Will recurrence and metastasis still occur after kidney cancer surgery with complete removal of kidney and tumor? Kidney cancer is still essentially a malignant tumor, and recurrence and metastasis of malignant tumors are still common problems faced by patients after surgery. Fundamentally, even if the tumor or the affected kidney is completely and thoroughly removed by surgery, there is still a possibility of local recurrence and distant metastasis after surgery for kidney cancer. According to official statistics, 20% to 30% of patients with stage I-III kidney cancer (tumor is still confined to the kidney or extra-renal fascia, which can theoretically be completely removed without residual tumor) will still have local recurrence or distant metastasis after surgery. The lungs are the most frequent organ for distant metastases, accounting for 50% to 60% of all metastatic sites. Recurrence or metastasis most often occurs 1-2 years after surgery, and the majority of recurrence or metastasis occurs within 3 years after surgery. Therefore, the occurrence of recurrence and metastasis should be closely monitored even after complete surgical resection of kidney cancer, which requires regular follow-up examinations within a period of time to detect recurrent or metastatic lesions as early as possible, because the earlier they are detected and treated in time, the more likely it is to slow down the progress of lesions and increase the survival time of patients. Why does metastasis occur after surgery when no distant metastases were found at the time of surgery? Is it that the surgery was not clean when the disease recurred after surgery? To understand this question, we need to have a scientific understanding of the nature of malignant tumors. Malignant tumor is a mutated cell arising from the malignant transformation of normal cells in the body. The normal cells of human body, like human beings or all living creatures in this world, have a life span and will live, grow old, get sick and die. Their appearance, their disappearance and their functions and roles are controlled by strict procedures, just like this society, people all perform their duties and obey the regulations so that the society can function in an orderly manner. However, there is a problem with the program controlling cell survival in tumor cells, such as the mutation of genes responsible for cell proliferation without the restraint of other genes, resulting in unlimited proliferation of tumor cells, which is the basis of rapid growth of tumor; another example is the loss or loss of function of genes responsible for cell death, resulting in immortality of tumor cells, which is the basis of resurgence of tumor; another example is the mechanism responsible for firmly fixing cells in their positions. This is the basis of malignant tumor metastasis; and then the mechanism responsible for fixing the cells in their own positions is changed, so that the originally fixed cells can easily leave their original positions and migrate to places where they do not belong. Therefore, malignant tumors, including kidney cancer, have this or that malignant nature from the moment they are born, one of the most vicious properties of which is the special ability to cause metastasis and infiltration of tumor cells. Although the possibility of metastasis is related to the size or growth time of the tumor, for example, the longer the kidney cancer has been affected, the larger the tumor invades other organs or the greater the chance of metastasis, the metastatic ability of malignant tumors is largely innate, which determines the uncertainty of the timing of metastasis of malignant tumors, which may occur in the late stage of tumor growth or the middle stage of growth, but may also occur in the early stage of tumor development. It may occur in the late stage of tumor growth or in the middle stage of growth, but it may also occur in the early stage of tumor development. The essence of metastasis of malignant tumor cells is that the cells are separated from their original nests, wandering in the tissues, penetrating the walls of blood vessels or lymphatic vessels, drifting in the human circulatory system with blood or lymph, and landing, taking root and sprouting in a suitable organ or tissue. It can be seen that there is a general chance and randomness in these processes. A 10 cm kidney cancer has a higher chance of metastasis than a 3 cm kidney cancer mostly because the former has more tumor cells, more blood vessels, and more chances of metastasis, but this does not mean that a 3 cm kidney cancer will not metastasize. Therefore, when kidney cancer is diagnosed, it is not possible to determine whether it has metastasis or not by the size and stage of the tumor, but only by the probability of whether it is more or less likely to have metastasis. Then, does the fact that no distant metastasis is found at the time of diagnosis mean that there is no metastasis? Obviously not, because although the sensitivity of our current clinical imaging methods is increasing, they can only detect tumor tissues of a certain volume, for example, CT or MRI can only detect tumors larger than 0.5-1.0 cm in diameter. A cubic centimeter tumor has about 10 billion cells and a cubic millimeter tumor has about one million cells, so imagine how long it takes for metastatic malignant tumor cells to divide and proliferate from one cell to 10 billion cells, which must be a long time, not including the relatively long quiescent time needed for metastatic cells to transition to a proliferative state in the new environment. Therefore, we cannot see metastatic cells until they have grown to a volume that we can detect, which means that metastases that are not detected before and at the time of surgery do not mean that they have not occurred. Pre-operative micrometastases (undetectable metastases) are likely the basis for the development of metastases after surgery. By the same token, microinfiltration (undetectable small amount of tumor cells infiltrating into the surrounding kidney tissues) before surgery is likely to be the source of tumor recurrence after surgery. Therefore, the metastasis and recurrence occurring after surgery are more related to the malignant nature of the tumor and secondary to the surgery itself. Of course, detecting or monitoring the metastasis of malignant tumors by detecting some tumor-specific indicators will greatly improve the possibility of detecting metastasis, but unfortunately, people have not found any specific indicators that can sensitively detect metastasis of kidney cancer, which is the research direction that clinicians and basic researchers of kidney cancer treatment have been devoted to. How long does it take to start review after kidney cancer surgery? How long does it take to review? Through clinical scientific statistics, it has been found that recurrence and metastasis of kidney cancer mostly occur within 3 years after surgery, and 1-2 years after surgery is the high incidence time of recurrence and metastasis. Therefore, we suggest that kidney cancer patients, whether they are in stage I, II or III, should be reviewed three months after surgery, every three months within two years, every six months from two to five years after surgery, and once a year after five years. It should be noted that there is no single follow-up plan that can be adapted to all patients, and the international guidelines for treatment and follow-up of kidney cancer only give a follow-up recommendation that is suitable for most patients. The follow-up plan for each patient needs to be individually designed. For example, for a patient with low grade kidney cancer of only 3.0 cm, the recurrence and metastasis rate is relatively low after complete surgical removal of the tumor, so a semi-annual follow-up of 2-3 years is sufficient for such a patient. However, for a larger tumor that has invaded the perirenal fat, or there is tumor thrombus in the vein, or the tumor is less differentiated (high malignancy), it is essential to follow up closely for 3-5 years, or even longer. For patients with large tumors and high possibility of local residual or recurrence, the focus of follow-up may be on the examination of surgical resection site, and it may be necessary to use CT and other means with higher sensitivity during follow-up. In addition, for some hereditary renal cancers, such as VHL syndrome and hereditary papillary renal carcinoma, because of their tendency to occur multiple times and in both kidneys, the examination of the contralateral kidney cancer becomes a priority during follow-up, and the necessary abdominal CT examination may be maintained for several years. What are the contents of postoperative follow-up and review of kidney cancer? The main purpose of postoperative follow-up examination of kidney cancer is to check whether there are recurrence, metastasis and new tumor, so as to make early intervention and treatment, improve treatment effect and prolong patient’s survival time. The first postoperative follow-up also aims to assess the kidney function, postoperative recovery status, and the presence of surgical complications. A CT scan of the kidney is recommended for the first postoperative review in patients who have undergone partial nephrectomy to understand the morphological changes of the kidney after surgery and to serve as a basic information for comparison in future reviews. During the first review, the patient should report to the doctor in detail about the postoperative recovery, including whether the pain and discomfort in the operated area have recovered, whether the incision has healed completely, whether the physical and mental state have recovered, and whether there are any abnormal symptoms and signs, such as coughing up blood, bone pain, etc. Generally speaking, 1-3 months after surgery, the patient will completely recover from the blow of surgery and return to the life of a healthy person. Of course, due to the difference of each person’s physical and psychological adjustment ability, the time and degree of complete recovery from surgery varies greatly. As for being able to accept and face the reality of malignant tumor diagnosis frankly in psychological terms, it may take longer time to complete. Blood biochemistry is an essential part of post-operative follow-up of kidney cancer, including testing blood routine to understand the patient’s hemoglobin level, whether anemia exists or whether the preoperative anemia has improved. The liver function test is used to understand the metabolism of the liver, which reflects the overall recovery status of the patient after surgery on one hand, and the liver is also a good site for metastasis of kidney cancer after surgery on the other hand. Renal cancer surgery causes direct loss of kidney functional units, so how the remaining kidney functional units function and whether they can take up the burden of urination and detoxification of the body are seriously related to the long-term quality of life after surgery. By testing blood creatinine, urea nitrogen and other indicators, we are able to understand whether the remaining kidney functional units of the patient are working effectively. In general, even one kidney can fully undertake all the physiological excretory functions of the body, but it should be noted that the normal range of commonly used renal function indicators is for two kidneys working together, then the renal function indicators may partially exceed these normal ranges when one kidney is used, such as blood creatinine >140 μmol/L (normal value <133 μmol/L), which is a common phenomenon in renal cancer This is a common phenomenon after surgery, and there is no need to be overly nervous about it. What is important is to observe the continuous change of kidney function, whether the blood creatinine is stable at a slightly higher value or continues to rise after surgery. If the kidney function is stable and unchanged, it is normal, while if the kidney function continues to deteriorate, it is necessary to be extra alert to the occurrence of postoperative renal failure. Local recurrence of kidney cancer after surgery mainly refers to the re-growth of tumor in the surgically resected area, including the recurrent growth of tumor tissue in the original kidney bed area, local lymph node metastasis, the growth of tumor in the surrounding organs and tissues after nephrectomy, such as adrenal gland, and the growth of tumor in the preserved kidney tissue after partial nephrectomy. Therefore, the postoperative review should firstly check the tissue recovery and the presence of tumor recurrence at the surgical site. Color ultrasound and CT are commonly used to examine this area. In general, the doctor will recommend the patient to have the ultrasound examination of the surgical site first, and if there are abnormal findings, further CT scan or CT enhanced scan will be necessary. It is worth noting that although CT has higher diagnostic sensitivity and accuracy than color ultrasound, the X-ray radiation brought about by CT test itself is harmful to patients' normal tissues and should not be used too frequently. Tumor metastasis of distant organs after kidney cancer surgery is the focus of follow-up review. The metastases of kidney cancer after surgery are usually found in the lungs, accounting for about 50%-60% of all metastases. Therefore, chest X-ray imaging is a mandatory item in the review. If there are suspicious findings on the X-ray, further CT examination of the lungs is required. It is important to note that there are many non-specific changes in the adult lung due to old inflammation, smoking and air pollution. It is important to monitor the dynamics of small lung nodules, mainly in comparison with previous lung examinations, to determine the growth of small nodules, because in general only tumorigenic lesions have the characteristic of continuous growth. Other metastatic sites of kidney cancer include liver, brain and bone. The examination of liver is mainly based on color ultrasound, and again further CT or MRI will be done when suspicious lesions are found. The examination of bone and brain is not a routine examination item after kidney cancer surgery, because the proportion of metastasis in these areas is still relatively low. If there are specific related symptoms, such as bone pain or neurological changes in the brain need to be alert and further examined. Among the biochemical tests, alkaline phosphatase is often included, because in some cases of bone metastases, elevated alkaline phosphatase is seen, so testing alkaline phosphatase in blood during follow-up can help detect early bone metastases. However, elevated alkaline phosphatase does not necessarily mean bone metastasis. Many other diseases of bone metabolism can also cause changes in alkaline phosphatase, so when elevated alkaline phosphatase in blood is found after kidney cancer surgery, further related tests are still needed to help diagnosis, such as nuclear scan of bone. Incision-related problems after kidney cancer surgery Incision-site related problems in nephrectomy patients are probably the most troubling problems for patients in the early postoperative period. The incision used for nephrectomy, especially for developmental nephrectomy, is usually an oblique subcostal incision in the lumbar region, which is the best incision to expose the kidney, but its course almost crosses the major muscles of the lumbar region, especially the direction of the incision is crossed with the nerves that govern the sensation of these muscles and the nearby skin, which means that this incision inevitably cuts the major muscles and related nerves of the lumbar region. Although the severed muscle must be re-sutured when the incision is closed, the severance and damage to the nerves innervating it is permanent. When the muscle leaves the nerve innervation, atrophy occurs, contraction is reduced, tension is weakened, then the abdominal wall muscles on one side of the operation will have a significantly lower restrictive effect on the internal organs than the other side of the healthy side, the result is that the two sides of the waist found by many patients are not generally high, and the operated side protrudes significantly, as if a lump had been born. This often causes many patients to panic and even suspect the recurrence of tumor. It should be said that this is one of the most common phenomena in the early post-operative period, only that in some patients it is very prominent while in others it is not obvious, but the damage to muscles and nerves is the same and inevitable with the current technology. As nerve and muscle repair occurs over time, this phenomenon may get better, but the likelihood of long-term unremission is also very high. This postoperative neuromuscular damage, although not affecting the patient's normal life, is an important issue that needs to be studied and addressed in clinical work. Fortunately, more and more kidney cancer surgeries can be done by minimally invasive means such as laparoscopy, and the damage to nerves and muscles by laparoscopic incision is much less than that of open surgery, and the treatment effect is no different from that of open surgery, so the more common application of laparoscopic surgery will better solve the problems related to the incision of kidney cancer surgery.