Combining multiple serum tumor markers improves detection of stage I epithelial ovarian cancer

OBJECTIVE

Currently available tumor markers for ovarian cancer are still inadequate in both sensitivity and specificity to be used for population-based screening. Artificial neural network (ANN) as a modeling tool has demonstrated its ability to assimilate information from multiple sources and to detect subtle and complex patterns. In this paper, an ANN model was evaluated for its performance in detecting early stage epithelial ovarian cancer using multiple serum markers.

METHODS

Serum specimens collected at four institutions in the US, The Netherlands and the United Kingdom were analyzed for CA 125II, CA 72-4, CA 15-3 and macrophage colony stimulating factor (M-CSF). The four tumor marker values were then used as inputs to an ANN derived using a training set from 100 apparently healthy women, 45 women with benign conditions arising from the ovary and 55 invasive epithelial ovarian cancer patients (including 27 stage I/II cases). A separate validation set from 27 apparently healthy women, 56 women with benign conditions and 35 women with various types of malignant pelvic masses was used to monitor the ANN's performance during training. An independent test data set from 98 apparently healthy women and 52 early stage epithelial ovarian cancer patients (38 stage I and 4 stage II invasive cases and 10 stage I borderline ovarian tumor cases) was used to evaluate the ANN.

RESULTS

ROC analysis confirmed the overall superiority of the ANN-derived composite index over CA 125II alone (p=0.0333). At a fixed specificity of 98%, the sensitivities for ANN and CA 125II alone were 71% (37/52) and 46% (24/52) (p=0.047), respectively, for detecting early stage epithelial ovarian cancer, and 71% (30/42) and 43% (18/42) (p=0.040), respectively, for detecting invasive early stage epithelial ovarian cancer.

CONCLUSIONS

The combined use of multiple tumor markers through an ANN improves the overall accuracy to discern healthy women from patients with early stage ovarian cancer. Analysis of multiple markers with an ANN may be a better choice than the use of CA 125II alone in a two-step approach for population screening in which a secondary test such as ultrasound is used to keep the overall specificity at an acceptable level.

Squamous Cell Carcinoma Antigen Isoforms in Serum from Cervical Cancer Patients

Squamous cell carcinoma antigen (SCCA) is a serological marker of squamous cell carcinomas (SCC). To study whether any of the SCCA isoforms would provide additional and more specific/sensitive clinical information than total SCCA, immunoassays specific for the different forms of SCCA (free SCCA2, total SCCA2, total SCCA1 and total SCCA) were developed. SCCA isoforms were determined before therapy and in follow-up samples from patients with cervical cancer and in serum samples from healthy females. Serum samples from patients with benign skin diseases (psoriasis and eczema) were also selected based on elevated SCCA levels. Rising levels of SCCA1 and SCCA2 were seen in patients with recurrence or progressive disease at the end of the study. The rise in SCCA2 was usually more prominent than that in SCCA1. The dominating serological form of SCCA was free SCCA2 both in healthy controls and in patients with cervical cancer. Both SCCA1 and SCCA2 were elevated in serum from cervical cancer patients and followed the clinical course of the disease during therapy monitoring. SCCA2 did not show improved tumor specificity as compared to SCCA1. A larger study is however necessary to make firm conclusions.

Three biomarkers identified from serum proteomic analysis for the detection of early stage ovarian cancer

Early detection remains the most promising approach to improve long-term survival of patients with ovarian cancer. In a five-center case-control study, serum proteomic expressions were analyzed on 153 patients with invasive epithelial ovarian cancer, 42 with other ovarian cancers, 166 with benign pelvic masses, and 142 healthy women. Data from patients with early stage ovarian cancer and healthy women at two centers were analyzed independently and the results cross-validated to discover potential biomarkers. The results were validated using the samples from two of the remaining centers. After protein identification, biomarkers for which an immunoassay was available were tested on samples from the fifth center, which included 41 healthy women, 41 patients with ovarian cancer, and 20 each with breast, colon, and prostate cancers. Three biomarkers were identified as follows: (a) apolipoprotein A1 (down-regulated in cancer); (b) a truncated form of transthyretin (down-regulated); and (c) a cleavage fragment of inter-alpha-trypsin inhibitor heavy chain H4 (up-regulated). In independent validation to detect early stage invasive epithelial ovarian cancer from healthy controls, the sensitivity of a multivariate model combining the three biomarkers and CA125 [74% (95% CI, 52-90%)] was higher than that of CA125 alone [65% (95% CI, 43-84%)] at a matched specificity of 97% (95% CI, 89-100%). When compared at a fixed sensitivity of 83% (95% CI, 61-95%), the specificity of the model [94% (95% CI, 85-98%)] was significantly better than that of CA125 alone [52% (95% CI, 39-65%)]. These biomarkers demonstrated the potential to improve the detection of early stage ovarian cancer.

Preoperative sensitivity and specificity for early-stage ovarian cancer when combining cancer antigen CA-125II, CA 15-3, CA 72-4, and macrophage colony-stimulating factor using mixtures of multivariate normal distributions

PURPOSE

In CA-125-based ovarian cancer screening trials, overall specificity and screening sensitivity of ultrasound after an elevated CA-125 exceeded 99.6% and 70%, respectively, thereby yielding a positive predictive value (PPV) exceeding 10%. However, sensitivity for early-stage disease was only 40%. This study aims to increase preoperative sensitivity for early-stage ovarian cancer while maintaining the annual referral rate to ultrasound at 2% by combining information across CA-125II, CA 15-3, CA 72-4, and macrophage colony-stimulating factor (M-CSF). For direct comparisons between marker panels, all sensitivity results correspond to a 98% fixed first-line specificity (referral rate 2%).

PATIENTS AND METHODS

Logistic regression, classification tree, and mixture discriminant analysis (MDA) models were fit to a training data set of preoperative serum measurements (63 patients, 126 healthy controls) from one center. Estimates from the training set applied to an independent validation set (60 stage I to II patients, 98 healthy controls) from two other centers provided unbiased estimates of sensitivity.

RESULTS

Preoperative sensitivities for early-stage disease of the optimal panels were 45% for CA-125II; 67% for CA-125II and CA 72-4; 70% for CA-125II, CA 72-4, and M-CSF; and 68% for all four markers (latter two results using MDA).

CONCLUSION

Efficiently combining information on CA-125II, CA 72-4, and M-CSF significantly increased preoperative early-stage sensitivity from 45% with CA-125II alone to 70%, while maintaining 98% first-line specificity. Screening trials with these markers using MDA followed by referral to ultrasound may maintain previously high levels of specificity and PPV, while significantly increasing early-stage screening sensitivity. MDA is a useful, biologically justified method for combining biomarkers.

Serum squamous cell carcinoma antigen and CYFRA 21-1 in cervical cancer treatment

PURPOSE

To analyze whether serum squamous cell carcinoma (SCC) antigen and cytokeratin-19 fragments (CYFRA) levels can assist in selecting patients with locally advanced cervical cancer who will benefit from combined treatment or additive surgery.

METHODS AND MATERIALS

Of 114 patients with cervical cancer Stage IB-IV, the first 39 patients received radiotherapy, the following 75 patients received identical radiotherapy plus concomitant chemotherapy (3 cycles of carboplatin and 5-fluorouracil). SCC antigen and CYFRA 21-1 serum levels were measured before treatment, after therapy, and during follow-up. Baseline tumor markers were related to tumor stage and size and clinical outcome.

RESULTS

Before treatment, SCC antigen was elevated (>1.9 microg/L) in 60% and CYFRA 21-1 (>2.2 microg/L) in 46% of patients. For all patients, disease-free survival (DFS) was better after combined treatment (67% vs. 43%, p < 0.0005). For patients with elevated baseline SCC antigen, DFS was better after combination therapy (67% vs. 27%, p = 0.001) which resulted more frequently in a normal SCC antigen (93% vs. 65%, p = 0.004). In contrast, in those with a normal baseline CYFRA 21-1, combined therapy resulted in a better DFS (p = 0.04). Patients who achieved a normal SCC antigen or CYFRA 21-1 after treatment had a better DFS (respectively 63 vs. 17% and 64 vs. 30%). Elevated SCC antigen posttreatment indicated residual tumor in 11/12 patients (92%), elevated CYFRA 21-1 in 7/10 patients (70%). Forty-seven patients had a tumor recurrence. At recurrence, SCC antigen was raised in 70% and CYFRA 21-1 in 69%.

CONCLUSIONS

In patients with an elevated pretreatment SCC antigen, SCC antigen normalized more frequently with combined treatment and those patients had a better DFS. Elevated SCC antigen or CYFRA 21-1 levels after treatment completion indicated residual tumor in respectively 92% and 70%. The presence of elevated posttreatment levels of SCC antigen or CYFRA 21-1 indicates the need for additional salvage surgery. SCC antigen proved to be superior to CYFRA 21-1 in predicting DFS and disease recurrence.