Total Inhibin – A New Ovarian Cancer Screening Test?

If researchers in Siena, Italy, are right, measurement of Inhibin, a hormone molecule produced by the ovary, could be an effective ovarian cancer screening test.

In a study published this month in The Journal of Clinical Endocrinology and Metabolism, the researchers measured total Inhibin levels using an Elisa-based assay, comparing results in women with ovarian cancers to those of normals and those with benign ovarian tumors and other cancers. Total Inhibin levels were highly sensitive and specific in detecting ovarian cancers. When combined with Ca125 levels, the results were superior to either test alone. (See graph above).

The percentage of cancers detected at 95% specificity varied according to the histological subtype but was always improved by the combination of total inhibin and CA-125. In detail, the detection rate of all tumors raised from 84–87% with single markers to 99% with combined markers (P < .05). The addition of total inhibin increased the CA-125 detection rate for mucinous tumors from 14 of 17 (82%) to 17 of 17 cases (100%) without loosing specificity (95%). Remarkably, the detection rate of clear cell adenocarcinomas increased from 59–68% with single markers to 96% with combined markers (P < .05)

The next step is a large multicenter trial.

Inhibin has been on the radar as a potential ovarian cancer marker for some years now. The problem has been that there are various Inhibin molecules, and the different kinds of ovarian cancers make one or more of these in any combination. Most Inhibin assays are specific to one or more of the subtypes, which limits them in detecting all ovarian cancers. It seems that the total Inhibin assay used in this study may have worked so well because of its lack of specificity, making it more useful as a screening test.

What I found most exciting is that the inhibin assay used is one that is already commercially available, meaning that, if these results hold true, then we won’t have to wait very long to implement screening.

Stay tuned…

7 Responses to Total Inhibin – A New Ovarian Cancer Screening Test?

  1. Wouldn’t it be nice…thanks for the info, this hadn’t hit my radar yet.

    I worry that we’ll never have a screening test due to the relatively low incidence.

  2. There are approximately 3,600 annual deaths due to cervical cancer from approx 10,500 diagnoses. However a screening programme and vaccine has been developed for this.

    Ovarian cancer claims approx 4 times as many deaths annually and its treatment is costly. Simple screening methods should be employed because the prognosis for stage 1 is excellent ranging from 87%-95% alive after five years. Stage 3c, the most common is a paltry 28%.

    This is an excellent article. Thank you.

  3. Simple screening methods should be employed because the prognosis for stage 1 is excellent ranging from 87%-95% alive after five years. Stage 3c, the most common is a paltry 28%.

    This is not as simple as that.

    Anon, have you ever heard of lead-time bias? 5-year survival rate is not a measure of how effective early detection is. Early detection always increases 5-year survival rate regardless of whether it works. Say two people died in 2000 at the age of 30 from cancer. But in one case, the cancer was diagnosed in late stage in 1999, in another case it was diagnosed early in 1994. You wouldn’t say that the second person is better off, right? Yet, the latter person was alive for 6 years after diagnosis while the former only 1 year. This is called lead-time bias and if you are a physician, I am amazed that you don’t know this simple concept.

    The only measure of screening test effectiveness is the effect on mortality i.e. how many people out of say 10,000 die of the desease in screened vs non-screened group.

    Every cancer is different. Pap smears actually prevent cancer rather than simply detect it early which is a huge difference.

    Is Stage 1 cancer curable because it is detected early or because it is less aggressive (which is why it was detected early in the first place)? Will the new test actually reduce mortality from ovarian cancer or will it simply result in increase of incidence (because of overdiagnosis)? How big the effect on mortality will be? How large will be the extent of overdiagnosis?

    Only studies will help to answer these questions. As much as one may want to prevent death from ovarian cancer, one shouldn’t forget possible harm associated with screening the whole population until the information is available. Just look up screening for neuroblastoma in Japan as an example of a screening program that caused more harm than good.

  4. ALL:
    Dr Smak says it best – Wouldn’t it be nice…

    As the various anonymous commenters have shown, having a test and implementing it in an effective way are two very different things. Only time, and multicenter trials will answer this one. It shouldn’t take that many years to get some meaningful results of a screening trial, especially if initially conducted in high risk women. Use of the test in low risk women will be another story….

  5. If it works that would be great b/c ovarian CA is hard to diagnose early otherwise. Even if the assay is already commercially available, though, insurers will balk at paying for its use as a routine screening test until it has proven itself in clinical trials…which could take awhile.

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