The increasing problem in Tayside of cervical cancer in younger women

Screening for cervical neoplasia in Dundee and Angus: 10 years on

OBJECTIVE

To evaluate the effect of changed cervical screening policies on a steady population with low migratory tendencies.

DESIGN

A retrospective analysis study.

SETTING

Dundee and Angus, Scotland.

SUBJECTS

All women who developed cervical carcinoma between 1957 and 1992.

MAIN OUTCOME MEASURES

The incidence of and mortality from cervical cancer after the introduction of organised cervical screening in 1962, according to age, stage, histology and screening history.

RESULTS

The initial fall in incidence of cervical cancer seen in women between 35 and 54 years after the introduction of cervical screening was not sustained during the last 10 years of our study and appears to have been transferred to women aged 55 years and older instead. After 1976 an increase in the incidence of cervical cancer was seen in women under 35 years. The reduction in mortality from cervical cancer appears to have reached a plateau since 1976. No effect of cervical screening was seen on the incidence of adenocarcinoma of the cervix.

CONCLUSIONS

The effect of changed cervical screening policies has been shown for a small population for a period of 35 years. The incidence of the higher stages of squamous cervical cancer continues to fall. The increase in incidence of cervical cancer in women under 35 years confirms similar trends seen in other countries. A background mortality rate refractory to further intensification of screening appears to have been reached. Adenocarcinoma of the cervix appears to gain in importance as cervical screening policies are shown to have their effect on its squamous counterpart.

Screening for cervical cancer--should the routine be challenged?

Despite the extensiveness of cervical cancer screening programs, certain major issues are still at stake: (a) substantial false negative rates are common, mostly due to impaired test quality, (b) the optimal length of interval between screenings is uncertain, being a function of available resources and the physicians' attitude, (c) the postmenopausal population, in which incidence is highest, is inadequately tapped. Efforts must be made to optimise the process through more stringent control measures, and a more comprehensive cover of the target population.

Localization and therapy of human cervical tumor xenografts with radiolabeled monoclonal antibody 1H10

Murine IgG3 monoclonal antibody (Mab) 1H10, which recognizes a tumor-associated antigen expressed on the surface of more than 40% of human cervical carcinoma tissues, was used for in vivo localization and therapy of cervical tumor xenografts. A human cervical carcinoma cell line, CaSki, was used as our experimental tumor system. Mab 1H10 antigen expression on the surface of CaSki cells was found to be cell-cycle independent. The ability of Mab 1H10 F(ab')2 to bind to CaSki tumor xenografts was verified by direct immunohistochemical staining of thin tumor sections with a Mab 1H10-peroxidase conjugate. Radioimmunoscintigraphy of nude mice bearing CaSki tumors after iv administration of [131I]1H10 F(ab')2 showed clear tumor images 48 hr after Mab injection. Radiolabeled Mab 1H10 F(ab')2 was found to specifically localize in solid CaSki tumors 96 hr after antibody injection. Radioactivity in tumor tissue was 4 times higher than that in kidney tissue and over 6 times higher than that in liver tissue. Mab 1H10 F(ab')2 binding to xenografted CaSki tumors was 17 times greater than a control IgG3 F(ab')2 after 96 hr. Therapy of athymic mice bearing established CaSki tumors with three iv injections of 100 microCi [131I]1H10 F(ab')2 resulted in extensive tumor necrosis and significant suppression (p < 0.05) of tumor growth compared to that in control mice. These results indicate that Mab 1H10 F(ab')2 may be clinically useful for detection or treatment of cervical cancer.

Characterization of a human cervical carcinoma-associated antigen by lectin binding and immuno-electron microscopy

The specific binding and nature of the epitope recognized by monoclonal antibody (Mab) 1H10, which binds an antigen expressed on human cervical tumors, was characterized by enzyme digestion, lectin competition assay and immuno-electron microscopy. Membrane homogenates of CaSki cervical carcinoma cells were digested with various enzymes, then analysed by SDS-PAGE and immunoblotting. Cells grown on coverslips were treated with various enzymes and in situ binding of Mab 1H10 to cells was analysed by electron microscopy. The ability of lectin-conjugates to block Mab 1H10 binding to CaSki cells was also examined. Treatment of samples with sodium periodate abrogated antigen recognition by Mab 1H10. Neuraminidase and hyaluronidase digestion decreased but did not eliminate Mab 1H10 binding to cells in situ. Chondroitinase ABC digestion, in contrast, removed Mab 1H10 binding sites both in vitro and in situ. Trypsin and chymotrypsin digestion of cell membrane homogenates decreased the molecular weight of the Mab 1H10 antigen but did not decrease the binding intensity. Wheat germ agglutinin (WGA) strongly bound to CaSki cells and partially blocked Mab 1H10 binding, indicating that the antigen contains N-acetyl-galactosamine residues at or near the epitope recognized by Mab 1H10. Ricinus communis agglutinin (RCA) exhibited a similar binding pattern to WGA. However, concanavalin A bound only weakly to CaSki cells and was ineffective at blocking Mab 1H10 binding. The tumor-associated antigen recognized by Mab 1H10 is concluded to be a chondroitin sulphate glycoprotein or proteoglycan rather than a mucopolysaccharide or lipoprotein.