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

Less than whole uterus irradiation for patients with locally advanced cervical cancer

INTRODUCTION

Current consensus guidelines for definitive cervical cancer intensity modulated radiation therapy (IMRT) recommend inclusion of the entire uterus within the clinical target volume, however this is debated. We aimed to evaluate outcomes of patients with cervical cancer who were treated with less than whole uterus irradiation.

METHODS

We identified 109 patients with FIGO Stage IB-IVA cervical cancer treated definitively with concurrent chemoradiation, including IMRT and brachytherapy, from 2010 to 2022 at a single institution where the practice was to include the gross cervix tumor with an internal target volume with differences in bladder filing accounted for, plus additional 5 mm planning target volume (PTV) margin. Local, regional, and distant recurrences were analyzed using competing risk methods, and a Wilcoxon rank sum test was performed to assess differences in dose to organs at risk based on the proportion of the uterus included in the PTV, with the median proportion of the uterus included (75 %) used as the cut-point.

RESULTS

The median follow-up time was 65 months (range 3-352 months). The 2-year cumulative incidence of LR for the entire cohort was 4.2 % (95 % confidence interval [CI] 1.3-9.7). Compared with patients who had ≥ 75 % of the uterus included in the PTV, patients who had < 75 % of the uterus included in the PTV had significantly lower bowel D200cc (p = 0.02). The cumulative incidence of local failure (LR) was not significantly different between the two groups.

CONCLUSIONS

Including less than the whole uterus for definitive cervix cancer IMRT does not seem to compromise local control. Less than whole uterus irradiation could be considered for carefully selected cervix cancer patients to decrease bowel dose and possible treatment-related toxicity.

Retrospective analysis of local recurrence pattern by computed tomography image-guided intracavitary and interstitial brachytherapy for locally advanced cervical cancer in a single Japanese institution

PURPOSE

The purpose of this study was to investigate the treatment results with focus on local control (LC) by computed tomography (CT)-guided intracavity brachytherapy and interstitial brachytherapy (ICBT/ISBT) for locally advanced cervical cancer (LACC).

METHODS AND MATERIALS

Patients with LACC undergoing ICBT/ISBT at least once in our institution between January 2017 and June 2019 were analyzed retrospectively. The primary endpoint was local control (LC), and the secondary endpoints were progression-free survival (PFS), overall survival (OS), and late toxicities. Differences between patient subgroups for prognostic factors in LC, PFS, and OS were analyzed using the log-rank test. The recurrence patterns of LC were also investigated.

RESULTS

Forty-four patients were included in the present study. The median high-risk clinical target volume (HR-CTV) at the initial brachytherapy was 48.2 cc. The median total dose of HR-CTV D90 (EQD2) was 70.7 Gy. The median followup period was 39.4 months. The 3-year LC, PFS and OS rates in all patients were 88.2%, 56.6%, and 65.4% (95% CI 50.3-78.0%), respectively. Corpus invasion and large HR-CTV (70 cc or more) were significant prognostic factors in LC, PFS, and OS. Marginal recurrences at the fundus of the uterus were detected in 3 of 5 patients in whom local recurrence was observed. Late toxicities of Grade 3 or higher were detected in 3 patients (6.8%).

CONCLUSIONS

Favorable LC was achieved by performing CT-guided ICBT/ISBT for LACC. The brachytherapy strategy for patients with corpus invasion or large HR-CTV may need to be reconsidered.

Brachytherapy: common pitfalls

Gynecologic radiation oncology is a demanding area of oncology requiring expertise in external beam and brachytherapy. Both physicians and physicists are called on to use their full complement of skills to employ state-of-the-art treatments to benefit patients. A wide variety of unusual presentations are frequent in gynecology, and hence, it is necessary to have a number of techniques available to offer the optimal treatments. The heterogeneity of treatments and the rarity of certain gynecological presentations lead to complexity and potential error. We reviewed previous gynecological high dose rate brachytherapy treatment images and plans for patients from the past decade and identified examples of common problems to share with the community. The strategies to prevent or recover from these pitfalls are also presented. With increasing number of applicator choices, it is critical for clinics to follow rigorous commissioning steps to ensure treatment process safety as described. The clinics should consider implementing a thorough on-boarding program and regular hands-on practice as a continuous quality improvement measure. The use of checklists can be invaluable and result in fewer human errors. Gynecological chart rounds that focus on brachytherapy are also encouraged. Lastly, an incident learning system to document small deviations that occur in the process, and a rigorous root cause analysis process could help prevent potential future incidents.

Too many women are dying from cervix cancer: Problems and solutions

One woman dies from cervix cancer every 2 min, adding up to over 270,000 deaths globally per year. This cancer affects a young population, and hence, the loss of life is staggering. There are many aspects of prevention, screening, and care that are suboptimal. A great deal is known about HPV induced carcinogenesis, yet clinical outcomes have been stagnant over decades. There has been no improvement in cervix cancer survival in the US since the mid-1970s [1]. With increased knowledge of the disease and greater worldwide resources including prevention, screening, and improved therapeutics, there is significant promise for fewer women to die from this virally induced cancer. We focus here on the major problems in prevention, screening, and delivery of care for cervix cancer and provide concrete solutions. With appropriate focus, a major improvement in survival from cervix cancer could be achieved in a short time span.

Outcomes of Computed Tomography-Guided Image-Based Interstitial Brachytherapy for Cancer of the Cervix Using GEC-ESTRO Guidelines

Locally advanced cancer of the cervix is treated by concurrent chemoradiation followed by brachytherapy. Interstitial brachytherapy is used to treat large tumors with involvement of parametrium, post-hysterectomy, and narrow, conical vagina. The GYN GEC-ESTRO working group described target volume delineation and also 3D image-based planning using MRI and 3D dose-volume parameters for brachytherapy of carcinoma cervix. CT-based as compared to MR-based image-guided brachytherapy (IGBT) is much more feasible and practical because MR access is still difficult for most departments. This is a retrospective study done to assess the local control in cancer of the cervix, treated based on these guidelines and dose received by 2 cm3 of the rectum as defined by the GEC-ESTRO guidelines and its correlation with long-term toxicity. Sixty-three patients of cancer of the cervix received 45 Gy/25 fractions of external beam radiotherapy with concurrent weekly cisplatin followed by interstitial brachytherapy. A central tandem was inserted into the uterine cavity. The needles were inserted based on the concept of gross tumor volume (GTV), high-risk clinical target volume (HRCTV), and intermediate-risk CTV (IR CTV) as defined by the GYN GEC-ESTRO guidelines. All patients underwent CT-based planning. A dose of 6.5 Gy × 4 fractions was delivered in two sessions such that the HRCTV received a total dose of 26 Gy. Dose optimization was done to prevent 2 cm3 of rectum from receiving > 400 cGy (60% of prescribed dose) per fraction and 2 cm3 of bladder from receiving 500 cGy per fraction. At a median follow-up of 41.5 months (range 6-106 months), 74.6% (47/63) of the patients were alive, with no local, loco-regional, or distant metastasis. Loco-regional control rate was 88% (56/63). Eight percent (5/63) of the patients developed grade I proctitis which was managed conservatively. There was no grades II, III, or IV proctitis. There was no bladder or sigmoid toxicity. GEC-ESTRO guidelines can be modified for CT-based planning also with very minimal late toxicity without compromising local control.

Knockdown of Wip1 Enhances Sensitivity to Radiation in HeLa Cells Through Activation of p38 MAPK

The objectives of the study were to investigate the functional role and potential mechanism of wild-type p53-induced phosphatase (Wip1) in cervical cancer cell line HeLa cells, along with the effect of knockdown of Wip1 in combination with γ-irradiation on the HeLa cells. Expression of Wip1 was silenced or overexpressed. After transfection, cell viability was determined. Moreover, γ-irradiation and SB203580 were performed to explore the effect of colony formation and cell apoptosis. Likewise, protein expression levels of p38, p-p38, p53, and p-p53 were assessed in the presence or not of SB203580 and overexpression of Wip1. Both the mRNA and protein levels of Wip1 were significantly decreased by transfection with Wip1-specific small interfering RNA (siRNA) but were significantly increased by transfection with pcDNA3.1-Wip1. Knockdown of Wip1 significantly decreased cell growth and colony formation ability and increased apoptotic rate. Additionally, better results were obtained by knockdown of Wip1 in combination with γ-irradiation. The protein expression levels of p-p38 (p < 0.05), p53 (p < 0.01), and p-p53 (p < 0.05) were all significantly increased by knockdown of Wip1. However, application of SB203580 reversed the effects. Our study confirms the important roles of Wip1 in cervical cancer. Knockdown of Wip1 enhances sensitivity to radiation in HeLa cells by inhibiting cell proliferation and inducing apoptosis through activation of p38 MAPK.

Treatment outcomes of patients with FIGO Stage I/II uterine cervical cancer treated with definitive radiotherapy: a multi-institutional retrospective research study

The purpose of this study was to analyze the patterns of care and outcomes of patients with FIGO Stage I/II cervical cancer who underwent definitive radiotherapy (RT) at multiple Japanese institutions. The Japanese Radiation Oncology Study Group (JROSG) performed a questionnaire-based survey of their cervical cancer patients who were treated with definitive RT between January 2000 and December 2005. A total of 667 patients were entered in this study. Although half of the patients were considered suitable for definitive RT based on the clinical features of the tumor, about one-third of the patients were prescribed RT instead of surgery because of poor medical status. The RT schedule most frequently utilized was whole-pelvic field irradiation (WP) of 30 Gy/15 fractions followed by WP with midline block of 20 Gy/10 fractions, and high-dose-rate intracavitary brachytherapy (HDR-ICBT) of 24 Gy/4 fractions prescribed at point A. Chemotherapy was administered to 306 patients (46%). The most frequent regimen contained cisplatin (CDDP). The median follow-up time for all patients was 65 months (range, 2-135 months). The 5-year overall survival (OS), pelvic control (PC) and disease-free survival (DFS) rates for all patients were 78%, 90% and 69%, respectively. Tumor diameter and nodal status were significant prognostic indicators for OS, PC and DFS. Chemotherapy has potential for improving the OS and DFS of patients with bulky tumors, but not for non-bulky tumors. This study found that definitive RT for patients with Stage I/II cervical cancer achieved good survival outcomes.

More accurate definition of clinical target volume based on the measurement of microscopic extensions of the primary tumor toward the uterus body in international federation of gynecology and obstetrics Ib-IIa squamous cell carcinoma of the cervix

PURPOSE

To more accurately define clinical target volume for cervical cancer radiation treatment planning by evaluating tumor microscopic extension toward the uterus body (METU) in International Federation of Gynecology and Obstetrics stage Ib-IIa squamous cell carcinoma of the cervix (SCCC).

PATIENTS AND METHODS

In this multicenter study, surgical resection specimens from 318 cases of stage Ib-IIa SCCC that underwent radical hysterectomy were included. Patients who had undergone preoperative chemotherapy, radiation, or both were excluded from this study. Microscopic extension of primary tumor toward the uterus body was measured. The association between other pathologic factors and METU was analyzed.

RESULTS

Microscopic extension toward the uterus body was not common, with only 12.3% of patients (39 of 318) demonstrating METU. The mean (±SD) distance of METU was 0.32 ± 1.079 mm (range, 0-10 mm). Lymphovascular space invasion was associated with METU distance and occurrence rate. A margin of 5 mm added to gross tumor would adequately cover 99.4% and 99% of the METU in the whole group and in patients with lymphovascular space invasion, respectively.

CONCLUSION

According to our analysis of 318 SCCC specimens for METU, using a 5-mm gross tumor volume to clinical target volume margin in the direction of the uterus should be adequate for International Federation of Gynecology and Obstetrics stage Ib-IIa SCCC. Considering the discrepancy between imaging and pathologic methods in determining gross tumor volume extent, we recommend a safer 10-mm margin in the uterine direction as the standard for clinical practice when using MRI for contouring tumor volume.

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

Background and purpose

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

Materials and methods

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

Results

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

Conclusions

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

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

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

Evaluation of microscopic tumor extension in early-stage cervical cancer: quantifying subclinical uncertainties by pathological and magnetic resonance imaging findings

We performed a detailed analysis of hysterectomy specimens of uterine cervical cancer to determine the appropriate length of uterine body to include within the clinical target volume. Between 2008 and 2011, 54 patients with uterine cervical carcinoma underwent hysterectomy. Those with quality pre-operative magnetic resonance imaging (MRI) data were included for analysis. Tumor sizes measured by MRI and microscopy were compared with regard to brachytherapy-oriented parameters. Detailed descriptive analysis focusing on the extent of tumor involvement was also performed. A total of 31 specimens were analyzed. The median maximal tumor length measured by MRI was slightly shorter than microscopic length (19 vs. 24 mm, respectively), while the maximal radius was almost identical. No tumors with a maximal size <2 cm by MRI (n = 6) extended to the uterine body ≥ 1/3. The majority of maximal tumor length underestimation on MRI was within 1 cm. Precise tumor delineation can be made by MRI. For patients with tumors <2 cm on MRI, treating the entire uterine body length may not be necessary. A 1-cm margin around an MRI-based gross tumor seems to be adequate to cover the actual tumor involvement.

Use of megavoltage computed tomography with image registration for high-dose rate treatment planning of an oral tongue cancer using a custom oral mold applicator with embedded lead shielding

PURPOSE

A patient with a lateral oral tongue cancer was treated with high-dose rate brachytherapy using an oral applicator with embedded lead shielding making conventional simulation, using either kilovoltage computed tomography or radiographs, impossible because of scatter artifact.

METHODS AND MATERIALS

Treatment simulation was accomplished using megavoltage computed tomography (MVCT) simulation on a helical tomotherapy unit. Because of difficulty in visualization of the catheters on the patient MVCT images, Velocity AI image registration software (Velocity Medical Solutions, Atlanta, GA) was used to register an MVCT of the applicator itself with the patient MVCT simulation. The treatment plan was manually optimized to prescribe 4Gy/fraction to the gross tumor volume.

RESULTS

The patient tolerated the treatment well, with no evidence of disease 6 months after treatment. Thermoluminescent dosimeter measurements showed that the shielding reduced the dose by up to 90%, depending on the location of the thermoluminescent dosimeter. While the patient was treated using dose distributions calculated in a homogeneous medium (Task Group-43), an approximation of the true dose distributions was retrospectively calculated using Acuros (Varian Medical Systems Inc., Palo Alto, CA), which accounts for heterogeneities in the patient.

DISCUSSION

Use of the MVCT with image registration allowed treatment planning in the presence of lead shielding. Dose-volume histograms showed that recalculation of the dose using heterogeneity correction did not affect the dose to the gross tumor volume, but that the dose to normal structures (maxilla and mandible) was reduced by the lead shielding.

CONCLUSION

The use of MVCT and image registration allows for optimized planning in the presence of shielding, which would not be possible with conventional kilovoltage computed tomography.

Radiotherapy quality assurance of the Japanese Gynecologic Oncology Group study (JGOG1066): a cooperative phase II study of concurrent chemoradiotherapy for uterine cervical cancer

BACKGROUND

To assess radiotherapy protocol compliance in a multi-institutional phase II study of concurrent chemoradiotherapy for patients with locally advanced cancer of the uterine cervix (JGOG1066).

METHODS

For study protocol development, various radiotherapy parameters were examined and consensus was reached by Japanese radiation oncologists with cervical cancer treatment expertise. Quality assurance (QA) was also discussed and included in the protocol. A credentialing process was used to select institutions for participation in the study. Individual case reviews referring to 18 QA items were undertaken for each patient. Radiotherapy data were submitted to the Japanese Gynecologic Oncology Group (JGOG) data center and reviewed by the members of the radiotherapy committee. The QA evaluation was classed as per protocol, deviation, and violation.

RESULTS

Individual case reviews were performed on 69 of 72 patients entered in the study. In 24 patients (35%), there were no deviations for any QA items. There were also no deviations seen for 5 of the 18 items in 69 patients evaluated. Deviations of 64 QA items were seen in 45 cases, and violations were seen in 4 cases (4 items). The most common deviation concerned appropriate application for the external beam radiotherapy (EBRT) boost to involved nodes or parametrium (32 cases). The 4 violations were identified in the QA items regarding high-dose rate intracavitary brachytherapy.

CONCLUSIONS

Radiotherapy protocol compliance was favorable except for the EBRT boost indications. The results of this study validate the quality of radiotherapy in JGOG1066, and indicate that the final analysis will provide meaningful results.

International brachytherapy practice patterns: a survey of the Gynecologic Cancer Intergroup (GCIG)

PURPOSE

To determine current practice patterns with regard to gynecologic high-dose-rate (HDR) brachytherapy among international members of the Gynecologic Cancer Intergroup (GCIG) in Japan/Korea (Asia), Australia/New Zealand (ANZ), Europe (E), and North America (NAm).

METHODS AND MATERIALS

A 32-item survey was developed requesting information on brachytherapy practice patterns and standard management for Stage IB-IVA cervical cancer. The chair of each GCIG member cooperative group selected radiation oncology members to receive the survey.

RESULTS

A total of 72 responses were analyzed; 61 respondents (85%) used HDR. The three most common HDR brachytherapy fractionation regimens for Stage IB-IIA patients were 6 Gy for five fractions (18%), 6 Gy for four fractions (15%), and 7 Gy for three fractions (11%); for Stage IIB-IVA patients they were 6 Gy for five fractions (19%), 7 Gy for four fractions (8%), and 7 Gy for three fractions (8%). Overall, the mean combined external-beam and brachytherapy equivalent dose (EQD2) was 81.1 (standard deviation [SD] 10.16). The mean EQD2 recommended for Stage IB-IIA patients was 78.9 Gy (SD 10.7) and for Stage IIB-IVA was 83.3 Gy (SD 11.2) (p = 0.02). By region, the mean combined EQD2 was as follows: Asia, 71.2 Gy (SD 12.65); ANZ, 81.18 (SD 4.96); E, 83.24 (SD 10.75); and NAm, 81.66 (SD, 6.05; p = 0.02 for Asia vs. other regions).The ratio of brachytherapy to total prescribed dose was significantly higher for Japan (p = 0.0002).

CONCLUSION

Although fractionation patterns may vary, the overall mean doses administered for cervical cancer are similar in Australia/New Zealand, Europe, and North America, with practitioners in Japan administering a significantly lower external-beam dose but higher brachytherapy dose to the cervix. Given common goals, standardization should be possible in future clinical trials.

Patient outcome study of concurrent chemoradiation, external beam radiotherapy, and high-dose rate brachytherapy in locally advanced carcinoma of the cervix

INTRODUCTION

A regimen of concurrent chemoradiation for definitive treatment of cervical cancer is widely used. This retrospective review has been conducted to determine the outcomes and late toxic effect associated with the specific regimen of whole-pelvic external beam radiotherapy of 45 Gy in 25 fractions with parametrial boosts of 5.4 or 9 Gy and HDR brachytherapy (BT) of 30 Gy in 5 fractions to point A delivered by tandem and ring. This protocol is accepted by the Gynecological Oncology Group and endorsed by the American Brachytherapy Society, but no late toxic effect data have been reported.

MATERIALS AND METHODS

The electronic records of sequential patients treated definitively at the Sunnybrook Odette Cancer Centre between January 2006 and December 2008 were reviewed. Patient-, tumor-, and treatment-related details (including external beam radiotherapy, BT, and chemotherapy) were obtained. Outcome measures included disease-free status, dates and sites of first recurrence, survival, and grade 3/4 late toxic effect results (Common Terminology Criteria Adverse Events 3.0 criteria). Exclusion criteria were no follow-up or a planned alternative regimen.

RESULTS

One hundred twenty-two patients (+11 excluded) were treated with a median follow-up of 18 months from diagnosis. The actuarial 2-year disease-free survival rate was 70%. The median time to recurrence was 8 months (range, 2-22 months). The median time to toxic effect was 10 months (range 4-27 months). Grade 3/4 toxic effect was observed in 13 patients (11%). The actuarial grade 3/4 toxic effect rate at 2 years was 14%.

CONCLUSIONS

Despite a relatively short follow-up, the toxicity of this regimen seems high compared with other retrospective series, although pelvic control is good. Consideration should be given to a reduction in BT dose alternatively when feasible image-guided BT may allow maintenance of tumor dose with reduced dose to organs at risk.