Whole abdomen radiation therapy in ovarian cancers: a comparison between fixed beam and volumetric arc based intensity modulation

Is Prophylactic Radiotherapy to the Lymphatic Drainage Area Necessary for Patients With Stage III Ovarian Cancer After Chemotherapy Following Surgery?

BACKGROUND

For patients with stage III epithelial ovarian cancer, there are limited studies on the effects of postoperative adjuvant radiotherapy (RT). Here we assessed the therapeutic efficacy and toxicity of postoperative radiotherapy to the abdominal and pelvic lymphatic drainage area for stage III epithelial ovarian cancer patients, who had all received surgery and chemotherapy (CT).

METHODS

We retrospectively collected patients with stage III epithelial ovarian cancer after cytoreductive surgery (CRS) and full-course adjuvant CT. The chemoradiotherapy (CRT) group patients were treated with intensity modulated radiotherapy (IMRT) to the abdominal and pelvic lymphatic drainage area in our hospital between 2010 and 2020. A propensity score matching analysis was conducted to compare the results between the CRT and CT groups. Kaplan-Meier analysis estimated overall survival (OS), disease-free survival (DFS), and local control (LC) rates. The log-rank test determined the significance of prognostic factors.

RESULTS

A total of 132 patients with median follow-up of 73.9 months (9.1-137.7 months) were included (44 and 88 for the CRT and RT groups, retrospectively). The baseline characteristics of age, histology, level of CA12-5, surgical staging, residual tumour, courses of adjuvant CT, and courses to reduce CA12-5 to normal were all balanced. The median DFS time, 5-year OS, and local recurrence free survival (LRFS) were 100.0 months vs 25.9 months (P = .020), 69.2% vs 49.9% (P = .002), and 85.9% vs 50.5% (P = .020), respectively. The CRT group mainly presented with acute haematological toxicities, with no statistically significant difference compared with grade III intestinal adverse effects (3/44 vs 6/88, P = .480).

CONCLUSION

This report demonstrates that long-term DFS could be achieved in stage III epithelial ovarian cancer patients treated with IMRT preventive radiation to the abdominal and pelvic lymphatic area. Compared with the CT group, DFS and OS were significantly prolonged and adverse effects were acceptable.

Is It Time to Reassess the Role of Radiotherapy Treatment in Ovarian Cancer?

With a 5-year survival rate of fewer than 50%, epithelial ovarian carcinoma is the most fatal of the gynecologic cancers. Each year, an estimated 22,000 women are diagnosed with the condition, with 14,000 dying as a result, in the United States. Over the last decade, the advent of molecular and genetic data has enhanced our understanding of the heterogeneity of ovarian cancer. More than 80% of women diagnosed with advanced illness have an initial full response to rigorous therapy at diagnosis, including surgery and platinum-based chemotherapy. Unfortunately, these responses are infrequently lasting, and the majority of women with ovarian cancer suffer recurrent disease, which is often incurable, despite the possibility of future response and months of survival. And what therapeutic weapons do we have to counter it? For many years, radiation therapy for ovarian tumors was disregarded as an effective treatment option due to its toxicity and lack of survival benefits. Chemotherapy is widely used following surgery, and it has nearly completely supplanted radiation therapy. Even with the use of more modern and efficient chemotherapy regimens, ovarian cancer failures still happen. After receiving first-line ovarian cancer chemotherapy, over 70% of patients show evidence of recurrence in the abdomen or pelvis. It is necessary to reinterpret the function of radiation therapy in light of recent technological developments, the sophistication of radiation procedures, and the molecular and biological understanding of various histological subtypes. This review article focuses on the literature on the use of radiation in ovarian tumors as well as its rationale and current indications.

Utility of adjuvant whole abdominal radiation therapy in ovarian clear cell cancer (OCCC): a pragmatic cohort study of women with classic immuno-phenotypic signature

BACKGROUND

To evaluate the initial experience and clinical utility of first-line adjuvant intensity-modulated whole abdominal radiation therapy (WART) in women with ovarian clear cell cancer (OCCC) referred to an academic center.

METHODS

Progression-free and overall survival was analyzed in a pragmatic observational cohort study of histologically pure OCCC patients over-expressing HNF-1ß treated between 2013 and end-December 2018. An in-house intensity-modulated WART program was developed from a published pre-clinical model. Radiation dose-volume data was curated to American Association of Physics in Medicine (AAPM) Task Group 263 recommendations. A dedicated database prospectively recorded presenting characteristics and outcomes in a standardized fashion.

RESULTS

Five women with FIGO (2018) stage IA to IIIA2 OCCC were treated with first-line WART. Median age was 58 years (range 47-68 years). At diagnosis CA-125 was elevated in 4 cases (median 56 kU/L: range 18.4-370 kU/L) before primary de-bulking surgery. Severe premorbid endometriosis was documented in 3 patients. At a median follow-up of 77 months (range 16-83 mo.), all patients remain alive and progression-free on clinical, biochemical (CA-125), and ¹⁸Fluoro-deoxyglucose (FDG) PET/CT re-evaluation. Late radiation toxicity was significant (G3) in 1 case who required a limited bowel resection and chronic nutritional support at 9 months post-WART; 2 further patients had asymptomatic (G2) osteoporotic fragility fractures of axial skeleton at 12 months post-radiation treated with anti-resorptive agents (denosumab).

CONCLUSIONS

The clinical utility of intensity-modulated WART in OCCC over-expressing HNF-1β was suggested in this small observational cohort study. The hypothesis that HNF-1β is a portent of platinum-resistance and an important predictive biomarker in OCCC needs further confirmation. Curating multi-institutional cohort studies utilizing WART by means of "Big Data" may improve OCCC care standards in the future.

RapidArc vs Conventional IMRT for Head and Neck Cancer Irradiation: Is Faster Necessary Better?

Purpose:

The aim of this study was to dosimetrically evaluate and compare double arc RapidArc (RA) with conventional IMRT (7 fields) plans for irradiation of locally advanced head and neck cancers (LAHNC), focusing on target coverage and doses received by organs at risk (OAR).

Methods:

Computed tomography scans of 20 patients with LAHNC were obtained. Contouring of the target volumes and OAR was done. Two plans were made for each patient, one using IMRT and the other double arc RA, and calculated doses to planning target volume (PTV) and OAR were compared. Monitor units for each technique were also calculated.

Results:

PTV coverage was similar with both techniques. The homogeneity index (HI) was higher for the IMRT plans with a value of 0.108 ± 0.021 compared to 0.0975 ± 0.017 for double arc RA plans (p-value of 0.540). The double arc RA plans achieved a better conformity with a CI95%= 1.01 ± 0.021 compared to 1.05 ± 0.057 achieved with the IMRT plans (p-value of 0.036). The average monitor units (MU) ±SD were 930.5 ± 142.42 for the IMRT plans as opposed to 484.25 ± 69.47 for the double arc RA plans (P-value of 0.002). Double arc plans provided better OAR sparing with a significant p-value of 0.002 and 0.004 for the right and left parotid glands, respectively.

Conclusions:

RA is a rapid and accurate technique that uses lower MUs than conventional IMRT. Double arc plans provide better dose conformity, OAR sparing and a more homogeneous target coverage compared to IMRT.

Fractionated Palliative Pelvic Radiotherapy as an Effective Modality in the Management of Recurrent/Refractory Epithelial Ovarian Cancers: An Institutional Experience

BACKGROUND

The advent of effective chemotherapeutic agents for ovarian carcinoma has made radical abdomino-pelvic radiation redundant. Nevertheless, palliative pelvic radiotherapy still has a role in palliating local symptoms. However, its effect on progression-free survival (PFS) may be debated.

AIMS

To study the outcome of fractionated palliative pelvic radiotherapy in relapsed ovarian cancers in terms of symptom control and PFS.

METHODS

Twenty-three patients of ovarian cancers, heavily pretreated with chemotherapy and with recurrent or residual pelvic masses, were planned for palliative pelvic radiotherapy to the dose of 46-50 Gy in 23-25 fractions in 4.5-5 weeks. Symptom control and outcomes have been analyzed.

RESULTS

Post-radiotherapy, abdominal pain was controlled in 15 out of 17 patients (88.2 %), bleeding per vaginum in all 5 patients and vaginal discharge stopped in 4 out of 5 patients (80 %). On follow-up, of 23 patients, 17 (74 %) had progressive disease post-radiation, and median time to disease progression was 10 months (range 1-49). On univariate analysis, increased PFS was observed in patients who received radiation late in their course of disease, those with serous histology, and with lesser disease bulk in pelvis (≤2 cm) prior to radiation initiation.

CONCLUSION

Fractionated palliative pelvic radiotherapy is an efficient method for symptom palliation in relapsed ovarian cancers. Patients who are heavily pretreated with chemotherapy and have a small-volume pelvic disease may show a prolonged PFS with addition of pelvic radiotherapy. Indications of radiotherapy, however, need to be defined.

Clinical utility of RapidArc™ radiotherapy technology

RapidArc™ is a radiation technique that delivers highly conformal dose distributions through the complete rotation (360°) and speed variation of the linear accelerator gantry. This technique, called volumetric modulated arc therapy (VMAT), compared with conventional radiotherapy techniques, can achieve high-target volume coverage and sparing damage to normal tissues. RapidArc delivers precise dose distribution and conformity similar to or greater than intensity-modulated radiation therapy in a short time, generally a few minutes, to which image-guided radiation therapy is added. RapidArc has become a currently used technology in many centers, which use RapidArc technology to treat a large number of patients. Large and small hospitals use it to treat the most challenging cases, but more and more frequently for the most common cancers. The clinical use of RapidArc and VMAT technology is constantly growing. At present, a limited number of clinical data are published, mostly concerning planning and feasibility studies. Clinical outcome data are increasing for a few tumor sites, even if only a little. The purpose of this work is to discuss the current status of VMAT techniques in clinical use through a review of the published data of planning systems and clinical outcomes in several tumor sites. The study consisted of a systematic review based on analysis of manuscripts retrieved from the PubMed, BioMed Central, and Scopus databases by searching for the keywords “RapidArc”, “Volumetric modulated arc radiotherapy”, and “Intensity-modulated radiotherapy”.

Accelerated large volume irradiation with dynamic Jaw/Dynamic Couch Helical Tomotherapy

BACKGROUND

Helical Tomotherapy (HT) has unique capacities for the radiotherapy of large and complicated target volumes. Next generation Dynamic Jaw/Dynamic Couch HT delivery promises faster treatments and reduced exposure of organs at risk due to a reduced dose penumbra.

METHODS

Three challenging clinical situations were chosen for comparison between Regular HT delivery with a field width of 2.5 cm (Reg 2.5) and 5.0 cm (Reg 5.0) and DJDC delivery with a maximum field width of 5.0 cm (DJDC 5.0): Hemithoracic Irradiation, Whole Abdominal Irradiation (WAI) and Total Marrow Irradiation (TMI). For each setting, five CT data sets were chosen, and target coverage, conformity, integral dose, dose exposure of organs at risk (OAR) and treatment time were calculated.

RESULTS

Both Reg 5.0 and DJDC 5.0 achieved a substantial reduction in treatment time while maintaining similar dose coverage. Treatment time could be reduced from 10:57 min to 3:42 min / 5:10 min (Reg 5.0 / DJDC 5.0) for Hemithoracic Irradiation, from 18:03 min to 8:02 min / 8:03 min for WAI and to 18:25 min / 18:03 min for TMI. In Hemithoracic Irradiation, OAR exposure was identical in all modalities. For WAI, Reg 2.5 resulted in lower exposure of liver and bone. DJDC plans showed a small but significant increase of ∼ 1 Gy to the kidneys, the parotid glans and the thyroid gland. While Reg 5.0 and DJDC were identical in terms of OAR exposure, integral dose was substantially lower with DJDC, caused by a smaller dose penumbra.

CONCLUSIONS

Although not clinically available yet, next generation DJDC HT technique is efficient in improving the treatment time while maintaining comparable plan quality.

Volumetric modulated arc therapy: a review of current literature and clinical use in practice

Volumetric modulated arc therapy (VMAT) is a novel radiation technique, which can achieve highly conformal dose distributions with improved target volume coverage and sparing of normal tissues compared with conventional radiotherapy techniques. VMAT also has the potential to offer additional advantages, such as reduced treatment delivery time compared with conventional static field intensity modulated radiotherapy (IMRT). The clinical worldwide use of VMAT is increasing significantly. Currently the majority of published data on VMAT are limited to planning and feasibility studies, although there is emerging clinical outcome data in several tumour sites. This article aims to discuss the current use of VMAT techniques in practice and review the available data from planning and clinical outcome studies in various tumour sites including prostate, pelvis (lower gastrointestinal, gynaecological), head and neck, thoracic, central nervous system, breast and other tumour sites.

Implementing RapidArc into clinical routine: a comprehensive program from machine QA to TPS validation and patient QA

PURPOSE

With the increased commercial availability of intensity modulated arc therapy (IMAT) comes the need for comprehensive QA programs, covering the different aspects of this newly available technology. This manuscript proposes such a program for the RapidArc (RA) (Varian Medical Systems, Palo Alto) IMAT solution.

METHODS

The program was developed and tested out for a Millennium120 MLC on iX Clinacs and a HighDefinition MLC on a Novalis TX, using a variety of measurement equipment including Gafchromic film, 2D ion chamber arrays (Seven29 and StarCheck, PTW, Freiburg, Germany) with inclinometer and Octavius phantom, the Delta4 systam (ScandiDos, Uppsala, Sweden) and the portal imager (EPID). First, a number of complementary machine QA tests were developed to monitor the correct interplay between the accelerating/decelerating gantry, the variable dose rate and the MLC position, straining the delivery to the maximum allowed limits. Second, a systematic approach to the validation of the dose calculation for RA was adopted, starting with static gantry and RA specific static MLC shapes and gradually moving to dynamic gantry, dynamic MLC shapes. RA plans were then optimized on a series of artificial structures created within the homogeneous Octavius phantom and within a heterogeneous lung phantom. These served the double purpose of testing the behavior of the optimization algorithm (PRO) as well as the precision of the forward dose calculation. Finally, patient QA on a series of clinical cases was performed with different methods. In addition to the well established in-phantom QA, we evaluated the portal dosimetry solution within the Varian approach.

RESULTS

For routine machine QA, the "Snooker Cue" test on the EPID proved to be the most sensitive to overall problem detection. It is also the most practical one. The "Twinkle" and "Sunrise" tests were useful to obtain well differentiated information on the individual treatment delivery components. The AAA8.9 dose calculations showed excellent agreement with all corresponding measurements, except in areas where the 2.5 mm fixed fluence resolution was insufficient to accurately model the tongue and groove effect or the dose through nearly closed opposing leafs. Such cases benefited from the increased fluence resolution in AAA10.0. In the clinical RA fields, these effects were smeared out spatially and the impact of the fluence resolution was considerably less pronounced. The RA plans on the artificial structure sets demonstrated some interesting characteristics of the PRO8.9 optimizer, such as a sometimes unexpected dependence on the collimator rotation and a suboptimal coverage of targets within lung tissue. Although the portal dosimetry was successfully validated, we are reluctant to use it as a sole means of patient QA as long as no gantry angle information is embedded.

CONCLUSIONS

The all-in validation program allows a systematic approach in monitoring the different levels of RA treatments. With the systematic approach comes a better understanding of both the capabilities and the limits of the used solution. The program can be useful for implementation, but also for the validation of major upgrades.