Oral cavity (mouth) and oropharynx (throat) cancers that are detected early are treated primarily with surgery or radiotherapy. These treatments are effective in curing cancer and improving survival. However, with surgery and radiotherapy alone there remains a chance that cancer will recur, which can shorten survival for patients. The addition of chemotherapy to surgery or radiotherapy may help improve survival.
Chemotherapy treatments are drugs that work by killing rapidly dividing cells such as cancer cells. There are other rapidly dividing cells in our body, such as those on our skin or in our gut. Chemotherapy can affect these healthy cells as well, which is why these treatments can have unpleasant side effects.
In the treatment of cancer, chemotherapy can be given before surgery or radiotherapy, during radiotherapy or after treatment with surgery or radiotherapy. There are also different types of chemotherapy that can be given either as pills or through the veins (intravenously). These differences in the ways of giving chemotherapy and types of chemotherapy are likely to have different effects on survival. At this time, we do not know which way is best.
This review updates one previously published in 2011.
What was the research?
A systematic review to examine whether chemotherapy given with either surgery or radiotherapy improves survival. We also wanted to know if chemotherapy given with surgery or radiotherapy improved the likelihood of shrinking the cancer and if these treatments reduced the risk of the cancer coming back.
Who conducted the research?
The research was conducted by a team led by Ambika Parmar of Sunnybrook Odette Cancer Center, Toronto, Canada on behalf of Cochrane Oral Health. Michaelina Macluskey, Niall Mc Goldrick, David I. Conway, Anne-Marie Glenny, Janet E. Clarkson, Helen V. Worthington and Kelvin K.W. Chan were also on the team.
What evidence was included in the review?
We included 100 randomised controlled trials, involving over 18,000 participants. Thirty‐six studies evaluated the use of chemotherapy before surgery or radiotherapy; 11 studies evaluated the use of chemotherapy after surgery or radiotherapy; 30 studies evaluated the use of chemotherapy together with radiotherapy; and 23 studies assessed different chemotherapy drugs given before, during or after surgery or radiotherapy.
What did the evidence say?
We found no clear evidence that chemotherapy given before surgery or radiotherapy improved survival. Similarly, chemotherapy given after surgery did not seem to lead to an improvement in survival.
We found treatment with radiotherapy and chemotherapy together after surgery, as compared to radiotherapy alone following surgery, may increase the likelihood of survival. Also, in patients who are not eligible for surgery, it may improve survival if chemotherapy is added to radiotherapy, as compared to radiotherapy treatment alone. There was not enough evidence to judge which chemotherapy drug is best to use.
How good was the evidence?
There were differences among the included studies in the type and number of participants they included, as well as the type of chemotherapy drug administered. These differences may impact the results. As such, we cannot be certain about these results and future research could change our conclusions.
What are the implications for treating this condition?
These results support the addition of chemotherapy together with radiotherapy in patients who have undergone surgery for cancers of the oral cavity or oropharynx. In patients who are not eligible for surgery, our results support the use of chemotherapy with radiotherapy as compared to radiotherapy alone.
What should researchers look at in the future?
We conclude that there is insufficient evidence to support the use of chemotherapy outside of these situations. We believe this highlights the need for further study into the use of chemotherapy together with surgery or radiotherapy.
Parmar A, Macluskey M, Mc Goldrick N, Conway DI, Glenny A-M, Clarkson JE, Worthington HV, Chan KKW. Interventions for the treatment of oral cavity and oropharyngeal cancer: chemotherapy. Cochrane Database of Systematic Reviews 2021, Issue 12. Art. No.: CD006386. DOI: 10.1002/14651858.CD006386.pub4
This post is an extended version of the review’s plain language summary, compiled by Anne Littlewood at the Cochrane Oral Health Editorial Base.