Stereotactic Body Radiation Therapy for Oligometastatic Ovarian Cancer: A Step Toward a Drug Holiday

Stereotactic Ablative Radiotherapy for Gynecological Oligometastatic and Oligoprogessive Tumors

Importance

The role of stereotactic ablative radiotherapy (SABR) for gynecologic malignant tumors has yet to be clearly defined despite recent clinical uptake.

Objective

To evaluate the outcomes of SABR in patients with oligometastatic and oligoprogressive gynecologic cancers.

Design, Setting, and Participants

In this retrospective pooled analysis, patients with oligometastatic and oligoprogressive gynecologic cancers receiving SABR at 5 institutions from Canada and the US were studied. Data were collected from January 2011 to December 2020, and data were analyzed from January to December 2023.

Exposure

Stereotactic ablative radiotherapy.

Main Outcomes and Measures

Cumulative incidence of local and distant recurrence, chemotherapy-free survival (CFS), and overall survival (OS) probabilities after SABR were calculated using Kaplan-Meier methods. Univariable and multivariable analysis was conducted using Cox regression methods.

Results

A total of 215 patients with 320 lesions meeting criteria were included in the analysis; the median (range) age at primary diagnosis was 59 (23-86) years. The median (range) follow-up from SABR was 18.5 (0.1-124.5) months. The primary site included the endometrium (n = 107), ovary (n = 64), cervix (n = 30), and vulva or vagina (n = 14). Local cumulative incidence of recurrence was 13.7% (95% CI, 9.4-18.9) and 18.5% (95% CI, 13.2-24.5) at 1 and 5 years, respectively. Distant cumulative incidence of recurrence was 48.5% (95% CI, 41.4-55.1) and 73.1% (95% CI, 66.0-79.0) at 1 and 5 years, respectively. OS was 75.7% (95% CI, 69.2-81.1) and 33.1% (95% CI, 25.3-41.1) at 1 and 5 years, respectively. The median CFS was 21.7 months (95% CI, 15.4-29.9). On multivariable analysis, local recurrence was significantly associated with nodal metastasis, lesion size, biologically effective dose, treatment indication, institution, and primary disease type. Distant progression-free survival was associated with nodal targets and lesion size. OS and CFS were significantly associated with lesion size.

Conclusions and Relevance

In this study, SABR appeared to have excellent local control with minimal toxic effects in this large patient group, and certain patients may achieve durable distant control and OS as well. It may be possible to delay time to chemotherapy in select patient subtypes and therefore reduce associated toxic effects. Prospective multicenter trials will be critical to establish which characteristics procure the greatest benefit from SABR use and to define the ideal time to implement SABR with other oncologic treatments.

The first real-world study on the role of carbon ion radiotherapy for oligo-metastatic, persistent, or recurrent (MPR) ovarian/fallopian tube cancer

Introduction

In the multidisciplinary management of oligometastatic, persistent, or recurrent (MPR) ovarian cancer, radiotherapy (RT) is becoming a more and more worthwhile treatment to potentially improve the chronicity of the disease. Particle beam RT has proved to be effective in several gynecological malignancies, but so far no data are available for ovarian cancer.

Material and Methods

This is a real-world, retrospective, bi-institutional, single-arm study aimed to assess the effectiveness and the safety of carbon ion RT (CIRT) in this setting. The co-first endpoints are 1-year and 2-year actuarial local control (LC) rates and the objective response rate (ORR) defined on a "per lesion" basis. The secondary endpoint was toxicity. Actuarial outcomes were evaluated using the Kaplan-Meier method while potential predictors were explored using the Log-rank test. Bi-variable logistic regression was employed in the analysis of factors predicting the complete response on a per-lesion basis.

Results

26 patients accounting for a total of 36 lesions underwent CIRT with a total median dose of 52.8 Gy[RBE] (range: 39-64 Gy[RBE]). Five patients received CIRT for re-irradiation. No concomitant systemic therapies were administered during CIRT. Within 12 months after the treatment, 17 lesions (47 %) achieved complete response while 18 (50 %) obtained a partial response with an ORR of 97 %. The achievement of a complete response is related to the dose per fraction (>4.2 Gy[RBE], p = 0.04) and total dose (>52,8 Gy[RBE], p = 0.05). The 1-year LC was 92 % and the 2-year LC was 83 %, according to the achievement of a CR (p = 0.007) and GTV ≤ 14 cm3 (p = 0.024). No grade > 3 toxicities were recorded both in naïve and re-irradiated patients. PARP-i and anti-VEGF seemed not to exacerbate the risk of severe toxicities.

Conclusions

CIRT was effective and safe in MPR ovarian cancers, even in the case of re-irradiation. Largest cohort studies and longer follow-up are needed to confirm these data.

Stereotactic radiotherapy for managing ovarian cancer oligoprogression under poly (ADP-ribose) polymerase inhibitors (PARPi)

OBJECTIVE

Poly (ADP-ribose) polymerase inhibitors (PARPi) have become a new standard of care for the maintenance treatment of advanced epithelial ovarian cancer. This study aims to evaluate the efficacy and safety of combining stereotactic body radiotherapy with PARPi continuation as a strategy to treat ovarian cancer oligoprogression on PARPi.

METHODS

This is a multicenter retrospective study including ovarian cancer patients treated with stereotactic body radiotherapy and PARPi continuation for oligoprogression under PARPi maintenance therapy between June 2012 and May 2023 in three Italian centers. PARPi treatment was continued until further disease progression or unacceptable toxicity. The primary endpoint was the next-line systemic therapy-free interval. The Kaplan-Meier method was used to assess local control, progression-free survival, and overall survival. Univariate and multivariate Cox regression analyses were performed to evaluate potential clinical outcomes predictors.

RESULTS

46 patients were included, with a total of 89 lesions treated over 63 radiotherapy treatments. Lymph nodes were the most frequently treated lesions (80, 89.9%), followed by visceral lesions (8, 9%) and one case with a bone lesion (1.1%). Median follow-up was 25.9 months (range 2.8-122). The median next-line systemic therapy-free interval was 12.4 months (95% CI 8.3 to 19.5). A number of prior chemotherapy lines greater than five was significantly associated with a reduced next-line systemic therapy-free interval (HR 3.21, 95% CI 1.11 to 9.32, p=0.032). At the time of analysis, 32 (69.6%) patients started a new systemic therapy regimen, while 14 (30.4%) remained on the PARPi regimen. The 2-year progression-free survival, local failure-free survival, and overall survival rates were 10.7%, 78.1%, and 76.5%, respectively. Four patients (8.7%) experienced acute toxicity with G1 gastrointestinal events.

CONCLUSION

Stereotactic body radiotherapy combined with PARPi continuation may be an effective and safe strategy for managing ovarian cancer patients with oligoprogression on PARPi maintenance therapy. Prospective research is warranted to shed more light on this approach.

Stereotactic Body Radiation Therapy for Gynecologic Malignancies: A Case-Based Radiosurgery Society Practice Review

PURPOSE

The use of stereotactic body radiation therapy (SBRT) for gynecologic malignancies is controversial. We discuss certain circumstances when highly precise SBRT may be a useful tool to consider in the management of selected patients.

METHODS AND MATERIALS

Case selection included the following scenarios, the first 2 with palliative intent, para-aortic nodal oligorecurrence of ovarian cancer, pelvic sidewall oligorecurrence of cervical cancer, and inoperable endometrial cancer boost after intensity modulated radiation to the pelvis treated with curative intent. Patient characteristics, fractionation, prescription dose, treatment technique, and dose constraints were discussed. Relevant literature to these cases was summarized to provide a framework for treatment of similar patients.

RESULTS

Treatment of gynecologic malignancies with SBRT requires many considerations, including treatment intent, optimal patient selection, fractionation selection, tumor localization, and plan optimization. Although other treatment paradigms including conventionally fractionated radiation therapy and brachytherapy remain the standard-of-care for definitive treatment of gynecologic malignancies, SBRT may have a role in palliative cases or those where high doses are not required due to the unacceptable toxicity that may occur with SBRT.

CONCLUSIONS

A case-based practice review was developed by the Radiosurgery Society to provide a practical guide to the common scenarios noted above affecting patients with gynecologic malignancies.

Efficacy of stereotactic body radiotherapy and response prediction using artificial intelligence in oligometastatic gynaecologic cancer

PURPOSE

We present a large real-world multicentric dataset of ovarian, uterine and cervical oligometastatic lesions treated with SBRT exploring efficacy and clinical outcomes. In addition, an exploratory machine learning analysis was performed.

METHODS

A pooled analysis of gynecological oligometastases in terms of efficacy and clinical outcomes as well an exploratory machine learning model to predict the CR to SBRT were carried out. The CR rate following radiotherapy (RT) was the study main endpoint. The secondary endpoints included the 2-year actuarial LC, DMFS, PFS, and OS.

RESULTS

501 patients from 21 radiation oncology institutions with 846 gynecological metastases were analyzed, mainly ovarian (53.1%) and uterine metastases(32.1%).Multiple fraction radiotherapy was used in 762 metastases(90.1%).The most frequent schedule was 24 Gy in 3 fractions(13.4%). CR was observed in 538(63.7%) lesions. The Machine learning analysis showed a poor ability to find covariates strong enough to predict CR in the whole series. Analyzing them separately, in uterine cancer, if RT dose≥78.3Gy, the CR probability was 75.4%; if volume was <13.7 cc, the CR probability became 85.1%. In ovarian cancer, if the lesion was a lymph node, the CR probability was 71.4%; if volume was <17 cc, the CR probability rose to 78.4%. No covariate predicted the CR for cervical lesions. The overall 2-year actuarial LC was 79.2%, however it was 91.5% for CR and 52.5% for not CR lesions(p < 0.001). The overall 2-year DMFS, PFS and OS rate were 27.3%, 24.8% and 71.0%, with significant differences between CR and not CR.

CONCLUSIONS

CR was substantially associated to patient outcomes in our series of gynecological cancer oligometastatic lesions. The ability to predict a CR through artificial intelligence could also drive treatment choices in the context of personalized oncology.

Machine-learning prediction of treatment response to stereotactic body radiation therapy in oligometastatic gynecological cancer: A multi-institutional study

BACKGROUND AND PURPOSE

We aimed to develop and validate different machine-learning (ML) prediction models for the complete response of oligometastatic gynecological cancer after SBRT.

MATERIAL AND METHODS

One hundred fifty-seven patients with 272 lesions from 14 different institutions and treated with SBRT with radical intent were included. Thirteen datasets including 222 lesions were combined for model training and internal validation purposes, with an 80:20 ratio. The external testing dataset was selected as the fourteenth Institution with 50 lesions. Lesions that achieved complete response (CR) were defined as responders. Prognostic clinical and dosimetric variables were selected using the LASSO algorithm. Six supervised ML models, including logistic regression (LR), classification and regression tree analysis (CART) and support vector machine (SVM) using four different kernels, were trained and tested to predict the complete response of uterine lesions after SBRT. The performance of models was assessed by receiver operating characteristic curves (ROC), area under the curve (AUC) and calibration curves. An explainable approach based on SHapley Additive exPlanations (SHAP) method was deployed to generate individual explanations of the model's decisions.

RESULTS

63.6% of lesions had a complete response and were used as ground truth for the supervised models. LASSO strongly associated complete response with three variables, namely the lesion volume (PTV), the type of lesions (lymph-nodal versus parenchymal), and the biological effective dose (BED10), that were used as input for ML modeling. In the training set, the AUCs for complete response were 0.751 (95% CI: 0.716-0.786), 0.766 (95% CI: 0.729-0.802) and 0.800 (95% CI: 0.742-0.857) for the LR, CART and SVM with a radial basis function kernel, respectively. These models achieve AUC values of 0.727 (95% CI: 0.669-0.795), 0.734 (95% CI: 0.649-0.815) and 0.771 (95% CI: 0.717-0.824) in the external testing set, demonstrating excellent generalizability.

CONCLUSION

ML models enable a reliable prediction of the treatment response of oligometastatic lesions receiving SBRT. This approach may assist radiation oncologists to tailor more individualized treatment plans for oligometastatic patients.

Case report: Interstitial implantation radiotherapy combined with immunotherapy and GM-CSF in oligometastatic platinum-resistant ovarian cancer

Background

Treatment for platinum-resistant ovarian cancer is challenging. Currently, platinum-resistant ovarian cancer is typically treated with non-platinum single-agent chemotherapy ± bevacizumab, but the prognosis is often extremely poor. In the treatment of platinum-resistant ovarian cancer patients, reports of triple therapy with interstitial implantation radiotherapy combined with immunotherapy and granulocyte-macrophage colony-stimulating factor (GM-CSF) (PRaG for short) are relatively rare.

Case description

Here, we report a patient with oligometastatic platinum-resistant ovarian cancer. The patient achieved partial response (PR) of the lesion and sustained benefit for more than six months after receiving interstitial implantation radiotherapy combined with immunotherapy along with GM-CSF.

Conclusion

This triple therapy may provide additional options for these patients.

Surgery for Recurrent Epithelial Ovarian Cancer

PURPOSE OF REVIEW

To review evidence around the value and challenges of surgery for recurrent epithelial ovarian cancer (ROC). Both cytoreductive and palliative aspects will be addressed RECENT FINDINGS: Prospective and retrospective evidence demonstrates a significantly longer remission derived from the combination of surgical and systemic modalities as opposed to systemic treatment alone in carefully selected ROC-patients who have relapsed more than 6 months from the end of their 1st line platinum-based chemotherapy. Nevertheless, this benefit appears to be limited when total macroscopic tumor clearance is not achieved. Selection algorithms to identify optimal surgical candidates are of paramount importance to prevent surgical morbidity without the equivalent oncological benefit. In the palliative setting, the risks and benefits of salvage surgery need to be counterbalanced with the advances of conservative techniques for optimal care. Well-defined selection algorithms to identify those who will benefit from surgery in the relapsed setting appear to be the key to oncologic and surgical success.

Aggressive Local Ablative Radiotherapy Mitigates Progression Risk in Oligometastatic Lung Adenocarcinoma

PURPOSE

This study aimed to determine the role of local ablative radiotherapy (LART) in oligometastatic/oligoprogressive lung adenocarcinoma.

MATERIALS AND METHODS

Patients (n=176) with oligometastatic lung adenocarcinoma treated with LART were identified, and those treated with LART at the initial diagnosis of synchronous oligometastatic disease (OMD group) or treated with LART when they presented with repeat oligoprogression (OPD group) were included.

RESULTS

In the OMD group (n=54), the 1- and 3-year progression-free survival (PFS) were 50.9% and 22.5%, respectively, whereas the 1- and 3-year overall survival in the OPD group were 75.9% and 58.1%, respectively. Forty-one patients (75.9%) received LART at all gross disease sites. Tyrosine kinase inhibitor (TKI) use and all-metastatic site LART were significant predictors of higher PFS (p=0.018 and p=0.046, respectively). In patients treated with TKIs at the time of LART (n=23) and those treated with all-metastatic site LART, the 1-year PFS was 86.7%, while that of patients not treated with all-metastatic site LART was 37.5% (p=0.006). In the OPD group (n=122), 67.2% of the patients (n=82) maintained a systemic therapy regimen after LART. The cumulative incidence of changing systemic therapy was 39.6%, 62.9%, and 78.5% at 6 months, 1 year, and 2 years after LART, respectively.

CONCLUSION

Aggressive LART can be an option to improve survival in patients with oligometastatic disease. Patients with synchronous oligometastatic disease receiving TKI and all-metastatic site LART may have improved PFS. In patients with repeat oligoprogression, LART might potentially extend survival by delaying the need to change the systemic treatment regimen.

Anti-tumour and radiosensitising effects of PARP inhibitor on cervical cancer xenografts

This study evaluated the radiosensitising effect of niraparib; a poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitor on HeLa cervical cancer cells in nude mice and explored its possible mechanism. Twenty-four 3-5-week-old female BALB/c nude mice, inoculated with HeLa cells into the right hind leg, were randomly assigned into eight groups with three mice per group and treated. The tumour volume was significantly reduced under niraparib + radiotherapy combination as compared to monotherapy and untreated mice. The tumour growth was significantly delayed by 23.33-39 days when treated with combination therapy (p<.05). Further, univariate analysis revealed prolonged time for tumour growth when radiotherapy was followed by niraparib (I.G.) rather than niraparib (I.P.) (p=.003). Combination therapy reduced levels of PARP-1 precursor, PARP-1 splicer, PAR and RAD51 protein with high expression of γ-H2AX/CC3 and low expression of Ki-67. Niraparib in combination with radiotherapy can enhance the formation of DNA double strand breaks in HeLa cells and up regulate the expression of γ-H2AX/CC3.IMPACT STATEMENTWhat is already known on this subject? Asia has the highest incidence of cervical cancer (58.2%). Poly(adenosine diphosphate-ribose) polymerases (PARPs) are family of enzymes involved in single-strand break (SSB) and double-strand break (DSB) repair pathways. Niraparib is an effective inhibitor of both PARP-1 and PARP-2 and has the ability to cross the blood-brain barrier.What the results of this study add? Our study demonstrated that the combination of niraparib and radiotherapy can significantly enhance the cytotoxicity induced by radiotherapy. The inhibition effect of radiotherapy combined with niraparib on the tumour growth of mice was prominent, thereby establishing the radio-sensitisation activity of niraparib.What are the implications of these findings for clinical practice and/or further research? Niraparib can improve the cytotoxic effect of radiotherapy by increasing the formation of DSBs and up regulating the expression of apoptotic protein in HeLa cells.

Study protocol for prospective multi-institutional phase III trial of standard of care therapy with or without stereotactic ablative radiation therapy for recurrent ovarian cancer (SABR-ROC)

BACKGROUND

Efforts have been made to investigate the role of salvage radiotherapy (RT) in treating recurrent ovarian cancer (ROC). Stereotactic ablative radiation therapy (SABR) is a state-of-the-art therapy that uses intensity modulation to increase the fractional dose, decrease the number of fractions, and target tumors with high precision.

METHODS

The SABR-ROC trial is a phase 3, multicenter, randomized, prospective study to evaluate whether the addition of SABR to the standard of care significantly improves the 3-year overall survival (OS) of patients with ROC. Patients who have completed the standard treatment for primary epithelial ovarian cancer are eligible. In addition, patients with number of metastases ≤ 10 and maximum diameter of each metastatic site of gross tumor ≤ 5 cm are allowed. Randomization will be stratified by (1) No. of the following clinical factors met, platinum sensitivity, absence of ascites, normal level of CA125, and ECOG performance status of 0-1; 0-3 vs. 4; (2) site of recurrence; with vs. without lymph nodes; and (3) PARP inhibitor; use vs. non-use. The target number of patients to be enrolled in this study is 270. Participants will be randomized in a 1:2 ratio. Participants in Arm 2 will receive SABR for recurrent lesions clearly identified in imaging tests as well as the standard of care (Arm 1) based on treatment guidelines and decisions made in multidisciplinary discussions. The RT fraction number can range from 1 to 10, and the accepted dose range is 16-45 Gy. The RT Quality Assurance (QA) program consists of a three-tiered system: general credentialing, trial-specific credentialing, and individual case reviews.

DISCUSSION

SABR appears to be preferable as it does not interfere with the schedule of systemic treatment by minimizing the elapsed days of RT. The synergistic effect between systemic treatment and SABR is expected to reduce the tumor burden by eradicating gross tumors identified through imaging with SABR and controlling microscopic cancer with systemic treatment. It might also be beneficial for quality-of-life preservation in older adults or heavily treated patients.

TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov (NCT05444270) on June 29th, 2022.

Efficacy and Safety of Stereotactic Body Radiation Therapy in Oligometastatic Uterine Cancer (MITO-RT2/RAD): A Large, Real-World Study in Collaboration With Italian Association of Radiation Oncology, Multicenter Italian Trials in Ovarian Cancer, and Mario Negri Gynecologic Oncology Group Groups

PURPOSE

This retrospective, multicenter study analyzes the efficacy and safety of stereotactic body radiation therapy in a large cohort of patients with oligometastatic/persistent/recurrent uterine cancer.

METHODS AND MATERIALS

Clinical and radiation therapy data from several radiation therapy centers treating patients by stereotactic body radiation therapy between March 2006 and October 2021 were collected. Objective response rate was defined as complete and partial response, and clinical benefit included objective response rate plus stable disease. Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer and Common Terminology Criteria for Adverse Events scales were used to grade toxicities. Primary endpoints were the rate of complete response to stereotactic body radiation therapy, and the 2-year actuarial local control rate "per-lesion" basis. Secondary endpoints were progression-free survival and overall survival, as well as toxicity.

RESULTS

In the study, 157 patients with oligometastatic/persistent/recurrent uterine cancer bearing 272 lesions treated by stereotactic body radiation therapy at 14 centers were analyzed. Lymph node metastases (137, 50.4%) were prevalent, followed by parenchyma lesions (135, 49.6%). Median total dose was 35 Gy (10-75.2), in 5 fractions (range, 1-10). Complete and partial responses were 174 (64.0%), and 54 (19.9%), respectively. Stable disease was registered in 29 (10.6%), and 15 (5.5%) lesions progressed. Type of lesion (lymph node), volume (≤13.7 cc) and total dose (BED10 >59.5 Gy) were significantly associated with a higher probability of achieving complete response. Patients achieving complete response (CR) "per-lesion" basis experienced a 2-year actuarial local control rate of 92.4% versus 33.5% in lesions not achieving complete response (NCR; P < .001). Moreover, the 2-year actuarial progression-free survival rate in patients with CR was 45.4%, and patients with NCR had a 2-year rate of 17.6% (P < .001). Finally, patients who had a CR had a 2-year overall survival rate of 82.7%, compared with 56.5% for NCR patients (P <.001). Severe acute toxicity was around 2%, including one toxic death due to gastric perforation, and severe late toxicity around 4%.

CONCLUSIONS

The efficacy of stereotactic body radiation therapy in this setting was confirmed. The low toxicity profile and the high local control rate in complete responder patients encourage the wider use of this approach.

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.

Stereotactic Body Radiation Therapy in Gynecologic Oligometastases: An Effective but Underutilized Approach

Historically, the role of radiation in gynecological metastatic disease involved palliation for pain or bleeding. Stereotactic Body Radiation Therapy (SBRT) has shown survival benefits in oligometastatic disease from varying primary histologies in recent randomized trials. However, gynecologic primary oligometastases have been underrepresented in these trials. Recent studies across gynecological malignancy types have similarly shown favorable outcomes and acceptable toxicities from treating recurrent or oligometastatic gynecologic cancer (ROMGC) patients with definitive radiation therapy. The largest body of literature reported on the use of SBRT in ovarian cancer, which was found to be an effective option, especially in the setting of chemo-resistant disease. Despite the encouraging outcomes using SBRT in oligometastatic gynecologic malignancies, SBRT remains underutilized given the lack of randomized studies studying ROMGC with long term follow-up. While waiting for future prospective trials to establish the role of SBRT as the standard of care in ROMGC patients, this review focuses on reporting the advantages and drawbacks of this technique and examines the current literature to help guide patient centered treatment decisions.

Radiotherapy in recurrent ovarian cancer: updated results of involved-field radiation therapy

OBJECTIVE

This study aimed to update the possible clinical benefits of radiation therapy in recurrent ovarian cancer.

METHODS

The medical records of 495 patients with recurrent ovarian cancer after initially undergoing maximal cytoreductive surgery and adjuvant platinum-based chemotherapy based on the pathologic stage between January 2010 and December 2020 were analyzed: 309 and 186 patients were treated without and with involved-field radiation therapy, respectively. Involved-field radiation therapy is defined as radiation therapy only to the areas of the body involved by tumor. The prescribed doses were ≥45 Gy (equivalent dose in 2 Gy/fraction). Overall survival was compared between patients treated with and without involved-field radiation therapy. The favorable group was defined as patients who satisfied at least four of the following factors: good performance, no ascites, normal CA-125, platinum-sensitive tumor, and nodal recurrence.

RESULTS

The median age of the patients was 56 years (range 49-63) and median time to recurrence was 11.1 months (range 6.1-15.5). 217 patients (43.8%) were treated at a single site. Radiation therapy, performance status, CA-125, platinum sensitivity, residual disease, and ascites were all significant prognostic factors. The 3-year overall survival of all patients, patients treated without radiation therapy, and patients treated with radiation therapy was 54.0%, 44.8%, and 69.3%, respectively. Radiation therapy was associated with higher overall survival rates in the unfavorable and favorable patient groups. Patient characteristics showed higher rates of normal CA-125, lymph node metastasis only, lower platinum sensitivity, and higher rates of ascites in the radiation therapy group. After propensity score matching, the radiation therapy group showed superior overall survival to the non-radiation therapy group. Normal CA-125, good performance status, and platinum sensitivity were associated with a good prognosis in patients treated with radiation therapy.

CONCLUSION

Our study showed that higher overall survival was observed in patients treated with radiation therapy in recurrent ovarian cancer.

Role of salvage radiotherapy for recurrent ovarian cancer

OBJECTIVE

This study aimed to report clinical outcomes of salvage radiotherapy for recurrent ovarian cancer and identify predictors of clinical outcomes.

METHODS

We retrospectively reviewed data of patients who received salvage radiotherapy for recurrent ovarian cancer between January 2011 and June 2021. Stereotactic body radiotherapy, involved-field radiotherapy with conventional fractionation, and non-involved-field radiotherapy with conventional fractionation were included in this study. Local failure-free survival, progression-free survival, chemotherapy-free survival, and overall survival were assessed. Additionally, potential prognostic factors for survival were analyzed.

RESULTS

A total of 79 patients were included with 114 recurrent lesions. The median follow-up was 18.3 months (range 1.7-83). The 2-year local failure-free survival, progression-free survival, chemotherapy-free survival, and overall survival rates were 80.7%, 10.6%, 21.2%, and 74.7%, respectively. Pre-radiotherapy platinum resistance (hazard ratio (HR) 3.326, p<0.001) and short pre-radiotherapy CA-125 doubling time (HR 3.664, p<0.001) were associated with poor chemotherapy-free survival. The 1-year chemotherapy-free survival rates of patients with both risk factors, a single risk factor, and no risk factor were 0%, 20.4%, and 53.5%, respectively. The difference between risk groups was statistically significant: low risk versus intermediate risk (p<0.001) and intermediate risk versus high risk (p<0.001).

CONCLUSIONS

Salvage radiotherapy for recurrent ovarian cancer resulted in local control with improved chemotherapy-free survival in carefully selected patients. Our results suggest that the consideration of pre-radiotherapy platinum resistance and pre-radiotherapy CA-125 doubling time could help with patient selection.

Granulosa cell tumors (GCTs) of the ovary: What is the role of radiotherapy?

Granulosa cell tumors of the ovary have an indolent behavior and a good prognosis, but a high incidence of local recurrence after surgery. The best treatment in the recurrent setting is unclear and randomized clinical trials on the management in the recurrent setting are lacking. The role of radiotherapy is controversial in adjuvant settings and unknown in case of relapse after surgery. This review aims to summarize the level of evidence of the role of radiation treatments for granulosa cell tumors of the ovary.

Ovarian Cancer Radiosensitivity: What Have We Understood So Far?

Radiotherapy has been increasingly considered as an active treatment to combine with other approaches (i.e., surgery, chemotherapy, and novel target-based drugs) in ovarian cancers to palliate symptoms and/or to prolong chemotherapy-free intervals. This narrative review aimed to summarize the current knowledge of the radiosensitivity/radioresistance of ovarian cancer which remains the most lethal gynecological cancer worldwide. Indeed, considering the high rate of recurrence in and out of the radiotherapy fields, in the era of patient-tailored oncology, elucidating the mechanisms of radiosensitivity and identifying potential radioresistance biomarkers could be crucial in guiding clinical decision-making.

Interstitial brachytherapy combined with PARP inhibitors in the treatment of chemoresistant recurrent epithelial ovarian cancer: A case report

Background

Chemoresistance generally develops in patients with advanced epithelial ovarian cancer, and the prognosis is still very poor, with an expected survival time of less than one year. For this population of individuals, there is currently no standard protocol for clinical benefit.

Case presentation

We report a case of an elderly woman diagnosed with stage IIIC high-grade serous ovarian cancer (HGSOC). During a follow-up time of 6 years, the patient initially received multiple sequential courses of chemotherapy with platinum-based regimens and with no maintenance therapy. Similar to most patients with advanced HGSOC, she developed platinum resistance and experienced poor treatment results with a short progression-free survival (PFS). Ultimately, we gave the patient traditional non-platinum-based chemotherapy with bevacizumab and high-dose-rate interstitial brachytherapy followed by olaparib as a maintenance therapy. Up to now, the patient did response well to the treatment, and the PFS had exceeded 12 months.

Conclusion

High-dose-rate interstitial brachytherapy combination with PARP inhibitors may be an option for isolated chemoresistant recurrent epithelial ovarian cancer.

Stereotactic body radiotherapy to defer systemic therapy in patients with oligorecurrent disease

•

SBRT may be used to defer systemic therapy in patients with oligorecurrence.

•

Low rates of systemic therapy after SBRT for all oligorecurrent lesions were observed.

•

Patients had favorable OS and few treatment-related toxicities.

•

New metastases were treated with repeat SBRT in 33.8% of patients.

•

Fewer lines of systemic therapy and a low baseline tumor volume were associated with longer systemic therapy-free interval.

Background

Patients who develop oligorecurrent disease may be treated with metastasis-directed stereotactic body radiotherapy (SBRT) to defer the start of systemic therapy and delay its potential side effects. We report oncological outcomes and patterns of failure in patients with oligorecurrent disease treated with SBRT and determine which factors impact the interval to initiation of systemic therapy.

Material/Methods

This retrospective study included patients with oligorecurrent disease (≤5 lesions) from any solid organ malignancy, treated with SBRT to all metastases and no systemic therapy for a minimum one month after SBRT between 01/2014 and 12/2019. The Kaplan-Meier method was used to analyze overall survival (OS) and progression-free survival (PFS), and the cumulative incidence of initiation of systemic therapy was analyzed assuming death without systemic therapy as a competing risk. Univariable and multivariable analyses are used to assess predictors of the systemic therapy-free interval.

Results

Among 545 patients treated with SBRT for oligometastatic disease, 142 patients were treated with SBRT only for oligorecurrent disease. The most common primary tumors were lung and gastrointestinal cancer in 47 (33.1 %) and 28 (19.7 %) patients, respectively. After a median follow-up of 25 months, the median PFS and OS was 6.1 months and 48.9 months, respectively. Distant metastases were the most common first failure, and oligometastatic distant failure occured in 86 patients (60.6 %). New metastases were treated with repeat SBRT in 48 patients (33.8 %). The 1- and 2-year cumulative incidence of initiation of systemic therapy was 24.6 % and 36.8 %, respectively. In multivariable analysis, the number of previous lines of systemic therapy and the cumulative volume of metastases were significantly associated with the interval to initiation of systemic therapy.

Conclusion

Selected patients with oligorecurrence achieved favorable OS and low cumulative incidence of initiation of systemic therapy. Prospective studies are warranted to determine how the deferral of systemic therapy impacts OS compared with immediate systemic therapy in combination with SBRT.

Clinical application of radiotherapy in patients with oligometastatic ovarian cancer: a sharp tool to prolong the interval of systemic treatment

BACKGROUND

With the advances of radiation technology, treatment of oligometastatic disease, with limited metastatic burden, have more chances to achieve long-term local control. Here we aim to evaluate the efficacy and safety of radiotherapy (RT) in oligometastatic ovarian cancer patients.

METHODS

A retrospective analysis collecting 142 patients (189 lesions) with oligometastatic ovarian cancer were included in the study. All pateints received radiotherapy and the curative effect and response rate were evaluated by diagnostic imaging after 1-3 months of radiotherapy with RECIST. Endpoints were the rate of complete response (CR), chemotherapy-free interval (CFI), local control (LC) rate and overall survival (OS) rate. Toxicity was evaluated by the Radiation Therapy Oncology Group (RTOG). Logistic and Cox regression were used for the uni- and multivariate analysis of factors influencing survival outcomes.

RESULTS

From 2013.1.1 to 2020.12.30, a total of 142 ovarian cancer patients (189 oligometastasis lesions) were included in the analysis. Prescribed doses to an average GTV of 3.10 cm were 1.8-8 Gy/fraction, median BED (28-115, a/b = 10 Gy), 5-28 fractions. For 179 evaluable lesions, the cases of CR, partial response (PR), stable disease (SD) and progressive disease (PD) after radiotherapy were 22,39,38 and 80 respectively. The disease control rate (DCR): CR + PR + SD was 55.31%, and the objective response rate (ORR): CR + PR was 34.08%. No patient developed grade 3 or higher side effect. The median CFI was 14 months (1-99 months), and the LC rate was 69.7%, 54.3% and 40.9% in 1 year, 2 years and 5 years respectively. GTV < 3 cm before treatment, platinum sensitivity, time from the last treatment ≥ 6 months, single lesion and BED(a/b = 10 Gy) ≥ 60 are the factors of good LC (p < 0.05). The total OS of 1 year, 2 years and 5 years were 67.1%, 52.6% and 30.3%, respectively. Single lesion (HR 0.598, 95%CI 0.405-0.884), DCR (HR 0.640, 95% CI 0.448-0.918) and ORR(HR 0.466, 95% CI 0.308-0.707) were the significant factors influencing 5-year OS.

CONCLUSION

For patients with oligometastatic ovarian cancer, radiotherapy has high LC, long chemotherapy-free interval, and survival benefits. Subgroup analysis shows that patients with single lesion and good local treatment results have higher overall survival rate, suggesting that active treatment is also beneficial for oligometastatic ovarian cancer patients.

Management of oligometastatic ovarian cancer recurrence during PARP inhibitor maintenance

OBJECTIVE

The benefit of surgery and maintenance treatment with PARP inhibitors (PARPi) has been clearly demonstrated in ovarian cancer. Also, the efficacy and safety of stereotactic body radiotherapy has been shown in patients with metastatic, persistent, and recurrent disease. The aim of this study is to evaluate the management of oligometastatic progression during PARPi maintenance treatment.

METHODS

This is an observational, retrospective, single-arm study conducted from June 2017 to December 2020 in patients with recurrent ovarian cancer with oligometastatic progression under PARPi maintenance treatment and receiving surgery or stereotactic body radiotherapy for such recurrence. PARPi treatment was continued until further progression of the disease. The primary objective of the study was the median prolongation of the treatment-free interval-p (without platinum) after local treatment.

RESULTS

A total of 186 patients with ovarian cancer were treated with PARPi at recurrence. Of these, 30 (16%) developed oligometastatic progression. The median age was 49.5 years (range 35-73). Olaparib, niraparib and rucaparib were administered to 33%, 60%, and 7% of patients, respectively. The median prolongation of the treatment-free interval-p of patients treated with surgery or stereotactic body radiotherapy was 6 and 10 months, respectively (p=0.53). The median treatment-free interval-p of patients treated with surgery or stereotactic body radiotherapy at the time of oligometastatic progression was 32 and 29 months, respectively (p=0.44). At the time of this publication, 50% of patients are still on treatment with PARPi following progression.

CONCLUSIONS

Patients with recurrent ovarian cancer who have oligometastic progression during PARPi maintenance may continue to benefit from PARPi if combined with local treatment.

The oligometastatic spectrum in the era of improved detection and modern systemic therapy

Metastases remain the leading cause of cancer-related mortality. The oligometastasis hypothesis postulates that a spectrum of metastatic spread exists and that some patients with a limited burden of metastases can be cured with ablative therapy. Over the past decade, substantial advances in systemic therapies have resulted in considerable improvements in the outcomes of patients with metastatic cancers, warranting re-examination of the oligometastatic paradigm and the role of local ablative therapies within the context of the improved therapeutic responses, shifting patterns of disease recurrence and possible synergy with systemic treatments. Herein, we reframe the oligometastatic phenotype as a dynamic state for which locally ablative, metastasis-directed therapy improves clinical outcomes, including by prolonging survival and increasing cure rates. Important risk factors defining the metastatic spectrum are highlighted that inform both staging and therapy. Finally, we synthesize the literature on combining local therapies with modern systemic treatments, identifying general themes to optimally integrate ablative therapies in this context.

Imaging to optimize gynecological radiation oncology

Gynecological cancers have particularly benefited from the increasing use of imaging to guide radiation treatment planning for both external beam radiation and brachytherapy. While the different gynecological cancers have varying use of imaging, certain trends predominate. CT represents an economical choice for evaluating initial disease extent or potential metastasis at follow-up, particularly for endometrial and ovarian cancers. F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT is particularly useful for assessing the initial disease extent and longer term treatment response of squamous predominant cancers, including cervical, vaginal, and vulvar cancers. With its excellent pelvic soft tissue discrimination, MRI provides the greatest assistance in evaluating the local extent of gynecological tumors, including initial evaluation for non-operative endometrial and vulvar cancer, and assessment before, after and during brachytherapy for cervix, locally recurrent endometrial, and primary vaginal cancers. With more limited availability of MRI, ultrasound can also help guide brachytherapy, particularly during procedures. The benefits of using imaging to better spare bone marrow or earlier assessment of treatment response are topics still being explored, in particular for cervical cancer. As imaging along with radiation oncology technologies continue to evolve and develop, such as with MRI-linacs and ultra high dose rate (FLASH) radiation, we may continue to see increasing use of imaging for advancing gynecological radiation oncology.

Role of stereotactic body radiotherapy in gynecologic radiation oncology

Stereotactic body radiotherapy (SBRT, also referred to as stereotactic ablative radiotherapy (SABR)) has been used in the treatment of primary and metastatic solid tumors, and increasingly so in gynecologic oncology. This review article aims to summarize the current literature describing the utility of SBRT in the primary, recurrent, and limited metastatic settings for gynecologic malignancies. The use of SBRT in both retrospective and prospective reports has been associated with adequate control of the treated site, particularly in the setting of oligometastatic disease. It is not, however, recommended as an alternative to brachytherapy for intact disease unless all efforts to use brachytherapy are exhausted. While phase I and II trials have established the relative safety and potential toxicities of SBRT, there remains a dearth of phase III randomized evidence, including the use of immunotherapy, in order to better establish the role of this technique as a method of improving more global outcomes for our patients with gynecologic cancers.

The role of radiotherapy in ovarian cancer

Epithelial ovarian cancer accounts for around 1.9% of all malignancies and often presents late at an advanced stage. Prognosis is therefore poor. Currently the mainstay of treatment is radical cytoreductive surgery and chemotherapy but, in the past, the standard of care also included adjuvant whole abdominal radiotherapy. This is no longer standard practice, largely due to high toxicity rates and the effectiveness of platinum-based chemotherapy. Presently, a role is emerging for modern radiotherapy techniques in both the salvage and palliative settings. This review aims to examine the historical use of radiotherapy in ovarian cancer before looking forward to its potential future role.

Stereotactic body radiotherapy in oligometastatic cervical cancer (MITO-RT2/RAD study): a collaboration of MITO, AIRO GYN, and MaNGO groups

Objective

This retrospective, multicenter study analyzes the efficacy and safety of stereotactic body radiotherapy in a large cohort of patients with oligometastatic/persistent/recurrent cervical cancer.

Methods

A standardized data collection from several radiotherapy centers that treated patients by stereotactic body radiotherapy between March 2006 and February 2021 was set up. Clinical and stereotactic body radiotherapy parameters were collected. Objective response rate was defined as a composite of complete and partial response, while clinical benefit included objective response rate plus stable disease. Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer and Common Terminology Criteria for Adverse Events scales were used to grade toxicities. The primary endpoints were the rate of complete response to stereotactic body radiotherapy, and the 2 year actuarial local control rate on a ‘per lesion’ basis. The secondary end points were progression-free survival and overall survival, as well as toxicity.

Results

A total of 83 patients with oligometastatic/persistent/recurrent cervical cancer bearing 125 lesions treated by stereotactic body radiotherapy at 15 different centers were selected for analysis. Of the sites of metastatic disease, lymph node metastases were most common (55.2%), followed by parenchyma lesions (44.8%). Median total dose was 35 Gy (range 10–60), in five fractions (range 1–10), with a median dose/fraction of 7 Gy (range 4–26). Complete, partial, and stable response were found in 73 (58.4%), 29 (23.2%), and 16 (12.8%) lesions, respectively, reaching 94.4% of the clinical benefit rate. Forty-six (55.4%) patients had a complete response. Patients achieving complete response on a ‘per lesion’ basis experienced a 2 year actuarial local control rate of 89.0% versus 22.1% in lesions not achieving complete response (p<0.001). The 2 year actuarial progression-free survival rate was 42.5% in patients with complete response versus 7.8% in patients with partial response or stable or progressive disease (p=0.001). The 2 year actuarial overall survival rate was 68.9% in patients with complete response versus 44.3% in patients with partial response or stable or progressive disease (p=0.015). Fifteen patients (18.1%) had mild acute toxicity, totaling 29 side events. Late toxicity was documented in four patients (4.8%) totaling seven adverse events.

Conclusion

Our analysis confirmed the efficacy of stereotactic body radiotherapy in oligometastatic/persistent/recurrent cervical cancer patients. The low toxicity profile encourages the wider use of stereotactic body radiotherapy in this setting.

Hypofractionated radiation therapy for unresectable or metastatic sarcoma lesions

Purpose

Given the relative radioresistance of sarcomas and their often large size, conventional palliative radiation therapy (RT) often offers limited tumor control and symptom relief. We report on our use of hypofractionated RT (HFRT) as a strategy to promote durable local disease control and optimize palliation.

Methods and Materials

We retrospectively reviewed 73 consecutive patients with sarcoma who received >10 fractions of HFRT from 2017 to 2020. Clinical scenarios included: (1) palliative or symptomatic intent (34%), (2) an unresectable primary (27%), (3) oligometastatic disease (16%), and (4) oligoprogressive disease (23%).

Results

The HFRT target was a primary tumor in 64% of patients with a median dose of 45 Gy in 15 fractions (59% ≥45 Gy). The 1-year disease-specific survival was 59%, which was more favorable for patients receiving HFRT for oligometastatic (1-year 100%) or oligoprogressive (1-year 73%) disease (P = .001). The 1-year local control (LC) of targeted lesions was 73%. A metastatic target (1-year 95% vs 60% primary; P = .02; hazard ratio, 0.27; P = .04) and soft tissue origin (1-year 78% vs 61% bone; P = .01; hazard ratio, 0.33; P = .02) were associated with better LC. The rate of distant failure was high with a 6-month distant metastasis-free survival of only 43%. For patients not planned for adjuvant systemic therapy (n = 53), the median systemic therapy break was 9 months and notably longer in oligometastatic (13 months), oligoprogressive (12 months) or unresectable (13 months) disease. HFRT provided palliative relief in 95% of cases with symptoms. Overall, 49% of patients developed acute grade 1 to 2 RT toxicities (no grade 3-5). No late grade 2 to 5 toxicities were observed.

Conclusions

HFRT is an effective treatment strategy for patients with unresectable or metastatic sarcoma to provide durable LC, symptom relief, and systemic therapy breaks with limited toxic effects.

Evaluation of patterns of progression on poly (ADP-ribose) polymerase inhibitor (PARPi) maintenance in ovarian cancer: a cross-sectional study

INTRODUCTION

Despite improvement in progression-free survival with poly (ADP-ribose) polymerase inhibitors (PARPi) as maintenance therapy for ovarian cancer, many patients will eventually progress on therapy. Oligoprogression is uniquely suited to considerations of local consolidation therapy in this setting, but not commonly used in ovarian cancer. In this study we evaluated the proportion of patients on PARPi maintenance who developed limited sites of disease, the location of progression, and their natural history.

METHODS

From January 2006 to December 2020, natural language processing software (DEEP6AI) was used to identify 58 patients with ovarian cancer treated with PARPi maintenance after complete or partial response after surgery and platinum-based chemotherapy at our institution. Patients were assessed for presence and location of recurrence based on radiologic findings.

RESULTS

The median patient age was 65 (IQR 57-71) years. Patients had a median of two lines of chemotherapy prior to starting PARPi. With a median follow-up of 48 (range 12-149) months, 32 (55%) patients had a recurrence on maintenance olaparib and 11 (34%) patients developed oligoprogression (≤3 sites). For the 11 patients with oligoprogression, three patients developed recurrence in one site, five in two sites, and three in three sites. The sites of oligoprogression were pelvic/periaortic nodal (27%), peritoneal (27%), liver (27%), lung/mediastinal (14%), and brain (5%). The median progression-free survival for the entire cohort was 6.0 months (95% CI 4.2 to 7.8); median overall survival was not met. There were no significant differences in overall survival (p=0.81) or progression-free survival (p=0.95) between patients with and without oligoprogression.

CONCLUSIONS

One-third of patients on PARPi maintenance experienced oligoprogression defined as limited to ≤3 sites. These patients may benefit from local consolidation therapy. A larger dataset is needed to validate these findings to assess if trials investigating local therapy for these patients is of value.

Phase I Trial of Stereotactic MRI-Guided Online Adaptive Radiation Therapy (SMART) for the Treatment of Oligometastatic Ovarian Cancer

PURPOSE

Stereotactic body radiation therapy is increasingly used to treat a variety of oligometastatic histologies, but few data exist for ovarian cancer. Ablative stereotactic body radiation therapy dosing is challenging in sites like the abdomen, pelvis, and central thorax due to proximity and motion of organs at risk. A novel radiation delivery method, stereotactic magnetic-resonance-guided online-adaptive radiation therapy (SMART), may improve the therapeutic index of stereotactic body radiation therapy through enhanced soft-tissue visualization, real-time nonionizing imaging, and ability to adapt to the anatomy-of-the-day, with the goal of producing systemic-therapy-free intervals. This phase I trial assessed feasibility, safety, and dosimetric advantage of SMART to treat ovarian oligometastases.

METHODS AND MATERIALS

Ten patients with recurrent oligometastatic ovarian cancer underwent SMART for oligometastasis ablation. Initial plans prescribed 35 Gy/5 fractions with goal 95% planning target volume coverage by 95% of prescription, with dose escalation permitted, subject to strict organ-at-risk dose constraints. Daily adaptive planning was used to protect organs-at-risk and/or increase target dose. Feasibility (successful delivery of >80% of fractions in the first on-table attempt) and safety of this approach was evaluated, in addition to efficacy, survival metrics, quality-of-life, prospective timing and dosimetric outcomes.

RESULTS

Ten women with seventeen ovarian oligometastases were treated with SMART, and 100% of treatment fractions were successfully delivered. Online adaptive plans were selected at time of treatment for 58% of fractions, due to initial plan violation of organs-at-risk constraints (84% of adapted fractions) or observed opportunity for planning target volume dose escalation (16% of adapted fractions), with a median on-table time of 64 minutes. A single Grade ≥3 acute (within 6 months of SMART) treatment-related toxicity (duodenal ulcer) was observed. Local control at 3 months was 94%; median progression-free survival was 10.9 months. Median Kaplan-Meier estimated systemic-therapy-free survival after radiation completion was 11.5 months, with concomitant quality-of-life improvements.

CONCLUSIONS

SMART is feasible and safe for high-dose radiation therapy ablation of ovarian oligometastases of the abdomen, pelvis, and central thorax with minimal toxicity, high rates of local control, and prolonged systemic-therapy-free survival translating into improved quality-of-life.

Online Magnetic Resonance-Guided Radiotherapy (oMRgRT) for Gynecological Cancers

Radiation therapy (RT) is increasingly being used in gynecological cancer management. RT delivered with curative or palliative intent can be administered alone or combined with chemotherapy or surgery. Advanced treatment planning and delivery techniques such as intensity-modulated radiation therapy, including volumetric modulated arc therapy, and image-guided adaptive brachytherapy allow for highly conformal radiation dose delivery leading to improved tumor control rates and less treatment toxicity. Quality on-board imaging that provides accurate visualization of target and surrounding organs at risk is a critical feature of these advanced techniques. As soft tissue contrast resolution is superior with magnetic resonance imaging (MRI) compared to other imaging modalities, MRI has been used increasingly to delineate tumor from adjacent soft tissues and organs at risk from initial diagnosis to tumor response evaluation. Gynecological cancers often have poor contrast resolution compared to the surrounding tissues on computed tomography scan, and consequently the benefit of MRI is high. One example is in management of locally advanced cervix cancer where adaptive MRI guidance has been broadly implemented for adaptive brachytherapy. The role of MRI for external beam RT is also steadily increasing. MRI information is being used for treatment planning, predicting, and monitoring position shifts and accounting for tissue deformation and target regression during treatment. The recent clinical introduction of online MRI-guided radiation therapy (oMRgRT) could be the next step in high-precision RT. This technology provides a tool to take full advantage of MRI not only at the time of initial treatment planning but as well as for daily position verification and online plan adaptation. Cervical, endometrial, vaginal, and oligometastatic ovarian cancers are being treated on MRI linear accelerator systems throughout the world. This review summarizes the current state, early experience, ongoing trials, and future directions of oMRgRT in the management of gynecological cancers.

Efficacy and safety of stereotactic body radiotherapy (SBRT) in oligometastatic/persistent/recurrent ovarian cancer: a prospective, multicenter phase II study (MITO-RT3/RAD)

BACKGROUND

Stereotactic body radiotherapy (SBRT) has shown promising results in the clinical setting of oligometastatic, persistent, or recurrent disease in several malignancies including ovarian cancer.

PRIMARY OBJECTIVE

The MITO-RT3/RAD trial is a prospective, multicenter phase II study aimed at identifying potential predictors of response and clinical outcome after SBRT treatment.

STUDY HYPOTHESIS

Radiotherapy delivered by pre-defined SBRT treatment schedules and shared constraints could improve the rate of complete response.

TRIAL DESIGN

All patients accrued will be treated with a radiotherapy dose in the range of 30-50 Gy by 1, 3, or 5 SBRT daily fractions to all sites of active metastatic disease according to diagnostic imaging. Schedules of treatment and dose prescription have been established before considering target sites and healthy organ dose constraints. Follow-up and monitoring of side effects will be carried out every 3 months for the first year with imaging and clinical evalutation, and every 4 months within the second year; thereafter, surveillance will be carried out every 6 months. The best response on a per lesion basis will be evaluated by computed tomographic (CT) scan, positron emission tomography/CT, or magnetic resonance imaging in case of brain lesions, every 3 months.

MAJOR INCLUSION/EXCLUSION CRITERIA

The study includes patients with oligometastatic, persistent, or recurrent ovarian cancer for which salvage surgery or other local therapies are not feasible due to any relative contra-indication to further systemic therapy because of serious co-morbidities, previous severe toxicity, unavailability of potentially active systemic therapy, or patient refusal.

PRIMARY ENDPOINT

The primary endpoint of the study is the clinical complete response rate to SBRT by imaging on a per lesion basis.

SAMPLE SIZE

Approximately 205 lesions will be treated (90 lymph nodes and 115 parenchyma lesions).

ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS

Fifty-two centers have expressed their intention to participate. Enrollment should be completed by March 2023 and analysis will be completed in September 2023.

TRIAL REGISTRATION

NCT04593381.

Radiation treatment for adult rare cancers: Oldest and newest indication

AIM

Aim of this analysis is to review the role of RT in the management of several rare tumors for adult patients.

METHODS

Collection data regarding RT and rare tumors was made by Pubmed.

RESULTS

For mucosal melanomas, RT is prescribed, being associated with lower local recurrence rate. For trachea tumors, RT was used as adjuvant or salvage treatment for unresectable disease. For pNET, RT can be a suitable option for post-surgical or unresectable/borderline. For bronchopulmonary neuroendocrine tumors the role of adjuvant treatments is uncertain. For hepatobiliary and ovarian malignancy, stereotactic body RT (SBRT) is a promising approach. For soft tissue sarcoma, perioperative treatments are indicated, and a growing role of SBRT in oligometastatic disease is recognized. For endocrine tumors, adjuvant RT has demonstrated benefits through reducing recurrence risk.

CONCLUSION

The radiotherapy is a frequent indication in adult rare cancers; thus the role of Radiation Oncologist must not be neglected.

Palliative Radiation Therapy for Metastatic, Persistent, or Recurrent Epithelial Ovarian Cancer: Efficacy in the Era of Modern Technology and Targeted Agents

PURPOSE

Metastatic, persistent, or recurrent epithelial ovarian cancer (MPR-EOC) remains a significant threat to patient mortality despite advances in novel targeted agents. Radiation therapy (RT) is often used as a palliative option. We report outcomes of a large series of MPR-EOC patients treated with modern palliative RT (PRT) in an era of novel systemic therapies.

METHODS AND MATERIALS

A retrospective review was conducted of women treated with PRT for MPR-EOC between 2007 and 2019 at an academic institution. Clinical response rates were recorded at <1 month, 1 to 3 months, and >3 months. Radiographic responses were categorized by RECIST 1.1 criteria. Overall response rate (ORR) was the sum of complete and partial response. Linear regression analyses of baseline characteristics were conducted for statistical testing.

RESULTS

Eighty-six patients with PMR-OC received 120 courses of palliative RT. Median follow-up was 8.6 months. Median age was 61 (range, 22-82). Thirty-six percent of women received central nervous system (CNS)-directed RT. In addition, 43% received targeted therapies before RT. Clinical ORR within 1 month and at last follow-up for non-CNS lesions was 79% and 61% (69% and 88% for CNS lesions, respectively). High-grade serous lesions were more likely to have clinical response (P = .04). Biologically effective doses (BED) >39 Gy were associated with improved clinical response in CNS lesions (P = .049). Bony sites were associated with worse clinical (P = .004) response in non-CNS lesions compared with soft tissue or nodal sites. Acute or late grade 3+ toxicities with bevacizumab were low (8.7%/4.3%).

CONCLUSIONS

PRT offers excellent rates of response for symptomatic patients with MPR-EOC within 1 month of treatment, with durable responses beyond 3 months. High-grade serous lesions were associated with improved response in all patients. Higher BED and soft tissue or nodal sites were associated with improved response in CNS and non-CNS patients, respectively. Acute or late toxicities with bevacizumab and PRT were low. Prospective investigation is warranted to determine the optimal PRT regimen.

Stereotactic Body Radiation Therapy: A Versatile, Well-Tolerated, and Effective Treatment Option for Extracranial Metastases From Primary Ovarian and Uterine Cancer

Purpose

Single extracranial metastases from ovarian and uterine malignancies have historically been treated with surgery or conventional radiation. We report mature local control (LC), overall survival (OS), progression free survival (PFS), and toxicity for patients who completed 5-fraction stereotactic body radiation therapy (SBRT).

Methods

Patients with biopsy-proven, single extracranial metastases from primary ovarian and uterine malignancies treated with 5-fraction SBRT were included. Patients were stratified based on tumor volume (small < 50 cc or large ≥ 50 cc) and dose (low dose < 35 Gy or high ≥ 35 Gy). Kaplan–Meier method was used to estimate LC, OS, and PFS.

Results

Between July 2007 and July 2012, 20 patients underwent SBRT to a single extracranial metastasis. Primary site was divided evenly between ovarian and uterine (n = 10 each). Metastases involved the liver (30%), abdominal lymph nodes (25%), lung (20%), pelvic lymph nodes (10%), spine (10%), and extremity (5%). The median gross tumor volume (GTV) was 42.5 cc (range, 5–273 cc) and the median dose to the GTV was 35 Gy (range, 30–50 Gy). At a median follow-up of 56 months, the 5-year LC and OS estimates were 73 and 46%. When stratified by tumor volume, the 5-year LC and OS for small tumors were significantly better at 100% (p < 0.01) and 65% (p < 0.02). When stratified by dose, the 5-year LC was 87.5% with high dose and 53.6% with low dose (p = 0.035). The 5-year PFS for the entire cohort was 20%. Four patients with small metastases who had complete response remained disease free at study completion and were considered cured (median PFS > 10 years). Treatment was generally well tolerated, and only one patient experienced a late grade III musculoskeletal SBRT related toxicity.

Conclusions

SBRT is a versatile, well-tolerated, and effective treatment option for single extracranial metastases from ovarian and uterine primary tumors. 35 Gy in five fractions appears to be a practical minimum effective dose. Four patients with small metastases were disease free at the study completion and considered cured. However, patients with larger metastases (≥50 cc) may require higher SBRT dosing or alternative treatments.

Recursive Partitioning Analysis for Local Control Achieved With Stereotactic Body Radiation Therapy for the Liver, Spine, or Lymph Nodes

Purpose

This study aims to develop a local control risk stratification using recursive partitioning analysis (RPA) for patients receiving stereotactic body radiation therapy (SBRT) for metastatic cancer.

Methods and Materials

A single institutional database of 397 SBRT treatments to the liver, spine, and lymph nodes was constructed. All treatments required imaging follow-up to assess for local control. Cox proportional hazards analysis was implemented before the decision tree analysis. The data were split into training (70%), validation (10%), and testing (20%) sets for RPA to optimize the training set.

Results

In the study, 361 treatments were included in the local control analysis. Two-year local control was 71%. A decision tree analysis was used and the resulting model demonstrated 93.10% fidelity for the validation set and 87.67% for the test set. RPA class 3 was composed of patients with non-small cell lung cancer (NSCLC) primary tumors and treatment targets other than the cervical, thoracic, and lumbar spines. RPA class 2 included patients with primary cancers other than NSCLC or breast and treatments targets of the sacral spine or liver. RPA class 1 consisted of all other patients (including lymph node targets and patients with primary breast cancer). Classes 3, 2, and 1 demonstrated 3-year local controls rates of 29%, 50%, and 83%, respectively. On subgroup analysis using the Kaplan-Meier method, treatments for lymph nodes and primary ovarian disease demonstrated improved local control relative to other treatment targets (P < .005) and primary disease sites (P < .005), respectively.

Conclusions

A local control risk stratification model for SBRT to sites of metastatic disease was developed. Treatment target and primary tumor were identified as critical factors determining local control. NSCLC primary lesions have increased local failure for targets other than the cervical, thoracic, or lumbar spines, and improved local control was identified for lymph node sites and breast or ovarian primary tumors.

Management of ovarian cancer: guidelines of the Italian Medical Oncology Association (AIOM)

INTRODUCTION

Ovarian cancer is the most lethal gynecologic malignancy. Over 5200 new cases of this tumor are diagnosed yearly in Italy, resulting in more than 3600 deaths. In terms of molecular biology, five different ovarian cancer subtypes should be distinguished.

METHOD

This article summarizes the evidence-based guidelines that the Italian Medical Oncology Association (AIOM) has developed with a multidisciplinary panel of experts, including pathologists, gynecologic oncologists, medical oncologists, and radiotherapists, with the support of methodologists, to help clinicians involved in the management of patients with ovarian cancer in their daily clinical practice.

RESULTS

The most relevant randomized clinical trials regarding surgery, chemotherapy, and molecularly targeted agents (bevacizumab and PARP inhibitors) in early, advanced, and recurrent disease have been critically analyzed. The levels of evidence and strength of recommendation have been reported for any issue.

CONCLUSION

Women with a clinical suspicion of ovarian cancer should be centralized in referral centers. The BRCA test should be requested for all women with nonmucinous and nonborderline tumors, regardless of age and family history. BRCA testing could be preferentially performed on neoplastic tissue. In the presence of a positive tumor test, a genetic test should always be performed on a blood sample to differentiate between germline mutations, which require counseling and genetic testing of family members, and somatic mutations.

Stereotactic Body Radiation Therapy for Mediastinal and Hilar Lymph Node Metastases

PURPOSE

Stereotactic body radiation therapy (SBRT) to metastatic mediastinal and hilar lymphadenopathy (MHL) is challenging owing to the proximity of centrally located organs-at-risk. As limited data exist on the safety and efficacy of SBRT for MHL, a retrospective review of clinical outcomes was conducted from a large academic center.

METHODS AND MATERIALS

Eligible patients received SBRT to MHL between 2014 to 2019 for the following indications: oligometastases, oligoprogression, or local control of a dominant area of progression. The primary endpoint was grade ≥3 toxicity (Common Terminology Criteria for Adverse Events, version 5.0). The cumulative incidence function evaluated local failure (LF) and starting or changing systemic therapy (SCST). Kaplan-Meier methodology estimated progression-free survival (PFS) and overall survival (OS).

RESULTS

Fifty-two patients (84 metastases) were included. Median follow-up was 20 months. Primary cancer sites included kidney (53.8%), lung (13.4%), breast (7.7%), and other (25.1%). Indications for SBRT were oligoprogression (n = 35; 67.3%), oligometastases (n = 10; 19.2%), or local failure of a dominant area of progression (n = 7; 13.5%). The majority (n = 31; 59.6%) received SBRT to a single lymph node metastasis. Median SBRT dose was 35 Gy (range, 30-50 Gy) with a median biologically effective dose of 59.5 Gy (range, 48-100 Gy). All treatments were in 5 fractions. Seven grade ≥3 toxicities were experienced by 6 patients (11.5%) and were mostly transient (5/7; 71%). There was a single (1.9%) grade 5 toxicity (radiation pneumonitis). The cumulative incidence of LF was 9.0% at 2 years. The cumulative incidence of SCST was 33.2% and 57.1% at 1 and 2 years, respectively. Median PFS was 4.0 months (95% confidence interval, 2.8-7.3) and median OS was 31.7 months (95% confidence interval, 23.8-87.5).

CONCLUSIONS

In one of the largest single institutional series of SBRT for MHL, moderate rates of grade ≥3 toxicity were observed, although the majority were transient. This treatment resulted in low LF rates and potentially delayed SCST for many patients.

Stereotactic Body Radiation Therapy in Oligometastatic Uterine Cancer: Clinical Outcomes and Toxicity

We report on clinical outcomes in patients with oligometastatic uterine cancer treated with stereotactic body radiation therapy (SBRT). Twenty-seven patients with 61 lesions were treated with SBRT. Median follow-up was 16.9 months. Local control was achieved in 49/61 (80.3%) lesions. One-year local-progression-free survival and overall survival were 75.9% and 65.4%. Lesions with favorable response were smaller than lesions with unfavorable response (p = .007). Liver lesions were less likely to achieve favorable response (p = .0128). There were no grade 3 or 4 events. Treatment with SBRT can provide excellent local control in oligometastatic uterine cancer with minimal toxicity.

Current and future strategies for treatment of ovarian clear cell carcinoma

Ovarian clear cell carcinoma (OCCC) is one of the five histological types of epithelial ovarian cancer (EOC). OCCC comprises 23% of all EOC cases in Japan, whereas the rate of OCCC in North America and Europe is much lower. OCCC is generally categorized as a rare gynecologic malignancy, and there is limited evidence for specific treatment. The clinical basis for treatment of OCCC is mostly based on retrospective studies, many of which were performed in Japan. Until recently, most randomized clinical trials for EOC have included OCCC; therefore, current treatment for OCCC is basically the same as that for other histologic types of EOC. However, the clinical characteristics of OCCC differ from those of high-grade serous carcinoma, particularly for chemosensitivity, and there is a need to develop new treatment for OCCC. The molecular background of OCCC has unique features: tumors are usually negative for p53 mutations and positive for ARID1A and/or PIK3CA mutations, whereas p53 mutations are common in high-grade serous or endometrioid carcinomas. These features may help in development of new treatment for OCCC. In this review, we described the current evidence for treatment of OCCC, including surgery, radiotherapy, chemotherapy, molecular targeted therapy and immunotherapy, and we discuss ongoing clinical trials and preclinical studies of new treatment approaches for OCCC.

Stereotactic Ablative Radiotherapy for Recurrent or Metastatic Gynecological Cancer: Extending Lives?

OPINION STATEMENT

Recent phase II clinical trials suggest that stereotactic ablative radiation therapy (SABR) can potentially improve survival for patients with oligometastatic cancer. However, these studies have mostly enrolled primaries other than gynecologic malignancies. While level I evidence is limited, recent publications exploring the use of SABR for oligometastatic gynecologic cancers have indicated a potential role for this treatment in para-aortic lymph node recurrences, and in visceral and brain metastases. The use of SABR for recurrences in the pelvis presents a number of challenges as these patients have often received previous radiation treatment. In these settings, care must be taken to avoid trespassing normal tissue tolerance with SABR leading to toxicity, especially as the potential benefit of SABR in this setting is not based on high-level evidence. Although SABR is feasible and in general safe for oligometastatic gynecologic malignancies, insufficient data are available to indicate whether it is associated with improved survival. Clinical judgment that incorporates patient and tumor factors is needed to determine if SABR is appropriate for selecting patients. Future directions include combining SABR with novel systemic therapies, determining optimal sequencing of treatments, and generating more robust randomized data pertaining to the use of SABR for oligometastatic gynecologic cancers.

Overall and chemotherapy-free survival following stereotactic body radiation therapy for abdominopelvic oligometastases

INTRODUCTION

Limited data establish the efficacy and safety of SBRT in the abdominopelvic (AP) space, where SBRT delivery is challenging due to the proximity of radiosensitive luminal gastrointestinal (GI) organs. The aim of this study was to assess clinical outcomes in patients with AP OM treated with SBRT.

METHODS

Eligible patients were those with OM (defined as metastases in ≤3 total sites) in the AP space (excluding liver) treated with SBRT. Descriptive statistics and Kaplan-Meier estimates of (LC), progression-free survival (PFS), overall survival (OS) and chemotherapy-free survival (CFS) were performed.

RESULTS

Fifty-one patients with 58 AP OM received SBRT between 2011 and 2015. Median follow-up was 21.9 months. All SBRT treatments were delivered in 5 fractions with a median dose of 35 Gy (25-40 Gy). Progression post-SBRT occurred in 38/51 patients (75%), with a median PFS of 4.9 months (95% CI: 2.5-7.5), and 2-year PFS of 29%. Rates of 2-and 4-year LC were 74% and 69%, respectively. Median OS was 42.6 months (95% CI: 31-55). Oligometastatic progression occurred in 21/38 patients, and of those, 48% (10/21) received further SBRT. Resulting 2- and 4-year CFS were 47% and 37%, respectively (median 15.1 months). Nineteen patients (37%) experienced a grade 1 or 2 acute toxicity. One grade 3 (acute) toxicity was observed. No grade 4 or 5 toxicities were detected.

CONCLUSIONS

SBRT to AP OM was associated with sustained LC, excellent OS and minimal toxicity. The use of SBRT allowed for prolonged CFS and the salvage of limited-burden distant failures.

Stereotactic body radiation therapy in the treatment of ovarian cancer

BACKGROUND

This study evaluates the outcomes and toxicity of stereotactic body radiation therapy (SBRT) in ovarian cancer.

METHODS

This retrospective analysis considered all patients treated with SBRT from 2009 to 2018 with a primary ovarian tumor. Follow-up included PET-CT and CT scans at 2-3 month intervals. Statistical analysis primarily consisted of univariate analysis, Cox proportional hazards analysis, and the Kaplan-Meier method.

RESULTS

The study included 35 patients with 98 treatments for lymph nodes (51), local recurrence (21), and de novo solid metastases (26). Median biologically effective dose (BED), gross tumor volume, and planning target volume were 38.40 Gy, 10.41 cc, and 25.21 cc, respectively. 52 lesions showed complete radiographic response, and two-year local control was 80%. Median overall survival (OS) was 35.2 months, and two-year progression-free survival (PFS) was 12%. On univariate analysis, Eastern Cooperative Oncology Group performance status > 0 was predictive of decreased OS (p = 0.0024) and PFS (p = 0.044). Factors predictive of local failure included lower BED (p = 0.016), treatment for recurrence (p = 0.029), and higher pre-treatment SUV (p = 0.026). Kaplan-Meier analysis showed BED ≤35 Gy (p < 0.005) and treatment for recurrence (p = 0.01) to be predictive of local failure. On Cox proportional hazards analysis, treatment of lymph nodes was predictive of complete radiographic response (hazard ratio (HR) = 4.95), as was higher BED (HR = 1.03). Toxicity included 27 cases of grade < 3 toxicity, and one grade 5 late toxicity of GI bleed from a radiation therapy-induced duodenal ulcer.

CONCLUSIONS

SBRT provides durable local control with minimal toxicity in ovarian cancer, especially with BED > 35 Gy and treatment for lymph nodes.

Rethinking the Role of Radiation Therapy in the Management of Epithelial Ovarian Cancer

Radiation has been relegated to a palliative role in the management of epithelial ovarian cancer (EOC). Contemporary radiation techniques, including intensity modulated radiation therapy (IMRT), stereotactic body radiation therapy (SBRT), and image-guided radiation therapy, enable conformal treatment that controls local disease with minimal morbidity. Recent studies from multiple institutions support the role of radiation in the ablative treatment of oligometastatic disease and control of locally recurrent and metastatic disease. Effective local treatment with radiation complements the role of systemic therapy in the management of EOC; reduces symptoms and disease burden, and may contribute to a prolonged drug free interval.