Ovarian cancer remains the most aggressive type of gynecological cancer, making the quest for better screening methods a paramount concern. Five-year survival for this type of cancer is about 40%, and more than half of the deaths caused by gynecological cancers are caused by ovarian malignancy. An important predictor of survival is what stage the cancer is diagnosed at, and a new study, published in the British Medical Journal, details a screening method researchers studied with the hope of identifying such cancers at earlier stages.
“We developed a polytomous risk prediction model that can reliably distinguish between benign, borderline, stage I invasive, stage II-IV invasive, and secondary metastatic adnexal tumours,” wrote the study authors—the International Ovarian Tumour Analysis group. The study included women who had an ovarian mass and had ultrasounds prior to surgery. Researchers initially developed the model using 3,506 patients who were recruited between 1999 and 2007, and then the model was validated on 2,403 women who were recruited between 2009 and 2012. Finally, the model was updated using the total of 5,909 women in the study.
In developing their so-called Assessment of Different NEoplasias in the adneXa (ADNEX) model, the researchers included nine variables: age, serum CA-125 level, type of center, maximum diameter of the lesion, proportion of solid tissue, number of papillary projections, more than 10 cyst locules, acoustic shadows, and ascites.
“The area under the receiver operating characteristic curve (AUC) for the classic discrimination between benign and malignant tumours was 0.94 (0.93 to 0.95) on temporal validation. The AUC was 0.85 for benign versus borderline, 0.92 for benign versus stage I cancer, 0.99 for benign versus stage II-IV cancer, and 0.95 for benign versus secondary metastatic,” the authors explained. “AUCs between malignant subtypes varied between 0.71 and 0.95, with an AUC of 0.75 for borderline versus stage I cancer and 0.82 for stage II-IV versus secondary metastatic. Calibration curves showed that the estimated risks were accurate.”
Of note to laboratorians, “proportion of solid tissue and serum CA-125 level had the strongest independent relations with the outcome, as judged by the test statistic for the model coefficients,” the authors wrote. Also, one limitation of the study was that the centers involved in the research used different assay kits for assessing CA-125 in participants. “This can also be interpreted as both a strength and a limitation: using different kits introduces variability in CA-125 levels (although this variability is minor), reflects clinical reality, and yields results that are less dependent on assay,” the authors explained.
However, the researchers found that CA-125 levels offered “little added value over ultrasound information when distinguishing benign from malignant tumours.” Still, the study demonstrates that serum CA-125 level is key to discriminating between stage II-IV cancer, as well as between stage I and secondary metastatic cancer.
The findings demonstrate that the ADNEX model “discriminates well between benign and malignant” ovarian tumors, and it “offers fair to excellent discrimination between four types of ovarian malignancy,” according to the study. “The use of ADNEX has the potential to improve triage and management decisions and so reduce morbidity and mortality associated with adnexal pathology.”
Read the study online.