Saturday, January 29, 2011

Age of cancer: we can reliably estimate and apply this knowledge? -Cancer Network

In their article, Patrone et al. use a modified version of Collins ' right to estimate the age of colorectal cancer, lung and breast cancer. Bill Collins, who claims that the likelihood of recurrence of a tumor is equal to the patient's age at diagnosis more than 9 months, has been applied mainly to pediatric cancers, tumours in particular embryonic.[1.2] the results of applying the law of Collins ' of these tumors were reasonable, although exceptions have been reported and the law is not applicable to all types of cancer.[3.4] its use in adults as used in this document is therefore unique.

The current study is based on the assumption of a constant growth of the cancer after surgery, that the authors admit is a potential limitation. Bias may also have been introduced into the patient selection "only surgery", especially those from retrospective studies, although the impact of this probably is diminished by the fact that older studies used were in most cases (probably from a time when there was less use of multimodal therapy that currently there is no). Finally, there is heterogeneity in tumor recurrence time based on the remaining burden after resection and intensity of follow-up. Some of these concerns are addressed by the use of mainly authors and prospective studies finding no difference between the rate of recurrence in retrospective studies and saw that in future studies, despite the differences in absolute terms.

Despite these limitations, the study concept is novel and extremely interesting. Still, the application of the results remains unclear. From the point of view of medical care, knowing the "age" of a tumor is unlikely to change management. The patient receives a new diagnosis of cancer, while this knowledge may relieve the anxiety about the emergency treatment, it may exacerbate the anxiety of the variety "what if". For example, a patient who has just said that his cancer is probably 5 to 6 years may berate herself with thoughts along the lines of "if only he had or hadn't done x then it would be in this situation right now."

One potential application of the results of the study, from the medical point of view is that you can perform a retrospective review of patient's contact with the health system during the period of the estimated age of his tumor. There were subtle physical exam or imaging findings that could be attributed to the patient's tumor reliably and applied to future patients to facilitate earlier diagnoses and, hopefully, a more favourable outcome? However, a less positive side of this potential application in our current environment of medicolegal is the possibility of increased risk of litigation due to perceived negligence (e.g., "Doctor X lost my Cancer 3 years ago").

As stated earlier, the conclusions of this article are based on the assumption of a constant growth rate of breast cancer after surgery and as a result, patients treated with chemotherapy, hormonal therapy, or radiation were excluded because of the potential of these therapies to alter the kinetics of growth. While the need for internal validity study estimating the age of a given cancer, this patient population limitation makes it difficult to use the results to determine the prognosis or longevity of postoperative follow-up after resection except in patients treated with surgery only. For all three cancers selected for this study (breast, lung and colon-rectum), a significant number of patients being treated with hormone therapy, radiation or chemotherapy adjuvant or neoadjuvant chemotherapy. It would be interesting to know the growth rates in these settings, and be able to provide a reasonable interval after which the recurrence is highly unlikely. We can then adapt the intensity of our follow-up accordingly. However, I imagine that these would be difficult to estimate given responses varied multimodal therapy of tumours.

Patrone et al. conclude that "age" typical of a tumor at diagnosis is about 5-6 years, while for lung and rectal cancer is 3-4 years, based on the time of occurrence in most patients. For these and many other types of cancer, the current standard is run fairly intensive clinical follow-up to the first 5 years after the first round of treatment. Subsequently, if there is no evidence of the disease recurring, cautiously consider the patient recovered and decrease the intensity of our vigilance. This period of five years neatly aligns with the time observed in this study. While this is reassuring, does not change the current paradigm.

Finally, the authors cite perhaps lead a similar analysis resected metastatic lesions and make inferences about their "age" than for the primary tumor. This knowledge would be extremely valuable to guide clinical decision making, especially now when increasingly aggressive metastasectomies are executed. Once again, however, this analysis would be difficult to interpret given our current multimodal therapeutic and unpredictable effects on tumor growth kinetics.

Overall, this book presents a concept interesting, exciting, but it is uncertain how the authors best results can be exploited.

financial reporting : the author has no significant financial interests or other relationships with producers of goods or supplier of any of the services referred to in this article.

View the original article here

No comments:

Post a Comment