Oncologic Emergencies PART – 2
(All the articles published in past are available at www.shyamhemoncclinic.com/blog/)
Question: Thank you Chiragbhai for initiating very interesting and important topic of oncologic emergencies, for a practicing non oncologist. A little knowledge in this direction can be lifesaving for several patients. I am sure everyone will come across at least few such patients in their life time. And with increasing cancer incidence and patients under aggressive treatment, this is going to be even more likely. Even from medicolegal point of view, it is important that doctors update their knowledge, and certainly not miss an emergency.
You gave us certain examples of oncologic emergencies. And then left us all guessing with one example at the end with questions. Let us see how many of us got this one correct. The questions was as follows:
A 64 year old patient with history of 40 pack year of smoking, otherwise healthy and fit until now. Comes to you with significant generalized weakness, constipation, mild headache off and on, increased urinary frequency, weight loss – over just last 7 days. What tests would you order? What oncologic emergencies are likely?
Ans: This patient has strong risk factor for lung cancer i.e. heavy smoking. He is exhibiting symptoms of HYPERCALCEMIA.
Hypercalcemia is a metabolic emergency. In adults, second most common cause is cancer.
Symptoms in cancer patient can be related to both high calcium and underlying cancer. Most common symptoms are as noted above. With calcium levels above 12, patient develops some or more symptoms. Above 15, is an absolute emergency. Patient may develop coma or cardiac arrest. Most such patients present in severe dehydration, due to polyuria. Severe constipation, headache, weakness are common.
Lung cancer, especially squamous cell carcinoma is most common cancer to develop hypercalcemia at some point in their course. About 10% of such patients develop hypercalcemia. Second most common is probably breast cancer with bone metastases. Other cancers associated with high calcium include kidney, thyroid, myeloma, lymphoma, and others.
Most cancers including lung cancer leads to hypercalcemia, not due to bone destruction, but due to effect of certain proteins released by cancer cells.
Most patients with hypercalcemia are in advance stage, and frequently quoted median survival is about 4.5 months. However this is not true for every cancer type, and with newer treatments, this number is likely better, at least for several cancer patients.
Diagnosis is simple, if you suspect. i.e. send Calcium level (correct for albumin). Also send for other electrolytes e.g. frequently sodium is very abnormal due to dehydration. Some prefer ionized calcium level. Diagnostic tests for suspected cancer can be done along side, starting from a chest x ray up to PET-CT scan. Since cancer diagnosis is obvious from minimal work up in most cases, sending PTH level and other tests are generally not required in most cases of cancer.
Treatment involves correcting calcium using various agents like bisphosphonates, denosumab, steroids, calcitonin, and occasionally dialysis. Choice of agent depends on tumor type, creatinine etc. Correction of dehydration, other electrolyte abnormalities is to be done simultaneously. And medical oncologist or hematologist should be involved as soon as possible, as in some cases, cancer related treatment has to be started very quickly as well.
Que: Thank you. What struck me is the fact that about 10% of lung cancer patients develop hypercalcemia. Plus other cancers. So this is really fairly common. Also the fact that aggressive treatment of associated dehydration is very important. Something a non oncologist can easily initiate if aware. What is the next emergency that we will cover?
Ans: Considering not enough time for other major emergencies, let us briefly discuss second metabolic issue, and potential emergency associated with cancer i.e. Hyponatremia – Low Sodium. Several patients can develop moderate to severe low sodium. This is related to SIADH – syndrome of inappropriate ADH secretion, in most cases. Some patients develop low sodium related to other mechanisms or from treatment side effects.
Can the readers tell us why cancer will lead to SIADH? And what are the most common cancers associated with SIADH?
November 16th 2019. Dr. Chirag A. Shah; M.D. Oncology/Hematology (USA), 079 26754001. Diplomate American Board of Oncology and Hematology. Ahmedabad. firstname.lastname@example.org