46 Gy_{α/β = 3}, respectively. Differences in dose-volume histogram parameter values among Def_E + B + I and other FPA methods were not statistically significant (P > .05).

CONCLUSIONS

Compared with the FPA-based method, deformable registration-based dose composites demonstrated lower OAR D_2cc and D_0.1cc values; however, the differences were not statistically significant. The current ABS-recommended FPA-based sheet can serve as an acceptable plan evaluation tool for clinical purposes.

The influence of overall treatment time to the efficiency of chemo-radiotherapy for locally advanced cervical cancer

Purpose

This study aims to clarify the influence of overall treatment time (OTT) on the efficiency of combined chemo-radiotherapy in cervical cancer.

Material and methods

This retrospective study enrolled 122 cervical cancer patients who had squamous cell carcinoma and had undergone definitive chemo-radiotherapy from 2009 to 2013. All patients received whole pelvic radiotherapy (WPRT) with the dose of 50 Gy in 25 fractions (with central shielding after 44 Gy) plus intracavitary brachytherapy with the dose of 28 Gy in four fractions. During WPRT, all patients received concurrent chemotherapy with weekly platinum-based regimen. The data of patient characteristics, OTT, treatment results and toxicities were collected and evaluated.

Results

The mean follow-up time was 36 months. The mean age of patients was 52 years old; 68% of patients were stage IIB related to International Federation of Gynaecology and Obstetrics staging. Pelvic control (PC), distant metastasis-free survival (DMFS), disease-free survival (DFS) and overall survival (OS) rates did not differ significantly in the data-derived cut points of 55·8 and 53 days. No statistically significant difference in treatment results between the two groups of OTT<49 and OTT≥62 days was observed.

Conclusions

In our data-derived cut point, OTT did not influence to PC, DMFS, DFS and OS. The influence of OTT on treatment results may be found in longer periods.

Are Doses to ICRU Reference Points Valuable for Predicting Late Rectal and Bladder Morbidity after Definitive Radiotherapy in Uterine Cervix Cancer?

Aims and Background

To evaluate whether doses or dose rates at International Commission on Radiation Units (ICRU) reference points are of value for predicting risks of late rectal and bladder morbidity in patients with uterine cervical cancer who have undergone external beam radiotherapy and intracavitary irradiation.

Methods

Late rectal complications and late bladder complications were evaluated in 54 patients who were treated by external beam radiotherapy followed by intracavitary irradiation between January 1996 and December 1999. External beam radiotherapy was delivered in 1.8 Gy daily fractions to a whole pelvis dose of 50.4 Gy followed by intracavitary irradiation at total point A doses ranging from 75 Gy to 85 Gy. Intracavitary irradiation was performed with dose rates of 0.5–0.7 Gy/h to point A in most patients, but 8 patients were treated at a higher dose rate (0.83–1.15 Gy/h) to shorten the hospitalization period. Biologically effective doses for the reference points were calculated using a linear quadratic model.

Results

Grade 3 rectal and bladder morbidity by Radiation Therapy Oncology Group (RTOG) criteria developed in 4 patients (7.4%) and 1 (1.9%), respectively. An age of >60 years (P = 0.01) and a total dose to the rectal reference point of ≥80 Gy (P = 0.03) were found to be correlated with a higher rate of rectal morbidity. Total dose (≥80 Gy), dose rate (≥0.75 Gy/h), and biologically effective doses (≥135 Gy3) at the bladder reference point were found to be significant factors for the development of late bladder morbidity. By multivariate analysis, age was identified as the only significant factor of late rectal complications, and biologically effective doses at the bladder reference point was the only significant factor of late bladder complications.

Conclusions

RTOG grade 3 late rectal and bladder morbidity developed in respectively 7.4% and 1.9% of the patients. The significant risk factors for late rectal and bladder morbidity were old age and biologically effective doses at the bladder reference point, respectively.

American Brachytherapy Task Group Report: A pooled analysis of clinical outcomes for high-dose-rate brachytherapy for cervical cancer

PURPOSE

Advanced imaging used in combination with brachytherapy (BT) has revolutionized the treatment of patients with cervical cancer. We present a comprehensive review of the literature for definitive radiation with high-dose-rate (HDR) BT. In addition, we investigate potential outcome improvement with image-based brachytherapy (IBBT) compared to studies using traditional Point A dosing. This review extensively investigates acute and late toxicities.

METHODS AND MATERIALS

This study reviews the literature from 2000 to 2015 with an emphasis on modern approaches including concurrent chemotherapy (chemoRT), radiation, and HDR BT and IBBT. Descriptive statistics and pelvic control (PC), disease-free survival (DFS), and overall survival (OS) outcomes were calculated using weighted means to report pooled analysis of outcomes.

RESULTS

Literature search yielded 16 prospective, 51 retrospective studies that reported survival outcomes, and 13 retrospective studies that focused on acute and late toxicity outcomes regardless of applicator type. There are 57 studies that report Point A dose specification with 33 having chemoRT, and 10 studies that use IBBT, 8 with chemoRT. Patients receiving radiation and chemoRT with HDR BT in the prospective studies, with >24 months followup, rates of PC were: for RT: 73%, SD: 11; CRT: 82%, SD: 8; DFS-RT: 55%, SD: 10; CRT: 65%, SD: 7; OS-RT: 66%, SD: 7; CRT: 70%, SD: 11. In the retrospective studies, the PC rates (weighted means) for the radiation and chemoradiation outcomes are 75% vs. 80%, and for DFS, the values were 55% vs. 63%, respectively. Comparing patients receiving chemoRT and IBBT to traditional Point A dose specification, there is a significant improvement in PC (p < 0.01) and DFS (p < 0.01) with IBBT. The range of genitourinary late toxicity reported for radiation was Grade 3: 1-6% and for chemoRT 2-20%. The range of late gastrointestinal toxicity for radiation was Grade 3: 4-11% and for chemoRT, 1-11%. For the late gynecologic toxicity, only 1 of the 16 prospective trials report a Grade 1-2 of 17% for radiation and 9% for chemoRT effects.

CONCLUSIONS

We present concise outcomes of PC, DFS, OS, and toxicity for cervical cancer patients treated with chemoradiation and HDR BT. Our data suggest an improvement in outcomes with the use of IBBT compared with traditional Point A dose prescriptions. In conclusion, HDR BT is a safe, effective modality when combined with IBBT.

External beam techniques to boost cervical cancer when brachytherapy is not an option-theories and applications

The management of locally advanced cervical cancer relies on brachytherapy (BT) as an integral part of the radiotherapy delivery armamentarium. Occasionally, intracavitary BT is neither possible nor available. In these circumstances, post-external beam radiotherapy (EBRT) interstitial brachytherapy and/or hysterectomy may represent viable options that must be adequately executed in a timely manner. However, if these options are not applicable due to patient related or facility related reasons, a formal contingency plan should be in place. Innovative EBRT techniques such as intensity modulated and stereotactic radiotherapy may be considered for patients unable to undergo brachytherapy. Relying on provocative arguments and recent data, this review explores the rationale for and limitations of non-brachytherapy substitutes in that setting aiming to establish a formal process for the optimal execution of this alternative plan.

A Comparative Analysis of Two Different Dose Fractionation Regimens of High Dose Rate Intracavitary Brachytherapy in Treatment of Carcinoma of Uterine Cervix: A Prospective Randomized Study

INTRODUCTION

High Dose Rate (HDR) intracavitary brachytherapy is an integral component in treatment of carcinoma uterine cervix. There is no consensus about optimal fractionation in HDR brachytherapy.

AIM

To assess the feasibility, tolerability of HDR intracavitary brachytherapy schedule of 8 Gy per fraction per week for 3 fractions over 6Gy per fraction per week for 4 fractions with or without chemotherapy in the treatment of carcinoma of uterine cervix.

MATERIALS AND METHODS

From 2013 to 2014 total 80 patients with carcinoma of the uterine cervix (Stages IIB and IIIB) were treated with External Beam Radiotherapy (EBRT) and High Dose Rate Intracavitary Brachytherapy (HDR- ICBT). During course of EBRT, those patients fit for brachytherapy were randomized to arm A- 6 Gy per fraction per week for 4 fractions and arm B - 8 Gy per fraction per week for 3 fractions.

RESULTS

The median follow up was 30 months, local control was 90% in Arm A and 83.3% in Arm B (p= 0.21) and the disease-free survival was 90% in Arm A and 83.3% in Arm B (p= 0.39). There is no significance difference for late rectal and bladder toxicities between two arms (p=0.43).

CONCLUSION

Taking into account of increased hospital burden of locally advanced cancer cervix patients in Indian context, HDR intracavitary brachytherapy schedule of 8 Gy per fraction per week x 3 fractions is the preferable option over 6 Gy per fraction per week x 4 fractions with regard to comparable loco-regional control, acute and late toxicity, disease free survival and better patients compliance to lesser fractionation schedule.

Californium-252 neutron brachytherapy combined with external pelvic radiotherapy plus concurrent chemotherapy for cervical cancer: a retrospective clinical study

Background

Cervical cancer is the sixth most common cancer in Chinese women. A standard treatment modality for cervical cancer is the combination of surgery, chemotherapy, external-beam radiotherapy and intracavitary brachytherapy. The aim of this study was to retrospectively assess the long-term treatment outcomes of patients with cervical cancer who were treated with californium-252 neutron brachytherapy combined with external-beam radiotherapy plus concurrent chemotherapy.

Methods

We retrospectively analyzed the medical records of 150 patients with primary stages IB-IVB cervical cancer who received neutron brachytherapy combined with external-beam radiotherapy concurrently with cisplatin chemotherapy. All patients were followed up. Using an actuarial analysis, patient outcomes and treatment-related adverse effects were evaluated and compared.

Results

The median overall survival (OS) was 33.2 months. The 3-year progression-free survival rates for patients with stages I–II, III, and IV diseases were 81.0% (68/84), 65.0% (39/60), and 0% (0/6), respectively; the 3-year OS rates were 90.5% (76/84), 85.0% (51/60), and 16.7% (1/6), respectively. Vaginal bleeding was controlled within the median time of 4.0 days. One month after treatment, 97.3% of patients achieved short-term local control. The local recurrence rates for patients with stages I–II, III, and IV disease were 4.8% (4/84), 11.7% (7/60), and 33.3% (2/6), respectively, and the occurrence rates of distant metastasis were 16.7% (14/84), 25.0% (15/60), and 100.0% (6/6), respectively. Cancer stage, tumor size, and lymph node metastasis were identified as prognostic risk factors, but only lymph node metastasis was found to be an independent prognostic factor. The most common adverse effects during treatment were grades 1 and 2 irradiation-related proctitis and radiocystitis.

Conclusion

For patients with cervical cancer, neutron brachytherapy combined with external-beam radiotherapy plus concurrent chemotherapy produces a rapid response and greatly improves local control and long-term survival rates with tolerable adverse effects.

Magnetic resonance image-guided brachytherapy for cervical cancer : Prognostic factors for survival

OBJECTIVE

The purpose of this work was to identify prognostic factors for survival after magnetic resonance image (MRI)-guided brachytherapy combined with external beam radiotherapy for cervical cancer.

MATERIAL AND METHODS

External beam radiotherapy of 45-50.4 Gy was delivered by either three-dimensional conformal radiotherapy or helical tomotherapy. Patients also received high-dose-rate MRI-guided brachytherapy of 5 Gy in 6 fractions.

RESULTS

We analyzed 128 patients with International Federation of Gynecology and Obstetrics stage IB-IVB cervical cancer who underwent MRI-guided brachytherapy. Most patients (96 %) received concurrent chemotherapy. Pelvic lymph node metastases and para-aortic lymphadenopathies were found in 62 % and 14 % of patients, respectively. The median follow-up time was 44 months. Complete remission was achieved in 119 of 128 patients (93 %). The 5‑year local recurrence-free, cancer-specific, and overall survival rates were 94, 89, and 85 %, respectively. Negative pelvic lymphadenopathy, gross tumor volume (GTV) dose covering 90 % of the target (GTV D90) of >110 Gy, and treatment duration ≤56 days were associated with better overall survival in univariate analyses. Multivariable analysis showed that GTV D90 of >110 Gy and treatment duration ≤56 days were possibly associated with overall survival with near-significant P-values of 0.062 and 0.073, respectively.

CONCLUSIONS

The outcome of MRI-guided brachytherapy combined with external beam radiotherapy in patients with cervical cancer was excellent. GTV D90 of >110 Gy and treatment duration ≤56 days were potentially associated with overall survival.

Encrusted cystitis after definitive radiotherapy for cervical cancer: a case report

PURPOSE

Encrusted cystitis is a rare chronic inflammatory disease characterized by calcified plaques of the bladder, previously altered by varies conditions as urological procedures, caused by urea-splitting bacteria. Only one case has been reported on encrusted cystitis occurring after surgery and radiation therapy for a pelvic neoplasm. We report on encrusted cystitis occurred after definitive radiotherapy for bulky uterine cervix cancer, and examine the doses to the bladder wall and the procedure of radiation treatment performed as a possible cause of the onset of the disease.

CASE PRESENTATION

A 52-year-old female developed encrusted cystitis, caused by Corynebacterium spp., after 14 months from definitive chemo-radiotherapy and 2/D brachytherapy treatment for FIGO stage IB2 uterine cervix cancer. For pelvic radiotherapy, the mean bladder dose was 48.47 Gy (range 31.20-51.91); maximal bladder point doses at each brachytherapy insertions were 7.62 Gy, 4.94 Gy and 6.27 Gy at first, second, and third fraction, respectively. Total biological effective dose (BED) at bladder point was 140.05 Gy₃. The patient was administered antibiotic therapy with linezolid and urine acidification with vitamin C; dietary norms were also suggested. After therapy, complete remission of symptoms and radiological findings were achieved, and the planned surgery for removing the calcified plaques was not completed. After 5 years from the cervical cancer diagnosis, the patient was disease-free without urinary symptoms.

CONCLUSIONS

The high doses administered to the bladder wall and the repeated catheterizations performed at each brachytherapy insertions may have favored the infection and promoted the occurrence of the encrusted cystitis.

Californium versus cobalt brachytherapy combined with external-beam radiotherapy for IIB stage cervical cancer: long-term experience of a single institute

PURPOSE

The purpose of this paper was to observe and compare long-term curative effects and complications of FIGO stage IIB cervical cancer patients (n = 232) treated with high-dose-rate (HDR) californium ((252)Cf) neutron or cobalt ((60)Co) photon intracavitary brachytherapy (ICBT) combined with external-beam radiotherapy (EBRT).

MATERIAL AND METHODS

The EBRT dose to the small pelvis was 50 Gy in both groups. The brachytherapy component of (252)Cf or (60)Co was added in the 3(rd) week of EBRT, 5 fractions were performed once per week resulting in a total ICBT dose of 40 Gy/Gyeq (point A).

RESULTS

Overall survival (OS) at 5, 10 and 15 years was 63.6%, 50.4% and 38.8% in the (252)Cf group and 62.2%, 50.5%, 39.9%, in the (60)Co group, respectively (p = 0.74). The percentage of tumour recurrence was statistically significantly lower in the (252)Cf group with 7.4% versus 17.1% in the (60)Co group (p = 0.02). Second primary cancers have developed similarly 9.1% and 8.1% cases for (252)Cf and (60)Co groups, respectively.

CONCLUSIONS

Our long-term retrospective study comparing (252)Cf and (60)Co isotopes with brachytherapy in combined treatment of FIGO IIB stage cervix carcinoma patients shows, that overall survival in the both groups are similar. However, the recurrence of tumour was significantly lower in the (252)Cf group. The incidence of second primary cancers was similar in both groups.

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.

Higher caseload improves cervical cancer survival in patients treated with brachytherapy

Objectives

Increased caseload has been associated with better patient outcomes in many areas of health care, including high-risk surgery and cancer treatment. However, such a positive volume vs. outcome relationship has not yet been validated for cervical cancer brachytherapy. The purpose of this study was to examine the relationship between physician caseload and survival rates in cervical cancer treated with brachytherapy using population-based data.

Methods

Between 2005 and 2010, a total of 818 patients were identified using the Taiwan National Health Insurance Research Database. Multivariate analysis using a Cox proportional hazards model and propensity scores was used to assess the relationship between 5-year survival rates and physician caseloads.

Results

As the caseload of individual physicians increased, unadjusted 5-year survival rates increased (P = 0.005). Using a Cox proportional hazard model, patients treated by high-volume physicians had better survival rates (P = 0.03), after adjusting for comorbidities, hospital type, and treatment modality. When analyzed by propensity score, the adjusted 5-year survival rate differed significantly between patients treated by high/medium-volume physicians vs. patients treated by low/medium-volume physicians (60% vs. 54%, respectively; P = 0.04).

Conclusions

Provider caseload affected survival rates in cervical cancer patients treated with brachytherapy. Both Cox proportional hazard model analysis and propensity scores showed association between high/medium volume physicians and improved survival.

Dosimetric evaluation of manually and inversely optimized treatment planning for high dose rate brachytherapy of cervical cancer

BACKGROUND

To compare five inverse treatment planning methods with the conventional manually optimized planning approach for brachytherapy of cervical cancer with respect to dosimetric parameters.

MATERIAL AND METHODS

Eighteen cervical cancer patients treated with magnetic resonance imaging (MRI)-guided high dose rate (HDR) brachytherapy were included in this study. Six plans were created for each of the 4 HDR brachytherapy fractions for each patient: 1 manually optimized and 5 inversely planned. Three of these were based on inverse planning simulated annealing (IPSA) with and without extra constraints on maximum doses of the target volume, and different constraints on doses to the organs at risk (OARs). In addition there were two plans based on dose to target surface points. The resulting dose-volume histograms were analyzed and compared from the dosimetric point of view by quantifying specific dosimetric parameters, such as clinical target volume (CTV) D₉₀, CTV D₁₀₀, conformal index (COIN), and D₂cm3 for rectum, bladder and the sigmoid colon.

RESULTS

Manual optimization led to a mean target coverage of 78.3% compared to 87.5%, 91.7% and 82.5% with the three IPSA approaches (p < 0.001). Similar COIN values for manual and inverse optimization were found. The manual optimization led to better results with respect to the dose to the OARs expressed as D₂cm3. Overall, the best results were obtained with manual optimization and IPSA plans with volumetric constraints including maximum doses to the target volume.

CONCLUSIONS

Dosimetric evaluation of manual and inverse optimization approaches is indicating the potential of IPSA for brachytherapy of cervical cancer. IPSA with constraints of maximum doses to the target volume is closer related to manual optimization than plans with constraints only to minimum dose to the target volume and maximum doses to OARs. IPSA plans with proper constraints performed better than those based on dose to target surface points and manually optimized plans.

Definitive radiotherapy for uterine cervix cancer: long term results for patients treated in the period from 1998 till 2002 at the Institute of Oncology Ljubljana

Background

The aim of this retrospective study was to analyse results of the two-dimensional (2D) uterine cervix cancer treatment at the Institute of Oncology Ljubljana from 1998 till 2002, before the three-dimensional (3D) approach was introduced in our clinical practice.

Methods

Ninety-eight patients with the following FIGO stage distribution were analysed: 10% IB, 7% IIA, 37% IIB, 4% IIIA and 42% IIIB. The influence of age, haemoglobin level, histology, grade, stage, lymph node status, cumulative point A dose, and an overall treatment time on the survival and local control (LC) were evaluated. Acute and late side effects were assessed.

Results

Five and 8-year overall survival (OS), disease specific survival (DSS) and LC rate were as follows: 47.2% and 43.0%, 54.7% and 53.4%, 74.9% and 72.5%, respectively. Point A dose and histology of the tumour influenced OS, positive lymph nodes DSS and point A dose LC rate. Probability of grade three and four late complications in the first five years was 7.1% for gastrointestinal tract and 3.3% for genitourinary system and vagina.

Conclusions

Point A dose was independent predictor of OS and LC rate, lymph node status predicted DSS, while histology of the tumour influenced OS.

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

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

Effect of brachytherapy technique and patient characteristics on cervical cancer implant dosimetry

Our purpose was to evaluate the relationship between brachytherapy technique and patient characteristics on dose to organs-at-risk (OARs) in patients undergoing high dose rate (HDR) brachytherapy for cervical cancer. From 1998 to 2008, 31 patients with cervical cancer with full dosimetric data were identified who received definitive external-beam radiation and HDR brachytherapy with tandem and ovoid applicators. Doses were recorded at point A, the International Commission on Radiation Units and Measurements (ICRU)-38 rectal point, the ICRU-38 bladder point, the vaginal surface, and the pelvic sidewall. Generalized estimating equations were used to determine the significance of changes in OAR to point A dose ratios with differences in brachytherapy technique or patient characteristics. Patients underwent a median of 5 brachytherapy procedures (range, 3 to 5), with a total of 179 procedures for 31 patients. For all brachytherapy treatments, the average ratios between the doses for the rectal, bladder, vaginal surface, and pelvic sidewall reference points to those at point A were 0.49, 0.59, 1.15, and 0.17, respectively. In general, decreased OAR dose was associated with a lower stage, younger age, increased ovoid size, increased tandem length, and earlier implant number. Increased tandem curvature significantly increased bladder dose and decreased rectal dose. Intravenous anesthesia usage was not correlated with improved dosimetry. This study allowed identification of patient and procedure characteristics influencing OAR dosing. Although the advent of 3-dimensional (3D) image-guided brachytherapy will bring new advances in treatment optimization, the actual technique involved at the time of the brachytherapy implant procedure will remain important.

Bladder-rectum spacer balloon in high-dose-rate brachytherapy in cervix carcinoma

PURPOSE

To compare bladder and rectum doses with the use of a bladder-rectum spacer balloon (BRSB) versus standard gauze packing in the same patient receiving 2 high-dose-rate intracavitary brachytherapy fractions.

METHODS AND MATERIALS

This was a randomized study to compare the reduction in bladder and rectum doses with the use of a BRSB compared with standard gauze packing in patients with carcinoma of the cervix being treated with high-dose-rate intracavitary brachytherapy. The patients were randomized between 2 arms. In arm A, vaginal packing was done with standard gauze packing in the first application, and BRSB was used in the second application. Arm B was the reverse of arm A. The International Commission for Radiation Units and Measurement (ICRU) point doses and doses to 0.1-cm(3), 1-cm(3), 2-cm(3), 5-cm(3), and 10-cm(3) volumes of bladder and rectum were compared. The patients were also subjectively assessed for the ease of application and the time taken for application. Statistical analysis was done using the paired t test.

RESULTS

A total of 43 patients were enrolled; however, 3 patients had to be excluded because the BRSB could not be inserted owing to unfavorable local anatomy. Thus 40 patients (80 plans) were evaluated. The application was difficult in 3 patients with BRSB, and in 2 patients with BRSB the application time was prolonged. There was no significant difference in bladder doses to 0.1 cm(3), 1 cm(3), 2 cm(3), 5 cm(3), and 10 cm(3) and ICRU bladder point. Statistically significant dose reductions to 0.1-cm(3), 1-cm(3), and 2-cm(3) volumes for rectum were observed with the BRSB. No significant differences in 5-cm(3) and 10-cm(3) volumes and ICRU rectum point were observed.

CONCLUSION

A statistically significant dose reduction was observed for small high-dose volumes in rectum with the BRSB. The doses to bladder were comparable for BRSB and gauze packing. Transparent balloons of variable sizes are recommended for patients with a less spacious vaginal cavity.

Evaluation of the response of concurrent high dose rate intracavitary brachytherapy with external beam radiotherapy in management of early stage carcinoma cervix

OBJECTIVES

To evaluate local disease control and early complications of concomitant brachytherapy with external beam-radiotherapy in early stage carcinoma cervix.

METHODS

Fifty patients of early stage carcinoma cervix (FIGO-IB/IIA) were randomly divided into study group concomitant external beam irradiation (EBRT) and HDR-ICBT (intra-cavitary brachytherapy, xrt = 50 Gy/25 Fr, HDR 5.2 Gy*5 Fr) and the control group EBRT followed by HDR-ICBT (xrt = 50 Gy/25 Fr, HDR 7.5 Gy*3 Fr). Acute reactions and local disease response were compared between treatment and at 6-month follow up.

RESULTS

Median overall treatment times were 38 and 61 days in the study and the control groups, respectively. Acute skin reactions and diarrhea were more in the study but manageable. At the completion of the study, there were 80 and 68 % complete responses, 16 and 20 % partial responses, 0 and 8 % stable diseases in the study group and the control group, respectively.

CONCLUSIONS

Response was better in the study group but statistically insignificant. Larger number of patients and longer follow up are required to arrive at concrete conclusion.

The effects of two HDR brachytherapy schedules in locally advanced cervical cancer treated with concurrent chemoradiation: a study from Chiang Mai, Thailand

Efficacy of different schedules of HDR brachytherapy in concurrent chemoradiotherapy was evaluated. The study compared the effectiveness of the two HDR brachytherapy schedules which have the same Biological Effective Dose (BED) in locally advanced cervical carcinoma that was treated with concurrent chemoradiotherapy. Included in the study were 377 randomly selected patients with advanced carcinoma of the cervix uteri who were treated during the period 2004-2006. Patients were divided into Group I: 7.2 Gy × 3 fractions and Group II: 6 Gy × 4 fractions. With a median follow-up time of 35 months, local control, disease-free survival and overall survival rates were 80.8%, 63.4%, 98.8% in group I and 86.7%, 63.8%, 97.3% in group II, respectively. There was no statistical significance in terms of local control, disease-free survival, overall survival and complication rates between the two treatment schedules which could be observed. Seven patients in group I developed acute grade 2-4 GI toxicities and two patients in group II. In GU toxicities, there were three patients in group I and three patients in group II who developed grade 2-4 toxicities. In late toxicity, no patient developed grade 3-4 GU toxicities in group I while two patients developed grade 3-4 GU toxicities in group II. In GI toxicities, there were five and six patients in group I and group II, respectively, who developed grade 3-4 severity. Both HDR schedules seem to be safe and effective for the treatment of locally advanced cervical cancer.

Clinical significance of cumulative biological effective dose and overall treatment time in the treatment of carcinoma cervix

The purpose of this retrospective study is to report the radiotherapy treatment response of, and complications in, patients with cervical cancer on the basis of cumulative biologic effective dose (BED) and overall treatment time (OTT).

Sixty-four (stage II - 35/64; stage III - 29/64) patients of cervical cancer were treated with combination of external beam radiotherapy (EBRT) and low dose rate intracavitary brachytherapy (ICBT). The cumulative BED was calculated at Point A (BED₁₀); and bladder, rectal reference points (BED_2,5) using the linear-quadratic BED equations.

The local control (LC) rate and 5-year disease-free survival (DFS) rate in patients of stage II were comparable for BED₁₀ <84.5 and BED₁₀ >84.5 but were much higher for BED₁₀ >84.5 than BED₁₀ <84.5 (P< 0.01) in stage III patients. In the stage II patients, The LC rate and 5-year DFS rate were comparable for OTT <50 days and for OTT >50 days but were much higher in stage III patients with OTT < 50 than OTT >50 days (P< 0.001). It was also observed that patients who received BED_2.5 <105 had lesser rectal (P< 0.001) and bladder complications than BED_2.5 >105. Higher rectal complication-free survival (CFS_R) rate, bladder complication-free survival (CFS_B) rate and all-type late complication-free survival rate were observed in patients who received BED_2.5 < 105 than BED_2.5 >105.

A balanced, optimal and justified radiotherapy treatment schedule to deliver higher BED₁₀ (>84.5) and lower BED_2.5 (< 105) in lesser OTT (< 50 days) is essential in carcinoma cervix to expect a better treatment outcome in all respects.

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.

The benefit of small bowel and pelvic bone sparing in excluding common iliac lymph node region from conventional radiation fields in patients with uterine cervical cancer: a dosimetric study

The purpose of this study was to compare dose reduction to the small bowel and sacral bone by two-field and four-field techniques when the common iliac lymph node region is excluded from the radiation field in external beam radiotherapy of uterine cervical cancer. Thirteen patients with cervical cancer were entered into the study. Conventional treatment plans based on bony landmarks were made with parallel-opposed two-field technique (C2F) and four-field box technique (C4F). Modified C2F (M2F) and C4F (M4F) plans of excluding the common iliac lymph node region from the conventional radiation fields were created in reference to the bifurcations of pelvic arteries in computed tomography images. For each patient, the dose volume histograms for the small bowel and sacral bone resulting from the C2F, C4F, M2F, and M4F plans were compared. The volumes were obtained at 10 levels of prescribed dose, at increments of 10%, from 5 Gy to 50 Gy. By sparing both small bowel and sacral bone, the M2F and M4F plans were significantly better than the C2F and C4F plans at any dose level (p < 0.05), respectively. In addition, the M4F plan was significantly better than the M2F plan in sparing both small bowel at 10-50% of the prescribed dose (p < 0.05) and sacral bone at 40-100% of the prescribed dose (p < 0.05). The present study suggests that modified treatment planning could be useful for selected patients for reducing small bowel complications and insufficiency fracture after radiotherapy.

Dose reduction study in vaginal balloon packing filled with contrast for HDR brachytherapy treatment

PURPOSE

Vaginal balloon packing is a means to displace organs at risk during high dose rate brachytherapy of the uterine cervix. We tested the hypothesis that contrast-filled vaginal balloon packing reduces radiation dose to organs at risk, such as the bladder and rectum, in comparison to water- or air-filled balloons.

METHODS AND MATERIALS

In a phantom study, semispherical vaginal packing balloons were filled with air, saline solution, and contrast agents. A high dose rate iridium-192 source was placed on the anterior surface of the balloon, and the diode detector was placed on the posterior surface. Dose ratios were taken with each material in the balloon. Monte Carlo (MC) simulations, by use of the MC computer program DOSXYZnrc, were performed to study dose reduction vs. balloon size and contrast material, including commercially available iodine- and gadolinium-based contrast agents.

RESULTS

Measured dose ratios on the phantom with the balloon radius of 3.4 cm were 0.922 ± 0.002 for contrast/saline solution and 0.808 ± 0.001 for contrast/air. The corresponding ratios by MC simulations were 0.895 ± 0.010 and 0.781 ± 0.010. The iodine concentration in the contrast was 23.3% by weight. The dose reduction of contrast-filled balloon ranges from 6% to 15% compared with water-filled balloon and 11% to 26% compared with air-filled balloon, with a balloon size range between 1.4 and 3.8 cm, and iodine concentration in contrast of 24.9%. The dose reduction was proportional to the contrast agent concentration. The gadolinium-based contrast agents showed less dose reduction because of much lower concentrations in their solutions.

CONCLUSIONS

The dose to the posterior wall of the bladder and the anterior wall of the rectum can be reduced if the vaginal balloon is filled with contrast agent in comparison to vaginal balloons filled with saline solution or air.

Exploring the potential of mixed-source brachytherapy for the treatment of cervical cancer using high-dose rate 192Ir and/or 50 kV electronic sources

PURPOSE

In this study, computer modeling was used to compare the relative doses with the bladder, rectum, and bowel when two different brachytherapy modalities were used to treat cervical cancer with a tandem and ovoid applicator. A standard high-dose rate (HDR) (192)Ir treatment plan was compared with a "mixed-source" brachytherapy (MSB) treatment plan in which a 50 kV electronic brachytherapy X-ray source was substituted for (192)Ir as the tandem source.

METHODS AND MATERIALS

A total of 15 three-dimensional CT data sets from cervical cancer patients previously treated with tandem and ovoid applicator were evaluated for the study. Bladder, rectum, bowel, and target volumes were contoured and separate treatment plans were created for MSB and HDR (192)Ir applications. Dose-volume histograms were analyzed for each organ at risk.

RESULTS

The mean %V(25) for the bladder was 43% vs. 70% for MSB and HDR (192)Ir methods, respectively. Similarly, for the rectum mean %V(25) was 34% vs. 48% for MSB and HDR (192)Ir. For the bowel, the mean %V(25) was 28% vs. 43% for the MSB and HDR (192)Ir methods, respectively. In 16 of 45 organs at risk, %D(2 cc) values were higher for MSB than HDR (192)Ir.

CONCLUSIONS

MSB is capable of providing target coverage to the cervix, uterus, and paracervical regions equivalent to that provided by HDR (192)Ir, while significantly reducing the overall dose to the bladder, rectum, and bowel. This reduction is associated with small regions of increased dose in a significant proportion of patients.

High Dose Rate Brachytherapy in the Treatment of cervical cancer: preliminary experience with cobalt 60 Radionuclide source-A Prospective Study

Iridium-192 is widely used for high-dose rate brachytherapy. Co-60 source with similar geometric and dosimetric properties are now available. It has a longer half life but higher energy than Iridium-192. If Co-60 source can produce similar results, it will be more economical for low resource settings.

Effectiveness of two different HDR brachytherapy regimens with the same BED value in cervical cancer

PURPOSE

To analyze the effectiveness of biologically effective dose (BED) in two different regimens of HDR brachytherapy keeping the same total BED to point A and to compare the relationship of overall treatment time in terms of local control and bladder and rectal complications.

MATERIAL AND METHODS

The study included two groups comprising a total of 90 cervical cancer patients who underwent external beam radiotherapy (EBRT) followed by HDR intracavitary brachytherapy (ICBT). EBRT treatment was delivered by a Co-60 teletherapy unit to a prescribed dose of 45 Gy with 1.8 Gy per fraction in 25 fractions over a period of five weeks. Parallel opposed anterior-posterior (AP/PA) fields with no central shielding were used, followed by the HDR ICBT dose, to point A, of either two fractions of 9.5 Gy with a gap of 10 days, or three fractions of 7.5 Gy with a gap of 7 days between the fractions. Gemcitabine (dose of 150 mg/m²) was given weekly to all the patients as a radiosensitizer. The calculate BED₃ to point A was almost the same in both groups to keep the same late complication rates. The doses, and BED₁₀ and BED₃, were calculated at different bladder and rectal point as well as at the lymphatic trapezoid points. During and after treatment patients were evaluated for local control and complications for 24 months.

RESULTS AND CONCLUSIONS

Doses and BEDs at different bladder, rectal and lymphatic trapezoid points, local control, and complications in both HDR ICBT groups did not have statistically significant differences (p > 0.05). Both HDR ICBT schedules are well tolerable and equally effective.

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.

CT-based 3D dose-volume parameter of the rectum and late rectal complication in patients with cervical cancer treated with high-dose-rate intracavitary brachytherapy

This study evaluated the efficacy of computed tomography (CT)-based three-dimensional (3D) dose-volume parameters of the rectum as predictor for late rectal complication (LRC) in cervical cancer patients treated with radiotherapy alone. Eighty-four patients treated with a combination of external radiotherapy and high-dose-rate intracavitary brachytherapy between January 2000 and December 2004 were retrospectively analyzed. Brachytherapy was prescribed with standard 2D planning. Patients underwent pelvic CT at brachytherapy. The external rectal wall was contoured on the CT images, and the minimum doses delivered to 0.1cc, 1cc, and 2cc of the most irradiated rectal volumes were calculated with dose-volume histograms. The International Commission of Radiation Units and Measurements (ICRU) rectal point dose was also calculated by conventional method. Total dose (external radiotherapy plus brachytherapy) to the rectum was transformed to the biologically equivalent dose in 2-Gy fractions with alpha/beta of 3 Gy (D(0.1cc), D(1cc), D(2cc) and D(ICRU)). The relationships between these dosimetric parameters and the incidence of LRC were analyzed. The 5-year overall actuarial rate of LRC was 26.4%. The values of D(0.1cc), D(1cc), and D(2cc) were significantly higher in patients with LRC than in those without (p < 0.001), but the difference in the values of D(ICRU) was not statistically significant (p = 0.10). The rate of LRC increased significantly with increasing D(0.1cc), D(1cc), and D(2cc) (p = 0.001). However, no positive dose-response relationship was observed between D(ICRU) and the rate of LRC (p = 0.42). The present study has suggested that CT-based 3D dose-volume parameters of the rectum may be effective for predicting LRC.

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.

Does the entire uterus need to be treated in cancer of the cervix? Role of adaptive brachytherapy

PURPOSE

To evaluate local control and toxicity by use of a method of adaptive cervical brachytherapy (ACB).

METHODS AND MATERIALS

From 1998 to 2008, we identified 65 cervical cancer patients with FIGO (International Federation of Gynecology and Obstetrics) Stage IB1-IVA disease who received definitive external beam radiation therapy and high-dose rate brachytherapy with tandem and ovoid applicators. As tumors regressed, 45 of 65 patients had the tandem source retracted from the uterine fundus at successive brachytherapy insertions, thus decreasing the number of (192)Ir dwell positions. Tests of trend and Fisher's exact test were used to identify the effect of ACB on disease control and toxicity. Kaplan-Meier analyses were performed to evaluate disease control and late complications.

RESULTS

The median follow-up was 24.5 months. Of the patients, 92% received chemotherapy. The 3-year overall survival, 3-year disease-free survival, 3-year distant metastasis-free survival, and local control rates were 67%, 76%, 79%, and 97%, respectively. There was only 1 isolated local failure, and there were no local failures beyond 1 year. Distant failure was involved in 93% of recurrences. No significant trend was identified regarding the extent of retraction of the tandem source start position with either failure or toxicity. Acute and actuarial 3-year late Grade 3 toxicity or greater occurred in 24.6% and 17% of patients, respectively.

CONCLUSIONS

ACB determined by clinical response yielded excellent local control rates. These data indicate that ACB may be useful in decreasing late toxicities from high-dose rate brachytherapy. With the advent of three-dimensional image-guided brachytherapy, additional methods to adapt treatment technique to changes in tumor volume warrant investigation.

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.

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.

Conformal and intensity-modulated radiotherapy for cervical cancer

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

Patterns of failure and prognostic factor analyses in locally advanced cervical cancer patients staged by magnetic resonance imaging and treated with curative intent

Earlier we had shown that tumor volume and corpus invasion were important prognostic factors in cervical cancer and that corpus invasion was associated with nodal metastases. In view of these findings, we wanted to examine the factors associated with the patterns of relapse in cervical cancer patients who were staged by magnetic resonance imaging (MRI) and treated with curative intent. This was a retrospective study of locoregionally advanced cervical cancer patients treated with curative intent. All patients had examination under anesthesia and pretreatment MRI. Potential prognostics examined were FIGO stage, clinical diameter, histology, corpus invasion, tumor volume, and age. Outcome measures examined were times to failure, local failure, nodal failure, and distant failure. There were 249 eligible patients. The median age of the patients was 58 years, 85% had squamous histology, and 63% of tumors exhibited corpus invasion. Median tumor volume was 33.5 mL (range 1–628). The mean follow-up was 4.5 years. Eighty-five patients had relapsed and 89 died (70 following failure and 19 otherwise). At 5 years, for all patients, the failure-free rate was 62%, the local failure–free rate 88%, the nodal failure–free rate 69%, and the distant failure–free rate 74%. Corpus invasion, tumor volume, and age were all highly significantly and independently related to risk of failure at local, nodal, and distant (except tumor volume) sites. In the presence of these factors, clinical tumor diameter and FIGO stage were not significantly related to risk of any type of failure

Effect of high-dose-rate 192Ir source activity on late rectal bleeding after intracavitary radiation therapy for uterine cervix cancer

PURPOSE

This retrospective study analyzed the effect of the activity of high-dose-rate (HDR) (192)Ir source on late rectal bleeding after HDR intracavitary radiotherapy (ICRT) in patients with uterine cervix cancer.

METHODS AND MATERIALS

One hundred thirty-two patients who underwent HDR-ICRT and external beam radiotherapy (EBRT) were analyzed. The rectal point dose in ICRT was calculated by inserting a lead wire into the rectal lumen and summed with the whole-pelvic EBRT dose. The rectal biologic effective dose (BED) was calculated. The relationship between averaged source activity or the BED and late rectal bleeding were analyzed.

RESULTS

Three-year actuarial rectal bleeding probabilities were 46% (> or =100 Gy(3)) and 18% (< or = 100 Gy(3)), respectively (p < 0.005). When patients were divided into four groups according to rectal BED (> or = or < or =100 Gy(3)) and source activity (> or = or < or =2.4 cGy.m(2).h(-1)), the group with both a high BED and high activity showed significantly greater probability (58% at 3 years; p < 0.005). It was noted that the probability of the group with BED of 100 Gy(3) or greater was high, but that was not the case with 2.4 cGy.m(2).h(-1) or less.

CONCLUSION

This is the first clinical report concerning the source activity effect of HDR (192)Ir on late rectal bleeding in patients undergoing HDR-ICRT. This suggests that when source activity is higher than 2.4 cGy.m(2).h(-1), ICRT should be performed with more caution not to exceed 100 Gy(3) in total.

Classical tandem-source dwelling covering the entire uterus: essential in modern intracavitary radiotherapy for cervical cancer?

PURPOSE

We investigated whether conventional tandem-source dwelling to cover the entire uterus, classically regarded as the target volume, is necessary in modern intracavitary radiotherapy (ICRT) for cervical cancer.

MATERIALS AND METHODS

The study included 95 cervical squamous cell carcinoma patients treated by high-dose-rate ICRT (point A dose was 6.0 Gy, with three to five insertions per patient) after external beam radiotherapy (EBRT), with central pelvic doses of 12-50 Gy. The tandem-source dwell length was adjusted to the target volume specified by magnetic resonance (MR) imaging. A tandem applicator was inserted as far as the uterine fundus in accordance with the post-EBRT MR-assessed cavity length. The pre-EBRT MR-specified target volume was used for the dwell-length adjustment. The safety of the dwell-length adjustment was assessed in terms of treatment failure.

RESULTS

The dwell-length adjustment was made in 248 of 366 total insertions with a dwell-length reduction of 5-55 mm (median 15 mm) at the corpus. Pelvic failure was identified in 22 patients with a 2-year pelvic disease-free survival rate of 75.6% but without evidence of failure at dwelling-skipped corpuses.

CONCLUSION

Given after pelvic EBRT and ICRT of full-length dwelling in part, which may have eradicated possible subclinical extension, adjustment of the tandem-source dwell length to the MR-specified target volume appeared to be safe.

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.