When it comes to Chemotherapy, Timing’s Everything

Keith I. Block, MD

When scheduling a health exam or procedure, most patients make their appointments based on convenience and availability. Research suggests there’s something else they should take into account: Timing.  Timing, as in the administration of any drugs they may be given, and timing, as in their own “biological clocks.”  

We now know that the results of many diagnostic tests – including blood tests, blood pressure readings and urinalysis, among others – can vary, depending on the time of day these tests are taken. In addition, doctors are finding that by taking a patient's body clock into consideration – a practice called chronotherapy – they are able to more effectively treat a wide range of illnesses, including asthma, arthritis, even cancer. And when it comes to treating cancer, the practice of synchronizing the administration of chemotherapy drugs to a patient’s malignancy, time zone and individual biological rhythm is called chronomodulated chemotherapy.

About chronomodulated chemotherapy

There are nine specific "clock-related" genes in our brainstems that control our time-dependent biological functions, including sleeping and eating patterns, heart rate, body temperature, and hormone production.  Similarly, cancer cells also have time controls; they divide and rest at different times each day. While rest and division also occurs among healthy cells, their timing differs from that of cancer cells. 


We can take advantage of this by administering the drugs at the specific time when cancer cells divide, and are more vulnerable to cell death, and when healthy cells are at rest, and least sensitive to toxicity from chemotherapy.  Research demonstrates chronotherapy not only improves treatment tolerance, but can improve response and survival as well.  In fact, the literature contains studies showing that chronomodulated chemotherapy can even allow for patients who previously needed to discontinue a chemotherapy protocol – either because it was ineffective, became ineffective prematurely, or was too debilitating to tolerate – and benefit from that identical drug protocol when it was administered via chronomodulated chemotherapy. 


Gold standard research supports the use of chronomodulated chemotherapy.  For example, for metastatic colon cancer patients, studies show that administering chemotherapy at the optimal time can halve toxicity and double treatment response.  For advanced metastatic ovarian cancer, a study in the journal Cancer reported that optimal timing of chemotherapy can reduce toxic side effects by 50 percent and quadruple five-year survival.  This is a four-fold improvement!  (Four times as many patients were alive at the five year mark). The same study demonstrated a 75 percent reduction in the need to cut the treatment dose! 


Chronotherapy at the Block Center

I brought this technology, software and knowledge to the U.S. from Europe in the mid 1990s, hoping to improve treatment tolerance among my patients, enhancing the benefits we were seeing from the integrative approach to treatment we were already providing.  (In fact, studies suggest that 1/3 of patients discontinue chemotherapy treatment prematurely due to the debilitating physical and psychological consequences). 


At the Block Center, we were implementing nutritional strategies and supplement formulations that could help diminish the side effects of chemotherapy – and my research team and I were conducting ongoing studies – when I came across the chronobiology evidence that sleep and activity cycles along with the timing of drug infusions were all clock dependent.  The extensive research that demonstrated decreased toxicity and improved survival with the use of chronotherapy persuaded me that we needed to bring this technology to our patients as soon as possible. 


At the Block Center, chronotherapy is administered using a portable, computerized pump, small enough to fit in a fanny pack.  The infusion of the chemotherapy drug resembles a sine wave curve, it starts infusing quite slowly, and ratchets up, hour by hour. It slowly increases to the middle point of the cycle where it peaks, meaning the drug will be infused at its highest rate, and then slowly ratchets back down. When the drug dosage reaches zero, the cycle is complete.


Though there are currently over 40 major centers in Europe that participate in cooperative research using this method of chemo administration, there are less than a handful of clinics in the U.S. that implement it.  Why is this?  Currently, cancer treatment in our country is scheduled at the convenience of the hospital, medical center, treating physician, etc., not at the optimal time for the patient.  In addition, the complexity of the technology would require training and incur expenses to the treating facility with no additional insurance coverage. 


However, the potential impact to reduce toxicity, improve response to treatment and even boost survival, makes the need to broaden access to this approach essential.  It is my hope that one day chronomodulated chemotherapy will be widely available in this country, as it is outside the U.S.

For more information on The Block Center for Integrative Cancer Treatment, visit BlockMD.com.

2 responses to “When it comes to Chemotherapy, Timing’s Everything

  1. Is there a general time of day to administer chemotherapy to maximize results (such a morning or afternoon) or is the chemo schedule personalized to meet each individual patient’s needs? If personalized for each patient, what factors are taken into consideration when determining the chemo dosing schedule? Lastly, if a patient isn’t local and is unable to travel to the Block Center frequently for treatment, can the patient initially meet with Dr Block amd then be treated with chronomodulayed chemotherapy under his direction from his/her home town, with additional support from his/her local on oncologist?

  2. Thank you Dr. Block for this valuable information. Your book, Life Over Cancer, has been a constant source of wonderful information to help my daughter stay in remission.
    Thank you so much.
    Judy Mays-Bohrer

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