Comments about biopsies and cancers
| Author : Pierre Allain
||Date : 2012-5-2
Any medical practice has its advantages and its disadvantages. Two recent letters published by the BMJ point out the potential danger of biopsies so frequently practiced for suspected cancers.
The letter of G David Stainsby reports the risk of seeding of cancer cells by prostate biopsy. The letter of Dunne underlines the risk of seeding cancerous cells by hepatic biopsies, from initially surgically resectable tumours. A paper of British Journal of Surgery of 2005 indicates that in patients with metastatic colorectal cancer and hepatic location the fact of having had hepatic biopsies before the surgical resection reduced of more than 30% the survival time at 4 years (compared to those who had not had biopsies).
The advantage of biopsy is to confirm the diagnosis by specifying whether or not there is a malignant tumour, at least if samplings were made in the right places. The other information expected from the biopsy is to characterize the tumour for the choice of the treatment but tumours are heterogeneous and there are few clinical data (about survival duration for example) showing the superiority of a treatment based on the results of the biopsy versus a standard treatment.
Risks of cancer biopsies have been suspected for a long time. Indeed, spontaneously, the risk of any initially localized tumour is to extend inside the affected organ and to disseminate remotely in the form of metastases. The fact of digging with needles, through healthy and diseased tissues to do samplings, at first sight seems likely to promote the extension of the tumour locally and alongside the path of the needle and to increase the risk of distant dissemination via blood and lymph. The existence of this disadvantage of biopsies is denied by the cancer specialists in general, their main argument being that there is no clinical study showing clearly the danger of biopsies. The other argument in favour of biopsies is that it is not possible to start a heavy chemotherapy without having the certainty of the existence of a cancer, which is given by the biopsy. However, a surgical resection without preliminary biopsy is possible in a certain number of cases. Lastly, means of exploration less invasive than biopsies exist and a strict monitoring of the evolution of the suspicious areas can often give an indication for the treatment.
For a patient, to know that he has perhaps a cancer is not reassuring and biopsies can give a response but to fear that biopsies could elicit worsening of the cancer, if it exists, is not either reassuring. Should this questioning about biopsies be raised? It can be stressful for patients but useful for physicians.