Although the incidence and mortality of cervical carcinoma have fallen more than 75 percent since 1950, around 13,700 new cases and 4,900 deaths occurred in 1998. The improvement is attributed to Papanicolaou (Pap) smear screening, but not all populations have benefited equally. The new national goals (Healthy People 2010) are for 97 percent of women to be screened at least once and for 90 percent to have been screened within three years. The two major strategies advocated to further improve the effectiveness of Pap screening are improved compliance with recommendations (i.e., increasing the uptake of screening by all eligible women) and converting the tests to liquid-based cytology. Montz and colleagues studied the potential benefits from each of these interventions.
The authors developed three model populations from a cohort of 100,000 women aged 20 to 80 years. Current data for rates of death, development of cervical cancer and outcomes of therapy were used to calculate the theoretic outcomes using separate analyses for all women, and black and white women. To calculate the impact of changing to liquid-based testing, the false-negative rate of conventional Pap testing was estimated as 49 percent and that of liquid-based testing as 27 percent. Other assumptions used in the model were derived from the current literature.
Achieving full compliance with Healthy People 2010 goals for Pap screening would reduce cervical cancer in all women by 22.9 percent, with 21.7 and 17 percent reductions for white and black women, respectively. With current patterns of compliance, universal change to liquid-based testing would result in a reduction of approximately 32 percent in cervical cancer in all three groups of women. If both interventions were achieved in conjunction, reductions of approximately 50 percent could be achieved in each of the populations studied.
The authors calculate that achieving both interventions simultaneously would cost an additional $20,424 per life saved for all women, $23,503 for white women and $11,346 for black women. If the liquid-based test were to be used with current compliance patterns, the cost per life saved for each group would be $15,296, $17,967 and $10,335 for each group, respectively. The authors calculate that the change to liquid-based testing would be cost-effective in improving outcomes from cervical cancer and particularly beneficial in high-risk populations.