Complementary role of 18F-FDG PET/CT for sentinel lymph node algorithm in endometrial cancer with high-risk factors for lymphatic metastasis

Acquired hypophosphatemic osteomalacia: case series from a Peruvian referral center (1999-2023)

BACKGROUND

Acquired hypophosphatemic osteomalacia (AHO) is a rare metabolic bone disorder characterized by hypophosphatemia and impaired bone mineralization. Tumor-induced osteomalacia (TIO) is the most common cause of AHO, caused by phosphaturic tumors that overproduce fibroblast growth factor 23 (FGF-23).

OBJECTIVE

To present the clinical characteristics, diagnostic challenges, and outcomes of seven cases of AHO in Peruvian patients between 1999 and 2023.

METHODS

A retrospective review of seven patients diagnosed with AHO was conducted. Clinical data, including diagnostic procedures, treatments, and outcomes, were collected.

RESULTS

Seven cases of AHO were reviewed. In case one, osteomalacia did not improve despite supraphysiological doses of vitamin D (ergocalciferol/cholecalciferol), and no tumor was detected with available tests, resulting in the patient's death. Cases two and three involved tumors located in the right leg and right hemithorax, respectively, with symptom resolution following total resection. In cases four, five, and seven, exhaustive exams failed to locate tumors. Cases four, six, and seven showed elevated FGF-23 levels, while case five had inappropriately normal FGF-23 levels. Case seven was the first patient in Peru to receive burosumab treatment. In case six, a tumor in the head of the femur was identified, but the patient opted for nonsurgical management.

CONCLUSION

The diagnosis of AHO is challenging, requiring a high index of clinical suspicion and biochemical confirmation. TIO is the most common cause of AHO, emphasizing the importance of locating the phosphaturic tumor. However, in some cases, the tumor remains elusive despite exhaustive diagnostic workups. This is particularly challenging in developing countries like Peru, where resources are limited.

Recent management of endometrial cancer: a narrative review of the literature

Endometrial cancer is a common female gynecological neoplasia and its incidence rate has increased in the past years. Due to its predominant symptoms, most women will present uterine bleeding. It is usually diagnosed at an early stage and surgery has an important role in the treatment plan. The prognosis and quality of life of these patients can be quite favorable, if proper treatment is offered by surgeons. Traditionally, more invasive approaches and procedures were offered to these patients, but recent data suggest that more conservative and minimal invasive choices can be adopted in the treatment algorithm. Minimal invasive surgery, such as laparoscopy and robotic surgery, should be considered as an acceptable alternative, compared to laparotomy with less comorbidities and similar oncological and survival outcomes. Furthermore, sentinel lymph node biopsy has emerged in the surgical staging of endometrial cancer, in order to replace comprehensive lymphadenectomy. It is associated with less intra- and postoperative complications, while preliminary data show no difference in survival rates. However, sentinel lymph node biopsy should be offered within a strict algorithm, to avoid residual metastatic disease. The aim of this review is to analyze all the available data for the application of minimal invasive surgery in early endometrial cancer and especially the role of sentinel lymph node biopsy.

18F-FDG PET/MRI and 18F-FDG PET/CT for the Management of Gynecological Malignancies: A Comprehensive Review of the Literature

OBJECTIVE

Positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro- D-glucose integrated with computed tomography (18F-FDG PET/CT) or magnetic resonance imaging (18F-FDG PET/MRI) has emerged as a promising tool for managing various types of cancer. This review study was conducted to investigate the role of 18F- FDG PET/CT and FDG PET/MRI in the management of gynecological malignancies.

SEARCH STRATEGY

We searched for relevant articles in the three databases PubMed/MEDLINE, Scopus, and Web of Science.

SELECTION CRITERIA

All studies reporting data on the FDG PET/CT and FDG PET MRI in the management of gynecological cancer, performed anywhere in the world and published exclusively in the English language, were included in the present study.

DATA COLLECTION AND ANALYSIS

We used the EndNote software (EndNote X8.1, Thomson Reuters) to list the studies and screen them on the basis of the inclusion criteria. Data, including first author, publication year, sample size, clinical application, imaging type, and main result, were extracted and tabulated in Excel. The sensitivity, specificity, and diagnostic accuracy of the modalities were extracted and summarized.

MAIN RESULTS

After screening 988 records, 166 studies published between 2004 and 2022 were included, covering various methodologies. Studies were divided into the following five categories: the role of FDG PET/CT and FDG-PET/MRI in the management of: (a) endometrial cancer (n = 30); (b) ovarian cancer (n = 60); (c) cervical cancer (n = 50); (d) vulvar and vagina cancers (n = 12); and (e) gynecological cancers (n = 14).

CONCLUSIONS

FDG PET/CT and FDG PET/MRI have demonstrated potential as non-invasive imaging tools for enhancing the management of gynecological malignancies. Nevertheless, certain associated challenges warrant attention.

Usefulness and potential pitfalls of pre-operative PET-CT in patients with endometrial cancer undergoing one- and two-step sentinel lymph node mapping: Do negative findings on PET-CT negativity really indicate node negativity?

OBJECTIVE

We investigated the utility of Positron emission tomography-Computed tomography (PET-CT) in the setting of two different sentinel lymph node (SLN) mapping techniques; the conventional cervical injection method (one-step) and the two-step method, which involves fundal injection followed by cervical injection.

METHODS

Patients with endometrial cancer undergoing FDG PET-CT followed by laparoscopic or robotic surgical staging with SLN mapping at the Yonsei Cancer Center between July 2014 and April 2021 were stratified into the PET-positive group (with suspected or likely lymph nodes metastasis) and PET-negative group. A chart review was performed for the number of harvested SLNs, patterns of SLN metastases, and recurrence.

RESULTS

Among 466 patients undergoing one-step (n = 276) and two-step (n = 190) SLN mapping, LN metastasis was identified in 21 of 434 PET-negative and 18 of 32 PET-positive patients. The sensitivity and specificity of PET-CT for diagnosing lymph node metastasis were 46.2% and 96.7%, respectively. Among PET-positive patients with LN metastasis, anatomical distribution was concordant in 14/18 patients (77.8%). Among PET-negative patients, four (2.3%) had metastatic para-aortic SLNs, including three (1.7%) with isolated para-aortic metastases; metastatic para-aortic SLNs were exclusively found in the two-step group. Among PET-positive patients, para-aortic SLN metastasis was identified in 35.7% of two-step and 16.7% of one-step group. Among the 21 PET false-negative patients, recurrence was seen in four patients (19%) after a median follow-up of 34 months (range: 7-70 months).

CONCLUSIONS

PET-CT served as a useful guide to clinicians with high anatomical concordance rate in patients with LN metastasis. However, despite high specificity, sensitivity was limited. SLN metastasis pattern, especially at the para-aortic level, indicates that the two-step SLN technique might be useful in PET-negative and PET-positive patients.

Diagnostic accuracy of sentinel node biopsy in non-endometrioid, high-grade and/or deep myoinvasive endometrial cancer: A Turkish gynecologic oncology group study (TRSGO-SLN-006)

INTRODUCTION

This study aimed to evaluate the diagnostic accuracy of the sentinel lymph node (SLN) mapping algorithm in high-risk endometrial cancer patients.

METHODS

Two hundred forty-four patients with non-endometrioid histology, grade 3 endometrioid tumors and/or tumors with deep myometrial invasion were enrolled in this retrospective, multicentric study. After removal of SLNs, all patients underwent pelvic ± paraaortic lymphadenectomy. Operations were performed via laparotomy, laparoscopy or robotic surgery. Indocyanine green (ICG) and methylene blue (MB) were used as tracers. SLN detection rate, sensitivity, negative predictive value (NPV) and false-negative rate (FNR) were calculated.

RESULTS

Surgeries were performed via laparotomy in 132 (54.1%) patients and 152 (62.3%) underwent both bilateral pelvic and paraaortic lymphadenectomy. At least 1 SLN was detected in 222 (91%) patients. Fifty-five (22.5%) patients had lymphatic metastasis and 45 patients had at least 1 metastatic SLN. Lymphatic metastases were detected by side-specific lymphadenectomy in 8 patients and 2 patients had isolated paraaortic metastasis. Overall sensitivity, NPV and FNR of SLN biopsy were 81.8%, 95% and 18.2%, respectively. By applying SLN algorithm steps, sensitivity and NPV improved to 96.4% and 98.9%, respectively. For grade 3 tumors, sensitivity, NPV and FNR of the SLN algorithm were 97.1%, 98.9% and 2.9%.

CONCLUSION

SLN algorithm had high diagnostic accuracy in high-risk endometrial cancer. All pelvic metastases were detected by the SLN algorithm and the isolated paraaortic metastasis rate was ignorable. But long-term survival studies are necessary before this approach becomes standard of care.

Sentinel Lymph Node Mapping in Endometrial Cancer: A Comprehensive Review

Endometrial cancer (EC) is known as a common gynecological malignancy. The incidence rate is on the increase annually. Lymph node status plays a crucial role in evaluating the prognosis and selecting adjuvant therapy. Currently, the patients with high-risk (not comply with any of the following: (1) well-differentiated or moderately differentiated, pathological grade G1 or G2; (2) myometrial invasion< 1/2; (3) tumor diameter < 2 cm are commonly recommended for a systematic lymphadenectomy (LAD). However, conventional LAD shows high complication incidence and uncertain survival benefits. Sentinel lymph node (SLN) refers to the first lymph node that is passed by the lymphatic metastasis of the primary malignant tumor through the regional lymphatic drainage pathway and can indicate the involvement of lymph nodes across the drainage area. Mounting evidence has demonstrated a high detection rate (DR), sensitivity, and negative predictive value (NPV) in patients with early-stage lower risk EC using sentinel lymph node mapping (SLNM) with pathologic ultra-staging. Meanwhile, SLNM did not compromise the patient’s progression-free survival (PFS) and overall survival (OS) with low operative complications. However, the application of SLNM in early-stage high-risk EC patients remains controversial. As revealed by the recent studies, SLNM may also be feasible, effective, and safe in high-risk patients. This review aims at making a systematic description of the progress made in the application of SLNM in the treatment of EC and the relevant controversies, including the application of SLNM in high-risk patients.

Initial experience with positron emission tomography/computed tomography in addition to computed tomography and magnetic resonance imaging in preoperative risk assessment of endometrial cancer patients

OBJECTIVE

Improved preoperative evaluation of lymph node status could potentially replace lymphadenectomy in women with endometrial cancer. PET/CT was routinely implemented in the preoperative workup of endometrial cancer at St Olav's University Hospital in 2016. Experience with PET/CT is limited, and there is no consensus about the use of PET/CT in the diagnostic workup of endometrial cancer. The aim of the study was to evaluate the diagnostic accuracy of PET/CT compared to standard CT/MRI in identifying lymph node metastases in endometrial cancer with histologically confirmed lymph node metastases as the standard of reference. We especially wanted to look at PET/CT as a supplement to the sentinel lymph node algorithm in the detection of paraaortic lymph nodes.

STUDY DESIGN

A retrospective study included all women undergoing surgery for endometrial cancer from January 2016 through July 2019 at St Olav's University Hospital. Clinical data, results of CT, MRI, and PET/CT, and histopathological results were analyzed.

RESULTS

Among 185 patients included, 27 patients (15 %) had lymph node metastases. 17 (63 %) had pelvic lymph node metastases, one (4 %) had isolated paraaortic lymph node metastases, and 9 (33 %) had lymph node metastases in both the pelvis and the paraaortic region. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of PET/CT for the detection of lymph node metastases were 63 %, 98 %, 85 %, 94 %, and 93 %, respectively. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of CT/MRI were 41 %, 98 %, 73 %, 91 %, and 90 %, respectively (p = 0.07). For the 26 pelvic lymph node metastases, PET/CT had a sensitivity of 58 %, compared to 42 % for CT/MRI (p = 0.22). PET/CT detected all 10 paraaortic lymph node metastases, for a sensitivity of 100 %, compared to 50 % for CT/MRI (p = 0.06).

CONCLUSIONS

PET is superior to CT/MRI for detection of lymph node metastases in endometrial cancer, particularly in detecting paraaortic lymph node metastases. The ability of preoperative PET to exclude paraaortic lymph node metastases may strengthen the credibility of the sentinel lymph node algorithm.