Tumor lysis syndrome after chemotherapy for metastatic colic carcinoma: About two adult cases

Tumor Lysis Syndrome (TLS) is a major oncological emergency involving metabolic perturbations. It occurs when tumor cells release their contents into the bloodstream, either spontaneously or in response to therapy. TLS is characterized by hyperuricemia, hyperkalemia, hyperphosphatemia and hypocalcemia following massive lysis of malignant cells. Although this syndrome is well described, it is rarely seen or suspected in solid malignancies. The frequency and severity of TLS is partly dependent upon the biology of the disease and type of therapy administered. We report in this work two cases of tumor lysis syndrome occurring after chemotherapy for endocrine colon carcinoma with small metastatic cells. Case Report Tumor lysis syndrome after chemotherapy for metastatic colic carcinoma: About two adult cases Abaza H1*, Sallami S2, Ben Chaabene A1 and Gara S1 1Clinical Biology Department, Institute Salah Azaïz, Tunis, Tunisia 2Surgery Department, Nabeul Hospital, Nabeul, Tunisia Received: 02 April, 2020 Accepted: 18 April, 2020 Published: 20 April, 2020 *Corresponding author: Abaza H, Clinical Biology Department, Institute Salah Azaïz, Tunis, Tunisia, E-mail:


Introduction
Tumor lysis syndrome is an oncological emergency with potentially serious consequence [1,2]. It results from massive tumor cell lysis, sometimes spontaneous but most often secondary to local or systemic treatment of cancerous lesions [2,3].

Observation 1
A 46-year old female who was in a normal state of health until fi ve months prior to this admission was diagnosed as having colonic cancer following initial work-up for upper right abdominal pain. She had no family history of cancer. She underwent left colectomy The three-layer immunoperoxidase histological analysis on dewaxed sections confi rmed an endocrine tumor with poorly differentiated small cells with positive cytoplasmic labeling for antichromogranin and for antisynaptophysin.
After the fi rst chemotherapy session (and despite hyperhydratation), the patient presented signifi cant localized pain in the right hypochondrium, tachypnea and tachycardia but without digestive intolerance. Biological tests revealed showed severe acidosis acute renal failure, hyperuricemia,

Observation 2
A 52-year-old women, with no signifi cant medical history, was diagnosed with a well differentiated adenocarcinoma of the left colic angle, metastasized to the liver and spleen. Multidisciplinary Concertation Meeting decided surgical ablation of the tumor and chemotherapy for metastasis She underwent a left colectomy followed by 3 monthly FOLFOXbased chemotherapy courses. One week after the third session, biological tests showed a serum elevation of uric acid to 500 μmol/l and of LDH to 600 IU/l. Despite alkaline hyperhydration, the evolution was marked by the progressive deterioration of the general state.

Discussion
Tumor lysis syndrome results from the massive destruction of neoplastic cells, most often following a chemotherapy or radiation therapy [1, 4,5]. More rarely, it can occur spontaneously or following hormone therapy, immunotherapy or corticosteroid therapy [3][4][5]. This syndrome most often associates hyperuricemia hyperkalemia, hyperphosphatemia, hypocalcemia and renal failure [1]. It occurs more frequently after aggressive treatment of rapidly developing tumors such as high grade malignant lymphomas or acute leukemias [5][6][7]. In recent years, there have been a few case reports about TLS developing in patients with colic carcinoma. Kidney failure can occur mainly due to precipitation of phosphocalcic crystals or acid uric. The released calcium will bind to the phosphates, leading on the one hand to the precipitation of crystals phosphocalcic and on the other hand to paradoxal hypocalcemia. If calcium phosphate precipitates in the cardiac conducting system, serious dysrytmias can occur [6].
The low prevalence of this syndrome in the case of solid tumors is mainly explained by their low proliferative index and their relatively slow response to specifi c treatments [6][7][8]. Most cases of solid tumors complicated by lysis syndrome are of endocrine origin with small cells, especially of bronchial localization [3,4,9]. Other histological types have also been described, such as choriocarcinoma or leimyosarcoma [3]. The fi rst lysis syndrome described in the literature for endocrine small cell colonic tumors was reported in 1988 [8].
We fi nd similarities between our observations and those in the literature, especially massive liver metastases and a high level of LDH before chemotherapy. Such fi ndings were considered by several authors as predisposing factors for lysis syndrome in this type of tumors. Clinical and biological anomalies associated with lysis syndrome are generally reversible when they are early diagnosed and correctly treated.
However, they can be complicated by severe hyperkalemia, cardiac arrhythmias and even sudden death [2,5,6]. In a series of 25 cases of solid tumors complicated by tumor lysis syndrome, nine deaths have been reported [4]. Due to rarity of lysis syndrome in solid tumors, systematic preventive measures (in particular alkaline hyperhydration and administration of allopurinol) are not justifi ed. However, due to the morbidity and mortality associated with it, it is recommended to carry out these measures as well as rigorous clinical and biological monitoring, especially in case of large mass tumors and high LDH levels, before and during all the specific treatments [7].
Quick identifi cation of TLS is critical as treatment involves early aggressive hydration to increase renal perfusion and urine output and therefore decrease the risk of crystal precipitation, and correction of electrolyte abnormalities1 [10].

Conclusion
The development of TLS in solid tumors is associated with increased mortality and therefore, a high index of suspicion is essential for early diagnosis and treatment initiation. TLS is only rarely associated with treatment of solid tumors.
Precautions should be taken to avoid this potentially fatal complication.