Prevalence of palliative radiotherapy abstracts presented at the annual scientific meetings of the Canadian Association of Radiation Oncology: 2003-2021.

PURPOSE: Approximately half of all radiotherapy (RT) is delivered with palliative intent. Clinical research in palliative RT aims to manage symptoms, improve quality of life (QoL), evaluate supportive care, and determine optimal dose-fractionation schedules. Our aim was to describe the prevalence of palliative research at the Canadian Association of Radiation Oncology (CARO) Annual Scientific Meeting (ASM) over time and compare this analysis to previously published work which evaluated the years 1992-2002. METHODS: Published abstracts (2003-2021) were independently reviewed by two authors who categorized each as curative-intent; palliative-intent; pertaining to both populations; or neither. Abstracts were considered palliative if they described incurable malignancy and interventions primarily for symptom control or QoL. Type of study, primary, site treated, and symptoms palliated were recorded. Descriptive and summary statistics were calculated including one-way ANOVA test for trend. RESULTS: Three hundred thirty-nine out of 4566 abstracts (7.4%, range 2.4-13.9% per year) were classified as palliative. 7.7% (26/339) described phase I-III trials. The main primary site was the lung (39/339) and the most common metastatic site was the bone (34.2%). QoL, symptom and toxicity outcomes were reported in 31.6% (107/339), 37.8% (128/339) and 17.7% (60/339), respectively. The most common symptom investigated was pain (38/339). The proportion of abstracts classified as curative, palliative or reporting toxicity endpoints demonstrated significant change over time (all p<0.0001). CONCLUSION: While proportion of palliative themed abstracts has increased with time, there remains a significant gap before equivalence with the prevalence of palliative RT in clinical practice is achieved.

HPV-independent Vulvar Squamous Cell Carcinoma is Associated With Significantly Worse Prognosis Compared With HPV-associated Tumors.

Vulvar squamous cell carcinomas (VSCC) represent the most common carcinoma of the female external genitalia, with increasing incidence. Although high-risk human papillomavirus (HPV) infection has long been implicated in the majority of cervical and anal squamous cell carcinomas, there is uncertainty about its prevalence and prognostic impact in VSCC. In this study, we conducted a retrospective integrated morphologic and multimodal HPV analysis of a cohort of 114 VSCC cases treated at the Princess Margaret Cancer Centre/University Health Network, Toronto, Canada between 2000 and 2010. VSCC histology was reviewed. We analyzed the cohort for HPV using polymerase chain reaction based method, and tissue microarray DNA and RNA in situ hybridization (ISH), and p16 immunohistochemistry. Among the 114 cases (age 70±16 yr), 36.7% of cases were classified as having histomorphology of HPV infection. HPV was detected in 31.9% (polymerase chain reaction), 14.0% (DNA ISH), and 27.3% (RNA ISH) of cases. p16 immunohistochemistry was positive in 37.8% of cases. On univariate analysis, HPV morphology (P=0.009), p16+ (P=0.00013), DNA ISH+ (P=0.021), and RNA ISH+ (P=0.00061) were associated with better 5-yr progression-free survival. DNA ISH+ (P=0.049) was associated with better 5-yr overall survival. On multivariate analysis, HPV morphology (P=0.033), p16+ (P=0.01), and RNA ISH+ (P=0.035) were associated with better 5-yr progression-free survival. In conclusion, a subset of VSCC is associated with HPV, which correlates with better outcome. Relatively inexpensive tests such as histomorphologic evaluation, p16 immunohistochemistry, and HPV RNA ISH can be used to predict outcome in VSCC. Therefore, routine reporting of HPV status in VSCC is recommended.

Assessment of outcomes in surgically staged I/II endometrial adenocarcinoma patients treated with postoperative vaginal vault radiotherapy only.

OBJECTIVE: To examine the efficacy of vaginal vault radiotherapy as adjuvant treatment for patients with high-grade, stage I/II endometrial adenocarcinoma who have been surgically staged. METHODS: A retrospective chart review of 77 women between 1995 and 2006 with high-grade surgically staged I and II endometrial adenocarcinoma, who were treated with postoperative vaginal vault radiotherapy alone, was performed. The primary study end points were recurrence risk and sites of recurrence. The secondary end points were disease-free and overall survival. Kaplan-Meier estimates were calculated for overall and disease-free survival. RESULTS: Seventy-seven women were identified and met inclusion criteria. Sixty-seven (87%) had grade 3 histologic features on final pathologic report. Forty-two patients (55%) were classified as stage IB, having superficial myometrial invasion; 21 (27%) were stage IC, with deep invasion; and 6 (8%) were stage II, involving the cervix. The median follow-up was 80 months (6.6 years). There were 10 recurrences (13.0%), of which 3 were local: 1 involving the vaginal apex; 1, the lower vagina and pelvic sidewall; and 1, the lower vagina. The 5-year recurrence risk was 11.2% and the 5-year survival probability 88.9%. CONCLUSIONS: It seems that for this cohort of 77 patients with surgically staged I and II grade 3 endometrial adenocarcinoma, adjuvant vaginal vault radiotherapy alone leads to acceptable recurrence rates and survival while minimizing morbidity.

Tumor and normal tissue dosimetry changes during MR-guided pulsed-dose-rate (PDR) brachytherapy for cervical cancer.

BACKGROUND AND PURPOSE: To analyze systematic changes in tumor and normal tissue anatomy and dosimetry using serial MR imaging during pulsed dose rate brachytherapy (PDR BT) for cervical cancer. MATERIAL AND METHODS: Forty-three patients with cervical cancer underwent MR-guided PDR BT using an intrauterine applicator alone after external beam radiotherapy. MR imaging was repeated on days 2 and 3 of treatment and the day 1 plan was applied to the re-contoured volumes. RESULTS: The mean uterine volume and mean HR CTV increased during treatment. This resulted in a decrease in the mean HR CTV D90 relative to the day 1 planned dose. There was no change in the mean bladder volume during treatment but the mean rectal volume increased. This correlated with an increase in the mean rectal dose. There were four local recurrences. There was no apparent relationship between either the planned or the delivered HR CTV D90 and local recurrence. There was only one case of late bladder toxicity but nine patients developed late rectal toxicity. The cumulative rectal dose during treatment was a better predictor of late rectal toxicity than the planned dose. CONCLUSIONS: Significant changes in tumor and normal tissue anatomy and dosimetry can occur during PDR BT and should be tracked and corrected using serial imaging and plan adaptation, especially when the day 1 tumor or normal tissue doses are close to the planning constraints.

Increased risk of locoregional recurrence for women with T1-2N0 triple-negative breast cancer treated with modified radical mastectomy without adjuvant radiation therapy compared with breast-conserving therapy.

PURPOSE: To evaluate the risk of locoregional recurrence (LRR) associated with locoregional treatment of women with primary breast cancer tumors negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (triple-negative breast cancer [TNBC]). PATIENTS AND METHODS: Patients diagnosed with TNBC were identified from a cancer registry in a single institution (n=768). LRR-free survival was estimated using Kaplan-Meier analysis. The Cox proportional hazards regression model was used to determine risk of LRR on the basis of locoregional management: breast-conserving therapy (BCT; ie, lumpectomy and adjuvant radiation therapy [RT]) and modified radical mastectomy (MRM) in the TNBC population and T1-2N0 subgroup. RESULTS: At a median follow-up of 7.2 years, 77 patients (10%) with TNBC developed LRR. Five-year LRR-free survival was 94%, 85%, and 87% in the BCT, MRM, and MRM + RT groups, respectively (P < .001). In multivariate analysis, MRM (compared with BCT), lymphovascular invasion and lymph node positivity were associated with increased LRR. Conversely, adjuvant chemotherapy was associated with decreased risk of LRR. For patients with T1-2N0 tumors, 5-year LRR-free survival was 96% and 90% in the BCT and MRM groups, respectively (P = .027), and MRM was the only independent prognostic factor associated with increased LRR compared with BCT (hazard ratio, 2.53; 95% CI, 1.12 to 5.75; P = .0264). CONCLUSION: Women with T1-2N0 TNBC treated with MRM without RT have a significant increased risk of LRR compared with those treated with BCT. Prospective studies are warranted to investigate the benefit of adjuvant RT after MRM in TNBC.