Prospective validation of diffusion-weighted MRI as a biomarker of tumor response and oncologic outcomes in head and neck cancer: Results from an observational biomarker pre-qualification study

PURPOSE

To determine DWI parameters associated with tumor response and oncologic outcomes in head and neck (HNC) patients treated with radiotherapy (RT).

METHODS

HNC patients in a prospective study were included. Patients had MRIs pre-, mid-, and post-RT completion. We used T2-weighted sequences for tumor segmentation which were co-registered to respective DWIs for extraction of apparent diffusion coefficient (ADC) measurements. Treatment response was assessed at mid- and post-RT and was defined as: complete response (CR) vs. non-complete response (non-CR). The Mann-Whitney U test was used to compare ADC between CR and non-CR. Recursive partitioning analysis (RPA) was performed to identify ADC threshold associated with relapse. Cox proportional hazards models were done for clinical vs. clinical and imaging parameters and internal validation was done using bootstrapping technique.

RESULTS

Eighty-one patients were included. Median follow-up was 31 months. For patients with post-RT CR, there was a significant increase in mean ADC at mid-RT compared to baseline ((1.8 ± 0.29) × 10-3 mm2/s vs. (1.37 ± 0.22) × 10-3 mm2/s, p < 0.0001), while patients with non-CR had no significant increase (p > 0.05). RPA identified GTV-P delta (Δ)ADCmean < 7% at mid-RT as the most significant parameter associated with worse LC and RFS (p = 0.01). Uni- and multi-variable analysis showed that GTV-P ΔADCmean at mid-RT ≥ 7% was significantly associated with better LC and RFS. The addition of ΔADCmean significantly improved the c-indices of LC and RFS models compared with standard clinical variables (0.85 vs. 0.77 and 0.74 vs. 0.68 for LC and RFS, respectively, p < 0.0001 for both).

CONCLUSION

ΔADCmean at mid-RT is a strong predictor of oncologic outcomes in HNC. Patients with no significant increase of primary tumor ADC at mid-RT are at high risk of disease relapse.

Teaching radiology in Egyptian medical schools: Where do we stand and how can we start?

Background

Radiology serves in the diagnosis and management of many diseases. Despite its rising importance and use, radiology is not a core component of a lot of medical school curricula. This survey aims to clarify current gaps in the radiological education in Egyptian medical schools. In February–May 2021, 5318 students enrolled in Egyptian medical schools were recruited and given a 20-multiple-choice-question survey assessing their radiology knowledge, radiograph interpretation, and encountered imaging experiences. We measured the objective parameters as a percentage. We conducted descriptive analysis and used Likert scales where values were represented as numerical values. Percentages were graphed afterwards.

Results

A total of 5318 medical students in Egypt answered our survey. Gender distribution was 45% males and 54% females. The results represented all 7 class years of medical school (six academic years and a final training year). In assessing students’ knowledge of radiology, most students (75%) reported that they received ‘too little’ education, while 20% stated the amount was ‘just right’ and only 4% reported it was ‘too much.’ Sixty-two percent of students stated they were taught radiology through medical imaging lectures. Participants’ future career plans were almost equally distributed. Near half of participants (43%) have not heard about the American College of Radiology Appropriateness Criteria (ACR-AR), while 39% have heard about it but are not familiar with.

Conclusions

Radiology is a novel underestimated field. Therefore, medical students need more imaging exposure. To accomplish this, attention and efforts should be directed toward undergraduate radiology education to dissolve the gap between radiology and other specialties during clinical practice. A survey answered by medical students can bridge between presence of any current defect in undergraduate radiology teaching and future solutions for this topic.

Multidisciplinary approach of teaching radiology to medical students in Egypt: Is this an effective method?

Background

In multidisciplinary education, different perspectives from more than one discipline are used to illustrate a certain topic. The aim of this study was to evaluate the effectiveness of an online, multidisciplinary radiology curriculum to teach radiology to medical students in Egypt. A multidisciplinary team of radiologists, surgeons, and internists taught a series of 5 case-based radiology sessions on a web conference platform. Topics included common clinical case scenarios for various body systems. Undergraduate medical students across Egypt were enrolled in the course. A pre-test–post-test design was used to evaluate the efficacy of each session. Upon course completion, students filled out a subjective survey to assess the radiology education series.

Results

On average, 1000 students attended each session. For each session, an average of 734 students completed both the pre-test and post-test. There was a statistically significant increase in post-test scores compared to pre-test scores across all 5 sessions (p < 0.001) with an overall average score improvement of 63%. A subjective survey at the end of the course was completed by 1027 students. Over 96% of students found the lecture series to be a worthwhile experience that increased their imaging knowledge and interest in radiology, and that the use of a multidisciplinary approach added educational value. About 66% of students also reported that the session topics were “excellent and clinically important.” There was a marked increase in reported confidence levels in radiology competencies before and after attendance of the sessions.

Conclusions

An online radiology curriculum with a multidisciplinary approach can be implemented successfully to reach a large group of medical students and meet their educational objectives.

Tobacco exposure as a major modifier of oncologic outcomes in human papillomavirus (HPV) associated oropharyngeal squamous cell carcinoma

Background

The incidence of oropharyngeal squamous cell carcinoma (OPSCC) in the US is rapidly increasing, driven largely by the epidemic of human papillomavirus (HPV)-mediated OPSCC. Although survival for patients with HPV mediated OPSCC (HPV+ OPSCC) is generally better than that of patients with non-virally mediated OPSCC, this effect is not uniform. We hypothesized that tobacco exposure remains a critical modifier of survival for HPV+ OPSCC patients.

Methods

We conducted a retrospective analysis of 611 OPSCC patients with concordant p16 and HPV testing treated at a single institute (2002–2013). Survival analysis was performed using Kaplan-Meier analysis and Cox regression. Recursive partitioning analysis (RPA) was used to define tobacco exposure associated with survival (p < 0.05).

Results

Tobacco exposure impacted overall survival (OS) for HPV+ patients on univariate and multivariate analysis (p = 0.002, p = 0.003 respectively). RPA identified 30 pack-years (PY) as a threshold at which survival became significantly worse in HPV+ patients. OS and disease-free survival (DFS) for HPV+ > 30 PY patients didn’t differ significantly from HPV- patients (p = 0.72, p = 0.27, respectively). HPV+ > 30 PY patients had substantially lower 5-year OS when compared to their ≤30 PYs counterparts: 78.4% vs 91.6%; p = 0.03, 76% vs 88.3%; p = 0.07, and 52.3% vs 74%; p = 0.05, for stages I, II, and III (AJCC 8th Edition Manual), respectively.

Conclusions

Tobacco exposure can eliminate the survival benefit associated with HPV+ status in OPSCC patients. Until this effect can be clearly quantified using prospective datasets, de-escalation of treatment for HPV + OPSCC smokers should be avoided.