Impact of treatment year on survival and adverse effects in patients with cervical cancer and paraortic lymph node metastases treated with definitive extended-field radiation therapy

Curative treatment for stage IIIC2 cervical cancer: what to expect?

Background

Since the GOG125 study, treating radically patients with positive para-aortic lymph nodes has been a valid approach. Nevertheless, literature lacks data on how to better treat these patients since they are usually excluded from trials. In this study, we aimed to report the outcomes of patients with advanced cervical cancer and positive para-aortic lymph nodes (PAN) treated in a single tertiary/academic institution and try to identify variables that may impact survival.

Materials and methods

We retrospectively reviewed patients with positive para-aortic lymph nodes treated in our institution. Demographic variables and treatment options were assessed and their impact on overall survival (OS), locorregional control, distant metastasis free survival, and para-aortic lymph node progression was analyzed.

Results

We assessed 65 patients treated from April 2010 to May 2017. Median OS was 38.7 months. Median locorregional and para-aortic progression free survivals were not reached. Median distant metastasis progression-free survival was 64.3 months. Better ECOG performance status (p > 0.001), concurrent chemotherapy (p = 0.031), and brachytherapy (p = 0.02) were independently related to better overall survival.

Conclusion

Patients with current stage IIIC2 cervix cancer may present long term survival. Treating positive PAN cervical cancer patients with concurrent chemoradiation including brachytherapy with curative intent should be standard. Poor PS and more advanced pelvic disease may represent a higher risk for worse outcomes. Distant metastases are still a challenge for disease control.

Use of specific duodenal dose constraints during treatment planning reduces toxicity after definitive para-aortic radiotherapy for cervical cancer

PURPOSE

To validate the safety of paraaortic nodal (PAN) radiation therapy (RT) for patients with cervical cancer when the duodenal dose is limited to V₅₅<15 cm³ and V₆₀<2 cm³.

METHODS AND MATERIALS

Ninety-seven patients who were treated with RT for cervical cancer between 2010 and 2018, received at least 56 Gy to grossly involved PANs. Patients were treated with concurrent chemoradiation (n=88, 91%), with 93% (n=90) receiving intensity-modulated RT (IMRT) to the initial PAN field, and 98% (n=95) receiving IMRT to a sequential PAN boost. V₅₅<15 cm³ and V₆₀ <2 cm³ criteria were implemented in 2014. Normal tissues were contoured on CT simulation datasets; the duodenum was contoured from the gastric outlet to the duodenojejunal flexure. Sixty-six patients (68%) had a resimulation scan after approximately 20 fractions. Composite duodenal doses were calculated using the initial CT for 50 patients (52%) and the resimulation CT for 47 patients (48%) depending on anatomic changes throughout treatment.

RESULTS

The median duodenal V₅₅ was 3.5 cm³ (interquartile range [IQR] 0.2-8.1 cm³) and the median V₆₀ was 0.3 cm³ (IQR 0.0-1.8). Constraints were exceeded in 18 patients, 16 (89%) of whom had been treated before 2014. Treatment for the 2 patients treated after 2014 had been complicated by significant weight loss and reduced anterior-posterior diameter, which likely overestimated the true dose on the composite plan. Only 1 patient experienced grade 3 duodenal toxicity (stricture requiring endoscopic balloon dilation 3 months after treatment); however, the stricture was outside the high-dose boost volume and the patient had a history of gastritis. Six patients (6%) had a first recurrence within the PAN region.

CONCLUSIONS

Limiting duodenal dose to V₅₅<15 cm³ and V₆₀<2 cm³ for patients with cervical cancer and PAN involvement is feasible and minimizes duodenal toxicity while maintaining acceptable local control rates.

The Role of Positron Emission Tomography Imaging in Radiotherapy Target Delineation

Positron emission tomography (PET) is an advanced functional imaging modality in oncology care for the diagnosis, staging, prognostication, and surveillance of numerous malignancies. PET can also offer considerable advantages for target volume delineation as part of radiation treatment planning. In this review, data and clinical practice from 6 general oncology disease sites are assessed to descriptively evaluate the role of PET in target volume delineation. Also highlighted are several specific and practical utilities for PET imaging in radiation treatment planning. Publication of several ongoing prospective trials in the future may further expand the utility of PET for target delineation and patient care.

A comparative dosimetric study of cervical cancer patients with para-aortic lymph node metastasis treated with volumetric modulated arc therapy vs. 9-field intensity-modulated radiation therapy

Background

To compare the dosimetric characteristics between volumetric modulated arc therapy (VMAT) and 9-field intensity-modulated radiation therapy (9F-IMRT) for cervical cancer patients with para-aortic lymph node (PALN) metastasis.

Methods

We selected 20 patients who had received extended-field radiotherapy for cervical cancer with PALN metastasis. IMRT and VMAT plans were compared in terms of target, organs at risk (OARs), homogeneity index (HI), conformity index (CI), the number of monitor units (MUs) and treatment time (s).

Results

The CI and HI of VMAT plans were superior to those of IMRT plans (P<0.05). As for OARs, the mean maximum doses (Dmean) to the kidneys in the VMAT plans were all lower than those in IMRT plans (P<0.001). V40, V50 of the rectum, and V40 of the bladder in VMAT plans involved fewer doses than IMRT plans (P<0.001). Compared with IMRT plans, VMAT reduced the average number of MUs by 51% and the average treatment time by 31%.

Conclusions

Both VMAT and IMRT plans can satisfy clinical dosimetric demands and protect OARs. VMAT has the best performance on CI and HI and can better protect the OARs. VMAT plans have fewer MUs and improve treatment efficiency.

Therapeutic Delivery of miR-29b Enhances Radiosensitivity in Cervical Cancer

Radioresistant cervical cancer is likely to give rise to local recurrence, distant metastatic relapse, and decreased survival rates. Recent studies revealed microRNA mediated regulation of tumor aggressiveness and metastasis; however, whether specific microRNAs regulate tumor radioresistance and can be exploited as radiosensitizing agents remains unclear. Here, we find that miR-29b could promote radiosensitivity in radioresistant subpopulations of cervical cancer cells. Notably, therapeutic delivery of miR-29b mimics via R11-SSPEI nanoparticle, whose specificity has been proved by our previous studies, can sensitize the tumor to radiation in a xenograft model. Mechanistically, we reveal a novel function of miR-29b in regulating intracellular reactive oxygen species signaling and explore a potential application for its use in combination with therapies known to increase oxidative stress such as radiation. Moreover, miR-29b inhibits DNA damage repair by targeting phosphate and tension homology deleted on chromsome ten (PTEN), and overexpression of PTEN could partially rescue miR-29b-mediated homologous recombination (HR)-DNA damage repair and increase radiosensitivity. These findings identify miR-29b as a radiosensitizing microRNA and reveal a new therapeutic strategy for radioresistant tumors.