Stage-Specific Risk of Recurrence and Death From Melanoma in Denmark, 2008-2021: A National Observational Cohort Study of 25 720 Patients With Stage IA to IV Melanoma

Importance

To ensure optimal treatment and surveillance of patients with melanoma, knowledge of the clinical stage-specific risk of recurrence, mortality, and recurrence patterns across the American Joint Committee on Cancer Eighth Edition (AJCC8) substages is needed.

Objective

To estimate stage-specific recurrence and melanoma-specific mortality rates, assess absolute stage-specific risks of recurrence and mortality, and describe stage-specific recurrence patterns, including conditional rates.

Design

Retrospective cohort study of prospectively collected nationwide population-based registry data.

Setting

Nationwide, population-based cohort study.

Participants

The 25 720 Danish patients, 18 years or older, diagnosed with first-time stage IA to IV cutaneous melanoma between January 1, 2008, and December 31, 2019, were included and followed up from time of primary treatment until December 31, 2021.

Exposures

First diagnosis of stage IA to IV cutaneous melanoma.

Main Outcomes

Stage-specific cumulative incidence of recurrence and melanoma-specific mortality, melanoma-specific recurrence-free survival, and assessed absolute stage-specific risks of recurrence and melanoma-specific mortality. Secondary outcomes were stage-specific recurrence patterns, including conditional rates, and melanoma-specific survival.

Results

We followed up 25 720 patients for a median of 5.9 years (95% CI, 58.9-59.3 years). Mean age was 59.1 years (95% CI, 58.9-59.3 years). Patients with stage IIB to IIC melanoma were older, had more comorbidities at diagnosis, and had the lowest rate of pathologic staging by sentinel node biopsy (81.6%-87.4%). A total of 10.6% of patients developed recurrence; first recurrence included distant recurrence, alone or with synchronous locoregional recurrence, in 56.6% of patients. We found a comparable risk of recurrence in stages IIIA and IIB (29.7% vs 33.2%) and in stages IIIB and IIC (35.9% vs 36.8%), respectively. Melanoma-specific mortality was comparable between stages IIIA and IIA (13.0% vs 13.6%) and between stages IIIB and IIB (18.4% vs 22.0%), respectively. These risk patterns persisted in cause-specific hazards models.

Conclusions and Relevance

This nationwide, population-based cohort study found that the increasing stages of the current AJCC8 staging system do not accurately reflect an increasing risk of recurrence and mortality in melanoma. The high proportion of distant recurrences suggests that hematogenous spread is a more common metastatic pathway than previously assumed, and surveillance with routine functional/cross-sectional imaging should be considered for stages IIB to IV. Future efforts should be put toward developing new tools for risk stratification and determining the survival effect of routine imaging in surveillance.

Prognostic Significance and Management of Sentinel Nodes in the Triangular Intermuscular Space of Patients with Melanoma

BACKGROUND

The clinical significance of sentinel nodes (SNs) in the triangular intermuscular space (TIS) of patients with melanoma is poorly understood. This study aimed to determine their incidence and positivity rate, and to report their management and patient outcomes.

METHODS

This was a single-institution retrospective cohort study of patients with unilateral or bilateral TIS SNs on lymphoscintigraphy treated between 1992 and 2017. Recurrence-free survival was analyzed.

RESULTS

Lymphoscintigraphy identified TIS SNs in 266 patients. They were bilateral in 17 patients. Of the 2296 patients with a melanoma on the upper back, 259 (11%) had TIS SNs. Procurement of SNs was not attempted in 122 (43%) of the 283 cases and failed in 11 cases (7%). An SN was successfully retrieved from the TIS in 145 patients (53%) and contained metastasis in 18 of 150 TIS SNs. This was the only positive SN in 12 patients (8%), upstaging all of them. Of the 18 patients with a positive SN in the TIS, 9 (50%) underwent completion axillary lymph node dissection, but no additional involved nodes were found in any of these patients. Recurrence in the TIS was observed in six patients (5%), none of whom had their TIS SN surgically pursued previously.

CONCLUSIONS

Lymphoscintigraphy showed TIS SNs in 11% of patients with melanomas on their upper back. In such cases, retrieval of TIS SNs is required for accurate staging and to minimize the risk of TIS recurrence.

Thin or early melanoma, risk factors and associated mortality

INTRODUCTION

The incidence of thin and early-stage melanoma is increasing in many populations, but the clinical significance of these lesions remains partly unknown.

METHODS

Firstly, melanoma deaths in Denmark (2009-2018) were followed back to establish melanoma debut in these persons. Secondly, using national registries of cancer incidence and mortality, 27,036 persons with thin or early-stage melanoma were followed-up for melanoma death.

RESULTS

It is estimated that in 11% of the persons who died from melanoma, the debut was a thin or early-stage melanoma. On follow-up of persons with thin or early-stage melanoma, the 20-year risk of dying from melanoma was 3%.

CONCLUSION

The absolute risk of melanoma death after a diagnosis with thin or early-stage melanoma is low. A subgroup of patients who are at a high risk may possibly be identified by a combination of stage, thickness, ulceration and dermal mitoses.

FUNDING

none.

TRIAL REGISTRATION

not relevant.

Association Between Melanoma Detected During Routine Skin Checks and Mortality

Importance

Early melanoma diagnosis is associated with better health outcomes, but there is insufficient evidence that screening, such as having routine skin checks, reduces mortality.

Objective

To assess melanoma-specific and all-cause mortality associated with melanomas detected through routine skin checks, incidentally or patient detected. A secondary aim was to examine patient, sociodemographic, and clinicopathologic factors associated with different modes of melanoma detection.

Design, Setting, and Participants

This prospective, population-based, cohort study included patients in New South Wales, Australia, who were diagnosed with melanoma over 1 year from October 23, 2006, to October 22, 2007, in the Melanoma Patterns of Care Study and followed up until 2018 (mean [SD] length of follow-up, 11.9 [0.3] years) by using linked mortality and cancer registry data. All patients who had invasive melanomas recorded at the cancer registry were eligible for the study, but the number of in situ melanomas was capped. The treating doctors recorded details of melanoma detection and patient and clinical characteristics in a baseline questionnaire. Histopathologic variables were obtained from pathology reports. Of 3932 recorded melanomas, data were available and analyzed for 2452 (62%; 1 per patient) with primary in situ (n = 291) or invasive (n = 2161) cutaneous melanoma. Data were analyzed from March 2020 to January 2021.

Main Outcomes and Measures

Melanoma-specific mortality and all-cause mortality.

Results

A total of 2452 patients were included in the analyses. The median age at diagnosis was 65 years (range, 16-98 years), and 1502 patients (61%) were men. A total of 858 patients (35%) had their melanoma detected during a routine skin check, 1148 (47%) self-detected their melanoma, 293 (12%) had their melanoma discovered incidentally when checking another skin lesion, and 153 (6%) reported "other" presentation. Routine skin-check detection of invasive melanomas was associated with 59% lower melanoma-specific mortality (subhazard ratio, 0.41; 95% CI, 0.28-0.60; P < .001) and 36% lower all-cause mortality (hazard ratio, 0.64; 95% CI, 0.54-0.76; P < .001), adjusted for age and sex, compared with patient-detected melanomas. After adjusting for prognostic factors including ulceration and mitotic rate, the associations were 0.68 (95% CI, 0.44-1.03; P = .13), and 0.75 (95% CI, 0.63-0.90; P = .006), respectively. Factors associated with higher odds of routine skin-check melanoma detection included being male (female vs male, odds ratio [OR], 0.73; 95% CI, 0.60-0.89; P = .003), having previous melanoma (vs none, OR, 2.36; 95% CI, 1.77-3.15; P < .001), having many moles (vs not, OR, 1.39; 95% CI, 1.10-1.77; P = .02), being 50 years or older (eg, 50-59 years vs <40 years, OR, 2.89; 95% CI, 1.92-4.34; P < .001), and living in nonremote areas (eg, remote or very remote vs major cities, OR, 0.23; 95% CI, 0.05-1.04; P = .003).

Conclusions and Relevance

In this cohort study, melanomas diagnosed through routine skin checks were associated with significantly lower all-cause mortality, but not melanoma-specific mortality, after adjustment for patient, sociodemographic, and clinicopathologic factors.

More sentinel lymph node biopsies for thin melanomas after transition to AJCC 8th edition do not increase positivity rate: A Danish population-based study of 7148 patients

BACKGROUND

We evaluated the outcome of sentinel lymph node biopsies (SLNB) in patients with thin melanoma before and after the implementation of AJCC 8th edition (AJCC8) and identified predictors of positive sentinel lymph nodes (+SLN).

METHODS

Patients diagnosed with T1 melanomas (Breslow thickness ≤1 mm) during 2016-2017 as per AJCC 7th edition (AJCC7) (n = 3414) and 2018-2019 as per AJCC8 (n = 3734) were identified in the Danish Melanoma Database.

RESULTS

More SLNBs were performed in the AJCC8 cohort compared to the AJCC7 (22.2% vs. 16.2%, p < 0.001), with no significant difference in +SLN rates (4.7% vs. 6.7%, p = 0.118). In the AJCC7 + SLN subgroup, no melanomas were ulcerated, 94.6% had mitotic rate (MR) ≥ 1, 67.6% were ≥0.8 mm and 32.4% would be T1a according to AJCC8. In the AJCC8 + SLN subgroup, 10.3% were ulcerated, 74.4% had MR≥ 1, 97.4% were ≥0.8 mm and 23.1% would be T1a according to AJCC7. On multivariable analysis younger age and MR ≥ 1 were significant predictors of +SLN.

CONCLUSION

More SLNBs were performed in T1 melanomas after transition to AJCC8 without an increase in +SLN rate. None of the AJCC8 T1b criteria were significant predictors of +SLN. We suggest that mitosis and younger age should be considered as indications for SLNB in thin melanoma.

[Merkel cell carcinoma]

Merkel cell carcinoma is a neuroendocrine skin carcinoma caused by the Merkel cell virus and ultraviolet radiation. Approximately 25 Danish patients are diagnosed each year. Merkel cell carcinoma is often located on the sun-exposed areas of the skin and definitive diagnosis is made by the pathologist. Patients are treated at the department of plastic surgery and oncology with treatment modalities including surgery, radiotherapy, immunotherapy and chemotherapy as summarised in this review.

Genetic predisposition to long telomeres is associated with increased mortality after melanoma: A study of 2101 melanoma patients from hospital clinics and the general population

Whether there is an association between measured and genetically predicted telomere length and melanoma mortality is unclear. We tested the hypothesis that measured and genetically predicted telomere length is associated with mortality after a melanoma diagnosis. We followed 2,101 patients with melanoma from hospital clinics and the general population for risk of death for up to 26 years. All had telomere length measured in DNA from leukocytes, and 2052 of these were genotyped for the three single nucleotide polymorphisms rs7726159 (TERT), rs1317082 (TERC), and rs2487999 (OBFC1); all three genotypes are associated with telomere length and combined into an allele count from 0 to 6. For each telomere-lengthening allele, the hazard ratios (HRs) for mortality in the age-adjusted and multivariable-adjusted Cox analysis were 1.12 (95% confidence interval: 1.02-1.23) and 1.11 (1.01-1.23). However, for each standard deviation increase in measured telomere length, HR for mortality was 0.97 (0.88-1.08). In conclusion, in more than 2000 melanoma patients from hospital clinics and from the general population, genetically predicted long telomeres were associated with increased mortality, but measured leukocyte telomere length was not.

The worse survival outcomes reported for melanoma patients having sentinel node biopsy after lymphoscintigraphy the previous day do not appear to be due to overnight migration of Tc99m-nanocolloid tracer

INTRODUCTION

It has been reported that the survival of patients having sentinel node (SN) biopsy for melanoma the day after lymphoscintigraphy using Tc99m-nanocolloid is worse than that of patients having lymphoscintigraphy and SN biopsy on the same day [1,2]. A possible explanation suggested is that overnight migration of the tracer from SNs to 2nd-tier nodes occurs, causing failure to remove true SNs.

MATERIALS AND METHODS

The possibility of overnight tracer migration leading to errors in SN-identification was investigated in 12 patients scheduled for lymphoscintigraphy the day before surgery by repeating SPECT-CT imaging the next morning, before their SN biopsy. The aim was to check whether onward migration of colloid from previously-identified SNs had occurred.

RESULTS

No significant migration of Tc99m-nanocolloid occurred overnight in any patient. All nodes reported to be SNs on day 1 imaging were also present and regarded as SNs on day 2 images. No new foci were visualised on day 2, but some that had been identified on day 1 were not seen on day 2.

CONCLUSIONS

Since migration of nanocolloid overnight did not occur, this cannot explain the reported survival disadvantage for patients undergoing SN biopsy the day after lymphoscintigraphy. A likely alternative possibility is that inadequate doses of radioisotope were used for next-day procedures, causing the mistaken removal of 2nd-tier nodes instead of true SNs more frequently. Further research is required to explain the reported reduction in survival of patients having next-day SN biopsy procedures, since the possibility has important clinical implications.

Reliable test of clinicians' mastery in skin cancer diagnostics

Differentiating between benign and malignant skin lesions can be very difficult and should only be done by sufficiently trained and skilled clinicians. To our knowledge there are no validated tests for reliable assessments of clinicians' ability to perform skin cancer diagnostics. To develop and gather validity evidence for a test in skin cancer diagnostics, a multiple-choice questionnaire (MCQ) was developed based on informal interviews with seven content experts from five skin cancer centers in Denmark. Validity evidence for the test was gathered from May until July 2019 using Messick's validity framework (content, response process, internal structure, relationship to other variables and consequences). Item content was revised through a Delphi-like review process and then piloted on 36 medical students and 136 doctors using a standardized response process. Results enabled an analysis of the internal structure and relationship to other variables of the test. Finally, the contrasting groups method was used to investigate the test's consequences (pass-fail standard). The initial 90-item MCQ was reduced to 40 items during the Delphi-like review process. Item analysis revealed that 25 of the 40 selected items were level I-III quality items with a high internal consistency (Cronbach's α = 0.83) and highly significant (P ≤ 0.0001) differences in test scores between participants with different occupations or levels of experience. A pass-fail standard of 12 (48%) correct answers was established using the contrasting groups' method. The skin cancer diagnostics MCQ developed in this study can be used for reliable assessments of clinicians' competencies.

Measured and genetically predicted plasma YKL-40 levels and melanoma mortality

PURPOSE

High plasma levels of YKL-40 might be associated with mortality in patients with melanoma, and it is unknown if YKL-40 is causally related to mortality.

EXPERIMENTAL DESIGN

We studied two cohorts: 2618 patients with melanoma from hospital clinics and 1413 general population patients with melanoma, totalling 4031 patients followed up for mortality end-points for up to 20 years. All were genotyped for CHI3L1 rs4950928, highly predictive of lifelong plasma YKL-40, and plasma YKL-40 levels were measured in 2165 patients. We tested the hypotheses that measured and genetically predicted high plasma YKL-40 are associated with increased mortality in patients with melanoma.

RESULTS

For the hospital melanoma cohort, age- and sex-adjusted hazard ratios for death in individuals with measured plasma YKL-40 in the 96-100th percentile versus 1-95th percentile and per 10-percentile increase were 1.52 (95% confidence interval, 1.07-2.16) and 1.07 (1.02-1.11), respectively, most pronounced for patients with localised melanomas. Each C-allele of the CHI3L1 rs4950928 genotype was associated with plasma YKL-40 level increases of 32% in the hospital melanoma cohort (p = 6 × 10^-48) and 43% in the general population melanoma cohort (p = 7 × 10^-13). Multifactorially adjusted ratios for these increases in the combined cohorts were 1.04 (1.00-1.09) observationally for measured plasma YKL-40 and 0.98 (0.86-1.12) for the genetically predicted plasma YKL-40.

CONCLUSION

Measured, but not genetically predicted, increasing plasma YKL-40 was associated with increased mortality in patients with melanoma. Plasma YKL-40 is a marker but less likely to be a cause of increased mortality in patients with melanoma.

Diverse presentations of acral melanoma

BACKGROUND

Acral melanoma (AM) is an uncommon melanoma subtype occurring on the palms, soles and nail apparatus. It often lacks the typical features of primary melanoma resulting in delayed diagnosis.

OBJECTIVE

This article aims to raise awareness of AM and promote a high index of clinical suspicion to enable early diagnosis and improve outcomes for patients with AM.

DISCUSSION

The diagnosis of AM is often delayed because its presentation mimics other benign conditions such as fungal infections and ulcers. When lesions that were thought to be benign fail to respond to appropriate therapies, biopsy is critically important to exclude AM or other malignant pathology. Clinician awareness of the diversity of AM presentations, maintaining AM as part of their differential diagnosis and facilitating early biopsy are essential for early diagnosis and improving outcomes in patients with AM.

Tumour response after hyperthermic isolated limb perfusion for locally advanced melanoma

INTRODUCTION

The aim was to describe tumour response, complications, recurrence and survival after hyperthermic isolated limb perfusion (ILP) with melphalan or melphalan in combination with tumour necrosis factor-alpha in patients with melanoma metastases confined to an extremity.

MATERIAL AND METHODS

A total of 84 perfusions were performed (53 women, 31 men, median age 63 years) from 1993 to 2010. 95% of the perfusions were administered to the lower limbs and 5% to the upper limbs. The inclusion criteria were recurrent and/or clinically apparent cutaneous/subcutaneous extremity in-transit melanoma metastases.

RESULTS

The response rate after ILP was 85%; 42% had complete response (CR), 43% partial response (PR), 12% no change (NC) and 3% progression. Two- and five-year survival rates were 57% and 31%, respectively, and they were higher for patients with than without lymph node metastases. Time from ILP to recurrence was a median of seven months (range 1-37 months) for patients with CR or PR. Survival was longer for patients with CR or PR than for patients showing NC or progression. Several patients had mild or moderate local toxicity reactions, two patients developed severe local toxicity.

CONCLUSION

ILP induces tumour regression in the vast majority of patients. One patient, i.e. 1% of the group, died from surgical complications. Otherwise, ILP treatment had an acceptable morbidity in this group of very sick patients. We are convinced that the treatment should be offered to improve local disease control in patients with multiple and/or recurrent melanoma confined to an extremity if surgical excision is not possible.

FUNDING

not relevant.

TRIAL REGISTRATION

not relevant.

The diagnostic value of adding dynamic scintigraphy to standard delayed planar imaging for sentinel node identification in melanoma patients

PURPOSE

The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients.

METHODS

Three hundred and seven consecutive melanoma patients referred for SN biopsy (SNB) were examined using combined imaging. Secondary interpretation of only the delayed static images was subsequently performed. In 220 patients (72%), complete surgical and pathological information relating to the SNB was available. The number of SNs identified and number of patients with positive SNs were compared between the two interpretations of the imaging studies and, when available, related to pathology data.

RESULTS

A slightly higher number of SNs (mean 0.12/patient) was identified when interpreting only delayed static images compared to combined imaging. In a direct patient-to-patient comparison, the number of SN(s) identified on the combined vs static images only showed moderate agreement (kappa value 0.56). In 38 patients (17%), positive SNs were identified by the combined procedure compared to 35 (16%) by static imaging only. Thus by static imaging only, tumour-positive SNs were not identified in 3 of 38 patients (8%).

CONCLUSION

For SN identification in melanoma patients, dynamic imaging combined with delayed static imaging and SPECT/CT is superior to delayed static imaging only because the latter is more likely to fail to identify SNs containing metastases.

Axillary sentinel node identification in breast cancer patients: degree of radioactivity present at biopsy is critical

BACKGROUND

The radioactivity present in the patient (Act(rem) ) at sentinel node (SN) biopsy will depend on injected activity amount as well as on the time interval from tracer injection to biopsy, which both show great variations in the literature. The purpose of this study was to analyse the influence of varying Act(rem) levels on the outcome of axillary SN biopsy in patients with breast cancer (BC).

MATERIAL AND METHODS

Eight hundred and fifty-eight patients with BC were consecutively referred to SN biopsy, 21% for a same-day and 79% of the patients for a 2-day procedure. Four hundred and nineteen patients underwent scintigraphy and 439 did not. For same-day procedures, 50 MBq (99m) Tc-nanocolloid (Nanocoll(®) ) was injected, and for 2-day procedures 110 MBq. For the analysis of SN biopsy outcome, the patients were divided into three Act(rem) groups: <10 (56% of the patients), 10-20 (23%), and >20 MBq (21%). During surgery, SNs were located using a hand-held gamma probe supported by image information when available and blue dye injection. Pathology included haematoxylin-eosin staining followed by immunohistochemistry.

RESULTS

The number of SNs removed (mean value 1·87 versus 2·14, P = 0·0003) and the probability of finding a malignant SN (P = 0·034) were lower in the <10 MBq group of patients compared with higher Act(rem) >20 MBq. Of the 25 patients with SN non-detection, 20 patients had an Act(rem) <10 MBq. Imaging had no significant influence on the number of patients with a malignant SN (P = 0·48).

CONCLUSION

Act(rem) above 10 MBq for nanocolloid tracer appears important for appropriate identification of SNs in patients with BC.

EANM-EORTC general recommendations for sentinel node diagnostics in melanoma

The accurate diagnosis of a sentinel node in melanoma includes a sequence of procedures from different medical specialities (nuclear medicine, surgery, oncology, and pathology). The items covered are presented in 11 sections and a reference list: (1) definition of a sentinel node, (2) clinical indications, (3) radiopharmaceuticals and activity injected, (4) dosimetry, (5) injection technique, (6) image acquisition and interpretation, (7) report and display, (8) use of dye, (9) gamma probe detection, (10) surgical techniques in sentinel node biopsy, and (11) pathological evaluation of melanoma-draining sentinel lymph nodes. If specific recommendations given cannot be based on evidence from original, scientific studies, referral is given to "general consensus" and similar expressions. The recommendations are designed to assist in the practice of referral to, performance, interpretation and reporting of all steps of the sentinel node procedure in the hope of setting state-of-the-art standards for good-quality evaluation of possible spread to the lymphatic system in intermediate-to-high risk melanoma without clinical signs of dissemination.

Radiation exposure to surgical staff during F-18-FDG-guided cancer surgery

PURPOSE

High-energy gamma probes have recently become commercially available, developed for (18)F-FDG probe-guided surgery. The radiation received by the staff in the operating room might limit the use of it, but has never been determined. We therefore wanted to measure the absorbed staff doses at operations where patients had received a preoperative injection of (18)F-FDG.

METHODS

Thirty-four patients with different cancers (breast cancer, melanoma, gastrointestinal cancers, respectively) were operated. At every operation the surgeon was monitored with a TLD tablet on his finger of the operating hand and a TLD tablet on the abdomen. The surgeon and anaesthesiologist were also monitored using electronic dosimeters placed in the trousers lining at 25 operations.

RESULTS

The dose rate to the surgeon's abdominal wall varied between 7.5-13.2 microSv/h, depending on tumour location. The doses to the anaesthesiologists and the finger doses to the surgeon were much lower. About 350-400 MBq, i.e. ca. eight times higher activities than those used in the present study are supposed to be necessary for guiding surgery. It can be calculated from the body doses measured that a surgeon can perform between 150-260 h of surgery without exceeding permissible limits for professional workers.

CONCLUSIONS

The radiation load to the operating staff will generally be so small that it does not present any limitation for FDG-guided surgery. However, it is recommended to monitor the surgical staff considering that the surgeon may be exposed to other radiation sources, and since the staff often includes women of child-bearing age.

Radiation doses to staff involved in sentinel node operations for breast cancer

BACKGROUND

The use of radioactive compounds for sentinel node biopsy is now a generally accepted part of the surgical treatment of breast cancer and melanoma, with the risk of radiation exposure to the operating team. The aim of this investigation was to study the levels of this exposure in relation to the permissible radiation dose limits.

METHODS

The radiation exposure to the hands and bodies of the operating surgeons (the 'risk persons') was measured by thermoluminescent dosimeters in 79 operations and to the pathologists handling the specimens in 17 cases. Radioactivity and dose rate measurement from tumours and breast specimens were also performed.

RESULTS

During an operation the mean skin dose (+/-SD) to the thermoluminescent dosimeters placed at the hand and the abdominal wall were 0.04 +/- 0.04 mSv (79 operations) and 0.01 +/- 0.02 mSv (67 operations) respectively. For the pathologist, the mean hand dose per operation was below the detection limit (17 operations). Correlation between the measured dose rate and the radioactive content of the tumours was 0.998.

CONCLUSIONS

The radiation exposure to the staff involved in sentinel node (SN) biopsy for breast cancer using radioactive labelled tracers will be considerably below the permissible limits, even with high numbers of SN biopsy procedures. Pregnant staff members should participate in <100 SN operations.

Factors of importance for scintigraphic non-visualisation of sentinel nodes in breast cancer

PURPOSE

The aim of this study was to analyse different factors of possible significance for non-visualisation of sentinel nodes (SNs) by preoperative lymphoscintigraphy, in order to enable improvement of the success rate of SN visualisation through modification or alteration of some of the factors.

METHODS

Between March 1998 and January 2003 we analysed a series of 442 women with unilateral stage T1 and clinical N0 breast cancer. Lymphoscintigraphy was performed after periareolar or peritumoural injection of 99mTc-albumin nanocolloid, with image acquisition after 2-6 h or 18-24 h. Until January 2001, all patients received around 20 MBq tracer, irrespective of time to operation. From January 2001, patients injected on the day before surgery received at least 100 MBq while patients injected on the day of surgery received around 50 MBq.

RESULTS

An SN was visualised in 87% of the patients, and at surgery the SN was detected with the hand-held gamma probe in 42% of the remaining patients. By multiple logistic regression analysis, statistically significant independent variables that increased the risk for non-visualisation were increasing age (p=0.0007), increasing body weight (p=0.0189) and peritumoural injection (p<0.0001). Significant interaction was found for imaging time and injected activity (p=0.0017).

CONCLUSION

This study conclusively shows that the risk of unsuccessful SN imaging increases with age and body weight. Our findings suggest that the scintigraphic success rate may be improved by periareolar (rather than peritumoural) injection. Early and late imaging procedures are equally efficient, but if a late imaging procedure is used, activity (adjusted for physical decay) in the patient on day 2 should be more than 10 MBq.