Preventive neck lymph node surgery improves early oral cancer survival
Dr Anil D’Cruz - Tata Memorial Centre, Mumbai, India
Oral cancer is a massive problem all over the world. Can you tell me what you were trying to do about this very important disease?
Oral cancer affects more than 300,000 people globally. Contrary to popular belief it’s not something that’s seen only in Southeast Asia, it’s a problem of both the developed and the developing world. Wherever you have a high incidence of tobacco consumption you will have oral cavity cancers. Now, a large proportion of oral cavity cancers present in early stage, that is T1/T2, particularly in the tongue where symptoms occur very early. These patients, when they present to the physician, have an ulcer or growth on the tongue and no lymph node metastasis clinically. Now the treatment of the primary is predominantly surgical which is widely excised. Controversy surrounds what should be done for the neck. There are two schools of thought, one that do the wait and watch approach and one that do the elective neck dissection approach.
Now it’s always tempting for doctors to… well, it’s difficult really because on the one hand you like to be conservative, on the other hand you’d like to do as much as possible. What were the data up until now illuminating that decision making process?
So I’m going to answer this question in two parts. The first is that data to date showed that the larger the tumour within T1/T2 and the deeper the tumour, the more the incidence of metastasis and you should operate these patients. But how do you gauge depth of tumour, which is a histological parameter, after you excise the primary? So you don’t have it when you sit across the table and counsel your patient. So people used depth as a surrogate to predict whether they should operate but there was absolutely no validated method to check the depth to date.
So what did you do in your study?
In our study all patients with T1/T2 cancers were randomised irrespective of their depth. It was barred to show a 10% improvement in survival from 60% to 70% and the usual statistical considerations to make it statistically significant.
And you had a good number of patients, itself quite an achievement.
So we had planned the study to 710 patients. The data and safety monitoring committee when auditing the study at 596 patients felt that there was an observed difference in depth rates between the therapeutic or the wait and watch versus the elective neck. So they asked us to look at our data. So we stopped the trial at 596 patients, we have presented data of the first 500 patients who have completed active treatment and about nine months of follow-up.
And what were those results?
The results on overall survival was there was an absolute benefit of 12.5% in patients who had their necks electively treated as opposed to those that had the wait and watch policy. Recurrences were also significantly lower in the elective neck dissection arm as opposed to those that had the wait and watch policy.
I think you’ve been able to interpret this in terms of the number of patients needed to treat?
Correct. So for every four patients you would prevent one recurrence and for every eight patients you would prevent one death.
So what are the clinical recommendations coming out of this?
All patients with early stage clinically node negative oral cancers should have an elective neck dissection. The next step would be to do smaller procedures in the neck, probably sentinel node biopsies, limited neck dissection to avoid morbidity to the shoulder and avoid dissection in and around the accessory nerve that passes through the field of dissection. The other reason why our study is very, very important: early oral cancers are treated out of oncology centres very often. The maxillofacial surgeons treat them, the general surgeons treat them, the non-oncology ENT surgeons treat them. So excising the primary in private practice is very simple and then the neck is left alone and that would have an impact, finally, on survival.
So the very brief take home message for doctors all over the world would be what?
Excise the primary with tumour-safe margins and do the neck in all patients.
All in one?