Radiation alone in the treatment of cancer of the uterine cervix: analysis of pelvic failure and dose response relationship

The Variability of Applicator Position among High Dose Rate Intracavitary Brachytherapy Applications in Cervical Cancer Patients Treated with Ring & Tandem Applicators

Objective

To evaluate the interindividual and intraindividual applicator position variability in high dose rate ring and tandem intracavitary brachytherapy applications in locally advanced cervical cancer.

Patients and Methods

Eight patients with locally advanced cervical cancer formed the study population. They had been treated in Dokuz Eylül University Department of Radiation Oncology between the years 2000 and 2005 with high dose rate intracavitary brachytherapy using ring and tandem applicators. The 3-dimensional geometric variation of the applicator center in craniocaudal, mediolateral and anteroposterior directions was determined on the basis of bony reference points in 24 pairs of orthogonal films obtained in the conventional simulator. Then the following evaluations were performed: 1) the applicator position variability in all applications (interindividual variability), 2) the intraindividual applicator position variability relative to the first application, 3) the intraindividual applicator position variability relative to the average of three applications. Among the potential factors that might influence the reproducibility of ring and tandem applications, age, stage, the period between external radiotherapy and brachytherapy were evaluated by univariate analysis.

Results

Standard deviation of interindividual applicator variability was 3.83 mm in craniocaudal, 0.39 mm in mediolateral and 2.86 mm in anteroposterior directions. The standard deviation of intraindividual variability relative to the first application was 1.91 mm in craniocaudal, 0.4 mm in mediolateral, and 4.26 mm in anteroposterior directions. The standard deviation of intraindividual variability relative to the average of three applications was 0.95 mm in craniocaudal, 1.86 mm in mediolateral, and 1.24 mm in anteroposterior directions. According to univariate analysis, no factor influenced applicator position variability.

Conclusions

In order to extract definitive conclusions about factors that affect positional reproducibility of ring and tandem applicators, studies are needed that include larger numbers of patients.

Tandem-ring dwell time ratio in Nigeria: dose comparisons of two loading patterns in standard high-dose-rate brachytherapy planning for cervical cancer

Purpose

In high-dose-rate (HDR) brachytherapy (BT), the source dwell times and dwell positions are essential treatment planning parameters. An optimal choice of these factors is fundamental to obtain the desired target coverage with the lowest achievable dose to the organs at risk (OARs). This study evaluates relevant dose parameters in cervix brachytherapy in order to assess existing tandem-ring dwell time ratio used at the first HDR BT center in Nigeria, and compare it with an alternative source loading pattern.

Material and methods

At the Radiotherapy Department, University College Hospital (UCH), Ibadan, Nigeria, a total of 370 standard treatment plans in two alternative sets were generated with HDR basic 2.6 software for one hundred and eighty five cervical cancer patients. The initial 185 individual plans were created for clinical treatment using the tandem-ring dwell time ratio of 1 : 1. Modifying the initial applicator loading ratio, the second set of plans with related dose data were also obtained for study purposes only. Total reference air kerma (TRAK), total time index (TTI), ICRU volume, treatment time, point B dose, ICRU bladder dose, and rectal points dose were evaluated for both sets of plans.

Results

The means of all evaluated dose parameters decreased when the existing tandem-ring dwell time ratio (1 : 1) was modified to other dwell weightings (1 : 1 – 3 : 1). These reductions were 13.43% (ICRU volume), 9.83% (rectal dose), 6.68% (point B dose), 6.08% (treatment time), 5.90% (TRAK), 5.88% (TTI), and 1.08% (bladder dose). Correspondingly, coefficients of variation changed by –7.98%, –5.02%, –5.23%, –4.20%, –3.93%, 8.65%, and 3.96% from the existing pattern to the alternative one.

Conclusion

Tandem-ring dwell time ratio has significant influence on dosimetric parameters. This study has indicated the need to modify the existing planning approach at UCH.

Brachytherapy for cervix cancer: low-dose rate or high-dose rate brachytherapy - a meta-analysis of clinical trials

Background

The literature supporting high-dose rate brachytherapy (HDR) in the treatment of cervical carcinoma derives primarily from retrospective series. However, controversy still persists regarding the efficacy and safety of HDR brachytherapy compared to low-dose rate (LDR) brachytherapy, in particular, due to inadequate tumor coverage for stage III patients. Whether LDR or HDR brachytherapy produces better results for these patients in terms of survival rate, local control rate and the treatment complications remain controversial.

Methods

A meta-analysis of RCT was performed comparing LDR to HDR brachytherapy for cervix cancer treated for radiotherapy alone. The MEDLINE, EMBASE, CANCERLIT and Cochrane Library databases, as well as abstracts published in the annual proceedings were systematically searched. We assessed methodological quality for each outcome by grading the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. We used "recommend" for strong recommendations, and "suggest" for weak recommendations.

Results

Pooled results from five randomized trials (2,065 patients) of HDR brachytherapy in cervix cancer showed no significant increase of mortality (p = 0.52), local recurrence (p = 0.68), or late complications (rectal; p = 0.7, bladder; p = 0.95 or small intestine; p = 0.06) rates as compared to LDR brachytherapy. In the subgroup analysis no difference was observed for overall mortality and local recurrence in patients with clinical stages I, II and III. The quality of evidence was low for mortality and local recurrence in patients with clinical stage I, and moderate for other clinical stages.

Conclusion

Our meta-analysis shows that there are no differences between HDR and LDR for overall survival, local recurrence and late complications for clinical stages I, II and III. By means of the GRADE system, we recommend the use of HDR for all clinical stages of cervix cancer.

Correlation of traditional point a with anatomic location of uterine artery and ureter in cancer of the uterine cervix

PURPOSE

Point A, used for dose specification for intracavitary brachytherapy for cervical cancer, is the point at which the uterine artery and ureter cross. This study assessed compatibility of commonly used traditional point A (TPA) and actual anatomic point A (APA).

METHODS AND MATERIALS

We visualized and placed radiopaque clips at the APA during pelvic and paraaortic lymphadenectomy in 11 patients with cervical carcinoma. Orthogonal and oblique radiographs were obtained after insertion of brachytherapy applicators. We measured the distance between the TPA and APA and estimated the brachytherapy dose to each of the two points.

RESULTS

A total of 64 brachytherapy treatments were performed. The mean distances between the TPA and APA were 5.2 +/- 1.0 cm on the right and 5.4 +/- 1.1 cm on the left. The estimated brachytherapy doses delivered to the APA as a percentage of the presumed 500-cGy fraction size to the TPA were 35.2% (176.6 +/- 59.0 cGy) on the right and 30.0% (150.2 +/- 42.9 cGy) on the left. The marked discrepancy in the position of the two points was not related to individual kinetic variations during brachytherapy treatment, tumor size, or bladder filling.

CONCLUSIONS

The conventional TPA does not provide an accurate estimate of the APA determined during lymphadenectomy, indicating a need to reevaluate the current practice for determining the brachytherapy prescription for cervical cancer. (ClinicalTrials.gov Identifier, NCT00319462).

Chemotherapy in the primary treatment of cervical carcinoma

Two major treatment modalities in cervical cancer include radiotherapy and surgery. In an attempt to improve the outcome, these modalities have been increasingly supplemented by chemotherapy. Chemotherapy can be combined with local therapies in various sequences. Of the two possible strategies using chemotherapy and radiotherapy (sequential or concomitant), the latter seems to be more effective. Platinum-based regimens applied concurrently with both definitive and post-operative radiation therapy were demonstrated to provide survival benefit in five of the six recently published randomised trials. The positive impact of chemotherapy added to radiotherapy has also been shown in a meta-analysis including 1894 patients in 19 randomised studies. This strategy, however, is accompanied by increased early toxicity. The benefit of chemotherapy applied prior to surgery remains debatable. The role of new cytotoxic and biological substances, as well as agents combating tumour hypoxia, warrants further clinical investigation.

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.

Braquiterapia intersticial para recidivas de câncer de colo uterino pós-radioterapia

OBJETIVO: Analisar a resposta e toxicidade da braquiterapia de alta taxa de dose (BATD) intersticial para carcinoma do colo do útero com recidiva pélvica pós-radioterapia. MATERIAIS E MÉTODOS: Entre 1998 e 2001, 11 pacientes com carcinoma de colo de útero e que tiveram recidiva pélvica pós-radioterapia receberam BATD intersticial. Idade: 41 a 71 anos (média: 56,5 anos); estádios (FIGO): IIA, IIB, IIIB e IVA. Nove (82%) pacientes tinham carcinoma de células escamosas e duas (18%), adenocarcinoma. Dose total de BATD: 20-30 Gy, em frações de 4-5 Gy. O seguimento variou de dois a 54 meses (média: 22,5 meses), através de exame físico periódico (três meses). Uma paciente faleceu sem avaliação de resposta. RESULTADOS: Dez pacientes (91%) tiveram resposta clínica completa, com duração de três a 46 meses (média: 18,9 meses). Três pacientes estão livres de doença (27%), duas estão vivas com doença (18%), três morreram (27%) e de três se perdeu o seguimento após nova recidiva (27%). A toxicidade para o trato urinário foi de 9% (uma paciente - grau III). CONCLUSÃO: A BATD intersticial é uma abordagem alternativa e viável para pacientes selecionadas que tiveram recidiva pós-radioterapia. Foi possível obter altas taxas de resposta com baixa toxicidade, considerando-se o grupo estudado, o tempo de seguimento e a re-irradiação.

Minimizing urinary bladder radiation dose during brachytherapy for carcinoma of the cervix using balloon inflation technique

PURPOSE

Radiotherapy is effective in treating cancer of the cervix. However, its success is associated with significant morbidity of the urinary bladder. This study has been designed to reduce the radiotherapy dose from the brachytherapy component of cervical cancer treatment to the urinary bladder to minimize radiation-induced morbidity.

MATERIALS AND METHODS

By inflating the balloon of a Foley catheter at the anterior fornix region, attempts were made to displace the urinary bladder in patients undergoing gynecological intracavitary brachytherapy. The radiation dose to the urinary bladder was then studied in 12 insertions without and 31 insertions with balloon inflation.

RESULTS

The increase in the distance from the intrauterine tandem source to a reference point in the base of the bladder and the resultant decrease in the radiation dose have been determined. A highly significant reduction in the radiation dose with an increase in distance between the source applicator and bladder base were achieved (p < 0.01 in both cases).

CONCLUSION

A significant reduction in radiation dose to the bladder base can be achieved by the technique described in this study. A three-dimensional plan generated using CT images can demonstrate the drawback of ICRU-38 bladder reference point. The technique is simple consistent and reproducible within an acceptable range.

IMRT dose escalation for positive para-aortic lymph nodes in patients with locally advanced cervical cancer while reducing dose to bone marrow and other organs at risk

PURPOSE

To evaluate the feasibility of dose-escalated para-aortic lymph node (PALN) intensity modulated radiation therapy (IMRT) in reducing the dose to bone marrow, bowel, spinal cord, and kidneys, compared with conventional radiation techniques of PALNs in patients with locally advanced cervical cancer and PALN metastases.

METHODS AND MATERIALS

Computed tomography scans and MRI studies of 5 cervical cancer patients with PALN involvement were transferred to an IMRT treatment planning workstation (Eclipse/Helios) for image fusion and definition of target volumes and critical structures. The positive PALNs identified on fused computed tomography-magnetic resonance images were defined as the gross target volume (GTV), and the PALN region was defined as the planning target volume. There were 2 distinct treatment regions: the PALN region superior to the isocenter and the whole-pelvis region inferior to the isocenter. Three treatment planning techniques were compared: AP/PA (both regions), 4-field box (both regions), and PALN-IMRT with 4-field box to the whole-pelvis field. With IMRT, the radiation dose to the GTV was escalated from the conventional 45 Gy to 60 Gy (2.4 Gy/fraction), whereas the planning target volume and whole-pelvis region received 45 Gy. The treatment planning isocenter was placed at the L4-L5 vertebral body interspace, and this allowed the two treatment regions to be abutted using independent jaws.

RESULTS

This study has demonstrated the feasibility of escalating the dose delivered to grossly positive PALNs to 60 Gy (2.4 Gy/fraction) with a 95.6% median GTV coverage, concomitantly with conventional treatment of the whole-pelvis region. PALN-IMRT significantly reduced V(40) bone marrow compared to the AP/PA and 4-field box techniques with a median of 21.3%, 98%, and 49.7%, respectively. The PALN-IMRT and 4-field box techniques showed a reduction in V(45) bowel over the AP/PA technique, but a level of statistical significance was not reached. The spinal cord received a significantly higher maximum dose when PALNs were treated with AP/PA fields. Alternatively, the use of the 4-field box technique yielded a significant increase in V(22) kidney on both sides. The placement of the treatment planning isocenter at the L4-L5 interspace allowed the PALN-IMRT and whole-pelvis regions to be treated with a relatively uniform dose at the abutment region.

CONCLUSION

In this dosimetric analysis, we demonstrated that dose-escalated PALN-IMRT with conventional whole-pelvis radiotherapy is feasible with significant sparing of critical normal structures compared to PALN conventional radiation techniques.

Conventional 4-field box radiotherapy technique for cancer cervix: potential for geographic miss without CECT scan-based planning

BACKGROUND

The advantage of 4-field radiation to the pelvis is that the use of lateral portals spares a portion of the small bowel anteriorly and rectum posteriorly. The standard lateral portals defined in textbooks are not always adequate especially in advanced cancer cervix.

METHODS

An analysis was done to determine adequacy of margins of standard lateral pelvic portals with CECT defined tumor volumes. The study included 40 patients of FIGO stage IIB and IIIB treated definitively for cancer cervix between 1998 and 2000. An inadequate margin was defined if the cervical growth and uterus were not encompassed by the 95% isodose.

RESULTS

An inadequate posterior margin was common with bulky disease (P = 0.06) and with retroverted uterus (P = 0.08). Menopausal status, FIGO stage, associated myoma, and age were of no apparent prognostic significance. Bulk retained significant on multivariate analysis. An inadequate anterior margin was common in premenopausal (P = 0.01); anteverted uterus (P = 0.02); associated myoma (P = 0.01); and younger patients (P = 0.03). It was not influenced by bulk or stage. Menopausal status and associated myoma retained significant on multivariate analysis.

CONCLUSION

Without the knowledge of precise tumor volume, the 4-field technique with standard portals is potentially risky as it may under dose the tumor through lateral portals and the standard AP/ PA portals are a safer option.

Transvaginal color Doppler sonography for predicting response to concurrent chemoradiotherapy for locally advanced cervical carcinoma

PURPOSE

This study was conducted to evaluate the potential role of transvaginal color Doppler sonography (TVCD) in predicting response to concurrent chemoradiotherapy for locally advanced cervical cancer.

METHODS AND MATERIALS

Tumor vascularity was assessed using TVCD before the start of concurrent chemoradiotherapy in 21 patients (median age, 47 years; range, 31-75 years) with histologically proven locally advanced cervical cancer. The lowest resistance index (RI), lowest pulsatility index (PI), and highest peak systolic velocity (PSV) from central vessels within the tumor were recorded and used for analysis. All patients were clinically evaluated by physical examination and CT scanning after completing the chemoradiotherapy protocol. Complete clinical response (CR) was determined when no residual tumor was found. Partial clinical response (PR) was determined when the tumor volume had decreased more than 50%.

RESULTS

CR was achieved in 11 patients (52%), whereas 10 (48%) had PR. The initial median tumor volume was not statistically different between those with CR (26 cm3) and those with PR (28 cm3) (p = 0.71). RI was higher in those tumors with CR (median, 0.47) than in those with PR (median, 0.29) (p < 0.01). Likewise, PI was higher in tumors with CR (median, 0.81) than in those with PR (median, 0.41) (p < 0.01). No differences were found in PSV. The likelihood ratio for CR for tumors with a lowest RI of 0.35 or more was 2.7 (95% confidence interval, 1.8-3.6) and the likelihood ratio for CR for tumors with a lowest PI of 0.45 or more was 3.3 (95% confidence interval, 2.1-4.5).

CONCLUSIONS

The results suggest that TVCD may be useful in predicting clinical response to concurrent chemoradiation in patients with locally advanced cervical cancer.

Radiation fields in gynecologic oncology: correlation of soft tissue (surgical) to radiologic landmarks

OBJECTIVES

(1). To determine if radiation fields defined by bony structure landmarks correlate to anatomic boundaries of lymph node dissection marked intraoperatively; and (2). to determine if a patient's body mass index (BMI) correlates with these anatomic or radiographic boundaries.

METHODS

One hundred patients undergoing exploratory laparotomy with pelvic and paraaortic lymph node dissection had three medium hemoclips placed at vascular junctions considered of clinical significance to lymph node dissection: insertion of the left ovarian vein into the renal vein, insertion of the right ovarian vein into the vena cava, inferior mesenteric artery (IMA), bifurcation of the aorta, bifurcation of the common iliacs (bilateral), and the insertion of the deep circumflex vein (DCV) in to the external iliac vein (bilateral). Postoperatively, an abdominal X-ray was obtained. Comparisons were made between these eight major vascular landmarks and radiographic bony landmarks that are used to define radiation field boundaries. The percentage of vascular landmarks that were encompassed or fell outside of traditional radiation fields was determined with a 1-cm margin considered an adequate boundary for radiation. These measurements were also compared to patient BMIs.

RESULTS

Radiation fields defined by traditional bony landmarks would adequately encompass the paraaortic lymph nodes in the majority of patients (91%). For pelvic radiation fields, there was a significant "miss" (39%) of common iliac lymph nodes. Approximately one quarter (26%) of patients would receive inadequate coverage of one or both of the lateral boundaries of pelvic radiation. There was no apparent correlation of BMI to vascular or bony landmarks.

CONCLUSIONS

Radiation fields determined by traditional bony landmarks do not adequately reflect the anatomic (surgical) landmarks associated with the lymphatic drainage of the female reproductive organs. Although the majority of tertiary care centers now use advanced imaging techniques (e.g. computed tomography) to plan their radiation treatments, the historical guidelines of radiographic landmarks are still used in smaller institutions and continue to be referenced in Gynecologic Oncology Group protocols. For centers still using radiographic landmarks, the application of hemoclips with X-ray identification is a low-cost modality that is easily reproducible and may be clinically useful in guiding treatment.

Radiotherapy alone in the treatment of uterine cervix cancer with telecobalt and low-dose-rate brachytherapy: retrospective analysis of results and variables

PURPOSE

This retrospective analysis aims to report results and variables from patients with cervix cancer treated by radiation therapy alone with telecobalt and low-dose-rate brachytherapy (LDRB).

METHODS AND MATERIALS

Between September 1989 and September 1995, 190 patients with histologic diagnosis of cervix carcinoma were treated with telecobalt for external beam radiotherapy (EBR), followed by one or two insertions of LDRB. Stage distribution according to patients was the following: IB, 12; IIA, 4; IIB, 105; and IIIB, 69. Median dose of EBR at whole pelvis was 40 Gy, and median parametrial doses for Stages II and III patients were 50 Gy and 60 Gy, respectively. Median doses of LDRB at point A for patients treated with one and two insertions were 38 Gy and 50 Gy, respectively.

RESULTS

Median follow-up time was 70 months (range: 8-127 months). Overall survival, disease-free survival, and 5-year local control of patients at Stages I, II, and III were 83%, 78%, and 46%; 83%, 82%, and 49%; and 92%, 87%, and 58%, respectively. Overall incidence of late complications in the rectum, small bowel, and urinary tract was 15.3% (19/190), 4.2% (8/190), and 6.8% (13/190), respectively. The actuarial 5-year rectal, small bowel, and urinary incidence of late complications was 16.1%, 4.6%, and 7.6%, respectively. Clinical stage was the only significant variable for overall 5-year survival (p = 0.001), for disease-free survival (p = 0.001), and for local control (p = 0.001). Stage II patients more than 50 years old had better disease-free survival and local control at 5 years (p = 0.004). None of the analyzed variables influenced the actuarial 5-year incidence of late complications.

CONCLUSIONS

Results of this series suggest that the use of telecobalt equipment for EBR with doses up to 50 Gy at whole pelvis, prior to brachytherapy, is an acceptable technique for radiation therapy alone in the treatment of cervix cancer, especially in developing countries, including Brazil, where telecobalt machines still prevail.

Is there a role for pelvic lymph node debulking in advanced cervical cancer?

OBJECTIVE

The purpose of this study is to determine if a survival advantage exists from surgical debulking of enlarged pelvic lymph nodes in advanced cervical cancer.

METHODS

Using information from studies published on the topic of debulking lymph nodes in locally advanced cervical cancer along with baseline control rates of standard treatment and patterns of failure, an estimate of how many patients with bulky pelvic lymph node disease would benefit from this procedure was calculated. The design and feasibility of a randomized trial to test this intervention is also discussed.

RESULTS

Based on our calculations 1, 2, and 4% of stage IB, IIB, and IIIB patients, respectively, would benefit from a debulking procedure. Based on our calculations with such small differences in survival along with other inclusion and exclusion criteria, a randomized trial, which would compare chemoradiation to chemoradiation and surgery, would require anywhere from 10,000-30,000 patients per arm.

CONCLUSIONS

A very small fraction of patients would benefit from a surgical debulking procedure of pelvic nodes. A randomized controlled trial to test this research question is not feasible. A subset population is identified which may benefit from a debulking approach.

Gynecologic brachytherapy I: Proper incorporation of brachytherapy into the current multimodality management of carcinoma of the cervix

The incidence of carcinoma of the cervix has continuously declined over the past decades because of effective screening. The International Federation of Gynecology and Obstetrics (FIGO) clinical staging, though universally used, is considered inadequate either to determine the type of treatment or to predict treatment outcome. Over the last 10 years, treatment of cervical cancer has become increasingly sophisticated with advances in external beam and brachytherapy in the radiotherapeutic management of this carcinoma. In particular, brachytherapy plays a major role in enhancing both local control and survival. Experience to date suggests that either high-dose-rate (HDR) or low-dose-rate (LDR) brachytherapy, when properly applied, can be effective and give similar rates of local control with minimal complications. This article analyzes the current literature regarding treatment techniques of radiotherapy with special emphasis on brachytherapy integration to optimize radiotherapy treatment outcome.

Patterns of failure in carcinoma of the uterine cervix treated with definitive radiotherapy alone

The purpose of this retrospective study was to evaluate the patterns of failure for the patients treated with definitive radiotherapy, and to discuss future treatment strategies for the uterine cervical cancer. From 1986 to 1995, 177 patients with stages I-III cervical cancer treated with a combination of two-axial conformal radiotherapy and radium brachytherapy were analyzed. The first treatment failures were pelvic failure in 11%, and distant metastases (DM) in 16% of the 177 patients. Paraaortic lymph nodes (PAN) were the most frequently metastatic regions (71%). In the pelvic control group, DM were in 6% of patients for stages I-II, and in 32% of patients for stage III. In the pelvic failure group, DM were in 75% of patients for stages I-II, and in 19% of patients for stage III. In stages I-II, the DM rate was significantly correlated with pelvic tumor control. However, there was no correlation in stage III. To improve survival, it is important to increase the pelvic tumor control rate for patients with stage I-II, and to increase the pelvic tumor and metastatic control rate in stage III. Additional treatments such as chemotherapy and/or PAN irradiation using conformal radiotherapy are required in stages I-II with locally bulky tumor and in stage III.

Intraoperative electron beam radiotherapy during radical surgery for locally advanced and recurrent cervical cancer

OBJECTIVE

The goal of this study was to determine the toxicity patterns and clinical usefulness of intraoperative electron beam radiotherapy (IOERT) in patients with unfavorable-outcome cervical cancer.

METHODS

From January 1986 to June 1999, 67 patients (36 recurrent, 31 primary disease) were treated with IOERT. Previously unirradiated patients received preoperative chemoradiation to 45 Gy with cisplatin 20 mg/m(2) and 5-fluorouracil 1000 mg/m(2). IOERT median dose was 12 Gy for primary disease (range: 10-25) and 15 Gy for recurrent disease (range: 10-20).

RESULTS

The 10-year control rate within the area treated with IOERT ("in-field" (IF)) for the entire group was 69.4, with 92.8 and 46.4% 10-year IF control rates for the primary and recurrent patients, respectively. IF control rate correlated with involvement of the parametrial margin (P = 0.001), amount of residual disease (P = 0.001), and pelvic lymph node involvement (P = 0.032). The overall incidence of toxic events that might be attributable to IOERT was 14.9%. Chronic pain was observed in 8 of 67 evaluable patients (11.9%) and motor neuropathy of the lower extremity in one patient (3.2%).

CONCLUSIONS

IOERT is a valuable boosting technique in the management of advanced but resectable cervical cancer. Patients, especially recurrent cases, with positive lymph nodes, parametrial involvement, and/or incomplete resections have poor local control rates despite IOERT at the doses used in this study.

Combined brachytherapy and surgery for early carcinoma of the uterine cervix: analysis of extent of surgery on outcome

PURPOSE

The aim of this retrospective study was to evaluate the survival data and rates and patterns of complications and recurrences for patients who had early uterine cervix carcinoma and underwent brachytherapy and subsequent surgery.

METHODS AND MATERIALS

Between January 1990 and December 1997, 192 women with cervical carcinoma (Stages IA2 with vascular invasion [n = 28], IB1 [n = 144], and IIA [n = 20]) underwent brachytherapy, delivering 60 Gy and then hysterectomy with external iliac lymphadenectomy. Piver class I, II, and III hysterectomies were performed on 136, 38, and 18 patients, respectively. Adjuvant chemoradiotherapy was delivered to patients with positive lymph nodes.

RESULTS

The median follow-up time was 61 months. After brachytherapy, a pathologically complete response (CR) was observed in 137 (71.3%) of 192 women. The distribution of CRs according to tumor stage was as follows: Stage IA2, 24 (85.7%) of 28; Stage IB1, 105 (72.9%) of 144; and Stage IIA, 8 (40%) of 20. Patients with Stage IB1 cancer had 13 lymph node metastases (9%), as did 6 with Stage IIA disease (30%). Pelvic recurrences occurred in 9 (4.6%) of the 192 patients; in 3, local relapses were associated with relapses at distant sites. Ten patients had systemic relapses (5.2%). Recurrences at distant sites were more frequent (p < 0.02) in partial responders, and other recurrences were more frequent in patients with lymph node metastases (p < 0.04). The overall 5-year disease-free survival rate was 91.2% (96.2% for Stage IA2, 91% for Stage IB1, and 84.4% for Stage IIA cancers). The class of hysterectomy did not influence the outcome. Late complications occurred in 28 patients (Grade 1, 24 [12.5%]; Grade 2, 4 [2%]; and Grade 3, 1 [0.5%] of 192 patients).

CONCLUSIONS

Combined treatments resulted in high local control and low morbidity rates in patients with early-stage cervical carcinoma. Limited surgery seemed to be adequate after intracavitary therapy.

Predicting response to neoadjuvant chemotherapy in patients with cervical carcinoma: can we do without any longer?

The aim of the study was to identify variables that may predict the response to neoadjuvant chemotherapy (NACT) in patients with cervical cancer as maturing data from the literature indicate that this therapeutic strategy might be beneficial to some but harmful to others. Clinico-pathologic variables including age, histology, tumor differentiation, as well as immunohistochemical overexpression of p53, mdm2, c-erbB-2, and cathepsin D in 37 of these patients were evaluated as possible predictors of response to the NACT. Fifty-five patients with stage IIB cervical cancer submitted to two courses of cisplatin/ifosfamide/mesna prior to definitive treatment with radical surgery or radiation therapy were the subjects of this study. The clinical response rate was 80% but none of the variables was able to predict response to NACT. Unless methods are found enabling us to predict response and therefore to identify those patients that could benefit from including NACT in the treatment of locally advanced cervical cancer, only women with primarily resectable tumors should be selected for this multimodality approach as a result of the possibility of cross-resistance with radiation therapy in nonresponders.

Combination of radiation therapy and interferon alpha-2b in patients with advanced cervical carcinoma: a pilot study

Carcinoma of the uterine cervix is the most frequent malignancy in women in developing countries. Based on the possible synergistic effect of the combination of interferon and radiotherapy, a clinical trial was conducted in patients with advanced cervical cancer. The objective was to evaluate the efficacy and security of such a therapeutic approach. This prospective phase II trial was done at the Instituto Nacional de Cancerología in Mexico City. The study included 17 consecutive patients with previously untreated squamous cell cervical cancer, clinical stages III and IV, and tumor mean size of 9.7 cm. The patients received radiotherapy and interferon alpha-2b at a dose of 5 x 106 IU/m2 3 times a week for 6 weeks. Eleven (64%) complete responses were obtained among these patients. Long-term survival was observed in 4 patients (24%) who achieved complete response and are alive after 10 years of follow-up. Immediate toxicity was mild. Late toxicity included the development of proctitis in 13 patients, colostomy was performed in 3 (23%) of them. Our results indicate that the combination of radiotherapy and this cytokine is an active therapy for squamous cell carcinoma of the uterine cervix.

Pilot study of concurrent cisplatin, 5-fluorouracil, and external beam radiotherapy prior to radical surgery +/- intraoperative electron beam radiotherapy in locally advanced cervical cancer

PURPOSE

The purpose of this study was to describe the feasibility of a combined preoperative chemoradiation program followed by radical surgery in advanced cervical cancer.

MATERIALS AND METHODS

From February 1988 to April 1997, 40 patients with carcinoma of the cervix were treated with preoperative external beam radiotherapy to 45 Gy in 5 weeks. Patients received concurrent continuous infusion cisplatin (20 mg/m2) and 5-fluorouracil (1500 mg) chemotherapy during the first (days 1-4) and fifth (days 22-25) weeks of the radiation course. Radical surgery was performed 4-6 weeks after the completion of the preoperative treatment. Intraoperative radiotherapy was given to 20 patients, based on intraoperative assessment.

RESULTS

Toxicity associated with chemoradiation was usually mild except in two patients who presented WHO grade 4 bone marrow aplasia. Three patients developed postoperative ureterovaginal fistula, and five patients developed long-term hydronephrosis that needed ureteral stenting. Clinical response was observed in 95% of the patients (55% complete response). The analysis of the surgical specimens revealed complete pathological response in 67.5% of the cases and partial pathological response in 32.5%. As expected, the degree of pathological response was predicted by the degree of clinical response (P = 0.001). Nine-year local control, distant metastases-free survival, disease-free survival, and overall survival were 86, 84, 81, and 85%, respectively. Patients displaying a complete pathological response had statistically significant improved local control (P = 0.004), distant metastases-free survival (P = 0.009), disease-free survival (P = 0.002), and overall survival (P = 0.038).

CONCLUSIONS

Cisplatin plus 5-fluorouracil preoperative chemoradiation is active and usually well tolerated in locally advanced carcinoma of cervix, inducing a high rate of clinical and pathological complete responses. When this therapy is followed by radical surgery, the local control rates are excellent, even in patients with advanced stages or poor response. These improved local control rates may be achievable only through extensive surgical resection, with a parallel increase in the complication rates.

Brachytherapy and vaginal hysterectomy for low-stage uterine cervix carcinoma

OBJECTIVE

The aim of this study was to assess safety and efficiency of a limited vaginal hysterectomy after brachytherapy in patients with early uterine cervix carcinoma without unfavorable prognostic factors. All tumors were less than 1.5 cm in diameter.

MATERIAL AND METHODS

Between October 1992 and December 1995, 22 patients with low-stage uterine cervix carcinoma (stage Ia2 with vascular invasion, 3 cases; stage Ib1, 19 cases) were included in this study. Patients underwent the following procedures: single utero-vaginal brachytherapy after a previous negative laparoscopic lymphadenectomy (median number of lymph nodes: 12) followed 6 weeks later by a limited vaginal hysterectomy.

RESULTS

Two mild intraoperative complications were noted. Venous hemorrhage (100 cc) occurred in one patient during lymphadenectomy and another patient experienced bladder injury during hysterectomy. These two complications were successfuly controlled with no need for laparotomy. Only one late complication was observed and was evaluated as a bladder grade G2(b) according to the Franco-Italian glossary. With a 30 (22-50) month follow-up, no recurrence was reported.

CONCLUSION

These results appear promising in patients with very early cervix carcinoma but remain to be confirmed on a larger scale.

Computed tomography analysis of causes of local failure in radiotherapy for cervical carcinoma

BACKGROUND

The authors analyzed the radiation dose to the periphery of the cervix and area of the cervix in relation to local failure of radiotherapy for carcinoma of the cervix using computed tomography (CT) images.

METHODS

Between 1981-1990, 127 consecutive patients were treated with definitive radiotherapy. Ninety-nine of these patients had CT images taken at the time of intracavitary therapy. Of these 99 patients, 80 were eligible for this analysis. After CT scanning, isodose curves relative to the point A dose were superimposed on the CT images. The minimum percent dose and minimum dose at the periphery of the cervix were estimated. The area of the cervix also was measured. These factors were examined in relation to the local tumor control rate.

RESULTS

Histograms of both the minimum percent dose and the cervical area showed significant differences between the local control and local failure groups (P <0.001). The local control rates were related to both the minimum percent dose and the cervical area, and differed significantly over and below the values of 60% and 18 cm2 (P <0.001 each), respectively. The local control patients, over and below the line: Y = -0.220X + 21.2, in which X (gray [Gy]) and Y (Gy) are the whole pelvis dose and the minimum dose, respectively, could be well differentiated with significance (91.7% vs. 25.0%; P <0.001).

CONCLUSIONS

Computed tomography analysis indicated that the local tumor control rate was related strongly to the minimum percent dose, the cervical area, and the pair of whole pelvis and minimum dose values. These factors were found to be more useful than the point A dose in predicting local tumor control.

[Treatment of cancers limited to the uterine cervix with simple hysterectomy using a vaginal approach after brachytherapy]

PURPOSE

In patients with early cervix carcinoma, both radiotherapy and surgery or combined modalities provide effective therapies. In the two last modalities, recommended surgery is radical hysterectomy. The purpose of this prospective study was to assess the value of a limited vaginal hysterectomy after brachytherapy in patients without any unfavorable prognostic factor.

PATIENTS AND METHODS

Twenty-two patients (stage Ia2 with vascular invasion: three patients, stage Ib 1:19 patients) with 1 cm median maximal tumor size and with previous negative laparoscopic lymphadenectomy (median number of lymph nodes: 12) underwent a limited vaginal hysterectomy 6 weeks after utero-vaginal brachytherapy.

RESULTS

Two mild intra-operative complications were noted. Venous hemorrhage (100 mL) occurred in one patient during lymphadenectomy and another patient presented bladder injury during hysterectomy. These two complications were successfully controlled with no need for laparotomy. Only one late complication was observed: bladder grade G2 (b). With a 29 months follow-up (20-48 months), no recurrence was reported.

CONCLUSION

These results appear promising in patients with very early cervix carcinoma but remain to be confirmed on a larger scale.

Treatment of carcinoma of the uterine cervix with concomitant cisplatin, 5-fluorouracil and split course hyperfractionated radiotherapy

To improve local and systemic control of bulky (>4 cm) and/or advanced primary cancer of the uterine cervix, 35 patients were treated with concomitant cisplatin (CDDP), 5-fluorouracil (5-FU) and split course hyperfractionated radiotherapy. Radiation was administered to the pelvis in five-day courses at a dose of 1.5 Gy twice daily every 21 days until a median dose of 45 Gy was reached. 15 Gy more were administered to involved parametrium or central tumor by external radiotherapy or brachytherapy. The irradiated zone was extended to include paraaortic lymph nodes if necessary. CDDP was administered at a dose of 20 mg m(-2) and 5 FU at a dose of 500 mg m(-2) from day one to day five of each course. The median number of combined treatment courses per patient was four (1-6). Local responses were obtained in 19 out of 24 patients in whom evaluation was feasible (i.e. who did not undergo surgery prior to combined therapy). Median survival was not attained with a median follow up of 33 months, three year overall survival was 62% and 52% in patients with local control and in the whole population respectively. Several patients with stage III and IV tumors achieved a very long survival. Acute toxicity was manageable but three patients required surgical repair of late radiation complications. This combined chemotherapy and radiotherapy resulted in good local control and did not rule out surgery.

Dynamics of pear-shaped dimensions and volume of intracavitary brachytherapy in cancer of the cervix: a desirable pear shape in the era of three-dimensional treatment planning

PURPOSE

To evaluate the dynamics of pear-shaped dimensions and volume of the intracavitary brachytherapy, and to define a desirable pear-shape in the era of three-dimensional (3D) treatment planning.

METHODS AND MATERIALS

Since Point A has been used for the dose specification, the pear shape defined the surface enclosed by Point A. This study utilized a new method of evaluating pear-shaped dimensions and its configuration. The pear shape was artificially divided into tandem and colpostat portions for evaluation of its changes. Width, height, and thickness at the tandem portion (Wt, Ht, and Tt) and at the colpostat portion (Wc, Hc, and Tc) were defined, respectively, on the frontal and sagittal plane. To evaluate the dynamics of the pear-shape configuration, 12 variations of applicator geometry and source loading were applied to generate the pear-shape isodose line and dose-volume histogram.

RESULTS

When the source strengths in the colpostats were reduced for optimization with the same dose to Point A dose, Wc, Hc, and Tc were decreased, whereas Wt, Ht, and Tt were increased without a change in the overall pear-shaped volume. When the separation of the colpostats was increased without a change in the source strength, Wc was increased, whereas Hc and Tc were reduced without a change in Wt, Ht, Tt and overall pear-shape volume. When the separation of colpostats and distal tandem source were increased, these changes at the colpostat portion were magnified. However, when both colpostat separation and its source strength were increased proportionally, Wc, Hc, and Tc were increased proportionally as well as its volume.

CONCLUSION

The dose specification at Point A is less meaningful without a desirable pear shape encompassing the tumor around the cervix. In the era of 3D treatment planning, understanding the dynamics of the pear shape should improve the individualized dosimetry according to tumor size and location. The relationships between a desirable pear shape and its tumor coverage should establish a more reliable dose specification for cancer of the cervix.

Radiation therapy of cervical cancer with dosimetric prevention of late pelvic complications

Two successive series of invasive carcinoma of the cervix (268 and 307 patients) were treated by radiation alone between 1973 and 1977 and 1978 and 1985. The main difference between these periods was the method used to determine the definitive dose delivered by intracavitary therapy. The treatment in all cases consisted of external and intracavitary radiotherapy. Computerized dosimetry was performed in all patients with determination of dose rate, maximum and mean cumulated doses at the reference points of the rectum and bladder. The tolerance doses to the rectum and bladder previously established and represented graphically were used prospectively for the patients from 1978 to 1985, permitting better coordination of the two treatments. The graph takes into account the fractionated tolerance to external irradiation and intracavitary radiotherapy. The systematic use of this method yielded results at six years for all stages which were comparable from one series to another. Parallel to this, the improvement in the number and gravity of the complications was significant, especially for grade 2 complications (P = 0.001) and, to a lesser degree, for grade 3 and 4 complications (P = 0.04). In conclusion, the respect of tolerance doses to the critical organs close to the principal tumoral volume represents an effective method for optimizing radiotherapeutic treatment for cervical cancer.

Inadequate adherence to radiotherapy in Latina immigrants with carcinoma of the cervix. Potential impact on disease free survival

BACKGROUND

Radiation therapy plays an important role in the loco-regional control of carcinoma of the cervix. Strict adherence to the radiation protocol, without the introduction of time breaks, has been shown to favorably affect loco-regional control and survival, making adherence a crucial variable for optimal outcome. Because carcinoma of the cervix is a common disease among Latinas, with survival rates worse than those of other ethnic groups in this country, the pattern of adherence to the prescribed radiation treatment among Latina patients seen at Los Angeles County Hospital were studied.

METHODS

The records of 69 consecutive Latina patients with cervical cancer who received radiation therapy at Los Angeles County Hospital were reviewed. Semi-structured interviews in a successive group of 30 similar patients were conducted to acquire preliminary information about their psychosocial characteristics.

RESULTS

The results demonstrate inferior rates of optimal adherence to radiation treatment among Latina immigrant patients when compared with the rates reported in the literature for the general population of cervical cancer patients in United States (16 vs. 63%). Furthermore, a large subset of patients (20%) in the series elected to discontinue treatment without a medical reason. When a comparable group of Latina patients was interviewed, potential practical, psychologic, and cultural barriers to optimal care were identified.

CONCLUSIONS

The results from this exploratory study support the need for further studies to document the pattern of adherence to radiotherapy in the rest of the country among this minority population. The results suggest that an intervention to improve information and adherence to radiation therapy may be necessary to assure Latinas a chance for rates of cure comparable with the national standards.

Irradiation alone or combined with surgery in stage IB, IIA, and IIB carcinoma of uterine cervix: update of a nonrandomized comparison

PURPOSE

Definitive radiation therapy alone or combined with surgery in carcinoma of the uterine cervix yields comparable tumor control and survival in Stages I and IIA when patients are adequately treated with either modality. Our 30-year institutional experience is described.

METHODS AND MATERIALS

This is a nonrandomized comparison of treatment results of 415 patients with Stage IB, 137 with Stage IIA, and 340 with Stage IIB carcinoma of the uterine cervix treated with irradiation alone and 197 with Stage IB, 44 with Stage IIA, and 65 with limited Stage IIB treated with pre- or postoperative irradiation and surgery. Irradiation alone consisted of a combination of external beam therapy and intracavitary insertions to deliver doses of 70 to 85 Gy to point A for patients with Stages IB and IIA disease and 80 to 90 Gy for patients with bulky or Stage IIB tumors. For patients treated with irradiation and surgery, various combinations of external beam and intracavitary therapy were used to deliver 60 to 75 Gy to point A. Surgical procedures consisted of radical hysterectomy with or without lymph node dissection in 130 patients with Stage IB, 28 patients with Stage IIA, and 10 patients with limited Stage IIB. Fifty-seven patients had total abdominal or conservative hysterectomy with or without lymph node dissection, and 3 had vaginal hysterectomy. In addition, 51 patients with Stage IIB tumors underwent pelvic lymphadenectomy after definitive irradiation.

RESULTS

The 5-year cause-specific survival (CSS) rates for patients with Stage IB nonbulky tumors treated with irradiation alone or irradiation combined with surgery were 90 and 85%, respectively, and the 10-year survival rate was 84% with either modality. In patients with bulky tumors (> 5 cm), the 5-year CSS rates were 61% with irradiation alone and 63% with irradiation plus surgery; at 10 years the rates were 61 and 68%, respectively (p = 0.5). For those with Stage IIA nonbulky tumors, the 5-year CSS rates were 75% with irradiation alone and 83% with combined irradiation and surgery, and 10-year CSS rates were 66 and 71%, respectively. In patients with Stage IIA bulky tumors, the 5-year CSS rates were 69% with irradiation alone and 60% with irradiation plus surgery, and at 10 years, 69 and 44%, respectively (p = 0.05). In patients with Stage IIB nonbulky tumors treated with irradiation alone or combined with surgery, the 5- and 10-year CCS rates were 72 and 65%, respectively; the corresponding survival rates with bulky tumors or bilateral parametrial involvement were 56 and 50%. Incidence of pelvic failures, alone or with distant metastasis, for Stage IB was 10% (43 out of 415) with irradiation alone and 14% (28 of 197) with irradiation plus surgery; for Stage IIA, 17% (23 out of 137) with irradiation alone and 20% (9 our of 44) with irradiation plus surgery; and for Stage IIB, 23% (88 out of 391) with irradiation alone and 29% (4 out of 14) with irradiation plus surgery. Grade 3 sequelae were comparable in both groups (irradiation alone, 5% to 11%; irradiation combined with surgery, 8% to 12%); the differences are not statistically significant. The most frequent major sequelae in 892 patients receiving irradiation only were rectovaginal fistula (13 cases, 1.5%), proctitis (10, 1.1%), small bowel obstruction (16, 1.8%), ureteral stricture (16, 1.8%), and vesicovaginal fistula (8, 0.9%). In 306 patients treated with irradiation plus surgery, the most commonly recorded major sequelae were small bowel obstruction/perforation (13 cases, 4.2%), ureteral stricture (8, 2.6%), vesicovaginal fistula (5, 1.6%), and rectovaginal fistula (4, 1.3%).

CONCLUSION

Irradiation alone or combined with surgery yields comparable pelvic tumor control, survival, and morbidity in patients with Stage IB, IIA, and limited IIB carcinoma of the uterine cervix.

Conventional four-field pelvic radiotherapy technique without computed tomography-treatment planning in cancer of the cervix: potential geographic miss and its impact on pelvic control

PURPOSE

To evaluate the impact of inadequate margins on pelvic control using the conventional four-field pelvic portals without computed tomography (CT)-treatment planning.

METHODS AND MATERIALS

Between 1986 and 1991, 34 patients with invasive cancer of the cervix were eligible for outcome study of conventional four-field radiation therapy (10 Stage I, 16 Stage II, 8 Stage III). The eligibility for this study includes four-field pelvic technique, definitive radiation therapy, and diagnostic CT scan of the pelvis. For this study, an inadequate margin is arbitrarily defined as < or = 1.0 cm of normal tissue around the CT-defined tumor volume.

RESULTS

All 34 patients had adequate margins for anterio-posterior/posterio-anterior portals. However, 19 patients had an inadequate margin at the posterior border (S2-S3 interspace) and/or custom-shaped rectal block for lateral pelvic portals. Two patients had inadequate margins at the anterior border (level of symphysis pubis) due to an enlarged uterus. With a median follow-up of 36 months, pelvic control for adequate margins and inadequate margins was 100% and 71% for Stage IB disease and 88% and 50% for Stage IIB disease, respectively. However, pelvic control for Stage IIIB disease was 50% for both groups. There was no difference in total dose to point A or point B between the two groups.

CONCLUSION

Our preliminary data show higher local failure in patients with an inadequate margin. For four-field pelvic radiation therapy, we strongly recommend CT-treatment planning. Otherwise, anterio-posterior/posterio-anterior pelvic therapy is the most reliable treatment for cancer of the uterine cervix.

Conventional four-field pelvic radiotherapy technique without CT treatment planning in cancer of the cervix: potential geographic miss

The advantage of 4-field radiation to the pelvis is the use of lateral ports which spare the small bowel anteriorly and a portion of the rectum posteriorly from radiation. However, guidelines for the lateral pelvic ports are poorly defined. This is a comparative analysis to determine adequate margins by correlating conventional lateral pelvic treatment portals with CT defined tumor volume. The study included 52 patients treated definitively for carcinoma of the uterine cervix between 1986 and 1991. The most common site of inadequate margin (< or = 1.0 cm) was at the rectal block. The incidence of inadequate margin ranged from 39% to 50% and was independent of the stage of the disease except non-bulky stage IB disease. The next most common site was at the posterior border where frequency of inadequate margin for cervical tumor depended on stage with 8% of stage IB, 27% of stage IIB and 22% of stage IIIB/IVA disease. For the anterior border, an enlarged uterus was the only reason for inadequate margin rather than cervical tumor in 8% of stage IB, 18% of stage IIB, and 27% of stage IIIB/IVA disease. Without knowledge of precise tumor volume, the 4-field pelvic technique is potentially dangerous, risking underdosing of the tumor volume. For 4-field pelvic radiotherapy, we strongly recommend CT treatment planning.

Continuous or split-course combined external and intracavitary radiotherapy of locally advanced carcinoma of the uterine cervix

From 1974 to 1984, 442 consecutive patients with carcinoma of the uterine cervix (FIGO IIB: 139, IIIA:10, IIIB:221, IVA:72) were referred for combined intracavitary (IRT) and external radiotherapy (ERT). To improve local control and reduce late rectosigmoid morbidity the treatment strategy was changed from continuous (CRT) to split-course radiotherapy (SCRT) in 1978. Stage by stage the 5-year actuarial estimates of survival, local control, and late morbidity did not differ in relation to strategy. In the patients with tumours larger than 8 cm, the SCRT involved an increased dose in point B, a reduced dose in point A from the IRT, a lower total dose in point A, and a 34 days' prolongation of the total treatment time (TTT). The resulting 5-year actuarial local control rates were significantly lower compared with those after CRT. No difference of late severe morbidity was found except in IVA patients. In the patients with tumours between 4 and 8 cm, the SCRT involved a reduced dose in point A from the IRT, an increased total dose in point A and B, and a 50 days' prolongation of the TTT. In patients with stage IIB, the 5-year actuarial central local control rate was lower (p = 0.06), and the 5-year estimate of late severe morbidity significantly higher after SCRT compared with CRT. It is concluded that the increase of the dose in point B in the SCRT was insufficient to prevent the deleterious effect on local tumour control of either the lower dose from IRT in point A, or the prolonged TTT. The increase of the total dose in the SCRT may explain why the late morbidity was not reduced, and may suggest that the TTT is of no significant importance for the risk of late normal tissue damage.

Three-dimensional treatment planning of intracavitary gynecologic implants: analysis of ten cases and implications for dose specification

PURPOSE

Results of 3-dimensional treatment planning for ten intracavitary gynecologic implants and implications for dose specification are presented.

METHODS AND MATERIALS

Using a computed tomographic (CT) compatible intracavitary applicator we have performed CT scans during gynecologic brachytherapy in 10 cases. A CT-based treatment planning system with 3-dimensional capabilities was used to calculate and display dose in three dimensions. Conventional point doses including the estimated bladder and rectal maximum doses and dose to Point A were acquired from orthogonal simulation films. CT maximum bladder and rectal doses and minimum cervix doses were ascertained from isodose lines displayed on individual CT images. Dose volume histograms for the bladder, rectum and cervix were generated and used to obtain volume of the cervix target volume receiving less than the prescribed dose and the volume of bladder and rectum receiving more than the orthogonal maximum doses. The 5 cc volume of bladder and rectum receiving the highest dose were also calculated.

RESULTS

Average values of CT point doses and volumes are compared with the traditionally obtained doses. As demonstrated by others, much higher bladder and rectal doses are found using the CT information. The minimum dose to the cervix target volume is lower than the dose to Point A in each case. CT maximum bladder and rectum and minimum cervix target doses may not be the best index doses to correlate with outcome because of the small volumes receiving the dose.

CONCLUSION

We hypothesize that clinically useful bladder, rectal and cervix target volume doses will include volume information which is obtainable with dose volume histogram analysis.

Results of treatment in stage IIB squamous cell carcinoma of the uterine cervix: comparison between two and one intracavitary insertion

To compare the results of treatment in stage IIB squamous cell carcinoma of the uterine cervix of two treatment regimens, two radium insertions vs one insertion, a prospective randomized study was carried out at Ramathibodi Hospital from 1 January 1983 to 31 December 1986, and the results were evaluated at the end of March 1991. The patients in treatment I (90 cases) received 40-41.4 Gy whole pelvic external irradiation and two intracavitary radium insertions, while patients in treatment II (53 cases) received 50.0-50.4 Gy and one intracavitary insertion. Both groups received the same total dose at point A, about 85-90 Gy. At 4 and 5 years, by the Kaplan-Meier survival curve, the disease-free survivals were 76 and 76% vs 79 and 79%, respectively, in treatment I and treatment II, which showed no significant difference by the log-rank test. Both groups had comparable serious complication rates, 0% vs 1.9%, respectively. However, grade I complications in treatment II, 35.8%, were higher than those in treatment I, 17.8% (P less than 0.01). Therefore, we concluded that treatment II provided the same disease-free survival and a very low rate of serious complications. To replace treatment I, the dose at the rectum and urinary bladder should be maintained with caution.

Optimization of high dose-rate cervix brachytherapy; Part I: Dose distribution

Computer controlled high dose-rate (HDR) brachytherapy afterloading machines are equipped with a single, miniaturized, high activity Ir-192 source that can be rapidly moved in fine increments among several channels. Consequently, by appropriate programming of source dwell positions and times, the dose distribution can be optimized as desired. We have explored the optimization potential of this new technology for two applications: (a) cervix brachytherapy, and (b) transvaginal irradiation. Cervix brachytherapy with a gynecologic ring applicator was simulated by 48 sources of relative activities ranging from 0.17 to 1.00 that were equally distributed between the tandem and the ring. The results confirmed that the optimized distribution of physical doses are superior to those achievable with standard brachytherapy sources and applicators. For example, with five-point optimization, the relative dose-rate in the rectum was only 47% of that in point A; for standard application the dose rate was 47% higher. For transvaginal application 27 sources of relative activities between 0.07-0.79 were placed in the ring and a single source of unit strength in the tandem. Using dose distribution homogeneity as an optimization criterion, the results (+/- 2.5%) were again superior to those obtained for commonly used double ovoid (+/- 15%), linear cylinder (+/- 27%), or a "T" source (31%).

Impact of dose in outcome of irradiation alone in carcinoma of the uterine cervix: analysis of two different methods

This is a retrospective analysis of 1211 patients with histologically proven invasive carcinoma of the uterine cervix with a minimum follow-up of 3 years treated with irradiation alone. The pelvic failure rates by stage were 9.6% for IB, 18.6% for IIA, 23% for IIB, 41% for III, and 75% for Stage IVA disease. External beam and intracavitary irradiation doses to point A and pelvic lymph nodes were calculated. In patients with Stage IB and IIA disease there was no significant correlation between doses to these points and pelvic tumor control. In Stage IIB doses of less than 6000 cGy to point A correlated with a high pelvic failure rate (8 of 12, 66.7%) in contrast to doses of 6000 to 9000 cGy (61 of 261, 23.4%) or higher than 9000 cGy (10 of 74, 13.5%) (p less than or equal to 0.01). In Stage III the pelvic failure rate with doses below 6000 cGy to point A was 72% (18 of 25) compared to 39% (71 of 180) for 6000 to 9000 cGy or 35% (27 of 77) with doses above 9000 cGy (p less than or equal to 0.01). TDF calculation of doses was carried out. In Stage IB and IIA there was no significant correlation between TDF to point A and probability of pelvic recurrence. In Stage IIB with TDF below 135, the pelvic recurrence rate was 41.6% (20 of 48) compared to 20% (61 of 305) with higher TDF (p less than or equal to 0.01). In Stage III the pelvic failure rate was 51% with TDF below 160 (70 of 136) in comparison with 29.5% (46 of 156) with higher TDF (p less than or equal to 0.01). Grade 2 sequelae of therapy were noted in about 10% of the patients and grade 3 in 4.7% of patients with Stage IB (18 of 384), 10.2% (12 of 128) with Stage IIA, 9.3% (33 of 353) with Stage IIB, and 8.2% (24 of 293) with Stage III disease. Doses from external beam and intracavitary irradiation to the rectum or the bladder neck were calculated. The actuarial incidence of major rectal or rectosigmoid sequelae was 2% to 4% with doses to the rectum of 6000 to 8000 cGy, 7% to 8% with 8000 to 9500 cGy, and 13% with doses higher than 9500 cGy (p less than or equal to 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

High dose rate afterloading intracavitary therapy in carcinoma of the cervix

From January 1984 through December 1986, 87 patients with previously untreated carcinoma of the cervix received external beam pelvic irradiation and high dose rate intracavitary therapy (HDRT). There were 18 Stage IIA patients, 39 Stage IIB, and 30 Stage IIIB. The median age was 60 years and the median follow-up time was 42 months for patients at risk. Radiotherapy consisted of external megavoltage irradiation to the whole pelvis (median dose 4600 cGy) combined with one (6 patients), two (51 patients), or three (30 patients) HDRT insertions. A high dose rate remote afterloading unit with 60Co sources was used to deliver the HDRT. The prescribed dose to point A was between 800 and 1000 cGy per treatment. The dose rate at point A initially was approximately 150 cGy/min and dropped to approximately 100 cGy/min during the duration of the study. Treatments with multiple fractions were given at weekly intervals. The overall actuarial survival at 5 years was 88% for Stage IIA, 64% for Stage IIB and 32% for Stage IIIB patients. Pelvic recurrence remained the major cause of failure. Grade III and IV late complications included proctitis and bowel obstruction in six patients each. We conclude that HDRT results are similar to those obtained with conventional low dose rate intracavitary systems. HDRT is cost effective and minimizes exposure to personnel. Several questions, such as the total number of insertions required, dose per HDRT insertion, and optimal HDRT insertion schedule remain unanswered and further experience is needed to better clarify these issues.