The protective role of postoperative radiation therapy in low and intermediate grade major salivary gland malignancies: A study of the Canadian Head and Neck Collaborative Research Initiative.

BACKGROUND: The objective of this study was to examine the utility of postoperative radiation for low and intermediate grade cancers of the parotid and submandibular glands. METHODS: The authors conducted a retrospective, Canadian-led, international, multi-institutional analysis of a patient cohort with low or intermediate grade salivary gland cancer of the parotid or submandibular gland who were treated from 2010 until 2020 with or without postoperative radiation therapy. A multivariable, marginal Cox proportional hazards regression analysis was performed to quantify the association between locoregional recurrence (LRR) and receipt of postoperative radiation therapy while accounting for patient-level factors and the clustering of patients by institution. RESULTS: In total, 621 patients across 14 tertiary care centers were included in the study; of these, 309 patients (49.8%) received postoperative radiation therapy. Tumor histologies included 182 (29.3%) acinic cell carcinomas, 312 (50.2%) mucoepidermoid carcinomas, and 137 (20.5%) other low or intermediate grade primary salivary gland carcinomas. Kaplan-Meier LRR-free survival at 10 years was 89.0% (95% confidence interval [CI], 84.9%-93.3%). In multivariable Cox regression analysis, postoperative radiation therapy was independently associated with a lower hazard of LRR (adjusted hazard ratio, 0.53; 95% CI, 0.29-0.97). The multivariable model estimated that the marginal probability of LRR within 10 years was 15.4% without radiation and 8.8% with radiation. The number needed to treat was 16 patients (95% CI, 14-18 patients). Radiation therapy had no benefit in patients who had early stage, low-grade salivary gland cancer without evidence of nodal disease and negative margins. CONCLUSIONS: Postoperative radiation therapy may reduce LLR in some low and intermediate grade salivary gland cancers with adverse features, but it had no benefit in patients who had early stage, low-grade salivary gland cancer with negative margins.

The involvement of Canadian physicians in promoting and providing unproven and unapproved stem cell interventions.

BACKGROUND: Direct to consumer offerings of unproven stem cell interventions (SCIs) is a pressing scientific and policy issue. According to media reports, providers of SCIs have emerged in Canada. This study provides the first systematic scan of Canadian providers and associated trends and claims. METHODS: The study sample consisted of 15 websites retrieved from a Google™ keyword search. The websites were assessed by a rater using a peer-reviewed coding frame that queried treatment location, stem cell offerings, treatment claims, supporting evidence, and legal and regulatory compliance. A second rater reviewed a subset of the websites for purposes of inter-rater reliability. Disagreements between raters were resolved by consensus. Data collected by the raters was analyzed in SPSS. RESULTS: Physicians are the dominant treatment providers in Canada. Providers operate in urban and semi-urban areas in the most populous provinces. SCIs provided are mainly autologous adult stem cells for multiple conditions including musculoskeletal disorders, spinal cord injury (SCI) and diabetes. Efficacy and benefits of treatment are prominently and positively portrayed, while risks are not mentioned or portrayed as trivial. Regulatory concerns are not discussed. CONCLUSIONS: The involvement of physicians in promoting and providing unproven and unapproved SCIs raises significant ethical, legal and regulatory concerns. Treatment claims and trends appear to contravene applicable professional standards, statutory obligations, and consumer protection laws. While the number of providers observed is still marginal, urgent and proactive regulatory response is needed to prevent proliferation of a potentially exploitative and harmful market for unproven SCIs in Canada.

An evidence-based estimate of the appropriate rate of utilization of radiotherapy for cancer of the cervix.

PURPOSE: Current estimates of the proportion of cancer patients who will require radiotherapy (RT) are based almost entirely on expert opinion. The objective of this study was to calculate the proportion of incident cases of cervical cancer that should receive RT by application of an evidence-based approach. METHODS AND MATERIALS: A systematic review of the literature was done to identify indications for RT for cervical cancer and to ascertain the level of evidence that supported each indication. A survey of Canadian gynecologic oncologists and radiation oncologists who treat cervical cancer was done to determine the level of acceptance of each indication among doctors who practice in the field. An epidemiologic approach was then used to estimate the incidence of each indication for RT in a typical North American population of patients with cervical cancer. RESULTS: The systematic review of the literature identified 29 different indications for RT for cervical cancer. The majority of the 75 experts who responded to the mail survey stated that they "usually" or "always" recommended RT in all but one of the clinical situations that were identified as indications for RT on the basis of the systematic review. The analysis of epidemiologic data revealed that, in a typical North American population, 65.4% +/- 2.5% of cervical cancer cases will develop one or more indications for RT at some point in the course of the illness, 63.4% +/- 2.3% will develop indications for RT as part of their initial management, and 2.0% +/- 0.9% will develop indications for RT for progressive or recurrent disease. The effects of variations in case mix on the need for RT was examined by sensitivity analysis, which suggested that the maximum plausible range for the appropriate rate of utilization of RT was 54.3% to 67.9%. The proportion of cases that required RT was stage dependent: 10.6% +/- 1.2% in Stage IA, 74.9% +/- 1.3% in Stage IB, 100% in Stages II and III, and 97.2% +/- 1.1% in Stage IV. CONCLUSIONS: This evidence-based estimate of the appropriate rate of use of RT for cervical cancer adds to the growing pool of knowledge about the need for RT that will ultimately provide a rational basis for long-term planning for RT programs and for auditing access to RT in the general population.