Negative Finding (2) – Screening for Ovarian Cancer Doesn’t Help

Ovarian cancer is diagnosed annually in roughly 22,000 women in the USA, and almost 14,000 women die from the disease each year.  The 5-year survival rate at diagnosis is approximately 30%, and it’s clear that in most cases the diagnosis is only made when the condition is well-advanced.  Seven key symptoms, each reported in at least 25% of cases, are abdominal bloating, fatigue, abdominal pain, indigestion, frequent urination, pelvic pain, and constipation.

Detecting ovarian cancer early in the course of the disease has the potential to improve prognosis; in subjects where the cancer is confined to the ovaries has a much higher 5-year survival rate – 92%.  This led researchers from the University of Utah to conduct a trial evaluating the possible benefits of screening for ovarian cancer; they studied the use of cancer antigen 125 (CA-125) levels and transvaginal ultrasound as screening tools.  Their findings are reported in the Journal of the American Medical Association. 

The investigators randomly allocated 78,000 women aged 55 to 74 to undergo either annual screening tests or ‘usual care’ between 1993 and 2001.  Screening involved annual CA-125 blood levels for 6 years and transvaginal ultrasound for 4 years.  All the participants were followed for a possible cancer diagnosis for 11 to 13 years, and for death up to early 2010. 

Ovarian cancer was diagnosed in 212 women in the screening group and in 176 of those under ‘usual care’ - 5.7 and 4.7 per 1,000 person-years, respectively.  There were 118 ovarian cancer deaths in the screening group and 100 deaths in the ‘usual care’ group – 3.1 and 2.6 per 1,000 person-years, respectively.  These differences were not statistically significant.  Thus screening with CA-125 tests and transvaginal ultrasound did not reduce overall mortality, compared with ‘usual care’.

On the other hand, screening resulted in a number of complications after surgery in women who had false-positive results from the screening tests; thus 15% of over 1,000 such surgeries resulted in a serious complication. 

It can be concluded that annual screening for ovarian cancer using CA-1215 testing and transvaginal ultrasound exam does not reduce ovarian cancer mortality, but does increase the risk of harm from screening-precipitated surgery.