Cancer Expert MD

When Dr. Silver, MD, was diagnosed with lymphoma about twenty-five years ago, he traveled to other countries to learn about the testing and treatments being used there. Much of what he found is still largely unknown to American patients. Laboratories in Germany and Greece offer blood-based tests that count circulating tumor cells, track how they respond during treatment, and test them against chemotherapy drugs, repurposed drugs and natural compounds. Patients in the United States can use these laboratories, usually by having blood drawn locally and shipped. This article explains what the main laboratories offer and, just as important, how strong the evidence behind each test is.

Cancer Expert MD has no financial relationship with any laboratory named here and receives nothing for referrals.

Germany: Maintrac (Bayreuth)

What it is. Maintrac was developed by the Pachmann laboratory in Bayreuth. Instead of first concentrating tumor cells from the blood, which loses many of them, it stains the whole white-cell fraction of a blood sample for epithelial cells and counts the circulating epithelial tumor cells directly with laser scanning. The test is designed to be repeated over time, so that the trend in cell numbers shows how the cancer is responding to treatment.

The evidence. Maintrac has a peer-reviewed track record. In a study published in the Journal of Clinical Oncology in 2008, the laboratory monitored women with breast cancer during chemotherapy after surgery. In about a quarter of patients, the cell count rose more than tenfold toward the end of treatment, and those patients had a far higher risk of relapse than patients whose counts fell.¹ A 2022 German study of 165 women receiving radiation after breast cancer surgery, followed for a median of nearly nine years, found that the change in cell counts over the course of radiation was the strongest predictor of later relapse.² The laboratory has also published on monitoring hormone therapy, HER2-targeted therapy and colorectal cancer treatment.

Best used for: tracking whether a treatment is working and watching for early signs of relapse, with the same test repeated over time.

Greece: RGCC (Research Genetic Cancer Centre)

What it is. RGCC, based in northern Greece, isolates circulating tumor cells from a blood sample using flow cytometry and then studies them in several ways. Its test menu includes:

Circulating tumor cell detection and counting, used as an initial test and for follow-up over time.

Drug sensitivity panels, which test the isolated cells against chemotherapy and targeted drugs and report the activity of tumor-related genes.

Natural substance panels, which test the cells against about fifty natural compounds and plant extracts, such as medicinal mushroom extracts, curcumin and vitamin C.

The evidence. RGCC’s tests are widely used by integrative physicians around the world. They answer a question almost no other laboratory addresses: which natural compounds and repurposed drugs affect a particular patient’s circulating cancer cells. However, published independent studies comparing its drug-sensitivity results with how patients actually respond are limited. The results are best read as one input, alongside tumor sequencing, standard imaging and other tests, rather than as a stand-alone guide.

Best used for: adding information about natural compounds and repurposed drugs that standard testing does not cover, particularly when no tumor tissue is available.

Germany: University Precision Oncology

Germany’s national cancer centers also run one of the world’s most comprehensive academic sequencing programs, MASTER, which uses whole-genome and RNA sequencing for patients with rare cancers or advanced cancers diagnosed at a young age, with every case reviewed by a national molecular tumor board. Patients enter through participating German cancer centers. Our article on tumor DNA and RNA sequencing explains why this comprehensive approach finds targets that standard panels miss.

How These Tests Compare With American Testing

In the United States, the FDA-cleared CellSearch system counts circulating tumor cells in metastatic breast, prostate and colorectal cancer, and tumor-informed ctDNA tests are widely available. What American laboratories rarely offer is repeated tumor cell monitoring designed to track treatment response, or testing of a patient’s cancer cells against natural compounds and repurposed drugs. The European tests fill those gaps. Our articles on circulating tumor cell testing, ctDNA and chemosensitivity testing explain the science behind each approach.

Practical Points

Ordering. These tests are usually ordered through a physician or practitioner who works with the laboratory. Blood is drawn locally into special tubes and shipped by courier.

Timing. Living cells must arrive quickly, so samples are drawn early in the week to avoid weekend delays.

Cost. These tests are generally not covered by U.S. insurance, so it is worth confirming the price before ordering.

Consistency. Different laboratories use different methods, so counts from one laboratory cannot be compared with counts from another. Follow-up tests should stay with the same laboratory.

Our book, The New Reality of Cancer, describes the testing available in each country in detail and how to combine European blood tests with American sequencing and imaging into one monitoring plan.

Frequently Asked Questions

What is the Greek cancer test?

Usually it refers to RGCC, a laboratory in Greece that isolates circulating tumor cells from a blood sample and tests them against chemotherapy drugs and natural compounds.

What is the Maintrac test?

A German blood test that counts circulating epithelial tumor cells and is repeated over time to show whether treatment is working. Rising counts during treatment have been linked to higher relapse risk in published studies.

Can American patients use these laboratories?

Yes. Blood is usually drawn locally through a practitioner who works with the laboratory and shipped to Europe by courier.

Are these tests covered by insurance?

Generally not in the United States, so confirm the cost before ordering.

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More articles on advanced cancer testing and all articles.

References

1. Pachmann K, Camara O, Kavallaris A, et al. Monitoring the response of circulating epithelial tumor cells to adjuvant chemotherapy in breast cancer allows detection of patients at risk of early relapse. Journal of Clinical Oncology. 2008;26(8):1208–1215.
2. Mäurer M, Schott D, Pizon M, et al. Increased circulating epithelial tumor cells (CETC/CTC) over the course of adjuvant radiotherapy is a predictor of less favorable outcome in patients with early-stage breast cancer. Current Oncology. December 2022. ClinicalTrials.gov NCT03935802.

This article is for education only. It is not medical advice and does not diagnose or treat any condition. Cancer Expert MD has no financial relationship with any laboratory, drug maker, supplement company, clinic or hospital.