Morphogenesis of cervical cancer.Findings from San Diego County Cytology Registry

Abstract

The San Diego Cytology Registry collected results on cytology examinations on more than 180,000 women; more than 60,000 of these had multiple examinations. The age‐specific prevalence and incidence rates for suspicious and positive cytology and for dysplasia, carcinoma in situ and invasive cancer of the cervix are presented. These are analyzed in terms of the morphogenesis of cervical cancer. Carcinoma in situ reaches its maximum incidence rate among women aged 25 to 29. The rates then decrease and continue at a low level after age 35. This peak of incidence at an early age has implications as to the pathogenesis of cervical cancer. Incidence rates for dysplasia also rise rapidly and at an earlier age than carcinoma in situ. Dysplasia remains at a high incidence over a longer age span than carcinoma in situ but decreases precipitously after age 40. Dysplasia and carcinoma in situ together would exceed the needs for invasive cervical cancer and some would need to terminate by regression. The prevalence rates for dysplasia and carcinoma in situ are several times greater than their respective incidence rates. Estimates of average duration for each are 3.8 years of dysplasia and 8.1 years of carcinoma in situ. Not all new disease developing from a population that has been repeatedly negative cytologically is found in a carcinoma in situ stage. The authors conclude that 10 to 15% of carcinomas of the cervix become invasive early in their development.

Screening histories of women with CIN 2/3 compared with women diagnosed with invasive cervical cancer: a retrospective analysis of the Norwegian Coordinated Cervical Cancer Screening Program

“…However, these estimates vary between 5 and 16 years [13,[18][19][20][21][22][23][24][25]. Recent knowledge on the natural history of HPV infection, which is believed to be the initiating causal factor, indicates an even shorter duration of the pre-invasive phase [26][27][28][29][30][31].…”

A computer simulation model for the practical planning of cervical cancer screening programmes

“…Estimates of the age-specific prevalence of dysplasia, carcinoma in situ (c.i.s.) and preclinical invasive disease in unscreened populations are available from several studies (Dunn & Martin, 1967;Bibbo et al, 1971;Fidler et al, 1968;Sweetnam et al, 1981;Parkin et al, 1982b). Prevalence of clinical cancer (women currently alive who have had a previous diagnosis of clinical cancer) must be estimated from incidence of clinical cancer prescreening, and survival rates for the same time period.…”

“…There has been a recent trend to the use of the terminology "cervical intra-epithelial neoplasia" (C.I.N.) for all pre-invasive abnormalities of the cervix (Richart & Barron, 1969;Koss, 1978 (Rotkin, 1973) or their partner (Skegg et al, 1982) The incidence of dysplasia (transfer 1 to 2) is derived from observed data (Dunn & Martin, 1967;Parkin et al, 1982b), and transition from clinical cancer to death (5 to 8) is derived from age/duration-specific survival rates for England and Wales (OPCS, 1980). Dysplasia is a relatively transient condition, and the high regression rates (2 to 1) used here (12.5-25% per year) are consistent with observed data (Stern & Neely, 1964;Fox, 1967;Nasiell et al, 1976).…”

The Unrealized Potential of Cervical Smears

“…The estimated average duration of dysplasia before it becomes carcinoma in situ is about 3.8 years, and the duration of carcinoma in situ before it develops into invasive carcinoma is estimated at 8.1 + years. 6 These are averages, and when dysplasia or carcinoma in situ is diagnosed it is often impossible for the clinician to ascertain how long the lesion has been present. Thus the need for examination of smears at close intervals in cases of dysplasia cannot be overemphasized.…”