High dose three-dimensional conformal boost using the real-time tumor tracking radiotherapy system in cervical cancer patients unable to receive intracavitary brachytherapy

Radiosensitization using hydrogen peroxide in patients with cervical cancer

The purpose of the present study was to analyze the feasibility and safety of radiosensitization using hydrogen peroxide for cervical cancer. In superficial tumors, breast cancer and hepatocellular carcinoma, the safety and effectiveness of radiosensitization has been reported; to the best of our knowledge, however, there are no reports on cervical cancer. A total of 20 patients with cervical cancer were recruited. Inclusion criteria were as follows: Patients who required radical external beam radiotherapy (RT); ineligible for or refused brachytherapy; age, ≥20 years; no hematogenous metastasis; Eastern Cooperative Oncology Group Performance Status up to 2; and had not undergone prior treatment. Hydrogen peroxide was used twice a week in combination with RT. A 3% hydrogen peroxide solution-soaked gauze was inserted into the vagina during RT. A total of 45 Gy was delivered in 25 fractions to the whole pelvis with a boost of 10 Gy in 5 fractions if pelvic or para-aortic metastatic lymph nodes were observed. Ultimately, 18 patients were evaluated. Among the 17 patients (excluding one patient with tumor in situ), the one- and two-year overall survival rates were both 90% in patients with stage I/II and 86% in stage III/IV cervical cancer. The adverse events were well tolerated with no severe acute or late adverse events. Although limited by small sample size, short observation time and low radiation dose, the present study demonstrated that radiosensitization treatment may be an option for patients who cannot undergo brachytherapy. The study was retrospectively registered at the university hospital medical information network center (no. UMIN000039045) on January 6, 2020.

Clinical outcomes following conventional external beam radiotherapy boost in Japanese patients with cervical cancer who are ineligible for intracavitary brachytherapy

OBJECTIVE

While external beam radiotherapy boost has been one of the standard management options for locally advanced cervical cancer that is not treatable with intracavitary brachytherapy, its efficacy remains unclear. We assessed clinical outcomes in Japanese patients with cervical cancer who underwent external beam radiotherapy alone and identified related prognostic factors.

METHODS

Patients treated with definitive external beam radiotherapy for cervical cancer unsuitable for intracavitary brachytherapy, including whole pelvic irradiation and external beam radiotherapy boost, were retrospectively examined. The endpoints were progression-free survival, overall survival and adverse events. Additionally, various patient-, tumor- and treatment-specific factors were evaluated to identify significant predictors of progression-free survival.

RESULTS

The study included 37 patients; 3 (8%), 5 (14%), 17 (46%) and 12 (32%) had clinical International Federation of Gynecology and Obstetrics (FIGO) stages I, II, III and IVA, respectively. A total radiation dose of 56-70.2 Gy was administered (84% of patients received 59.4-60.4 Gy). The median follow-up period after radiotherapy was 17 (range, 2-84) months. The progression-free survival rates at 1 and 2 years were 45 and 29%, respectively; the corresponding overall survival rates were 74 and 43%, respectively. On univariate and multivariate analyses of progression-free survival at 2 years, International Federation of Gynecology and Obstetrics stage IVA and a maximum primary tumor diameter >5 cm were associated with significantly worse outcomes (P = 0.026 and P = 0.027, respectively).

CONCLUSION

Approximately 70% of patients with cervical cancer treated with external beam radiotherapy boost instead of intracavitary brachytherapy experienced disease progression within 2 years. These results stress the necessity of devising alternative non-intracavitary brachytherapy treatment approaches, particularly for patients with International Federation of Gynecology and Obstetrics stage IVA and bulky primary tumors.

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

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

Robotic radiosurgery as an alternative to brachytherapy for cervical cancer patients

BACKGROUND AND PURPOSE

To compare MRI-guided brachytherapy (BT) and two different dose prescriptions for robotic radiosurgery (RRS) in locally advanced cervical cancer.

METHODS AND MATERIALS

Eleven patients with FIGO stage IIB-IIIB cervical cancer underwent RRS instead of BT for various reasons. A total dose of 30 Gy was administered in five fractions. The maximum dose was chosen such that the prescribed dose was 70 % of the maximum dose (RRS70). To simulate BT more closely, additional plan calculations were carried out for a higher maximum dose with the same enclosing dose of 30 Gy being now 25 % of the maximum dose (RRS25). BT plans were calculated for the same patients (BTRRS). Finally, the resulting three sets of treatment plans were compared with 38 other patients treated with MRI-guided BT and the same dose prescription (BTref). Plan comparisons were performed based on DVH parameters with regard to target coverage (V100), conformation number (CN), and sparing of the organs at risk (OARs).

RESULTS

The best coverage of V100 = 100 ± 0 % was obtained with RRS25, followed by RRS70 with 97.1 ± 2.7 %, BTref with 90.9 ± 8.9 %, and the intraindividual BTRRS with 80.6 ± 6.4 %. The sparing of OARs was associated with D0.1 cc, D2 cc, and D5 cc to the rectum, sigmoid, and bladder walls. OAR doses were compliant with the GEC-ESTRO guidelines and comparable among RRS70, RRS25, BTRRS, and BTref. By contrast, RRS25 could not fulfill these guidelines, exceeding considerably the tolerable dose constraints for the walls of the critical OARs.

CONCLUSION

Despite of the excellent coverage and higher maximum dose, the unacceptably high exposure to the OARs disqualified RRS25 as an alternative for BT in cervical cancer patients. By contrast, RRS70 offered the best protection for the OARs, comparable to BT, and even better target coverage and conformity than BT.

Correlations of dynamic contrast-enhanced magnetic resonance imaging with morphologic, angiogenic, and molecular prognostic factors in rectal cancer

PURPOSE

To investigate the correlations between parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and prognostic factors in rectal cancer.

MATERIALS AND METHODS

We studied 29 patients with rectal cancer who underwent gadolinium contrast-enhanced, T1-weighted DCE-MRI with a three Tesla scanner prior to surgery. Signal intensity on DCE-MRI was independently measured by two observers to examine reproducibility. A time-signal intensity curve was generated, from which four semiquantitative parameters were calculated: steepest slope (SLP), time to peak (Tp), relative enhancement during a rapid rise (Erise), and maximal enhancement (Emax). Morphologic prognostic factors including T stage, N stage, and histologic grade were identified. Tumor angiogenesis was evaluated in terms of microvessel count (MVC) and microvessel area (MVA) by morphometric study. As molecular factors, the mutation status of the K-ras oncogene and microsatellite instability were assessed. DCE-MRI parameters were correlated with each prognostic factor using bivariate correlation analysis. A p-value of <0.05 was considered significant.

RESULTS

Erise was significantly correlated with N stage (r=-0.387 and -0.393, respectively, for two independent data), and Tp was significantly correlated with histologic grade (r=0.466 and 0.489, respectively). MVA was significantly correlated with SLP (r= -0.532 and -0.535, respectively) and Erise (r=-0.511 and -0.446, respectively). MVC was significantly correlated with Emax (r=-0.435 and -0.386, respectively). No significant correlations were found between DCE-MRI parameters and T stage, K-ras mutation, or microsatellite instability.

CONCLUSION

DCE-MRI may provide useful prognostic information in terms of histologic differentiation and angiogenesis in rectal cancer.

Stereotactic body radiotherapy (SBRT): Technological innovation and application in gynecologic oncology

OBJECTIVES

Stereotactic body radiotherapy (SBRT) is a novel form of noninvasive, highly conformal radiation treatment that delivers a high dose to tumor. The advantage of the technique resides in its ability to provide a high dose to tumor but spare normal tissues to an extent not previously possible. In this paper we will provide an introduction and review of this technology with regard to its use in gynecologic malignancies. Preliminary results from our experience are presented for the purpose of illustrating the range of SBRT applications in gynecologic oncology.

METHODS

A comprehensive literature review was conducted and our experience from the past three years was reviewed.

RESULTS

Six case series are published that report results of SBRT for gynecologic malignancies. Sixteen gynecologic patients have been treated with SBRT at our institution. Treatment sites include pelvic and periaortic nodes (9 patients), oligometastatic disease (2), and cervical or endometrial primary tumors when other conventional external radiation or brachytherapy techniques were unsuitable (5). Preliminary follow-up at a median of 11 months (range, 0.3-33 months) demonstrates 79% locoregional control, 43% distant failure, and 50% overall survival.

CONCLUSIONS

SBRT boosts to macroscopic periaortic node recurrences and other sites seem to provide local control and a possibility of long-term disease-free survival in carefully selected patients. Previously this had been difficult to achieve with conventional radiotherapy because of the proximity of periaortic nodes to small bowel. SBRT also offers a novel approach for minimally invasive treatment in the management of gynecological cancer where current surgical and radiotherapy techniques are unsuitable.