HDR versus LDR gynecological brachytherapy revisited

High-Dose-Rate Brachytherapy in Cervical and Endometrial Cancer Patients: A Retrospective Study From a Tertiary Cancer Center in the UAE

Purpose This study evaluates the therapeutic outcomes and practical application of high-dose-rate (HDR) brachytherapy in managing cervical and endometrial cancers at a tertiary hospital in the UAE, focusing on treatment efficacy, safety, and patient-reported outcomes. Methods A retrospective analysis was conducted on 368 female patients treated between January 2008 and January 2022. Data included demographic information, cancer type, histopathology, treatment details, and survival outcomes. Statistical analyses were performed using descriptive and inferential statistics. Results The cohort comprised 275 cervical cancer patients (74.73%) and 93 endometrial cancer patients (25.27%). The majority were non-nationals (79.62%). The mean age was 57 years. Squamous cell carcinoma was the most common histopathological type (63.59%). HDR brachytherapy was administered to 290 patients (79.89%). The 12-month survival probability was significantly higher in the HDR-Brachy group (75%, 95% CI: 60% to 85%) compared to the noHDR-Brachy group (50%, 95% CI: 35% to 65%), with a hazard ratio of 0.953 (p=0.0035). At the last review, 86.68% of patients were alive, and disease progression was observed in 37.88% of patients. Conclusion HDR brachytherapy significantly improves survival outcomes in cervical and endometrial cancer patients. Continued efforts to enhance access and standardize brachytherapy protocols are essential to optimize treatment efficacy and patient outcomes in similar healthcare settings.

AAPM medical physics practice guideline 13.a: HDR brachytherapy, part A

The American Association of Physicists in Medicine (AAPM) is a nonprofit professional society whose primary purposes are to advance the science, education, and professional practice of medical physics. The AAPM has more than 8000 members and is the principal organization of medical physicists in the United States. The AAPM will periodically define new practice guidelines for medical physics practice to help advance the science of medical physics and to improve the quality of service to patients throughout the United States. Existing medical physics practice guidelines (MPPGs) will be reviewed for the purpose of revision or renewal, as appropriate, on their fifth anniversary or sooner. Each medical physics practice guideline represents a policy statement by the AAPM, has undergone a thorough consensus process in which it has been subjected to extensive review, and requires the approval of the Professional Council. The medical physics practice guidelines recognize that the safe and effective use of diagnostic and therapeutic radiology requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guidelines and technical standards by those entities not providing these services is not authorized. The following terms are used in the AAPM practice guidelines: (1) Must and must not: Used to indicate that adherence to the recommendation is considered necessary to conform to this practice guideline. (2) Should and should not: Used to indicate a prudent practice to which exceptions may occasionally be made in appropriate circumstances. Approved by AAPM's Executive Committee April 28, 2022.

Endoluminal High-Dose-Rate Brachytherapy with a Palliative aim in Esophageal Cancer: Preliminary Results at the Institut Gustave Roussy

Ten patients with advanced esophageal carcinoma were treated with endoluminal high-dose-rate brachytherapy at the Institut Gustave Roussy. Eight of them had recurrences after external beam radiotherapy. They were treated with a high-dose rate iridium-192 source. Five patients received 6 sessions of 4 Gy, 4 patients 3 sessions of 4 Gy, and 1 patient received 3 sessions of 8 Gy. The interval time between each session was 1 week. Seventy percent of patients improved their dysphagia, with 80% endoscopic tumor response. The Karnofsky index was improved in most of the patients. The mean survival was 4 months, and dysphagiafree survival was 2.5 months. Two patients had treatment toxicity but only a transitory WHO G1 esophagitis. Endoesophageal high-dose-rate curietherapy seems an effective technique in palliative treatments. We found low toxicity and an excellent tolerance to treatment in previously irradiated patients. The efficacy of the treatment is highly dependent on a precise tumor volume evaluation.

Dedicated high dose rate 192Ir brachytherapy radiation fields for in vitro cell exposures at variable source-target cell distances: killing of mammalian cells depends on temporal dose rate fluctuation

Afterloading brachytherapy is conducted by the stepwise movement of a radioactive source through surgically implanted applicator tubes where at predefined dwell positions calculated dwell times optimize spatial dose delivery with respect to a planned dose level. The temporal exposure pattern exhibits drastic fluctuations in dose rate at a given coordinate and within a single treatment session because of the discontinuous and repeated source movement into the target volume. This could potentially affect biological response. Therefore, mammalian cells were exposed as monolayers to a high dose rate 192Ir source by utilizing a dedicated irradiation device where the distance between a planar array of radioactive source positions and the plane of the cell monolayer could be varied from 2.5 mm to 40 mm, thus varying dose rate pattern for any chosen total dose. The Gammamed IIi afterloading system equipped with a nominal 370 GBq (10 Ci) 192-Ir source was used to irradiate V79 Chinese hamster lung fibroblasts from both confluent and from exponential growth phase with dose up to 12 Gy (at room temperature, total exposure not exceeding 1 h). For comparison, V79 cells were also exposed to 6 MV x-rays from a clinical linear accelerator (dose rate of 2.5 Gy min-1). As biological endpoint, cell survival was determined by standard colony forming assay. Dose measurements were conducted with a diamond detector (sensitive area 7.3 mm2), calibrated by means of 60Co radiation. Additionally, dose delivery was simulated by Monte Carlo calculations using the EGSnrc code system. The calculated secondary electron fluence spectra at the cell location did not indicate a significant change of radiation quality (i.e. higher linear energy transfer) at the lower distances. Clonogenic cell survival curves obtained after brachytherapy exhibited an altered biological response compared to x-rays which was characterized by a significant reduction of the survival curve shoulder when dose rate fluctuations were high. Therefore, also for the time scale of the present investigation, cellular effects of radiation are not invariant to the temporal pattern in dose rate. We propose that with high dose rate variation the cells activate less efficiently their DNA damage response than after continuous irradiation.

Changes in applicator positions and dose distribution between high dose rate brachytherapy fractions in cervix carcinoma patients receiving definitive radiotherapy

This study examines the change of applicator geometry and its effect on rectal/rectum (R) and bladder (B) doses, and obtained radiobiological equivalent doses (RED), between each high dose rate (HDR) brachytherapy (BT) fraction in cervical carcinoma patients. BT using a tandem (T) and two ovoids (O) is included, and any discrepancies in applicator positions among the fractions were calculated. Whether the change of applicator position had an effect on the calculated R and B doses was analysed. Furthermore, the relationship between the size of tumour, the magnitude of displacement and the change in R and B doses was also investigated. Lastly, the changes in R and B RED were noted. The average magnitude of displacement was between 2.0 mm and 16.9 mm, showing time trend. There was no relationship between tumour size and the magnitude of discrepancy of Left O, Right O, T, R, B, and neither change in R and B doses (p>0.05). The mean differences of R and B doses were between 49-78 cGy, and 70-84 cGy, respectively. The magnitude of discrepancy and changes in doses showed no correlation (p>0.05). There were no significant differences in REDs for bladder (p = 0.8) and rectum (p = 0.2). In conclusion, there were significant differences in the applicator positions R and B and R and B doses among the fractions, which confirm the necessity of treatment planning in each HDR BT fraction. However, the total calculated R and B REDs did not show a remarkable difference.

Low-dose-rate brachytherapy is superior to high-dose-rate brachytherapy for bladder cancer

PURPOSE

To determine the efficacy and safety of a high-dose-rate (HDR) brachytherapy schedule in the treatment of bladder cancer and to investigate the impact of different values of repair half-times and alpha/beta ratios on the design of the HDR schedule.

METHODS AND MATERIALS

Between 2000 and 2002, 40 patients with T1G3 and T2 bladder carcinoma were treated with 30 Gy external beam radiotherapy followed by interstitial HDR brachytherapy to a total dose of 32 Gy in 10 sessions of 3.2-Gy fractions in two fractions daily with a 6-h interfraction interval. The local control rate and toxicity were compared with a historical group of 108 patients treated with 30 Gy external beam radiotherapy followed by 40-Gy interstitial low-dose-rate (LDR) brachytherapy. The HDR schedule was designed to be biologically equivalent to the previously used LDR schedule with the linear-quadratic model, including incomplete mono-exponential repair.

RESULTS

The local control rate at 2 years was 72% for HDR vs. 88% for LDR brachytherapy (p = 0.04). In the HDR group, 5 of 30 evaluable patients encountered serious late toxicity: 4 patients developed a contracted bladder with inadequate capacity (<100 mL), and 1 patient required cystectomy because of a painful ulcer at the implant site. In the LDR group, only 2 of 84 assessable patients developed serious late toxicity. One patient developed a persisting vesicocutaneous fistula and the other a urethral stricture due to fibrosis. The difference in observed late toxicity for HDR vs. LDR was statistically significant (p = 0.005). The increased late toxicity with the HDR schedule compared with the LDR schedule suggests a short repair half-time of 0.5-1 h for late-responding normal bladder tissue.

CONCLUSION

Local control of HDR brachytherapy for bladder cancer was disappointing and late toxicity unexpectedly high. The increase in late toxicity suggested a short repair half-time of 0.5-1 h for late-responding normal bladder tissue, which would not support HDR brachytherapy in the treatment of bladder cancer. The analysis demonstrated that the calculation of equivalent HDR schedules on the basis of the LDR schedules used in clinical practice might be hazardous.

Amifostine in clinical oncology: current use and future applications

Amifostine (Ethyol), an inorganic thiophosphate, is a selective broad-spectrum cytoprotector of normal tissues that provides cytoprotection against ionizing radiation and chemotherapeutic agents, thus preserving the efficacy of radiotherapy and chemotherapy. This review summarizes the preclinical data and clinical experience with amifostine, and provides insight into future clinical directions. Amifostine, an inactive pro-drug, is transformed to an active thiol after dephosphorylation by alkaline phosphatase found in the normal endothelium. The absence of alkaline phosphatase in the tumoral endothelium and stromal components, and the hypovascularity and acidity of the tumor environment, may explain its cytoprotective selectivity. The cytoprotective mechanism of amifostine is complicated, involving free radical scavenging, DNA protection and repair acceleration, and induction of cellular hypoxia. Intravenous administration of amifostine 740-900 mg/m(2) before chemotherapy and 250-350 mg/m(2) before each radiotherapy fraction are widely used regimens. The US Food and Drug Administration has approved the use of amifostine as a cytoprotector for cisplatin chemotherapy and for radiation-induced xerostomia. Ongoing trials are being conducted to determine the efficacy of amifostine in reducing radiation-induced mucositis and other toxicities. Novel schedules and routes of administration are under investigation, and may further simplify the use of amifostine and considerably broaden its applications.

Clinical use of a non-isocentric C-arm unit for on-line filmless reconstruction of brachytherapy applicators

PURPOSE

In this paper it is described how a mobile non-isocentric C-arm can be used to reconstruct brachytherapy applicators using an 'isocentric' imaging set-up without using an orthogonal reconstruction box.

METHODS

The images are on-line digitally transferred to the treatment planning system. In order to determine the physical dimensions of the C-arm a simple method is presented that makes use of the relation between the magnification factor and the translational degrees of freedom of the C-arm. A phantom has been used to determine the overall reconstruction accuracy.

RESULTS

The accuracy in the reconstruction of the distance between two points is better than 2 mm when using radiographs. If digital images are used the maximum error in reconstructed distances equals 3.6 mm for points located in the corners of the field of view, whereas in the central part of the field the errors are less than 2 mm.

High-dose-rate brachytherapy may be radiobiologically superior to low-dose rate due to slow repair of late-responding normal tissue cells

BACKGROUND AND PURPOSE

Recent analysis of morbidity for patients treated with the continuous hyperfractionated accelerated radiotherapy (CHART) regimen demonstrates that repair half-times for late-reacting normal tissue cells are of the order of 4-5 h, which is considerably longer than previously believed. This would reduce repair of these tissue cells during a course of low-dose rate (LDR) brachytherapy, but have no effect at high-dose-rate (HDR), where there is no repair during, and full repair between fractions, regardless of repair half-time. The effect this has upon radiobiologic comparison of LDR and HDR is the topic of this paper.

METHODS AND MATERIALS

The linear-quadratic (L-Q) model is used to compare late-effect biologically effective doses (BEDs) of LDR and HDR, for constant BED (tumor). The effects of dose rate (for LDR), fractionation (for HDR), and geometrical sparing of normal tissues are all considered. Repair half-times observed in the CHART study are used to investigate the potential impact of long repair times on the comparison of LDR and HDR.

RESULTS

It is demonstrated that, for a repair half-time of 1.5 h for tumor cells, if the half-time for repair of late-reacting normal tissue cells exceeds about 2.5 h, LDR becomes radiobiologically inferior to HDR. Even with the least HDR-favorable combinations of parameters, HDR at over about 5 Gy/fraction ought to be radiobiologically superior to LDR at 0.5 Gy/h, so long as the time between HDR fractions is long compared to the repair half time. It is also shown that any geometrical sparing of normal tissues will benefit HDR more than LDR.

CONCLUSION

The previously held belief that LDR must be inherently superior radiobiologically to HDR is wrong if the long repair times demonstrated in the recent CHART study are applicable to other late-reacting normal tissues. This could explain why HDR has been so successful in clinical practice, especially for the treatment of cervical cancer, despite previous convictions of radiobiologic inferiority of this modality.

Single dose irradiation response of pig skin: a comparison of brachytherapy using a single, high dose rate iridium-192 stepping source with 200 kV X-rays

An experimental brachytherapy model has been developed to study acute and late normal tissue reactions as a tool to examine the effects of clinically relevant multifractionation schedules. Pig skin was used as a model since its morphology, structure, cell kinetics and radiation-induced responses are similar to human skin. Brachytherapy was performed using a microSelectron high dose rate (HDR) afterloading machine with a single stepping source and a custom-made template. In this study the acute epidermal reactions of erythema and moist desquamation and the late dermal reactions of dusky mauve erythema and necrosis were evaluated after single doses of irradiation over a follow-up period of 16 weeks. The major aims of this work were: (a) to compare the effects of iridium-192 (192Ir) irradiation with effects after X-irradiation; (b) to compare the skin reactions in Yorkshire and Large White pigs; and (c) to standardize the methodology. For 192Ir irradiation with 100% isodose at the skin surface, the 95% isodose was estimated at the basal membrane, while the 80% isodose covered the dermal fat layers. After HDR 192Ir irradiation of Yorkshire pig skin the ED50 values (95% isodose) for moderate/severe erythema and moist desquamation were 24.8 Gy and 31.9 Gy, respectively. The associated mean latent period (+/- SD) was 39 +/- 7 days for both skin reactions. Late skin responses of dusky mauve erythema and dermal necrosis were characterized by ED50 values (80% isodose) of 16.3 Gy and 19.5 Gy, with latent periods of 58 +/- 7 days and 76 +/- 12 days, respectively. After X-irradiation, the incidence of the various skin reactions and their latent periods were similar. Acute and late reactions were well separated in time. The occurrence of skin reactions and the incidence of effects were comparable in Yorkshire and Large White pigs for both X-irradiation and HDR 192Ir brachytherapy. This pig skin model is feasible for future studies on clinically relevant multifractionation schedules in a brachytherapy setting.

Bilateral radical radiotherapy in a patient with uterus didelphys

We report a case of congenital abnormality of uterus didelyphys in a patient who developed invasive carcinoma of the cervix. She received radical radiotherapy by a combination of external beam pelvic radiotherapy and high dose rate brachytherapy by insertion of afterloading catheters into both uterine canals. A newly defined prescription point was used midway between the two catheters and 2 cm above the mean cervical os position. The classical point A was regarded as inappropriate in this patient with a rare condition. Acute toxicity was minor and the patient is tumour free with no significant normal tissue late effects after follow-up of nearly 3 years.

Treatment results and prognostic factors in inoperable carcinoma of the cervix treated with external plus high dose brachytherapy

Patients with inoperable carcinoma of the cervix treated with external plus high dose rate brachytherapy (HDRB), between 1988 and 1995 were evaluated retrospectively. According to stage, 5 year survival rates were 67.3% in stage IIb and 52.6% in stage III (P = 0001) and disease free survival (DFS) rates were 54.0% in stage IIb and 43.9% in stage III (P = 0.01). The following parameters were studied: age; stage; external beam dose; brachytherapy dose; total dose to point A; tumor mass; tumor response rate; bilateral or unilateral invasion of parametria in stage IIb; and bilateral or unilateral invasion of pelvic wall in stage IIIb; and the existence of hydronephrosis. The only significant parameter of 5 year survival and local control was tumor mass (P = 0.003).

The clinical radiobiology of brachytherapy

The unique geometrical features of brachytherapy, together with the wide variety of temporal patterns of dose delivery, result in important interactions between physics and radiobiology. These interactions exert a major influence on the way in which brachytherapy treatments should be evaluated, both in absolute and comparative terms. This article reviews the main physical and radiobiological aspects of brachytherapy and considers examples of their influence on specific types of treatment. The issues relating to the optimization of high dose rate brachytherapy are presented, together with the implications of multiphasic repair kinetics for low dose-rate and pulsed high dose rate brachytherapy. The opportunities for application of radiobiological principles to improve various brachytherapy techniques, together with the integration of brachytherapy with teletherapy, are also outlined. Equations for the numerical evaluation of brachytherapy treatments are presented in the Appendices.

Late complications after postoperative radiotherapy in endometrial cancer: analysis of 317 consecutive cases with application of linear-quadratic model

PURPOSE

To evaluate the incidence and risk factors for late complications after postoperative radiotherapy in endometrial cancer patients.

METHODS AND MATERIAL

We performed a detailed retrospective analysis of 317 endometrial cancer patients given postoperative radiotherapy. A total of 247 patients (78%) received both intracavitary (BRT) and external beam irradiation (XRT); 49 patients (15%) received only BRT, and 21 (7%) only XRT. BRT included radium (Ra) and cesium (Cs). The mean dose rate for both isotopes at 0.5 cm from the applicator surface was 0.47 +/- 0.06 and 1.42 +/- 0.41 Gy/h, and the mean total dose was 50.5 +/- 10.3 and 48.4 +/- 15.0 Gy, respectively. Mean BRT dose at 0.5 cm was 50.1 +/- 11.7 Gy (range 14.5-71.0). Mean XRT dose in the International Commission on Radiation Units and Measurements (ICRU) reference point was 49.0 +/- 3.7 Gy (range 22.0-66.0) given in fractions of 1.54-2.49 Gy (mean 2.0 +/- 0.17) with a two- or four-field technique. Follow-up ranged from 4 to 21 years (median 7.3). Normalized total dose (NTD) including XRT and BRT doses was calculated based on a linear quadratic equation.

RESULTS

Five-year overall survival rate was 75%, and 5-year disease-free survival (censored for noncancer deaths) was 81%. Late radiotherapy complications of any grade occurred in 158 patients (51%), including bowel complications in 41% and urinary bladder complications in 21%. A total of 37 grade 3 or 4 complications were observed in 33 patients (11%), of whom 32 were treated with both XRT and BRT. Severe bowel and/or urinary bladder complications occurred in 24 patients: in 14 of 72 patients (19.4%) who received XRT and Cs BRT, and in 10 of 172 patients (6.0%) applied XRT and Ra BRT. The higher proportion of severe bowel and/or bladder complications in the former group was due to the particularly frequent rate of these events (30.0%) in a subset of 47 patients who received XRT combined with Cs BRT at the dose rate of 1.7 Gy/h and the total BRT dose of 60 Gy. Higher NTD, XRT fraction dose, BRT dose rate, Cs BRT, two-field XRT technique, short overall radiotherapy time, and older age were correlated with increased late-event risk in univariate analysis. Multivariate Cox analysis demonstrated that the independent risk factors for late bowel complications were NTD (p = 0.000) and BRT dose rate (p = 0.036), whereas for bladder complications they were BRT dose rate (p = 0.005) and XRT fraction dose (p = 0.041). Neither clinical factor (age, parity, prior abdominal surgery, FIGO stage, diabetes mellitus, or hypertension) nor the surgery-to-radiotherapy interval, nor overall radiotherapy time was independently associated with the risk of late bladder or bowel complications.

CONCLUSIONS

The risk of late complications after postoperative radiotherapy in endometrial cancer depends mainly on treatment-related factors: NTD, BRT dose rate, and XRT fraction dose. The use of combined XRT and BRT increases the risk of late effects. NTD calculations including BRT dose rate and XRT fraction dose enable estimation of radiobiologically equivalent dose and can decrease the risk of mistakes when the radiotherapy regimen is changed.

Modern brachytherapy: current state and future prospects

This article reviews the current trends and future developments in brachytherapy. Established techniques including interstitial and high-dose rate brachytherapy are discussed with particular reference to lung, oesophageal, cervical and endometrial cancer. Intra-operative high-dose rate brachytherapy and other new techniques are also mentioned.

Calculation of integrated biological response in brachytherapy

PURPOSE

To present analytical methods for calculating or estimating the integrated biological response in brachytherapy applications, and which allow for the presence of dose gradients.

METHODS AND MATERIALS

The approach uses linear-quadratic (LQ) formulations to identify an equivalent biologically effective dose (BEDeq) which, if applied to a specified tissue volume, would produce the same biological effect as that achieved by a given brachytherapy application. For simple geometrical cases, BED multiplying factors have been derived which allow the equivalent BED for tumors to be estimated from a single BED value calculated at a dose reference point. For more complex brachytherapy applications a voxel-by-voxel determination of the equivalent BED will be more accurate. Equations are derived which when incorporated into brachytherapy software would facilitate such a process.

RESULTS

At both high and low dose rates, the BEDs calculated at the dose reference point are shown to be lower than the true values by an amount which depends primarily on the magnitude of the prescribed dose; the BED multiplying factors are higher for smaller prescribed doses. The multiplying factors are less dependent on the assumed radiobiological parameters. In most clinical applications involving multiple sources, particularly those in multiplanar arrays, the multiplying factors are likely to be smaller than those derived here for single sources. The overall suggestion is that the radiobiological consequences of dose gradients in well-designed brachytherapy treatments, although important, may be less significant than is sometimes supposed. The modeling exercise also demonstrates that the integrated biological effect associated with fractionated high-dose-rate (FHDR) brachytherapy will usually be different from that for an "equivalent" continuous low-dose-rate (CLDR) regime. For practical FHDR regimes involving relatively small numbers of fractions, the integrated biological effect to tissues close to the treatment sources will be higher with HDR than for LDR. Conversely, the integrated biological effect on structures more distant from the sources will be less with HDR. This provides quantitative confirmation of an idea proposed elsewhere, and suggests the existence of a potentially useful biological advantage for HDR brachytherapy delivered in relatively small fraction numbers and which is not apparent when considering radiobiological effect only at discrete reference points.

CONCLUSION

The estimation and direct calculation of integrated biological response in brachytherapy are both relatively straightforward. Although the tabular data presented here result from considering only simple geometrical cases, and may thus overestimate the consequences of dose gradients in multiplanar clinical applications, the methods described may open the way to the development of more realistic radiobiological software, and to more systematic approaches for correlating physical dose and biological effect in brachytherapy.

Intrauterine high dose rate afterloading brachytherapy: experience of fractionated therapy using a cervical sleeve technique

Using a standard three-channel Manchester-type tube and ovoid high dose rate applicator system, 46 consecutive patients have been treated for carcinoma of the cervix or endometrium. To facilitate fractionated treatments using high dose rate afterloading, a technique has been developed using an indwelling cervical sleeve inserted under an initial general anaesthetic. All patients received at least two insertions; in five patients we have delivered a total of six consecutive fractions on an outpatient basis without anaesthesia once the sleeve was in situ. Acute morbidity related to the procedure was some degree of uterine pain, which was relieved with nitrous oxide inhalation, and mild, but self-limiting, vaginal discharge. Complete late morbidity data are not yet available, but, in 30% of 25 evaluable patients, minor problems have been observed, particularly vaginal oedema and stenosis. Only one major late event has required surgery. Fractionated afterloading intrauterine brachytherapy can be delivered on an outpatient basis without anaesthesia using this cervical sleeve technique.

Case report: low dose rate and high dose rate intracavitary brachytherapy in a patient with carcinoma of the cervix

The role of low dose rate (LDR) intracavitary radiotherapy in the management of carcinoma of the uterine cervix is well established. However, there are selected groups of patients in whom high dose rate (HDR) intracavitary radiotherapy may have particular advantages. A case report of a patient with carcinoma of the cervix who received both LDR and HDR intracavitary radiotherapy is presented. A comparison of the normal tissue doses produced by the two forms of brachytherapy is made. The choice of dose for the HDR treatment was calculated using standard linear quadratic isoeffect equations. The relative clinical merits of LDR and HDR treatments in gynaecological cancer are discussed.

Cervical cancer (cervix uteri)

This synthesis of the literature on radiotherapy for cervical cancer (cervix uteri) is based on 59 scientific articles, including 8 randomized studies, 1 prospective study, and 36 retrospective studies. These studies involve 34,024 patients. Due to favorable anatomy and exceptionally good radiation tolerance of nearby pelvic organs, particularly the uterus, radiotherapy has become the dominant treatment method for cervical cancer. Surgery alone is used at the earliest stages where small tumor volumes are involved. Further pathological findings, where cancer is more extensive than expected preoperatively, or when lymph node metastases are discovered, motivate postoperative radiotherapy even at early stages. There is general agreement that advanced cervical cancer should be treated by radiotherapy alone. Clinical trials are under way that combine radiotherapy and chemotherapy, and even surgery. Two different methods of intracavitary brachytherapy are currently in use, low-dose rate therapy and high-dose rate therapy. High-dose rate therapy appears to be economically more favorable. The possibility of higher risks for later complications associated with high-dose rate therapy has not been fully studied.

Patient preference for high or low dose rate brachytherapy in carcinoma of the cervix

High and low dose rate are two competing methods of brachytherapy. Existing data do not support choosing one method over the other for treating carcinoma of the uterine cervix. Arguments include clinical efficacy, monetary cost, radiation safety, and patient preference. There are no published data on patient preference. We developed a questionnaire to elicit patient preference and to measure its strength. Subjects received descriptions of both treatment options and their probable outcomes. We elicited preference for one low or three high dose rate fractions, and for two low or five high dose rate fractions, assuming both methods to be isoeffective. Strength of initial preference was measured by asking subjects how much of a change, in either the changes for cure or the chances for toxicity, would make them change preference. The questionnaire was completed by female staff at our centre (n = 90), by a group of previously treated patients (n = 18), and by a group of newly diagnosed patients (n = 20). When both methods were assumed to be isoeffective, only 34% of the 38 patients preferred three fractions of high dose rate to one fraction of low dose rate. However, when high dose rate was assumed to be 2% more curative, or 6% less toxic, a simple majority of 50% then said they would prefer high dose rate. Both preference and strength of preference for low dose rate were significantly associated with a greater travelling distance for treatments. Age, marital status, family structure, education, employment, and family income were not associated. In summary, a majority of our patients preferred low dose rate brachytherapy.(ABSTRACT TRUNCATED AT 250 WORDS)