Chemotherapy’s Paradox: Can It Spread Cancer? Insights from a Chinese Study and Implications for Treatment, By Mrs. (Dr) Abigail Knight (Florida)
A recent study by Chinese scientists, published in the peer-reviewed journal Cancer Cell on July 3, 2025, has sparked significant discussion in the oncology community. The research, led by Professor Hu Guohong from the Chinese Academy of Sciences' Shanghai Institute of Nutrition and Health, alongside researchers from Fudan University and Qilu Hospital of Shandong University, reveals a paradoxical effect of chemotherapy: while it effectively targets primary tumours, it may also awaken dormant cancer cells, potentially accelerating cancer spread to distant organs like the lungs. This finding, detailed in articles from the South China Morning Post and Bangkok Post, raises critical questions about current cancer treatment protocols and whether alternative and lifestyle-based approaches should play a larger role in managing cancer. Below, I explore the study's findings, its implications for cancer treatment, and whether it strengthens the case for alternative therapies.
The study focused on how chemotherapeutic drugs, such as doxorubicin and cisplatin, can inadvertently promote cancer metastasis by reactivating dormant disseminated tumour cells (DTCs). These cells, which can travel from primary tumours to distant sites in the body, often remain inactive for years, evading chemotherapy because they are not actively dividing. The researchers developed a novel tracing approach to confirm that chemotherapy-induced reactivation of these dormant cells, rather than the growth of pre-existing proliferative cells, is responsible for metastatic relapse, particularly in breast cancer patients.
The mechanism involves chemotherapy triggering senescence, an accelerated aging state, in fibroblasts, a type of connective tissue cell. Senescent fibroblasts release proteins that prompt immune cells called neutrophils to form neutrophil extracellular traps (NETs). These NETs alter the lung's extracellular matrix, creating an environment that supports the growth of dormant cancer cells, effectively "waking them up" and promoting metastasis. This discovery sheds light on why some breast cancer patients experience cancer spread to organs like the lungs despite successful treatment of their primary tumours.
However, the study also offers hope. The researchers found that combining chemotherapy with senolytic drugs, which target and eliminate senescent cells, reduced senescent fibroblasts in the lungs of mice. Specifically, the senolytic drugs dasatinib and quercetin showed promise in mitigating chemotherapy's metastatic side effects. A phase II clinical trial is now underway to test this combination in patients with triple-negative breast cancer, an aggressive form of the disease that does not respond to standard hormone therapies.
This study is significant because it provides direct evidence of a long-suspected paradox: treatments like chemotherapy, designed to kill cancer cells, may inadvertently promote cancer spread in some cases. This aligns with earlier findings, such as a 2025 study from the University of Chicago, which suggested that high-dose radiotherapy could similarly trigger metastatic tumour growth. Together, these discoveries challenge the conventional reliance on aggressive treatments like chemotherapy and radiation as standalone solutions.
The findings highlight the need for a more nuanced approach to cancer treatment. While chemotherapy remains effective at shrinking primary tumours, its potential to awaken dormant cells underscores the importance of addressing the tumour microenvironment and preventing metastatic relapse. The identification of senolytic drugs as a potential adjunct therapy is a promising step toward improving outcomes. Since senolytics like dasatinib and quercetin have already shown acceptable safety profiles in clinical settings, their integration into chemotherapy regimens could offer a practical way to enhance treatment efficacy while reducing the risk of metastasis.
Moreover, the study emphasises the value of precision medicine. By understanding the molecular mechanisms behind chemotherapy-induced metastasis, researchers can develop targeted strategies to interrupt this process. The ongoing clinical trial for triple-negative breast cancer patients is a critical test of whether these findings can translate into real-world benefits, potentially setting a precedent for broader applications across other cancer types.
The study's findings do not negate the value of chemotherapy but suggest that its role in cancer treatment may need re-evaluation. This naturally raises the question: do these insights strengthen the case for alternative and lifestyle-based approaches to cancer management? To answer this, we must consider the evidence for both conventional and alternative strategies, as well as the broader context of cancer care.
Chemotherapy, despite its risks, remains a cornerstone of cancer treatment due to its proven ability to reduce tumour burden and extend survival in many cases. For example, drugs like cisplatin have been critical in addressing shortages and improving outcomes for cancers like nasopharyngeal carcinoma, as seen in recent U.S. approvals of Chinese-manufactured drugs. However, the Chinese study underscores that chemotherapy is not a one-size-fits-all solution and may require complementary therapies to mitigate unintended consequences like metastasis.
Alternative and lifestyle-based approaches, such as dietary interventions, exercise, stress reduction, and complementary therapies like immunotherapy or herbal treatments, have gained attention for their potential to support cancer treatment and prevention. While these approaches are often promoted as less invasive, their efficacy varies widely, and rigorous scientific evidence is often lacking compared to conventional treatments.
For instance, a 2019 study by the Chinese Academy of Sciences found that ivermectin, an anti-parasitic drug, enhanced the effectiveness of chemotherapy against drug-resistant cancer cells in mice and human cell cultures. This suggests that some alternative therapies, when rigorously tested, could complement conventional treatments. Similarly, immunotherapy approaches, such as those using modified viruses or immune system enhancers, have shown promise in Chinese studies for boosting anti-tumour effects.
Lifestyle interventions also have a role. Diets rich in anti-inflammatory foods, regular physical activity, and stress management, can improve overall health and potentially reduce cancer risk or recurrence. However, these approaches are not substitutes for medical treatment, especially in aggressive cancers like triple-negative breast cancer, where rapid intervention is critical. The Chinese study's focus on senolytic drugs suggests that targeted pharmacological interventions, rather than broad lifestyle changes alone, may be necessary to address specific mechanisms like chemotherapy-induced metastasis.
The study does not tip the scales definitively toward alternative and lifestyle approaches but highlights the need for an integrated strategy. Combining chemotherapy with senolytic drugs, as explored in the clinical trial, represents a hybrid approach that leverages conventional treatment's strengths while addressing its limitations through targeted interventions. Lifestyle changes can complement this by supporting overall health and potentially reducing inflammation, which may exacerbate cancer progression. For example, reducing systemic inflammation through diet could theoretically support the tumour-suppressing environment that senolytics aim to restore.
However, patients and clinicians must approach alternative therapies with caution. Claims about "natural" cures or untested treatments often lack the rigorous evidence required to replace or even supplement chemotherapy. The study's findings advocate for evidence-based adjuncts, like senolytics, rather than a wholesale shift to alternative modalities. Patients considering lifestyle or alternative approaches should consult with oncologists to ensure compatibility with their treatment plans.
This research underscores the complexity of cancer as a disease and the need for ongoing innovation in treatment. The identification of chemotherapy's role in awakening dormant cells is a call to action for researchers to explore similar mechanisms in other cancers and treatments. For instance, could radiation or immunotherapy also trigger similar effects? The University of Chicago's findings on radiotherapy suggest this is a possibility worth investigating.
The study also highlights the importance of global collaboration in cancer research. Chinese scientists, alongside international efforts, are advancing our understanding of cancer's molecular underpinnings. Recent developments, such as China's contributions to pancreatic cancer biomarkers and low-cost cell therapies, demonstrate the potential for innovative, accessible treatments.
For patients, this study emphasises the importance of personalised treatment plans. Not all patients will experience chemotherapy-induced metastasis, but identifying those at risk through biomarkers or imaging could guide the use of adjunct therapies like senolytics. This aligns with the growing field of precision oncology, where treatments are tailored to individual tumour profiles.
While alternative and lifestyle approaches have a role in supporting overall health, they are not yet robust enough to replace or significantly shift away from conventional treatments like chemotherapy. Instead, the future lies in integrating evidence-based adjuncts, like senolytics, with lifestyle interventions to create comprehensive, personalised treatment plans. As research progresses, particularly with the ongoing phase II trial for triple-negative breast cancer, we may see a new standard of care that balances efficacy with the prevention of metastatic relapse, offering hope to patients worldwide.
No medical advice is offered here; for information purposes only!
"A team of Chinese scientists has found that the spread of cancer from original tumour sites to distant organs can be caused by chemotherapy triggering the awakening of dormant cancer cells.
Their findings shed light on why breast cancer patients can experience cancer metastasis in organs like the lungs despite successful treatment of their primary tumours.
The team also found that the use of specific drugs in combination with chemotherapy could be used to inhibit this process in mice, and a clinical trial is already under way in breast cancer patients.
"We demonstrate that chemotherapeutic drugs, including doxorubicin and cisplatin, enhance proliferation and lung metastasis of dormant breast cancer cells," the team wrote in a paper published in the peer-reviewed journal Cancer Cell on July 3.
"This study provides direct evidence of dormancy awakening and reveals a mechanism underlying [the] detrimental effect of chemotherapy on metastasis, highlighting potential strategies to improve cancer treatment."
Cancer patients are dying to survive
Researchers in the United States previously found that high doses of radiation therapy to treat cancer could paradoxically lead to the growth of metastatic tumours.
Many patients who undergo chemotherapy to treat primary tumours, the original tumour site in the body where cancer cells first start to develop, can have cancer relapses in other organs even after complete primary tumour regression.
This has led to research into whether chemotherapy can have a similar paradoxical effect, in which it both treats primary tumours and triggers cancer metastasis.
"It is postulated that the reactivation, or awakening, of dormant disseminated tumour cells (DTCs) in distant organs results in metastatic relapse after the asymptomatic period," the team said.
Studies have shown that disseminated cancer cells, which travel from primary tumours to sites in the body, can be found even during the early stages of primary cancer formation, according to a news release by the Chinese Academy of Sciences (CAS).
These cells can stay in a dormant state for years, during which they do not grow and multiply, allowing them to evade chemotherapy.
Researchers have previously identified molecular mechanisms that regulate metastatic relapse and disseminated cancer cell dormancy. However, it has not been clear whether metastasis results from the reactivation of dormant cells or the growth of rare, non-dormant disseminated cells.
"Understanding the exogenous causes of DTC awakening will help disease management of cancer survivors, offering opportunities to prevent and interrupt metastatic relapse after initial therapies," the researchers said in their paper.
To study this, the team led by Hu Guohong, a professor at CAS' Shanghai Institute of Nutrition and Health, along with researchers from Fudan University and Qilu Hospital of Shandong University, developed a cancer cell dormancy tracing approach.
The team confirmed that chemotherapy-induced reactivation of dormant cells from breast cancer could lead to metastatic relapse in the lungs of mice.
Their findings demonstrated that the "awakening of dormant DTCs, but not accumulation of pre-existing proliferative DTCs, is responsible for metastases induced by chemotherapy".
Chemotherapy induces senescence - an accelerated state of ageing in which cells stop multiplying and release inflammation-causing chemicals - in specialised connective tissue called fibroblasts.
The team found that senescent fibroblasts release proteins that cause immune cells called neutrophils to form weblike formations, called neutrophil extracellular traps, which change the environment in the lung into one that helps dormant cancer cells restart their growth.
The remodelling of the extracellular matrix, a complex network of molecules that support and surround cells, also degrades tumour-suppressing factors.
"We explored if chemotherapy-induced senescent fibroblasts could be a therapeutic target to improve the effect of chemotherapy on metastasis inhibition," the team said.
The researchers discovered that combining senolytic drugs, which eliminate senescent cells, with the chemotherapy drug doxorubicin reduced senescent fibroblasts in the lungs of mice.
"Since the senolytics have shown acceptable safety profiles and benefits in clinics, this could be a promising strategy and warrant further clinical investigation," they said.
The team said that, based on these study results, a phase II clinical trial was under way to explore the safety of combining the senolytic drugs dasatinib and quercetin with chemotherapy to treat triple-negative breast cancer.
Triple-negative breast cancer is an invasive and aggressive form of the disease that cannot be treated with the usual hormone therapy used to help treat such cancers."
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