Introduction

Papanicolaou (Pap) smear screening is a recognized way of detecting cancer of the cervix, and is generally recommended for almost all women in industrialized countries. Its use has doubtless led to the substantial reduction in the number of cases and deaths from cervical cancer that's been observed over the years. However, in the USA there are literally millions of women who have had complete hysterectomies, where the cervix of the uterus is also removed, and who are therefore not at risk of cervical cancer. How many of these are having unnecessary annual Pap smears? A study published in the Journal of the American Association has looked into this.

What was done

In 1996 the US Preventive Services Task Force recommended that routine Pap smears were unnecessary for women who had had a complete, or 'total', hysterectomy for benign disease, such as uterine fibroids. This study was designed to see whether Pap smear screening had, in fact, decreased in such women since the recommendation was issued.

The US Centers for Disease Control and Prevention (CDC) conducted an annual telephone survey of health care in adults from 1992 to 2002. In each year of the survey, a sample of women over 18 who had undergone hysterectomy (not necessarily complete) were asked whether they had had a Pap smear in the previous 3 years.

Information on the timing, type, and indication for hysterectomy were then obtained from the National Inpatient Sample and other sources.

What the analysis showed

The survey revealed 188,000 women who had had hysterectomies; roughly 69% of them had subsequent Pap smears. This frequency did not change from year to year during 1992 to 2002. Quite clearly, the 1996 recommendation had no effect whatsoever.

The next step was to calculate the likely number for the US population as a whole. Overall, 21% of US women have undergone hysterectomy - that's about 22 million women over 18 in 2002. Of these, about 15 million had a Pap smear within the previous 3 years. About 1.8 million of these women had their hysterectomy in the previous 3 years, so that their Pap smear may have been done before their surgery.

Of the remaining 13.2 million, up to 1.1 million may still have had a cervix (i.e. they had a 'sub-total' hysterectomy), and up to 2.2 million had their hysterectomy because of cancer of the cervix. This leaves approximately 10 million women, or 46% of those who had a hysterectomy, who had unnecessary Pap smears in 2002.

What this means

Some people might claim that a Pap smear could detect cancer in tissues remaining after a hysterectomy. However, smears from the vagina can only detect cancer of the vagina, which is extremely rare - it's less common than cancer of the tongue or the small intestine. Obviously, an awful lot of Pap smears (about 10 million a year?) are being done unnecessarily.

Both patients and gynecologists need to be aware of this analysis. If you're a woman who has had a hysterectomy, ask you gynecologist, "Is a Pap smear really necessary?" You can help keep health costs down! Of course, if you haven't had a hysterectomy, have regular Pap smears - every 2 years, or more often if necessary.