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| Tumour markers | Prognostic value of markers evolution | |
One important prognostic factor for many tumours is the sharp diminution of tumour marker under treatment.
In ovarian carcinoma, the absence of return to normal values of Ca-125 after three chemotherapy courses generally signifies a resistance to chemotherapy (at least to these agents).
A too slow fall of β-HCG and αFP in testis tumours (taking into account their half-lives) predicts a poor response to chemotherapy
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Schematic representation of β-HCG after treatment by chemotherapy of a testicular choriocarcinoma Half-life of β-HCG is around 2 - 3 days. If a complete response is observed, the marker falls down to an negligible level (green line). If the fall is longer than the half-life, it may exist a chemo-resistance and relapse will happen (pink line). The upper line (blue) illustrates a complete resistance to chemotherapy. (note the vertical semi-logarithmic scale). |
In prostate cancer, such a predictive value can be given to the fall of PSA after local treatment.
For instance, a local treatment either by radical prostatectomy or by curative radiotherapy, the PSA falls according to the disappearance rate of tumour cells.
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PSA modifications after local treatment by radical prostatectomy. The green curve shows the cure, the violet one shows the developing metastases (unfortunately non detected before surgery !). Yellow and red curves are in favour of remaining tumour cells outside the surgical limits. Please note the horizontal scale in days : radical prostatectomy take off all the cells in one day. |
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Evolution of PSA values after local treatment by curative radiotherapy (or brachytherapy). Same comments as for radical prostatectomy. But notice the difference in time scale : in months for radiotherapy. The photons destroyed the cells when they begin to divide (during the next weeks). |
In metastatic prostatic cancers, it is quite interesting to study the slope of PSA values after the institution of hormone therapy (either surgical or chemical castration). When the fall is quick and complete, the patient can hope to enjoy a prolonged good quality remission ; when it is incomplete or slow, the slope translates the presence of hormone resistant clones (work by Miller J.I et al in 1992)
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Evolution of PSA levels after hormone treatment of metastatic prostate carcinoma A complete and quick fall of PSA is a good sign of complete remission. A slow and incomplete fall lets fear an early relapse. |
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