A simple method of obtaining equivalent doses for use in HDR brachytherapy

CT Angiography-Guided Needle Insertion for Interstitial Brachytherapy in Locally Advanced Cervical Cancer

CT angiography might be a suitable procedure to avoid arterial puncture in combined intracavitary and interstitial brachytherapy for cervical cancer curatively treated with combined chemoradiation and brachytherapy boost. Data in the literature about this technique are scarce. We introduced this method and collected brachytherapy data from patients treated in our department between May 2021 and April 2024. We analyzed the applicator subtype, needle insertion (planned versus implanted), implanted depth and the role of CT angiography in selecting needle trajectories and insertion depths. None of the patients managed through this protocol experienced atrial puncture and consequent hemorrhage. Needle positions were accurately selected with the aid of CT angiography with proper coverage of brachytherapy targets and avoidance of organs at risk. CT angiography is a promising method for guiding needle insertion during interstitial brachytherapy.

Quality Assurance for Stereotactic Body Radiation Therapy for Gynecologic Malignancies

The use of stereotactic body radiation therapy (SBRT) is not well studied or reported in the treatment of gynecologic malignancies, despite its success in the definitive management of other cancer sites. This report describes a rigorous quality assurance process for patients to undergo dose escalation to the pelvis via stereotactic photon beam irradiation. Patients who receive SBRT must be ineligible for conventional brachytherapy boost and undergo comprehensive informed consent. Fiducial placement, bowel prep, Foley catheter placement with standardized bladder filling, computerized tomography (CT) simulation with whole-body immobilization, magnetic resonance imaging (MRI)-assisted target delineation, planning aims based on the established brachytherapy literature, and physics consultation for SBRT plan optimization are necessary. Prior to each fraction, the simulation position is reproduced and verified with on-table cone beam CT, and the position is maintained with whole-body immobilization. Following treatment, the treating physician is active in survivorship and toxicity management. Gynecologic SBRT is an ongoing area of study, and preliminary successes in delivering high-quality stereotactic dose escalation suggest prospective investigation is warranted. By adhering to strict quality control measures and following a pre-defined best standard of practice, patients with gynecologic malignancies who are ineligible for traditional brachytherapy procedures can be safely treated with SBRT.

The impact of brachytherapy boost for anal canal cancers in the era of de-escalation treatments

PURPOSE

To analyze clinical outcomes of high-dose-rate (HDR) interstitial brachytherapy boost (ISBT) after external beam radiation therapy (EBRT) or chemoradiotherapy (CRT) for the treatment of anal canal cancers (ACC).

METHODS AND MATERIALS

A total of 78 patients with ACC were treated at our institution by ISBT. Local Control (LC), disease-free survival (DFS), overall survival (OS), colostomy-free survival (CFS) and toxicity rates were analyzed.

RESULTS

With a median followup (FU) of 59.8 months (95% CI [55.8-64.2]), six (7.7%) local recurrences with 2 patients (2.6%) having persistent disease at 3 months were observed. The 5-year rate of LC for the entire population was 92% [83-96%]. The 5-year DFS rate was 86% [76-93%]. The 5-year OS was 96% [88-99%]. In the univariate analysis, chemotherapy was significantly associated with morbidity grade ≥2. Late digestive toxicity grade ≥3 was reported in 8.9% patients, 1 patient underwent colostomy due to toxicity. The 5-year CFS rate was 88% [79-94%].

CONCLUSIONS

HDR interstitial brachytherapy boost provide excellent rates of tumor control and colostomy-free survival with a favorable profile of GI toxicity. Continence in anal cancer survivors is a challenge and the boost technique must be discussed in a multidisciplinary approach as part of de-escalation treatments.

Brachytherapy outcome modeling in cervical cancer patients: A predictive machine learning study on patient-specific clinical, physical and dosimetric parameters

PURPOSE

To predict clinical response in locally advanced cervical cancer (LACC) patients by a combination of measures, including clinical and brachytherapy parameters and several machine learning (ML) approaches.

METHODS

Brachytherapy features such as insertion approaches, source metrics, dosimetric, and clinical measures were used for modeling. Four different ML approaches, including LASSO, Ridge, support vector machine (SVM), and Random Forest (RF), were applied to extracted measures for model development alone or in combination. Model performance was evaluated using the area under the curve (AUC) of receiver operating characteristics curve, sensitivity, specificity, and accuracy. Our results were compared with a reference model developed by simple logistic regression applied to three distinct clinical features identified by previous papers.

RESULTS

One hundred eleven LACC patients were included. Nine data sets were obtained based on the features, and 36 predictive models were built. In terms of AUC, the model developed using RF applied to dosimetric, physical, and total BT sessions features were found as the most predictive [AUC; 0.82 (0.95 confidence interval (CI); 0.79 -0.93), sensitivity; 0.79, specificity; 0.76, and accuracy; 0.77]. The AUC (0.95 CI), sensitivity, specificity, and accuracy for the reference model were found as 0.56 (0.52 ...0.68), 0.51, 0.51, and 0.48, respectively. Most RF models had significantly better performance than the reference model (Bonferroni corrected p-value < 0.0014).

CONCLUSION

Brachytherapy response can be predicted using dosimetric and physical parameters extracted from treatment parameters. Machine learning algorithms, including Random Forest, could play a critical role in such predictive modeling.

Intensity modulated high dose rate ocular brachytherapy using Se-75

PURPOSE

We propose an alternative to LDR brachytherapy for the treatment of ocular melanomas by coupling intensity modulation, through the use of a gold shielded ring applicator, with a middle energy HDR brachytherapy source, Se-75. In this study, we computationally test this proposed design using MCNP6.

METHODS AND MATERIALS

An array of discrete Se-75 sources is formed into a ring configuration within a gold shielded applicator, which collimates the beam to a conical shape. Varying this angle of collimation allows for the prescription dose to be delivered to the apex of various sized targets. Simulations in MCNP6 were performed to calculate the dosimetric output of the Se-75 ring source for various sized applicators, collimators, and target sizes.

RESULTS

The prescription dose was delivered to a range of target apex depths 3.5-8 mm in the eye covering targets 10-15 mm in diameter by using various sized applicators and collimators. For a 16 mm applicator with a collimator opening that delivers the prescription dose to a depth of 5 mm in the eye, the maximum percent dose rate to critical structures was 30.5% to the cornea, 35.7% to the posterior lens, 33.3% to the iris, 20.1% to the optic nerve, 278.0% to the sclera, and 267.3% to the tumor.

CONCLUSIONS

When using Se-75 in combination with the proposed gold shielded ring applicator, dose distributions are appropriate for ocular brachytherapy. The use of a collimator allows for the dose to more easily conform to the tumor volume. This method also reduces treatment time and cost, and it eliminates hand dose to the surgeon through the use of a remote afterloader device.

Comparative dosimetrical analysis of intensity-modulated arc therapy, CyberKnife therapy and image-guided interstitial HDR and LDR brachytherapy of low risk prostate cancer

Background

The objective of the study was to dosimetrically compare the intensity-modulated-arc-therapy (IMAT), Cyber-Knife therapy (CK), single fraction interstitial high-dose-rate (HDR) and low-dose-rate (LDR) brachytherapy (BT) in low-risk prostate cancer.

Materials and methods

Treatment plans of ten patients treated with CK were selected and additional plans using IMAT, HDR and LDR BT were created on the same CT images. The prescribed dose was 2.5/70 Gy in IMAT, 8/40 Gy in CK, 21 Gy in HDR and 145 Gy in LDR BT to the prostate gland. EQD2 dose-volume parameters were calculated for each technique and compared.

Results

EQD2 total dose of the prostate was significantly lower with IMAT and CK than with HDR and LDR BT, D90 was 79.5 Gy, 116.4 Gy, 169.2 Gy and 157.9 Gy (p < 0.001). However, teletherapy plans were more conformal than BT, COIN was 0.84, 0.82, 0.76 and 0.76 (p < 0.001), respectively. The D₂ to the rectum and bladder were lower with HDR BT than with IMAT, CK and LDR BT, it was 66.7 Gy, 68.1 Gy, 36.0 Gy and 68.0 Gy (p = 0.0427), and 68.4 Gy, 78.9 Gy, 51.4 Gy and 70.3 Gy (p = 0.0091) in IMAT, CK, HDR and LDR BT plans, while D_0.1 to the urethra was lower with both IMAT and CK than with BTs: 79.9 Gy, 88.0 Gy, 132.7 Gy and 170.6 Gy (p < 0.001). D₂ to the hips was higher with IMAT and CK, than with BTs: 13.4 Gy, 20.7 Gy, 0.4 Gy and 1.5 Gy (p < 0.001), while D₂ to the sigmoid, bowel bag, testicles and penile bulb was higher with CK than with the other techniques.

Conclusions

HDR monotherapy yields the most advantageous dosimetrical plans, except for the dose to the urethra, where IMAT seems to be the optimal modality in the radiotherapy of low-risk prostate cancer.

Dose fusion and efficacy evaluation of different radical radiotherapy doses for cervical cancer

BACKGROUND

The recommended external beam radiotherapy (EBRT) dose for cervical cancer is 40-50 Gy, but there is no consensus. In this study, 45-Gy and 50.4-Gy treatment groups were compared for fused doses to target tumor areas and organs at risk (OARs), clinical efficacy, and quality of life.

METHODS

Seventy-nine cases receiving radical radiotherapy within the past 3 years were retrospectively analyzed. EBRT and three-dimensional brachytherapy dose fusion values were calculated for target areas and OARs using Elastix V5.0. Clinical efficacy was assessed using Response Evaluation Criteria in Solid Tumors (RECIST), adverse events using Common Terminology Criteria for Adverse Events v4.03 (CTCAE4.03), and quality of life using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30).

RESULTS

Minimum fused dose delivered to 90% of the high-risk clinical target volume (HRCTV D90) did not differ significantly between 45-Gy and 50.4-Gy groups, whereas D2cc values of rectum and bladder (OARs) were significantly lower in the 45-Gy group (both p < 0.05). Further analysis showed that these D2cc differences resulted primarily from EBRT. No grade III-IV adverse events were observed in either group during follow up. Short-term clinical efficacy, adverse events, and EORTC QLQ-C30 functional and symptom scales also did not differ significantly between groups (all p > 0.05). However, quality of life was markedly higher in the 45-Gy group (p < 0.05).

CONCLUSION

Appropriate EBRT dose reduction can reduce OAR irradiation without compromising total target area dose or clinical efficacy. Dose fusion can facilitate the judicious choice of EBRT to limit OAR exposure, reduce adverse events, and enhance the quality of life.

Biological dose summation of external beam radiotherapy for the whole breast and image-guided high-dose-rate interstitial brachytherapy boost in early-stage breast cancer

Purpose

To develop an alternative method for summing biologically effective doses of external beam radiotherapy (EBRT) with interstitial high-dose-rate (HDR) brachytherapy (BT) boost in breast cancer. The total doses using EBRT boost were compared with BT boost using our method.

Material and methods

Twenty-four EBRT plus interstitial HDR-BT plans were selected, and additional plans using EBRT boost were created. The prescribed dose was 2.67/40.05 Gy to whole breast and 4.75/14.25 Gy BT or 2.67/10.7 Gy EBRT to planning target volume (PTV) boost. EBRT and BT computed tomography (CT) were registered twice, including fitting the target volumes and using the lung, and the most exposed volume of critical organs in BT were identified on EBRT CT images. The minimal dose of these from EBRT was summed with their BT dose, and these EQD2 doses were compared using BT vs. EBRT boost. This method was compared with uniform dose conception (UDC).

Results

D₉₀ of PTV boost was significantly higher with BT than with EBRT boost: 67.1 Gy vs. 56.7 Gy, p = 0.0001. There was no significant difference in the dose of non-target and contralateral breast using BT and EBRT boost. D₁ to skin, lung, and D_0.1 to heart were 58.6 Gy vs. 66.7 Gy (p = 0.0025), 32.6 Gy vs. 50.6 Gy (p = 0.0002), and 52.2 Gy vs. 58.1 Gy (p = 0.0009), respectively, while D_0.1 to ribs was 44.3 Gy vs. 37.7 Gy (p = 0.0062). UDC overestimated D₁ (lung) by 54% (p = 0.0001) and D₁ (ribs) by 28% (p = 0.0003).

Conclusions

Based on our biological dose summation method, the total dose of PTV in the breast is higher using BT boost than with EBRT. BT boost yields lower skin, lung, and heart doses, but higher dose to ribs. UDC overestimates lung and ribs doses.

Biological dose summation of intensity-modulated arc therapy and image-guided high-dose-rate interstitial brachytherapy in intermediate- and high-risk prostate cancer

Purpose

To present an alternative method for summing biologically effective doses of intensity-modulated arc therapy (IMAT) as teletherapy (TT), with interstitial high-dose-rate (HDR) brachytherapy (BT) boost in prostate cancer. Total doses using IMAT boost was compared with BT boost using our method.

Material and methods

Initially, 25 IMAT TT plus interstitial HDR-BT plans were included, and additional plans using IMAT TT boost were created. The prescribed dose was 2/44 Gy to the whole pelvis, 2/60 Gy to the prostate and seminal vesicles, and 1 × 10 Gy BT or 2/18 Gy IMAT TT to the prostate. Teletherapy computed tomography (CT) was registered with ultrasound (US) of BT, and the most exposed volume of critical organs in BT were identified on these CT images. The minimal dose of these from IMAT TT was summed with their BT dose, and these EQD₂ doses were compared using BT vs. IMAT TT boost. This method was compared with uniform dose conception (UDC).

Results

D₉₀ of the prostate was significantly higher with BT than with IMAT TT boost: 99.3 Gy vs. 77.9 Gy, p = 0.0034. The D₂ to rectum, bladder, and hips were 50.3 Gy vs. 76.8 Gy (p = 0.0117), 64.7 Gy vs. 78.3 Gy (p = 0.0117), and 41.9 Gy vs. 50.6 Gy (p = 0.0044), while D_0.1 to urethra was 96.1 Gy vs. 79.3 Gy (p = 0.0180), respectively. UDC overestimated D₂ (rectum) by 37% (p = 0.0117), D₂ (bladder) by 5% (p = 0.0214), and underestimated D_0.1 (urethra) by 1% (p = 0.0277).

Conclusions

Based on our biological dose summation method, the total dose of prostate is higher using BT boost than the IMAT. BT boost yields lower rectum, bladder, and hips doses, but higher dose to urethra. UDC overestimates rectum and bladder dose and underestimates the dose to urethra.

FIGO Classification 2018: Validation Study in Patients With Locally Advanced Cervix Cancer Treated With Chemoradiation

PURPOSE

In 2018, the International Federation of Gynecology and Obstetrics (FIGO) proposed a new staging for cervical cancer. The present study was designed to reclassify patients with locally advanced cervix cancer and perform a comparative evaluation with FIGO 2009.

METHODS AND MATERIALS

Patients with locally advanced cervical cancer (stage IB2-IVA) who had baseline cross-sectional imaging and received (chemo-) radiation and brachytherapy were included. Survival outcomes were analyzed according to FIGO 2009. Patients were then reclassified according to FIGO 2018, and TNM classification outcomes were analyzed. FIGO stage and known prognostic factors were included in univariate analysis, and multivariate analysis was performed to investigate the prognostic value of clinical stage.

RESULTS

Six hundred thirty-two patients were included. Overall, 185 (29.3%) patients had pelvic adenopathy, and 51 (8.2%) had positive paraortic nodes. At a median follow-up of 33 months, 116 (18.3%) patients had recurrence. Three-year disease-free survival (DFS) according to FIGO 2009 for stage IB, IIA, IIB, IIIA, IIIB, and IVA was 86%, 91%, 76%, 57%, 65%, and 61%, respectively. The 3-year DFS after restaging according to FIGO 2018 for stage IB, IIA, IIB, IIIA, IIIB, IIIC1, IIIC2, and IVA was 100%, 93%, 84%, 53%, 77%, 74%, 61%, and 61%, respectively. Patients with clinically significant lymphadenopathy had inferior outcomes compared with node-negative patients (62.9% vs 77.8%; P = .002). Patients with ≥3 paraortic nodes had poorer DFS than patients with <3 paraortic lymphadenopathy (13.6% vs 56.3%; P = .001). Furthermore, patients with primary tumor volume >30 cm³ had worse 3-year DFS than those with primary tumor volume ≤30 cm³ (67.4% vs 78.5%; P = .002).

CONCLUSIONS

FIGO 2018 modification is associated with heterogenous outcomes in node-positive patients that are affected by primary tumor and nodal volume. We propose a modification to the existing TNM staging system to allow more robust classification of outcomes.

Non-invasive stereotactic ablative boost in patients with locally advanced cervical cancer

INTRODUCTION

The current literature is insufficient to guide care for patients with cervical cancer ineligible for brachytherapy. Stereotactic ablative radiotherapy boost is a clinical necessity for these patients, but highly debated among radiation oncologists.

OBJECTIVE

To report toxicity and survival outcomes in a large cohort of patients with locally advanced cervical cancer treated with a non-invasive stereotactic ablative radiotherapy boost instead of brachytherapy METHODS: Patients with locally advanced cervical cancer were entered, between January 2008 and December 2018, who were recommended definitive intent external boost after pelvic radiotherapy to 45-50.4 Gy concurrent with weekly cisplatin and simultaneous/sequential nodal boost up to 55-66 Gy. Simulation CT was facilitated using radio-opaque fiducials, empty rectum, dedicated bladder filling, and whole body vaculoplastic immobilization. Kaplan-Meier survival estimates were used to report local/regional recurrences, distant metastases, cancer-specific survival, and overall survival.

RESULTS

A total of 25 patients were analyzed. Median follow-up was 25 months (range 6-54). Patients received stereotactic ablative radiotherapy due to refusal of brachytherapy (9/25, 36%), medical co-morbidities limiting implantation (9/25, 36%), or technical infeasibility (7/25, 28%). Typical fractionation was 24-30 Gy in 4-5 fractions (24/25, 96%). The most common long-term toxicity was grade 1-2 vaginal dryness, discomfort, stenosis, and/or dyspareunia (4/25, 16%). One patient had new post-treatment grade 4 fistula in an area of previous tumor erosion (1/25, 4%). Overall survival, cancer specific survival, loco-regional control, and distant control were 95.5%, 100%, 95.5%, and 89.1%, respectively, at 2 years.

CONCLUSION

Further study of stereotactic ablative radiotherapy boost for cervical cancer is needed; a brachytherapy-similar approach portends clinical success with 95.5% overall survival and loco-regional control at 2 years.

A planning study of focal dose escalations to multiparametric MRI-defined dominant intraprostatic lesions in prostate proton radiation therapy

OBJECTIVES

The purpose of this study is to investigate the dosimetric effect and clinical impact of delivering a focal radiotherapy boost dose to multiparametric MRI (mp-MRI)-defined dominant intraprostatic lesions (DILs) in prostate cancer using proton therapy.

METHODS

We retrospectively investigated 36 patients with pre-treatment mp-MRI and CT images who were treated using pencil beam scanning (PBS) proton radiation therapy to the whole prostate. DILs were contoured on co-registered mp-MRIs. Simultaneous integrated boost (SIB) plans using intensity-modulated proton therapy (IMPT) were created based on conventional whole-prostate-irradiation for each patient and optimized with additional DIL coverage goals and urethral constraints. DIL dose coverage and organ-at-risk (OAR) sparing were compared between conventional and SIB plans. Tumor control probability (TCP) and normal tissue complication probability (NTCP) were estimated to evaluate the clinical impact of the SIB plans.

RESULTS

Optimized SIB plans significantly escalated the dose to DILs while meeting OAR constraints. SIB plans were able to achieve 125, 150 and 175% of prescription dose coverage in 74, 54 and 17% of 36 patients, respectively. This was modeled to result in an increase in DIL TCP by 7.3-13.3% depending on α / β and DIL risk level.

CONCLUSION

The proposed mp-MRI-guided DIL boost using proton radiation therapy is feasible without violating OAR constraints and demonstrates a potential clinical benefit by improving DIL TCP. This retrospective study suggested the use of IMPT-based DIL SIB may represent a strategy to improve tumor control.

ADVANCES IN KNOWLEDGE

This study investigated the planning of mp-MRI-guided DIL boost in prostate proton radiation therapy and estimated its clinical impact with respect to TCP and NTCP.

IMRT and brachytherapy comparison in gynaecological cancer treatment: thinking over dosimetry and radiobiology

Background

The role of radiotherapy and brachytherapy in the management of locally advanced cervical and endometrial cancer is well established. However, in some cases, intracavitary brachytherapy (ICBRT) is not recommended or cannot be carried out. We aimed to investigate whether external-beam irradiation delivered by means of intensity-modulated radiation therapy (IMRT) might replace ICBRT in gynaecological cancer when the standard ICBRT boost delivering cannot be administered for technical or clinical reasons.

Materials and methods

Fifteen already delivered treatments for gynaecological cancer patients were analysed. The treatments were performed through 3-dimensional conformal radiotherapy (3D-CRT) to the whole-pelvis up to the dose of 45–50.4 Gy followed by a boost dose administered with ICBRT in high-dose-rate or pulsed-dose-rate modality. For each patient, IMRT plans were elaborated to mimic the ICBRT. We analysed the ICBRT boost versus IMRT boost in terms of dosimetric and radiobiological aspects.

Results

Mean conformity index value calculated on boost volume was 0.73 for ICBRT and 0.97 for IMRT. Mean conformation number was 0.24 for ICBRT boost and 0.78 for IMRT boost. Mean normal tissue complication probability (NTCP) values for 3D-CRT plus ICBRT and for IMRT (pelvis plus boost) were, respectively, 28% and 5% for rectum; 1.5% and 0.1% for urinary bladder and 8.9% and 6.1% for bowel.

Conclusions

Our findings suggest that IMRT may represent a viable alternative in delivering the boost in patients diagnosed with gynaecological cancer not amenable to ICBRT.

Standard Chemoradiation and Conventional Brachytherapy for Locally Advanced Cervical Cancer: Is It Still Applicable in the Era of Magnetic Resonance-Based Brachytherapy?

Purpose Recent guidelines recommend magnetic resonance imaging-based brachytherapy (MRBT) for locally advanced cervical cancer. However, its implementation is challenging within the developing world. This article reports the outcomes of patients with locally advanced cervical cancer treated with chemoradiation and point A-based brachytherapy (BT) using x-ray- or computed tomography-based planning. Methods Patients treated between January 2014 and December 2015 were included. Patients underwent x-ray- or computed tomography-based BT planning with an aim to deliver equivalent doses in 2 Gy (EQD2) > 84 Gy₁₀ to point A while minimizing maximum dose received by rectum or bladder to a point or 2 cc volume to < 75 Gy EQD2 and < 90 Gy EQD2, respectively_. The impact of known prognostic factors was evaluated. Results A total of 339 patients were evaluated. Median age was 52 (32 to 81) years; 52% of patients had stage IB2 to IIB and 48% had stage III to IVA disease. There was 85% compliance with chemoradiation, and 87% of patients received four or more cycles. Median point A dose was 84 (64.8 to 89.7) Gy. The median rectal and bladder doses were 73.5 (69.6 to 78.4) Gy₃ and 83 (73.2 to 90.0) Gy₃, respectively. At a median follow-up of 28 (4 to 45) months, the 3-year local, disease-free, and overall survival for stage IB to IIB disease was 94.1%, 83.3%, and 82.7%, respectively. The corresponding rates for stage III to IVA were 85.1%, 60.7%, and 69.6%. Grade III to IV proctitis and cystitis were observed in 4.7% and 0% of patients, respectively. Conclusion This audit demonstrates good 3-year outcomes that are comparable to published MRBT series. Conventional BT with selective use of interstitial needles and MRBT should continue as standard procedures until level-I evidence for MRBT becomes available.

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

PURPOSE

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

METHODS AND MATERIALS

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

RESULTS

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

CONCLUSIONS

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

In vivo dosimetry using MOSkin detector during Cobalt-60 high-dose-rate (HDR) brachytherapy of skin cancer

The MOSkin, a metal-oxide semiconductor field-effect transistor based detector, is suitable for evaluating skin dose due to its water equivalent depth (WED) of 0.07 mm. This study evaluates doses received by target area and unavoidable normal skin during a the case of skin brachytherapy. The MOSkin was evaluated for its feasibility as detector of choice for in vivo dosimetry during skin brachytherapy. A high-dose rate Cobalt-60 brachytherapy source was administered to the tumour located at the medial aspect of the right arm, complicated with huge lymphedema thus limiting the arm motion. The source was positioned in the middle of patients' right arm with supine, hands down position. A 5 mm lead and 5 mm bolus were sandwiched between the medial aspect of the arm and lateral chest to reduce skin dose to the chest. Two calibrated MOSkin detectors were placed on the target and normal skin area for five treatment sessions for in vivo dose monitoring. The mean dose to the target area ranged between 19.9 and 21.1 Gy and was higher in comparison with the calculated dose due to contribution of backscattered dose from lead. The mean measured dose at normal skin chest area was 1.6 Gy (1.3-1.9 Gy), less than 2 Gy per fraction. Total dose in EQD₂ received by chest skin was much lower than the recommended skin tolerance. The MOSkin detector presents a reliable real-time dose measurement. This study has confirmed the applicability of the MOSkin detector in monitoring skin dose during brachytherapy treatment due to its small sensitive volume and WED 0.07 mm.

Laparoscopic Allograft Spacer Placement to Minimize Bowel Dose During Re-irradiation with Interstitial Brachytherapy

In primary or re-irradiation of gynecologic malignancies, achieving optimal dosimetry with adjacent normal tissue becomes challenging. Surgical spacers are tissue-equivalent materials placed within the patient to protect organs at risk from long-term radiation effects and are commonly used in prostate cancer. We report the use of an allograft mesh to protect adhesed bowel from high-dose radiation for definitive treatment of recurrent endometrial cancer. An 88-year-old female was diagnosed with International Federation of Gynecology and Obstetrics (FIGO) stage II endometrial cancer after she developed urinary frequency, hesitancy, and hematuria. She underwent neoadjuvant chemoradiation, followed by laparoscopic hysterectomy with bilateral salpingo-oophorectomy and adjuvant vaginal cuff brachytherapy. She developed 1.8 cm bilateral vaginal cuff recurrence and was dispositioned for interstitial brachytherapy. An allograft mesh spacer was placed laparoscopically before repeat, high dose rate brachytherapy to protect nearby structures. Dose-escalation was achieved without compromising normal tissue constraints. The patient tolerated the procedure without evidence of long-term toxicity at one year. Multidisciplinary discussion may help identify patients who would benefit from spacer placement before select dose-escalated radiation therapy. Laparoscopic allograft mesh is one of many types of surgical spacers available for such patients.

High-dose-rate vs. low-dose-rate interstitial brachytherapy boost for anal canal cancers

PURPOSE

The purpose of this study was to analyze and compare clinical outcomes of low-dose-rate (LDR) and high-dose-rate (HDR) interstitial brachytherapy boost (ISBT) after EBRT or radio chemotherapy for the treatment of anal canal cancers.

METHODS AND MATERIALS

One hundred patients with anal canal cancers were treated at our institution by ISBT [LDR (n = 50); HDR (n = 50)]. Chronic toxicity rates, local control, disease-free survival, overall survival, and colostomy-free survival of the two different dose-rate brachytherapy modalities were analyzed and compared.

RESULTS

With a median followup of 42.2 months (95% CI, [34.5-48.8]), 9 (9% [4.8-16.2%]) local recurrences were observed, 4 (8% [3.2-18.8%]) in LDR vs. 5 (10% [4.4-21.4%]) in HDR group (odds ratio [OR] = 1.28 [0.32-5.07], p = 0.73). The 5-year rate of local control for the entire population was 90% [81-95%], 93% [79-98%] vs. 86% [69-94%] for LDR and HDR, respectively (p = 0.38). The 5-year disease-free survival rate for all patients was 82% [71-90%], 88% [73-95%] vs. 72% [44-88%] for LDR and HDR, respectively (p = 0.21). The 5-year overall survival rate for global population was 94% [84-98%], with no significant differences between LDR (97% [79-100%]) and HDR (93% [80-98%]) (p = 0.27). The 5-year colostomy-free survival rate was 92% [83-96%], respectively, 95% [83-99%] vs. 86% [69-94%] for LDR and HDR (p = 0.21). Significant differences were found in terms of chronic toxicity rates, with 28 (56% [42.3-68.8%]) patients concerned in low-dose-rate brachytherapy vs. 17 (34% [22.4-47.9%]) in high-dose-rate brachytherapy (OR = 0.40 [0.18-0.91], p = 0.03).

CONCLUSIONS

Local recurrence rates were comparable between both groups; HDR brachytherapy seem to have a better toxicity profile. Our data confirmed the finding that HDR can be used to safely administer ISBT without increasing chronic toxicity.

Pelvic side wall recurrence in locally advanced cervical carcinoma treated with definitive chemoradiation-clinical impact of pelvic wall dose

OBJECTIVE

Pelvic side wall dose in locally advanced cervical carcinoma treated with definitive chemoradiation has been debated. The present study investigated relationship of disease recurrence with dose for the pelvic side wall. It also attempted to identify minimal dose that significantly reduced recurrence.

METHODS

Pelvic side wall recurrence at median 24 months was assessed clinically and radiologically across three groups of patients receiving variable pelvic wall doses using no parametrial boost, external beam or interstitial boost, or dose escalated combined external beam with interstitial boost.

RESULTS

At 24 months, recurrence occurred in 3/155 boost vs 40/130 no boost patients. (p < 0.0001). Receiver operating characteristic curve analysis demonstrated cut-off pelvic wall dose to be 58.9 Gy (p < 0.0001). Dose escalated combined boost showed no significant benefit compared to single modality parametrial boost (p = 0. 0.553).

CONCLUSION

Mean pelvic wall dose of at least 58.9 Gy offers clinically significant benefit in pelvic wall control. Doses recommended by guidelines should be adhered to in the patients' best interests.

ADVANCES IN KNOWLEDGE

This preliminary study determined a relationship between recurrence rates and dose to the pelvic side wall and also a cut-off dose that significantly improved pelvic wall control in locally advanced cervical cancer.

Multiparametric MRI-guided dose boost to dominant intraprostatic lesions in CT-based High-dose-rate prostate brachytherapy

OBJECTIVE

The purpose of this study is to investigate the dosimetric feasibility of delivering focal dose to multiparametric (mp) MRI-defined DILs in CT-based high-dose-rate (HDR) prostate brachytherapy with MR/CT registration and estimate its clinical benefit.

METHODS

We retrospectively investigated a total of 17 patients with mp-MRI and CT images acquired pre-treatment and treated by HDR prostate brachytherapy. 21 dominant intraprostatic lesions (DILs) were contoured on mp-MRI and propagated to CT images using a deformable image registration method. A boost plan was created for each patient and optimized on the original needle pattern. In addition, separate plans were generated using a virtually implanted needle around the DIL to mimic mp-MRI guided needle placement. DIL dose coverage and organ-at-rick (OAR) sparing were compared with original plan results. Tumor control probability (TCP) was estimated to further evaluate the clinical impact on the boost plans.

RESULTS

Overall, optimized boost plans significantly escalated dose to DILs while meeting OAR constraints. The addition of mp-MRI guided virtual needles facilitate increased coverage of DIL volumes, achieving a V150 > 90% in 85 % of DILs compared with 57 % of boost plan without an additional needle. Compared with original plan, TCP models estimated improvement in DIL control by 28 % for patients with external-beam treatment and by 8 % for monotherapy patients.

CONCLUSION

With MR/CT registration, the proposed mp-MRI guided DIL boost in CT-based HDR brachytherapy is feasible without violating OAR constraints, and indicates significant clinical benefit in improving TCP of DIL. It may represent a strategy to personalize treatment delivery and improve tumor control.

ADVANCES IN KNOWLEDGE

This study investigated the feasibility of mp-MRI guided DIL boost in HDR prostate brachytherapy with CT-based treatment planning, and estimated its clinical impact by TCP and NTCP estimation.

Stereotactic Body Radiation Therapy, Intensity-Modulated Radiation Therapy, and Brachytherapy Boost Modalities in Invasive Cervical Cancer: A Study of the National Cancer Data Base

BACKGROUND AND PURPOSE

Our objective was to determine whether stereotactic body radiotherapy (SBRT), intensity-modulated radiation therapy (IMRT), and brachytherapy boost techniques have comparable overall survival in treating cervical cancer when adjusted for known prognostic factors.

MATERIALS AND METHODS

We used the National Cancer Database to study women with invasive cervical cancer who were treated with radiation between 2004 and 2013. A logistic regression model was built to identify factors associated with the receipt of SBRT and IMRT. Outcomes were compared using Kaplan-Meier and propensity score matching.

RESULTS

Of all 15,905 patients, 14,394 (90.5%) received brachytherapy, 42 (0.8%) received SBRT, and 1468 (9.2%) received IMRT. After propensity score matching, there was no significant difference in overall survival (OS) for patients who received SBRT boost versus brachytherapy boost (hazard ratio = 1.477, 95% confidence interval = 0.746-2.926, P = 0.263) but a significant OS detriment in patients who received IMRT boost versus brachytherapy boost (hazard ratio = 1.455, 95% confidence interval = 1.300-1.628, P < 0.001).

CONCLUSIONS

In a propensity-matched analysis, those who received SBRT boost had equal OS when compared with brachytherapy, but those who received IMRT boost had worse OS when compared with brachytherapy.

Comparative analysis of image-guided adaptive interstitial brachytherapy and intensity-modulated arc therapy versus conventional treatment techniques in cervical cancer using biological dose summation

Purpose

To compare image-guided adaptive interstitial brachytherapy (BT) and intensity-modulated arc therapy (IMAT) with conventional treatment techniques in cervical cancer using an alternative biological dose summation method.

Material and methods

Initially, 21 interstitial BT and IMAT plans of patients with cervical cancer were included and additional plans were created (inverse optimized interstitial, optimized intracavitary, non-optimized intracavitary BT plans, and conformal external beam radiotherapy [EBRT]). The most exposed volume of critical organs in BT were identified manually on EBRT CT images. Biological total doses (EQD2) were calculated and compared between each combination of BT and EBRT plans. This method was compared with uniform dose conception (UDC) in IMAT and conformal EBRT plans.

Results

The D₉₀ of high-risk CTV and D₂ of bladder and sigmoid were different in BT techniques only: p = 0.0149, < 0.001, < 0.001, respectively. The most advantageous values were obtained in the interstitial treatment plans and inverse optimized interstitial plans did not differ dosimetrically from these, while optimized intracavitary plans resulted in worse dose-volume parameters, and the worst of all were intracavitary plans without optimization. The D₂ of rectum was significantly lower with IMAT than with conformal EBRT plans (p = 0.037) and showed the same trend in BT plans as the other parameters (p < 0.001). The UDC dose summation method overestimated D₂ of bladder, rectum, and sigmoid (p < 0.001 for all).

Conclusions

Although optimization improves the quality of conventional BT plans, interstitial plans produce significantly higher dose coverage of high-risk clinical target volume (HR-CTV) and lower doses to organs at risk (OARs). IMAT plans decrease the dose to the rectum. UDC overestimates OARs doses.

Five-year overall survival following chemoradiation among HIV-positive and HIV-negative patients with locally advanced cervical carcinoma in a South African cohort

OBJECTIVES

In South Africa, where HIV prevalence among adults is 18.9%, cervical carcinoma is the second most common malignancy in women. However, oncology services are considerably more accessible in South Africa than in many neighbouring countries. This study reports five-year overall survival in a cohort of HIV-positive and -negative cervix carcinoma patients undergoing primary radiotherapy at a single institution in South Africa.

METHODS

Prospective cohort study of all locally advanced cervix carcinoma patients referred for radiotherapy (EBRT) from July 2007 to November 2011. Overall survival (OS) was the primary end-point.

RESULTS

A total of 492 patients commenced treatment with radical intent, including 71 HIV-positive patients (14.4%) and 421 HIV-negative patients (85.6%). Of the 433 who were prescribed standard fractionation EBRT, 384 were prescribed concurrent platinum-based chemotherapy (88.7%). Fewer HIV-positive than HIV-negative patients (58.5% vs. 76.1%; p = 0.007) completed ≥4 cycles. The OS of HIV-negative patients was 49.5% (95%CI; 44.6%-54.4%) at 5 years. The OS of HIV-positive patients was significantly lower, 35.9% (95% CI; 23.9%-48.0%) at 5 years (p = 0.002). In our Cox models, factors affecting outcome were HIV infection, stage IIIB disease, presence of hydronephrosis, and delivery of concurrent chemotherapy.

CONCLUSION

In our large cohort, HIV-positive patients had poorer survival than HIV-negative patients, however nearly 40% survived 5 years, justifying provision of the best standard of care to HIV-positive patients with cervical carcinoma.

Image-based multichannel vaginal cylinder brachytherapy for the definitive treatment of gynecologic malignancies in the vagina

PURPOSE

Brachytherapy is integral to vaginal cancer treatment and is typically delivered using an intracavitary single-channel vaginal cylinder (SCVC) or an interstitial brachytherapy (ISBT) applicator. Multi-channel vaginal cylinder (MCVC) applicators allow for improved organ-at-risk (OAR) sparing compared to SCVC while maintaining target coverage. We present clinical outcomes of patients treated with image-based high dose-rate (HDR) brachytherapy using a MCVC.

METHODS AND MATERIALS

Sixty patients with vaginal cancer (27% primary vaginal and 73% recurrence from other primaries) were treated with combination external beam radiotherapy (EBRT) and image-based HDR brachytherapy utilizing a MCVC if residual disease thickness was 7 mm or less after EBRT. All pts received 3D image-based BT to a total equivalent dose of 70-80 Gy.

RESULTS

The median high-risk clinical target volume was 24.4 cm³ (interquartile range [IQR], 14.1), with a median dose to 90% of 77.2 Gy (IQR, 2.8). After a median follow-up of 45 months (range, 11-78), the 4-year local-regional control, distant control, DFS, and OS rates were 92.6%, 76.1%, 64.0%, and 67.2%, respectively. The 4-year LRC rates were similar between the primary vaginal (92%) and recurrent (93%) groups (p = 0.290). Pts with lymph node positive disease had a lower rate of distant control at 4 years (22.7% vs. 89.0%, p < 0.001). There were no Grade 3 or higher acute complications. The 4-year rate of late Grade 3 or higher toxicity was 2.7%.

CONCLUSIONS

Clinical outcomes of pts with primary and recurrent vaginal cancer treated definitively in a systematic manner with combination EBRT with image-guided HDR BT utilizing a MCVC applicator demonstrate high rates of local control and low rates of severe morbidity. The MCVC technique allows interstitial implantation to be avoided in select pts with ≤7 mm residual disease thickness following EBRT while maintaining excellent clinical outcomes with extended 4-year follow-up in this rare malignancy.

Radiobiological considerations in combining doses from external beam radiotherapy and brachytherapy for cervical cancer

The recommended radio-therapeutic treatment for cervix cancer consists of a first phase of external beam radiotherapy (EBRT) plus a second phase of brachytherapy (BT), the combined treatment being delivered within 8 weeks. In order to assess a comprehensive dosimetry of the whole treatment, it is necessary to take into account that these two phases are characterized by different spatial and temporal dosimetric distributions, which complicates the task of the summation of the two contributions, EBRT and BT. Radiobiology allows to tackle this issue pragmatically by means of the LQ model and, in fact, this is the usual tool currently in use for this matter. In this work, we describe the rationale behind the summation of the dosimetric contributions of the two phases of the treatment, EBRT and BT, for cervix cancer, as carried out with the LQ model. Besides, we address, from a radiobiological point of view, several important considerations regarding the use of the LQ model for this task. One of them is the analysis of the effect of the overall treatment time in the result of the global treatment. Another important question considered is related to the fact that the capacity of LQ to predict the treatment outcomes is deteriorated when the dose per fraction of the radiotherapic scheme exceeds 6-10 Gy, which is a typical brachytherapy fractionation. Finally, we analyze the influence of the uncertainty and the variability of the main parameters utilized in the LQ model formulation in the assessment of the global dosimetry.

Adjuvant external beam radiation and brachytherapy for vaginal resection margin positive cervical cancer

PURPOSE

To evaluate the treatment outcomes of adjuvant external beam radiation therapy (EBRT) and vaginal brachytherapy (VB) following radical hysterectomy in cervical cancer patients with involved vaginal resection margin (VRM). Materials and.

METHODS

We retrospectively reviewed the medical records of 21 patients treated with postoperative EBRT and VB for positive VRM FIGO stage IB-IIA cervical cancer between 2003 and 2015. Concurrent platinum-based chemotherapy was administered to all patients.

RESULTS

The median whole pelvis EBRT dose was 50.4 Gy (range, 45 to 50.4 Gy). In the VB, the median dose per fraction, number of fractions, and total dose delivered were: 4 Gy (range, 3.0 to 4.0 Gy), 4 fractions (range, 3 to 5 fractions), and 16 Gy (range, 12 to 20 Gy), respectively. At a median follow-up of 46 months (range, 9 to 122 months), local recurrence was observed in 2 patients, and distant metastasis was present in 7 patients. All patients with local recurrence subsequently developed distant metastases. The 5-year local control, disease-free survival, and overall survival rates were 89.1%, 65.9%, and 62.9%, respectively. Of the 21 patients, 7 patients (33.3%) reported grade 2 acute toxicity; however, there were no grade 3 or higher acute adverse events. Grade 1-2 late toxicities were observed in 8 patients. Late grade 3 urinary toxicity was reported in 1 patient. Conclusions: Adjuvant EBRT and VB showed excellent local control and low toxicity in cervical cancer patients with positive VRM. Although limited by its retrospective nature, the findings from our study provide evidence supporting the use of additional VB in pathologically involved VRM.

A Monte Carlo investigation of the dose distribution for 60Co high dose rate brachytherapy source in water and in different media

In this study, the dosimetric characterization for The BEBIG ⁶⁰Co High Dose Rate (HDR) brachytherapy source model Co0.A86 was investigated and the validity of the EGS5 Monte Carlo code to reproduce the dosimetric parameters in water phantom was checked. In addition, the dose distribution for different tissue phantoms was calculated. The BEBIG ⁶⁰Co HDR brachytherapy source was modeled using EGS5 Monte Carlo simulation code. A description of the source design, geometry and materials used in this work were provided. According to the update TG43-U1 formalism of AAPM, the air kerma strength, the dose rate constant, 2D rectangular dose distribution in water were calculated, moreover, the results of the radial dose function were obtained in water and different tissue phantoms; bone, lung, adipose tissue, breast and muscle. The obtained results were tabulated and presented in graphical formats for the comparison with available data. The calculated value of the air kerma strength of this study, 3.0419 U Bq^-1, agree well with that of the other Monte Carlo calculation. The 2D look-up along-away rectangular dose were obtained in water, the results were similar to the published data for all distances larger than 1 cm, for the distances near to the source region on the transversal source axis small differences are apparent. The radial dose function were presented in graphical format for the comparison between the dose distribution in water and different tissue phantoms. The EGS5 results obtained in this study shows good consistency with the published data for the dosimetric parameters of the of the BEBIG ⁶⁰Co HDR brachytherapy source. It seems that the radial dose function calculated in water differed in tissue phantoms due to the atomic composition and densities for media that are not taken account by the TG43-U1 formalism.

Plesiobrachytherapy for chest wall recurrences of breast cancer after mastectomy and radiotherapy for breast cancer

PURPOSE

The purpose of the study was to evaluate the results of high-dose-rate plesiobrachytherapy for local relapse after mastectomy and radiotherapy in terms of both local control and survival.

METHODS

We reviewed retrospectively 43 patients who experienced a chest wall relapse of breast cancer after local excision (22 patients) or not (21 patients). Patients were treated with an individually designed mold with four to six fractions of 3-6 Gy high-dose-rate brachytherapy, two fractions per week. Mean total dose was 24 Gy.

RESULTS

After surgical resection, the 3- and 5-year local control rates were 80% and 73%, respectively. For nonresectable patients, the overall response rate was 86%, and the 3-year infield local control and chest wall local control were 51% and 26%, respectively. The 5-year survival rate was 50.5% for the whole population, 62% after surgery, and 45.4% for irresectable patients. Acute Grade 2 or 3 toxicity occurred in 43% of the patients, resolving in a few days. Two patients had a local necrosis lasting 3 to 7 months. Late toxicity was observed in 5 patients.

CONCLUSIONS

High-dose-rate plesiobrachytherapy is a simple outpatient technique to treat chest wall local relapse of breast cancer. As a reirradiation technique, its tolerance is acceptable. This technique may obtain long-term local control after incomplete surgery; in case of nonresectable disease, a high response rate was observed, which might improve the quality of life of these patients.

Effects of vaginal cylinder position on dose distribution in patients with endometrial carcinoma in treatment of vaginal cuff brachytherapy

PURPOSE

To investigate the impact of different cylinder positions on dosimetry of critical structures in patients with endometrial carcinoma undergoing three-dimensional image-based vaginal cuff brachytherapy (VCB).

MATERIAL AND METHODS

We delivered VCB at a dose of 4 Gy to a depth of 5 mm in the vaginal cuff of 15 patients using three different cylinder positions (neutral [N], parallel [P], and angled [A]) according to the longitudinal axis of the patient. We analyzed the dose-volume distribution and volumetric variability of the rectum and bladder. We converted the total doses to equivalent doses in 2 Gy (EQD₂) using a linear-quadratic model (a/b = 3 Gy).

RESULTS

The mean rectum volume for the N, P, and A positions was 68.2 ± 22.7 cc, 79.3 ± 33.7 cc, and 74.2 ± 29.6 cc, respectively. The mean rectum volume for the P position was significantly larger than that for the N position (p = 0.03). Relative to the N position, the A position resulted in a lower total EQD₂ in the highest irradiated 2 cc (D_2cc; p = 0.001), 1 cc (D_1cc; p = 0.004), and 0.1 cc (D_0.1cc; p = 0.047) of the rectum. Similarly, the P position resulted in a lower EQD₂ in the D_2cc (p = 0.018) and D_1cc (p = 0.024) of the rectum relative to the N position. In the bladder, the P position resulted in a higher EQD₂ in the D_2cc relative to the N position (p = 0.02). There was no dosimetric difference between the P and A positions in either the rectum or the bladder.

CONCLUSIONS

Vaginal cuff brachytherapy in the P and A positions is significantly superior to that in the N position in terms of rectum dosimetry. The bladder dose in the N position is considerably lower than that in the other positions.

Dose-volume correlation of cumulative vaginal doses and late toxicity after adjuvant external radiation and brachytherapy for cervical cancer

PURPOSE

To investigate dose-response relationship between vaginal doses and long-term morbidity.

METHODS AND MATERIALS

Patients receiving adjuvant pelvic (chemo) radiation and brachytherapy for cervical cancer from January 2011 to December 2014 were included. Baseline vaginal length was determined clinically and from imaging at BT planning. Dose points were defined along mucosa and at 5 mm depth at 12, 3, 6, and 9 'o' clock positions at every 2 cm from apex to introitus. Cumulative equivalent doses in 2 Gy were calculated. Vaginal stenosis was reported in reference to baseline length according to CTCAE version 3.0. Receiver operator characteristics curve was used to identify dose thresholds for univariate and multivariate analysis.

RESULTS

Overall, 78 women with median age of 49 (32-71) years were included. The median dose at vaginal apex mucosa and 5 mm depth was 118 Gy₃ (78-198) and 81 Gy₃ (70-149) respectively. At median follow-up of 36 (18-60) months, vaginal stenosis ≥25%, and grade ≥ II telangiectasia was observed in 33.3% and 45.7%, respectively. On receiver operator characteristics analysis, apical mucosal dose >142 Gy₃ and recto-vaginal point dose >86 Gy₃ predicted for stenosis on univariate (p = 0.02, p = 0.06) and multivariate analysis (p = 0.04). The probability of stenosis increased from 32% at 70 Gy₃, 38% at 80 Gy₃, and 45% at 90 Gy₃ rectovaginal point dose. No correlation was observed between vaginal doses and telangiectasia and vaginal stenosis and sexual quality of life.

CONCLUSION

Vaginal apex mucosal dose >142 Gy₃ independently predicts for vaginal stenosis.

Spatial features of dose-surface maps from deformably-registered plans correlate with late gastrointestinal complications

This study investigates the associations between spatial distribution of dose to the rectal surface and observed gastrointestinal toxicities after deformably registering each phase of a combined external beam radiotherapy (EBRT)/high-dose-rate brachytherapy (HDRBT) prostate cancer treatment. The study contains data for 118 patients where the HDRBT CT was deformably-registered to the EBRT CT. The EBRT and registered HDRBT TG43 dose distributions in a reference 2 Gy/fraction were 3D-summed. Rectum dose-surface maps (DSMs) were obtained by virtually unfolding the rectum surface slice-by-slice. Associations with late peak gastrointestinal toxicities were investigated using voxel-wise DSM analysis as well as parameterised spatial patterns. The latter were obtained by thresholding DSMs from 1-80 Gy (increment  =  1) and extracting inferior-superior extent, left-right extent, area, perimeter, compactness, circularity and ellipse fit parameters. Logistic regressions and Mann-Whitney U-tests were used to correlate features with toxicities. Rectal bleeding, stool frequency, diarrhoea and urgency/tenesmus were associated with greater lateral and/or longitudinal spread of the high doses near the anterior rectal surface. Rectal bleeding and stool frequency were also influenced by greater low-intermediate doses to the most inferior 20% of the rectum and greater low-intermediate-high doses to 40-80% of the rectum length respectively. Greater low-intermediate doses to the superior 20% and inferior 20% of the rectum length were associated with anorectal pain and urgency/tenesmus respectively. Diarrhoea, completeness of evacuation and proctitis were also related to greater low doses to the posterior side of the rectum. Spatial features for the intermediate-high dose regions such as area, perimeter, compactness, circularity, ellipse eccentricity and confinement to ellipse fits were strongly associated with toxicities other than anorectal pain. Consequently, toxicity is related to the shape of isodoses as well as dose coverage. The findings indicate spatial constraints on doses to certain sections of the rectum may be important for reducing toxicities and optimising dose.

HIV Infection and Survival Among Women With Cervical Cancer

Purpose Cervical cancer is the leading cause of cancer death among the 20 million women with HIV worldwide. We sought to determine whether HIV infection affected survival in women with invasive cervical cancer. Patients and Methods We enrolled sequential patients with cervical cancer in Botswana from 2010 to 2015. Standard treatment included external beam radiation and brachytherapy with concurrent cisplatin chemotherapy. The effect of HIV on survival was estimated by using an inverse probability weighted marginal Cox model. Results A total of 348 women with cervical cancer were enrolled, including 231 (66.4%) with HIV and 96 (27.6%) without HIV. The majority (189 [81.8%]) of women with HIV received antiretroviral therapy before cancer diagnosis. The median CD4 cell count for women with HIV was 397 (interquartile range, 264 to 555). After a median follow-up of 19.7 months, 117 (50.7%) women with HIV and 40 (41.7%) without HIV died. One death was attributed to HIV and the remaining to cancer. Three-year survival for the women with HIV was 35% (95% CI, 27% to 44%) and 48% (95% CI, 35% to 60%) for those without HIV. In an adjusted analysis, HIV infection significantly increased the risk for death among all women (hazard ratio, 1.95; 95% CI, 1.20 to 3.17) and in the subset that received guideline-concordant curative treatment (hazard ratio, 2.63; 95% CI, 1.05 to 6.55). The adverse effect of HIV on survival was greater for women with a more-limited stage cancer ( P = .035), those treated with curative intent ( P = .003), and those with a lower CD4 cell count ( P = .036). Advanced stage and poor treatment completion contributed to high mortality overall. Conclusion In the context of good access to and use of antiretroviral treatment in Botswana, HIV infection significantly decreases cervical cancer survival.

Carcinoma of the cervix in elderly patients treated with radiotherapy: patterns of care and treatment outcomes

OBJECTIVE

The aim of this analysis was to examine the management of cervix cancer in elderly patients referred for radiotherapy and the results of treatment in terms of overall survival (OS), relapse-free survival (RFS), and treatment-related toxicities.

METHODS

Patients were eligible if they were aged ≥75 years, newly diagnosed with cervix cancer and referred for radiotherapy as part of their treatment. Patient details were retrieved from the gynaecology service database where clinical, histopathological treatment and follow-up data were prospectively collected.

RESULTS

From 1998 to 2010, 126 patients aged ≥75 years, met selection criteria. Median age was 81.5 years. Eighty-one patients had definitive radiotherapy, 10 received adjuvant radiotherapy and 35 had palliative radiotherapy. Seventy-one percent of patients had the International Federation of Gynecology and Obstetrics stage 1b-2b disease. Median follow-up was 37 months. OS and RFS at 3 years among those treated with curative intent were 66.6% and 75.9% respectively with majority of patients dying without any evidence of cervix cancer. Grade 2 or more late toxicities were: bladder 5%, bowel 11%, and vagina 27%. Eastern Cooperative Oncology Group (ECOG) status was a significant predictor of OS and RFS with each unit increment in ECOG score increased the risk of death by 1.69 times (p<0.001).

CONCLUSION

Following appropriate patient selection, elderly patients treated curatively with radiotherapy for cervix cancer have good disease control. Palliative hypofractionated regimens are well tolerated in patients unsuitable for radical treatment.

HIV Status and Acute Hematologic Toxicity Among Patients With Cervix Cancer Undergoing Radical Chemoradiation

INTRODUCTION

Women infected with the human immunodeficiency virus (HIV) have a higher risk of developing cervix carcinoma than do other women who are thought to be more vulnerable to acute toxicities during chemoradiation. We compared HIV-positive/HIV-negative patients with cervix carcinoma at a single institution with respect to cancer treatment toxicities.

METHODS AND MATERIALS

Among patients with stage Ib1-IIIb invasive cervical carcinoma who received radiation or chemoradiation with curative intent, we evaluated demographic and clinical characteristics of HIV-positive and HIV-negative patients. Treatment regimens were documented and toxicities scored as per Radiation Therapy Oncology Group guidelines. We developed logistic regression models for the associations of grade 3/4 toxicities with HIV status.

RESULTS

Complete data were available on 213 patients, including 36 (16.8%) who were HIV positive. More than 85% of both HIV-positive and HIV-negative patients received a minimum of 68-Gy equivalent dose in 2-Gy-fraction external beam and high-dose-rate brachytherapy. More HIV-positive than HIV-negative patients were prescribed radiation alone (38.9% vs 24.29%, P = 0.01), experienced at least 1 grade 3/4 toxicity (38.9% vs 26.6%), or developed grade 3/4 leucopenia (30.6% vs 10.2%, P = 0.003).In a multivariable model, patients who developed a grade 3/4 toxicity were 4 times as likely to have received chemotherapy (odds ratio, 4.41 [95% confidence interval, 1.76-11.1]; P = 0.023) and twice as likely to be HIV positive (odds ratio 2.16 [95% confidence interval, 0.98-4.8]; P = 0.05) as women who did not experience such toxicities.

CONCLUSIONS

HIV-positive patients with cervical carcinoma received adequate radiotherapy but were less likely than HIV-negative patients to complete chemotherapy. Few HIV-positive or HIV-negative patients who received radiotherapy without chemotherapy experienced grade 3/4 toxicity. However, among patients who received chemotherapy, those who were HIV positive were more likely than others to experience hematologic toxicity.

A practical review of magnetic resonance imaging for the evaluation and management of cervical cancer

Cervical cancer is a leading cause of mortality in women worldwide. Staging and management of cervical cancer has for many years been based on clinical exam and basic imaging such as intravenous pyelogram and x-ray. Unfortunately, despite advances in radiotherapy and the inclusion of chemotherapy in the standard plan for locally advanced disease, local control has been unsatisfactory. This situation has changed only recently with the increasing implementation of magnetic resonance image (MRI)-guided brachytherapy. The purpose of this article is therefore to provide an overview of the benefits of MRI in the evaluation and management of cervical cancer for both external beam radiotherapy and brachytherapy and to provide a practical approach if access to MRI is limited.

Brachytherapy for malignancies of the vagina in the 3D era

Vaginal cancer is an uncommon malignancy and can be either recurrent or primary. In both cases, brachytherapy places a central role in the overall treatment course. Recent technological advances have led to more advanced brachytherapy techniques, which in turn have translated to improved outcomes for patients with malignancies of the vagina. The aim of this manuscript is to outline the incorporation of modern brachytherapy into the treatment of patients with vaginal cancer including patient selection along with the role of brachytherapy in conjunction with other treatment modalities, various brachytherapy techniques, treatment planning, dose fractionation schedules, and normal tissue tolerance.

Dose-response effect of human equivalent radiation in the mandible

BACKGROUND

Despite widespread use of adjuvant irradiation for head and neck cancer, the extent of damage to the underlying bone is not fully understood but is associated with pathologic fractures, nonunion, and osteoradionecrosis. The authors' laboratory previously demonstrated that radiation significantly impedes new bone formation in the murine mandible. We hypothesize that the detrimental effects of human equivalent radiation on the murine mandible results in a dose-dependent degradation in traditional micro-computed tomography (micro-CT) metrics.

METHODS

Fifteen male Sprague-Dawley rats were randomized into 3 radiation dosage groups: low (5.91 Gy), middle (7 Gy), and high (8.89 Gy), delivered in 5 daily fractions. These dosages approximated 75%, 100%, and 150%, respectively, of the biologically equivalent dose that the human mandible receives during radiation treatment. Hemimandibles were harvested 56 days after radiation and scanned using micro-CT. Bone mineral density, tissue mineral density, and bone volume fraction were measured along with microdensitometry measurements.

RESULTS

Animals demonstrated dose-dependent adverse effects of mucositis, alopecia, weight loss, and mandibular atrophy with increasing radiation. Traditional micro-CT parameters were not sensitive enough to demonstrate statistically significant differences between the radiated groups; however, microdensitometry analysis showed clear differences between radiated groups and statistically significant changes between radiated and nonradiated groups.

CONCLUSIONS

The authors report dose-dependent and clinically significant adverse effects of fractionated human equivalent radiation to the murine mandible. The authors further report the limited capacity of traditional micro-CT metrics to adequately capture key changes in bone composition and present microdensitometric histogram analysis to demonstrate significant radiation-induced changes in mineralization patterns.

High-dose-rate vaginal brachytherapy with chemotherapy for surgically staged localized uterine serous carcinoma

Purpose

To evaluate our institutional experience combining carboplatin-paclitaxel (C/T) chemotherapy with high-dose-rate (HDR) intra-vaginal brachytherapy (IVB) following comprehensive surgical staging in localized uterine serous carcinoma (USC).

Material and methods

Institutional chart review identified 56 patients with FIGO 2009 stage I-II USC treated between 2000-2010. Patients underwent total hysterectomy, bilateral salpingo-oopherectomy, and comprehensive surgical staging including pelvic and para-aortic lymph node dissection, omentectomy, and peritoneal cytology. Chemotherapy was 6 cycles of C/T, and the IVB dose was 14 Gy in 2 fractions, prescribed to 0.5 cm from the cylinder surface. Kaplan-Meier methods were used to estimate recurrence-free survival (RFS) and overall survival (OS).

Results

The median follow-up time was 49 months (range: 9-145). The 5-yr RFS and OS were 85% and 93%, respectively. In all cases of recurrence (n = 8), the first site of failure was extra-pelvic. There were no isolated vaginal recurrences, however, there was one vaginal apex recurrence recorded at 19 months in a patient with simultaneous lung metastases. Thus, the 2-year vaginal RFS was 98%.

Conclusions

Excellent vaginal/pelvic control rates were observed. Further study of HDR brachytherapy dose and fractionation in combination with chemotherapy is worthwhile.

External beam radiotherapy plus single-fraction high dose rate brachytherapy in the treatment of locally advanced prostate cancer

PURPOSE

To evaluate the efficacy and toxicity of external beam radiation therapy (EBRT) plus high-dose-rate brachytherapy (HDRB) as a boost in patients (pts) with intermediate or high-risk prostate cancer.

METHODS AND MATERIALS

From 2002 to July 2012, 377 pts with a diagnosis of intermediate or high-risk prostate cancer were treated with EBRT plus HDRB. Median patient age was 66 years (range, 41-86). Most patients (347 pts; 92%) were classified as high-risk (stage T2c-T3, or PSA>20 ng/mL, or GS ⩾ 8), with 30 patients (8%) considered intermediate risk. All patients underwent EBRT at a prescribed dose of 60.0 Gy (range, 45-70 Gy) to the prostate and seminal vesicles. A total of 120 pts (31%) received a dose of 46 Gy (45-50 Gy) to the true pelvis. All pts received a single-fraction 9 Gy (9-15 Gy) HDR boost. Most patients (353; 94%) were prescribed complete androgen deprivation therapy (ADT). Overall survival (OS), cause-specific survival (CSS), and biochemical relapse-free survival (BRFS) rates were calculated. In the case of BRFS, patients with <26 months of follow-up (n=106) were excluded to minimize the impact of ADT.

RESULTS

The median follow-up for the entire sample was 50 months (range, 12-126), with 5-year actuarial OS and CSS, respectively, of 88% (95% confidence interval [CI]: 84-92) and 98% (95% CI: 97-99). The 5-year BRFS was 91% (95% CI: 87-95) in the 271 pts with ⩾ 26 months (median, 60 months) of follow-up. Late toxicity included grade 2 and 3 gastrointestinal toxicity in 17 (4.6%) and 6 pts (1.6%), respectively, as well as grades 2 and 3 genitourinary toxicity in 46 (12.2%) and 3 pts (0.8%), respectively.

CONCLUSION

These long-term outcomes confirm that EBRT plus a single-fraction HDRB boost provides good results in treatment-related toxicity and biochemical control. In addition to the excellent clinical results, this fractionation schedule reduces physician workload, treatment-related expenses, patient discomfort and risks associated with anaesthesia. We believe these findings support the use of single-fractionation boost techniques.

Ultrasound guided conformal brachytherapy of cervix cancer: survival, patterns of failure, and late complications

Objective

The aim of this study was to report on the long-term results of transabdominal ultrasound guided conformal brachytherapy in patients with cervical cancer with respect to patterns of failures, treatment related toxicities and survival.

Methods

Three hundred and nine patients with cervical cancer who presented to Institute between January 1999 and December 2008 were staged with magnetic resonance imaging and positron emission tomography and treated with external beam radiotherapy and high dose rate conformal image guided brachytherapy with curative intent. Follow-up data relating to sites of failure and toxicity was recorded prospectively.

Results

Two hundred and ninety-two patients were available for analyses. The median (interquantile range) follow-up time was 4.1 years (range, 2.4 to 6.1 years). Five-year failure free survival and overall survival (OS) were 66% and 65%, respectively. Primary, pelvic, para-aortic, and distant failure were observed in 12.5%, 16.4%, 22%, and 23% of patients, respectively. In multivariate analysis, tumor volume and nodal disease related to survival, whereas local disease control and point A dose did not.

Conclusion

Ultrasound guided conformal brachytherapy of cervix cancer has led to optimal local control and OS. The Melbourne protocol compares favorably to the more technically elaborate and expensive GEC-ESTRO recommendations. The Melbourne protocol's technical simplicity with real-time imaging and treatment planning makes this a method of choice for treating patients with cervical cancer.