Prachi Mittal

RECIST 1.1 versus clinico-radiological response assessment for locally advanced cervical cancer: implications on interpreting survival outcomes of future trials

To investigate differences in standard clinico-radiological evaluation versus Response Evaluation Criteria In Solid Tumors (RECIST) 1.1 for reporting survival outcomes in patients with locally advanced cervical cancer treated with chemoradiation and brachytherapy. Between November 2017 and March 2020, patients recruited in cervical cancer trials were identified. MRI at diagnosis and at least one follow-up imaging was mandatory. Disease-free survival and progression-free survival were determined using standard evaluation (clinical examination and symptom-directed imaging) and RECIST 1.1. Agreement between criteria was estimated using κ value. Sensitivity analysis was done to test the sensitivity, specificity, and accuracy of RECIST 1.1 in detecting response to treatment. Sixty-nine eligible patients had at least one target lesion. Thirty-three patients (47.8%) had pathological lymph nodes. Of these 33 patients, RECIST 1.1 classified only 18% (6/33) as 'target nodal lesions' and the remaining nodes as 'non-target'. There were 6 (8.7%) and 8 (11.6%) patients with disease events using RECIST 1.1 and standard evaluation, respectively. The disease-free survival at 12, 18, and 24 months using RECIST 1.1 was 94.2%, 91.2%, 91.2%, and with standard evaluation was 94.2%, 89.7%, and 88.2%, respectively (p=0.58). Whereas, progression-free survival at 12, 18, and 24 months using RECIST 1.1 and standard evaluation were same (94.2%, 91.2%, and 91.2%, respectively). The κ value was 0.84, showing strong agreement in assessing disease-free survival, although an absolute difference of 3% between endpoint assessment methodologies. RECIST 1.1 had a sensitivity of 75% (95% CI 34.91% to 96.81%), specificity of 100% (95% CI 94.13% to 100%), and accuracy of 97.1% (95% CI 89.92% to 99.65%). The study showed 1.5% and 3% difference in disease-free survival at 18 and 24 months and no difference in progression-free survival between RECIST 1.1 and standard evaluation in a patient cohort with low event rate.

Clinical outcomes of adaptive intracavitary and interstitial brachytherapy technique in locally advanced cervical cancer: A real-world data

To evaluate clinical outcomes of CT-based adaptive intracavitary and interstitial brachytherapy (IC followed by IC-ISBT) in locally advanced cervical cancer (LACC) in resource-constrained settings. LACC patients treated with adaptive brachytherapy techniques were analyzed to evaluate treatment characteristics and clinical outcomes. The Kaplan-Meier method was used for survival analysis, and the log-rank test for univariate analysis. Out of 141 eligible patients with LACC, 87 (61.7%) patients received external beam radiotherapy (EBRT) in referral hospitals, while 54 (38.3%) were treated at our center. We divided our cohort into two groups: poor EBRT responder group (n = 70 [49.6%]) where IC-ISBT was adapted to achieve optimum tumor doses and OAR optimization group 71 (50.4%) where IC-ISBT was performed to reduce OAR doses. Median HRCTV-D90 dose was 88 Gy (range 70-109 Gy) with median HRCTV volume 33cc (range 15-96). Median D2cc doses to OARs were 90 Gy (range 70-107), 71 Gy (range 55-105) and 70 Gy (range 47-90) to bladder, rectum and sigmoid, respectively. At median follow-up of 32 months, 3-year local control (LC), locoregional control (LRC), disease-free survival (DFS) and overall survival (OS) were 83%, 75%, 64% and 72%, respectively. Subgroup analysis revealed significantly better outcomes for OAR optimization compared to poor EBRT responders, with 3-year LC (95% vs. 70.1%, p < 0.001), LRC (87.3% vs. 62.7%, p < 0.001), DFS (79.2% vs. 49.4%, p < 0.001), and OS (86.2% vs. 57.4%, p < 0.001) CONCLUSION: In resource-constrained settings, implementation of Adaptive IC-ISBT is a viable alternative for optimizing OAR doses in LACC. However proactive approach employing IC-ISBT for tumor dose-escalation from first fraction of BT is warranted for improving LC in poor EBRT responders.

Longitudinal Costs of Image-Guided Intensity-Modulated Radiation Therapy Versus Three-Dimensional Conformal Radiation: Lessons From Phase III PARCER Trial for Shaping Resource-Stratified Guidelines in Low- and Middle-Income Countries

PURPOSE The PARCER trial provided level I evidence for image-guided intensity-modulated radiation therapy (IG-IMRT) in patients with cervical cancer. Further information regarding long-term financial impact is imperative for adoption into the National Cancer Grid of India cervical cancer resource-stratified guidelines. METHODS Patient data from the PARCER trial were analyzed to evaluate the cost implications of transitioning to IG-IMRT. Lacking differences in outcomes between the three-dimensional conformal radiation (3D-CRT) and IG-IMRT, differences in treatment costs, adverse event incidence, and toxicity management costs were examined. The overall financial impact was estimated by adding the treatment costs, toxicity management, and wage loss. This was extrapolated nationally to determine if a transition to IG-IMRT would be feasible for the Indian health care system. RESULTS Of the 300 patients in the PARCER trial, 93 faced grades ≥2 adverse events (3D-CRT = 59, IG-IMRT = 34). Patients in the 3D-CRT and IG-IMRT arms spent an average of 2.39 years and 1.96 years in toxicity, respectively. The average toxicity management and the yearly financial impact per patient were, respectively, 1.50 and 1.44 times higher for 3D-CRT patients compared with IG-IMRT patients. Extrapolation to the national level showed that treatment with 3D-CRT led to a 2.88 times higher cost ratio when compared with treatment with IG-IMRT. CONCLUSION Although the initial costs of IG-IMRT are high, on the basis of longitudinal data, it is financially inefficient to treat with 3D-CRT. Resource-stratified guidelines should include longitudinal health intervention costs rather than solely initial costs for policy decisions to implement advanced radiation technology.