In a long-term study of over 200 thousand participants, screening failed to significantly reduce deaths from ovarian and fallopian tube cancers, which is why the authors do not recommend screening in the general population.
The prognosis of ovarian cancer remains poor, and the majority of women (58%) are not diagnosed with the disease until it reaches an advanced stage (III or IV). With a 5-year survival rate of 27% for stage III ovarian cancer and 13% for stage IV ovarian cancer, it is still the most lethal of all gynecologic cancers.1
Survival rates of more than 90% for women in whom the disease is detected at stage I have spurred efforts at early detection. Many studies resorted to a combination of the serum biomarker CA125 and transvaginal ultrasonography for this purpose. Despite extensive efforts, there is no evidence to date that such screening reduces mortality.
Scientists at University College London conducted the randomized controlled trial 'UKCTOCS' (UK Collaborative Trial of Ovarian Cancer Screening), the results of which appeared in the Lancet in mid-May.2 The study included 202,500 postmenopausal women aged 50-74 years from 13 centers in the United Kingdom who had no pre-existing neoplasms and no family history of increased risk for ovarian cancer. The researchers assigned the women in a 1:1:2 ratio to either annual multimodal screening (MMS), annual transvaginal ultrasound, or no screening.
After ample 16 years of follow-up, the incidence of ovarian or fallopian tube cancer was the same in the three groups (1.0%), as was the incidence of death from ovarian and fallopian tube cancer (0.6%).
Compared with the cohort without screening, 47.2% more stage I carcinomas and 24.5% fewer stage IV carcinomas were found in the MMS group. Overall, the incidence of stage I or II disease was 39.2% higher in the MMS group than in the no-screening group, while the incidence of stage III or IV disease was 10.2% lower.
However, the reduced incidence of advanced disease in the MMS group was not enough to translate into lives saved. 1,206 women died from the disease: 296 (0.6%) of 50,625 in the MMS group, 291 (0.6%) of 50,623 in the ultrasound group, and 619 (0.6%) of 101,314 in the no screening group. There was no significant reduction in ovarian and fallopian tube cancer deaths in the MMS or ultrasound group compared with the no screening group.
First author Professor Usha Menon, considered one of the UK's leading specialists in gynecologic malignancies, said, "UKCTOCS is the first study to show that screening can definitely detect ovarian cancer earlier. However, this very large, methodologically thorough study clearly shows that screening did not save lives with any of the approaches we tested. Therefore, we cannot recommend ovarian cancer screening with these methods for the general population."3 Prof. Menon conclude: "We are disappointed because this is not the result that we and everyone involved in the study hoped for and worked for over so many years. To save lives, we need a better screening test that detects ovarian cancer earlier and in more women than the multimodal screening strategy we used."
References:
1. Ovarian cancer survival statistics. Cancer Research UK https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/ovarian-cancer/survival (2015).
2. Menon, U. et al. Ovarian cancer population screening and mortality after long-term follow-up in the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS): a randomised controlled trial. The Lancet 0, (2021).
3. UCL. Screening for ovarian cancer did not reduce deaths. UCL News https://www.ucl.ac.uk/news/2021/may/screening-ovarian-cancer-did-not-reduce-deaths (2021).