Kenyan oncologists have disputed a recent American study whose findings showed that chemotherapy drugs used by breast cancer patients could increase chances of cancer cells migrating to a different part of the patient’s body, and trigger a ‘repair’ system, allowing them to grow back stronger.
Scientists at the Albert Einstein College of Medicine in New York examined the impact of chemotherapy on breast cancer patients, and found that while shrinking the tumours, chemotherapy simultaneously opens a gateway for tumours to spread into the blood system.
However, Kenyan experts have disputed this saying that the study, using lab mice and 20 patients, sought to understand how different patients react to chemotherapy.
“The scientists simply wanted to find out whether we could potentially predict which patients will respond poorly to chemotherapy before surgery,” explained Dr Miriam Mutebi, an oncologist who does surgeries on breast cancer patients.
RESPONSE DIFFERS FROM PATIENT TO PATIENT
Dr Mutebi said that the study does not discourage the use of chemotherapy but rather suggests that its timing be reviewed in particular patients.
“Patients may have varying responses to chemotherapy ranging from a complete response, to a partial response. The challenge lies in predicting which subset of patients will respond to treatment,” she said.
The main goal of pre-operative (neo-adjuvant) chemotherapy for breast cancer is to shrink tumours so women can have a lumpectomy (surgery to remove cancer or other abnormal tissue from your breast) rather than a more invasive mastectomy (removal of the whole breast).
According to Dr Mutebi, chemotherapy can help reduce the size of the tumour before surgery, making the surgery safer because the surgeon is less likely to leave any growth behind during the operation.
Dr George Karagiannis of the Albert Einstein College of Medicine found the number of doorways was increased in 20 patients receiving two common chemotherapy drugs.
He also discovered that in mice, breast cancer chemotherapy increased the number of cancer cells circulating the body and in the lungs.
“One approach would be to obtain a small amount of tumour tissue after a few doses of preoperative chemotherapy.
PRE-OPERATIVE CHEMOTHERAPY CAN PROMOTE METASTASIS
If we observe that the markers scores are increased we would recommend discontinuing chemotherapy and having surgery first, followed by post-operative chemotherapy,” he said.
“In this study we only investigated chemotherapy-induced cancer cell dissemination in breast cancer. We are currently working on other types of cancer to see if similar effects are elicited.” Cancer becomes incredibly difficult to treat – often fatal – once it spreads to other organs; it is then classified as Stage 4.
But pre-operative chemotherapy can, instead, promote metastasis, scientists concluded from experiments in lab mice and human tissue, published in the journal Science Translational Medicine. It was therefore initially used only on large tumours after being introduced about 25 years ago.
“The choice of 3mm tumours was used in an attempt to reflect their population where patients typically present with early breast cancers less than 2cm in size,” explained Dr Mutebi.
Though no robust clinical conclusions can be drawn from these findings, this preliminary work highlights areas new areas of potential research enquiry and development. Breast cancer is the second most prevalent type of cancer in Kenya. In 2012, approximately 4,500 women had breast cancer, and nearly half were below 50 years according to the Kenya Network of Cancer Organisations.
“Chemotherapy remains a critical component of the management of patients with breast cancer and more studies, both lab and population based, into how this could be delivered more efficiently, can only be beneficial for our patients,” she said, adding that the results from the study would “definitely require large clinical trials in human patients to see whether the findings of this single study hold up in the ‘real world’.”
“This is particularly pertinent for sub-Saharan Africa and Kenya where three-quarter of our patients present with advanced cancers usually 5cm or greater,” she added.