Can Pretreatment MRI and Planning CT Radiomics Improve Prediction of Complete Pathological Response in Locally Advanced Rectal Cancer Following Neoadjuvant Treatment?

OBJECTIVE(S): The treatment response to neoadjuvant chemoradiation (nCRT) differs largely in individuals treated for rectal cancer. In this study, we investigated the role of radiomics to predict the pathological response in locally advanced rectal cancers at different treatment time points: (1) before the start of any treatment using baseline T2-weighted MRI (T2W-MR) and (2) at the start of radiation treatment using planning CT. METHODS: Patients on nCRT followed by surgery between June 2017 to December 2019 were included in the study. Histopathological tumour response grading (TRG) was used for classification, and gross tumour volume was defined by the radiation oncologists. Following resampling, 100 and 103 pyradiomic features were extracted from T2W-MR and planning CT images, respectively. Synthetic minority oversampling technique (SMOTE) was used to address class imbalance. Four machine learning classifiers built clinical, radiomic, and merged models. Model performances were evaluated on a held-out test dataset following 3-fold cross-validation using area under the receiver operator characteristic curves (AUC) with bootstrap 95% confidence intervals. RESULTS: One hundred and fifty patients were included; 58/150 with TRG 1 were classified as complete responders, and rest were incomplete responders (IR). Clinical models performed better (AUC = 0.68) compared to radiomics models (AUC = 0.62). Overall, the clinical + T2W-MR model showed best performance (AUC = 0.72) in predicting the pathological response prior to therapy. Clinical + Planning CT-merged models could only achieve the highest AUC of 0.66. CONCLUSION: Merging clinical and baseline T2W-MR radiomics enhances predicting pathological response in rectal cancer. Validation in larger cohorts is warranted, especially for watch and wait strategies.

Strategies for primary HPV test-based cervical cancer screening programme in resource-limited settings in India: Results from a quasi-experimental pragmatic implementation trial.

BACKGROUND: In order for low and middle income countries (LMIC) to transition to Human Papilloma Virus (HPV) test based cervical cancer screening, a greater understanding of how to implement these evidence based interventions (EBI) among vulnerable populations is needed. This paper documents outcomes of an implementation research on HPV screening among women from tribal, rural, urban slum settings in India. METHODS: A mixed-method, pragmatic, quasi-experimental trial design was used. HPV screening on self-collected cervical samples was offered to women aged 30-60 years. Implementation strategies were 1) Assessment of contextual factors using both qualitative and quantitative methods like key informant interviews (KII), focus group discussions (FGDs), pre-post population sample surveys, capacity assessment of participating departments 2) enhancing provider capacity through training workshops, access to HPV testing facility, colposcopy, thermal ablation/cryotherapy at the primary health care centers 3) community engagement, counselling for self-sampling and triage process by frontline health care workers (HCWs). Outcomes were assessed using the RE-AIM (Reach, Effectiveness, adoption, implementation, maintenance) framework. RESULTS: Screening rate in 8 months' of study was 31.0%, 26.7%, 32.9%, prevalence of oncogenic HPV was 12.1%, 3.1%, 5.5%, compliance to triage was 53.6%, 45.5%, 84.6% in tribal, urban slum, rural sites respectively. Pre-cancer among triage compliant HPV positive women was 13.6% in tribal, 4% in rural and 0% among urban slum women. Unique challenges faced in the tribal setting led to programme adaptations like increasing honoraria of community health workers for late-evening work and recalling HPV positive women for colposcopy by nurses, thermal ablation by gynaecologist at the outreach camp site. CONCLUSIONS: Self-collection of samples combined with HCW led community engagement activities, flexible triage processes and strengthening of health system showed an acceptable screening rate and better compliance to triage, highlighting the importance of identifying the barriers and developing strategies suitable for the setting. TRIAL REGISTRATION: CTRI/2021/09/036130.

Development and validation of a novel scoring system to predict the risk of uterine perforation during intracavitary brachytherapy for cervical cancer.

OBJECTIVE: To develop and validate a novel scoring system for predicting the risk of uterine perforation during brachytherapy (BT) in cervical cancer patients and to stratify patients based on this score to guide the use of ultrasound guidance during BT. METHODS: Fifty patients with uterine perforation during BT between January 2018 and December 2020 were included. Common reasons for perforation were identified and a scoring system was developed. This was then applied to a cohort of 50 patients without perforation. The 2 cohorts were compared using the χ² test. To validate the scoring system, all newly diagnosed patients who underwent BT in 2021 were scored, and analysed using χ² test and receiver operator characteristic curves. RESULTS: The mean score in the test cohort was 10.16 (range=7-14) and 5.92 (range=5-8) for patients with and without perforation. In the validation cohort, the mean score was 6.9 (range=5-10) and 9.33 (range=7-11) for those with and without perforation. Patients with a score <8 were classified as low risk, while those with a score ≥8 were classified as high risk. Among the criteria evaluated for validation, response to external beam radiotherapy, uterine position, cervico-uterine angle (uterine flexion), identification of cervical os at BT assessment, and the total score were significant predictors, while previous history of perforation, uterine length, and additional uterine anomaly were not. CONCLUSION: The novel scoring system is an effective predictor of perforation risk during BT. Implementing this during BT assessment can optimize the need for ultrasound guidance during the procedure.

Utility of Mid-treatment DWI in Selecting Pathological Responders to Neoadjuvant Chemoradiotherapy in Locally Advanced Esophageal Cancer.

PURPOSE: Pathological complete response correlates with better clinical outcomes in locally advanced esophageal cancer (LA-EC). However, there is lack of prognostic markers to identify patients in the current setting of neoadjuvant chemoradiotherapy (NACRT) followed by surgery. This study evaluates the utility of mid-treatment diffusion-weighted imaging (DWI) in identifying pathological responders of NACRT. METHODS: Twenty-four patients with LA-EC on NACRT were prospectively recruited and underwent three MRI (baseline, mid-treatment, end-of-RT) scans. DWI-derived apparent diffusion coefficient (ADC) mean and minimum were used as a surrogate to evaluate the treatment response, and its correlation to pathological response was assessed. RESULTS: Mid-treatment ADC mean was significantly higher among patients with pathological response compared to non-responders (p = 0.011). ADC difference (ΔADC) between baseline and mid-treatment correlated with tumor response (p = 0.007). ADC at other time points did not correlate to pathological response. CONCLUSION: In this study, mid-treatment ADC values show potential to be a surrogate for tumor response in NACRT. However, larger trials are required to establish DW-MRI as a definite biomarker for tumor response.

Training for next-generation gynaecologic surgical & radiation oncologists - opportunities & challenges.

The global increase in cancer burden is a challenge for countries with scarce resources. Amongst all the malignancies, gynaecological cancer still continues to have a high incidence and prevalence leading to significant morbidity and mortality. While a multipronged strategy of decreasing the gynaecological cancer burden is a global priority, one of the key strategies to decrease the morbidity and mortality is to train gynaecological oncology specialists. Most of the developed nations have an established gynaecologic oncology training programme in the form of a well-designed curriculum and skill training. However, in developing countries where the actual disease burden of these cancers is highest, such focused training programmes have only started emerging and evolving over the past two decades. While it is a positive step to initiate such training programmes in a country like India, there are still gaps in the uniformity of curriculum and training. Also, exposure to modern practices in gynaecologic oncology surgery, chemotherapy and technology in radiation oncology, especially brachytherapy, is still insufficient in many centres. This review discusses some of the challenges and opportunities in the still evolving programmes for training gynaecologic oncologists in India.