Statistic approach

Hello, thank you for the last response. Now I am very puzzled by using statistics in oncology. For example, you say that radiation decreases recurrences by 50%. Does it mean that, for example, recurrences are 15% with small tumors without radiation and after radiation they are 7.5%(15*50%)? Then it's only 7.5% advantage! Can you give me any hint where I can find detailed statistic results? They should be very different for different types and sizes of tumors! Why all of them are "in average"? Why it's still not known about sentinel node dicsection? Why these results are not obtained on highly reproductive animals close to humans (rats, pigs, rabits)? At least you could get general rules! It should be a lot of in common for all mammals (cells, vesels, lymphatic system)! Actually my question is about the best statistical sources - what can I do - I should this analysis myself! Thank you.

[CCF-RN,MSN-rf]

Dear nelly8:  I would suggest that you consider obtaining Dr. Susan Love's Breast Book.  Review chapters 23, 27 and 28.  I believe this will help you to understand why statistics are not perfect and can only be used as guidelines.  Regarding sentinel lymph node mapping.  We know there are incidences of skip metastasis and we are working, through human experience, on determining which populations may be able to benefit from sentinel lymph node mapping instead of axillary node dissection.  We cannot use animals for a very simple reason.  In order to treat cancer - the animals have to get cancer.  We can inject these animals with cancer cells but they will not all get the cancer.  Just like humans - each body handles it differently and it makes methodical research very difficult.  We can test mice, but they are genetically alike so it makes the results less applicable to humans.

[surgeon]

40% of women who have lumpectomy without radiation will get recurrance within the breast. With radiation, it's less than 10%. That's been shown over and over. Radiation has been around a long time. Sentinal node surgery has been around a lot less time. It's been used in the breast for only around 5 years. In order to get meaningful data, one has to get studies that randomize people into various groups, and follow them for many years. We know a lot more now than we did 10, 20, 50 years ago. We will know more in 10, 20, 50 years. We are where we are.