Inguinal sentinel lymph node biopsy for staging anal cancer

Dosimetric quantification of the incidental irradiation of the 'true' (deep) ano-inguinal lymphatic drainage of anal cancer patients not described in conventional contouring guidelines

INTRODUCTION

The ano-inguinal lymphatic drainage (AILD) is located in the subcutaneous adipose tissue of the proximal medial thigh. Findings from fluorescence methods give us new information about anatomical conditions of the AILD. Current contouring guidelines do not advise the inclusion of the 'true' AILD into the clinical target volume (CTV). Aim of this work was the retrospective analysis of the incidental dose to the AILD in an anal cancer (AC) patient cohort who underwent definitive chemoradiation (CRT) therapy with Volumetric Arc Therapy - Intensity Modulated Radiation Therapy (VMAT-IMRT).

METHODS

VMAT-IMRT plans of 15 AC patients were analyzed. Based on findings from new fluorescence methods we created a new volume, the expected AILD. The examined dosimetric parameters were the minimal, maximal and mean dose and V10-V50 that were delivered to the AILD, respectively.

RESULTS

The median volume of AILD was 1047 cm³. Mean D_min, D_max and D_mean were 7.5 Gy, 58.9 Gy and 40.8 Gy for AILD. The clinical relevant dose of 30.0 Gray covered in mean 76% of the volume of the AILD, respectively.

CONCLUSIONS

Only 76% of the AILD-volume received at least an expected required treatment dose of 30 Gy incidentally. Concerning the low number of loco-regional relapses in AC patients after definitive CRT one has to balance increased side effects against a rigid oncological-anatomical interpretation of the local lymphatic drainage by including the AILD into the standard CTV.

Nodal stage migration and prognosis in anal cancer: a systematic review, meta-regression, and simulation study

BACKGROUND

In patients with squamous cell carcinoma of the anus (SCCA), lymph node positivity (LNP) indicates poor prognosis for survival and is central to radiotherapy planning. Over the past three decades, LNP proportion has increased, mainly reflecting enhanced detection with newer imaging modalities; a process known as nodal stage migration. If accompanied by constant T stage distributions, prognosis for both lymph node-positive and lymph node-negative groups may improve without any increase in overall survival for individual patients; a paradox termed the Will Rogers phenomenon. Here, we aim to systematically evaluate the impact of nodal stage migration on survival in SCCA and address a novel hypothesis that this phenomenon results in reduced prognostic discrimination.

METHODS

We did a systematic review and meta-regression to quantify changes in LNP over time and the impact of this change on survival and prognostic discrimination. We searched MEDLINE, Embase, and the Cochrane Library to identify randomised trials and observational studies in patients with SCCA published between Jan 1, 1970, and Oct 11, 2016. Studies were eligible if patients received chemoradiotherapy or radiotherapy as the main treatment, reported LNP proportions (all studies), and reported overall survival (not necessarily present in all studies). We excluded studies with fewer than 50 patients. We extracted study-level data with a standardised, piloted form. The primary outcome measure was 5-year overall survival. To investigate scenarios in which reduced prognostic discrimination might occur, we simulated varying true LNP proportions and true overall survival, and compared these with expected observed outcomes for varying levels of misclassification of true nodal state.

FINDINGS

We identified 62 studies reporting LNP proportions, which included 10 569 patients. From these, we included 45 studies (6302 patients) with whole cohort 5-year overall survival, 11 studies with 5-year survival stratified by nodal status, and 20 studies with hazard ratios in our analyses of temporal changes. In 62 studies, the LNP proportions increased from a mean estimate of 15·3% (95% CI 10·5-20·1) in 1980 to 37·1% (34·0-41·3) in 2012 (p<0·0001). In 11 studies with prognostic data, increasing LNP was associated with improved overall survival in both lymph node-positive and lymph node-negative categories, whereas the proportions with combined tumour stage T3 and T4 remained constant. In 20 studies, across a range of LNP proportions from 15% to 40%, the hazard ratios for overall survival of lymph node-positive versus lymph node-negative patients decreased significantly from 2·5 (95% CI 1·8-3·3) at 15% LNP to 1·3 (1·2-1·9; p=0·014) at 40% LNP. The simulated scenarios reproduced this effect if the true LNP proportions were 20% or 25%, but not if the true LNP proportions were 30% or greater.

INTERPRETATION

We describe a consequence of staging misclassification in anal cancer that we have termed reduced prognostic discrimination. We used this new observation to infer that the LNP proportions of more than 30% seen in modern clinical series (11 out of 15 studies with a median year since 2007) are higher than the true LNP proportion. The introduction of new staging technologies in oncology might misclassify true disease stage, spuriously informing disease management and ultimately increasing the risk of overtreatment.

FUNDING

Bowel Disease Research Foundation.

Value of staging squamous cell carcinoma of the anal margin and canal using the sentinel lymph node procedure: an update of the series and a review of the literature

Background:

Inguinal metastases in patients affected by anal cancer are an independent prognostic factor for local failure and overall mortality. Since 2001, sentinel lymph node biopsy was applied in these patients. This original study reports an update of personal and previous published series, which were compared with Literature to value the incidence of inguinal metastases T-stage related and the overall incidence of false negative inguinal metastases at sentinel node.

Methods:

In all, 63 patients diagnosed with anal cancer submitted to inguinal sentinel node. Furthermore a research in the Pub Med database was performed to find papers regarding this technique.

Results:

In our series, detection rate was 98.4%. Inguinal metastases were evidentiated in 13 patients (20.6%). Our median follow-up was 35 months. In our series, no false negative nodes were observed.

Conclusion:

Sentinel node technique in the detection of inguinal metastases in patients affected by anal cancer should be considered as a standard of care. It is indicated for all T stages in order to select patients to be submitted to inguinal radiotherapy, avoiding related morbidity in negative ones. An overall 3.7% rate of false negative must be considered acceptable.

New approach to anal cancer: Individualized therapy based on sentinel lymph node biopsy

Oncological treatment is currently directed toward a tailored therapy concept. Squamous cell carcinoma of the anal canal could be considered a suitable platform to test new therapeutic strategies to minimize treatment morbidity. Standard of care for patients with anal canal cancer consists of a combination of radiotherapy and chemotherapy. This treatment has led to a high rate of local control and a 60% cure rate with preservation of the anal sphincter, thus replacing surgical abdominoperineal resection. Lymph node metastases represent a critical independent prognostic factor for local recurrence and survival. Mesorectal and iliac lymph nodes are usually included in the radiation field, whereas the inclusion of inguinal regions still remains controversial because of the subsequent adverse side effects. Sentinel lymph node biopsies could clearly identify inguinal node-positive patients eligible for therapeutic groin irradiation. A sentinel lymph node navigation procedure is reported here to be a feasible and effective method for establishing the true inguinal node status in patients suffering from anal canal cancer. Based on the results of sentinel node biopsies, a selective approach could be proposed where node-positive patients could be selected for inguinal node irradiation while node-negative patients could take advantage of inguinal sparing irradiation, thus avoiding toxic side effects.

Imaging of anal carcinoma

OBJECTIVE

The purpose of this article is to review the role of imaging in the management of patients with anal cancer. The relevant anatomy, imaging techniques, and interpretation of images of patients before and after therapy will be discussed.

CONCLUSION

Anal carcinomas are uncommon but increasing in frequency. Radiologists must recognize typical patterns of disease at initial evaluation, posttherapy appearances, and when to suspect residual or recurrent disease to guide clinicians and achieve optimal patient outcome.

Limited value of staging squamous cell carcinoma of the anal margin and canal using the sentinel lymph node procedure: a prospective study with long-term follow-up

Background

Selection of patients with anal cancer for groin irradiation is based on tumor size, palpation, ultrasound, and fine needle cytology. Current staging of anal cancer may result in undertreatment in small tumors and overtreatment of large tumors. This study reports the feasibility of the sentinel lymph node biopsy (SLNB) in patients with anal cancer and whether this improves the selection for inguinal radiotherapy.

Methods

A total of 50 patients with squamous anal cancer were evaluated prospectively. Patients without a SLNB (n = 29) received irradiation of the inguinal lymph nodes based on lymph node status, tumor size, and location of the primary tumor. Inguinal irradiation treatment in patients with a SLNB was based on the presence of metastases in the SLN.

Results

SLNs were found in all 21 patients who underwent a SLNB. There were 5 patients (24%) who had complications after SLNB and 7 patients (33%) who had a positive SLN and received inguinal irradiation. However, 2 patients with a tumor-free SLN and no inguinal irradiation developed lymph node metastases after 12 and 24 months, respectively.

Conclusions

We conclude that SLNB in anal cancer is technically feasible. SLNB can identify those patients who would benefit from refrain of inguinal irradiation treatment and thereby reducing the incidence of unnecessary inguinal radiotherapy. However, because of the occurrence of inguinal lymph node metastases after a tumor-negative SLNB, introduction of this procedure as standard of care in all patients with anal carcinoma should be done with caution to avoid undertreatment of patient who otherwise would benefit from inguinal radiotherapy.

Sentinel node biopsy in squamous-cell carcinoma of the anal canal

BACKGROUND

Radiochemotherapy is the standard treatment for patients with carcinoma of the anal canal. Therefore, a surgical specimen is not usually obtained. Inguinal lymph node metastases cannot be accurately predicted by either clinical examination or imaging techniques. In this study, we applied the sentinel node technique in patients with anal canal squamous-cell carcinoma to determine whether this provided more reliable staging of tumors.

METHODS

From May 2007 to May 2009, we enrolled 11 patients (7 women) with a mean age 65 (range 39-80) years with squamous-cell carcinoma of the anal canal and clinically and radiologically negative groin lymph nodes. The patients were staged with endorectal ultrasound, computed tomographic scan, magnetic resonance imaging of the pelvis, and positron emission tomography. There were two T1, four T2, and five T3 tumors (International Union Against Cancer classification). Lymphoscintigraphy with peritumoral 99mTc colloid injection was performed 16 to 18 h before surgery. During the surgery, patent blue dye was injected peritumorally, and the sentinel inguinal node was identified by a handheld gamma probe and dye visualization.

RESULTS

The sentinel lymph node was detected in all 11 patients by scintigraphy; in 9 cases, the lymph node was in the inguinal region. All of these patients underwent radioguided node biopsy, and a total of 12 lymph nodes were removed. The average diameter of the resected nodes was 8 (range 4-20) mm. No serious complications occurred. In three patients, metastases were identified in the lymph node.

CONCLUSIONS

Sentinel node biopsy is a more accurate method than clinical or radiological techniques to stage the disease of patients with anal carcinoma.

Sentinel lymph node in patients with rectal cancer invading the anal canal

BACKGROUND

To assess the feasibility of the sentinel lymph node procedure in patients with rectal cancer extending to the anal canal.

METHODS

Between January 2005 and April 2008, 15 patients with adenocarcinoma of the rectum with direct invasion of the anal canal and no clinical evidence of inguinal involvement were prospectively enrolled in the study. The sentinel node procedure consisted of a combination of preoperative radiocolloid lymphoscintigraphy and intraoperative detection of the inguinal sentinel node with a gamma probe. Patent blue dye was also used to facilitate direct identification of the blue-stained lymph node. After removal, the sentinel node was studied by hematoxylin-eosin staining and immunohistochemistry.

RESULTS

Detection and removal of inguinal sentinel nodes was possible in all patients. Four patients (26.7%) had sentinel nodes identified as positive for metastatic adenocarcinoma. All positive cases also had metastases detected in perirectal lymph nodes; three of them developed hepatic or pulmonary metastases within 6 months after surgery. Of the 11 patients with negative sentinel nodes, only four (36.4%) also presented metastatic perirectal lymph nodes. Although none of the negative cases developed late inguinal metastases, three developed systemic or pelvic recurrence within 12 months after surgery.

CONCLUSIONS

The standardized procedure was highly effective in sampling inguinal sentinel nodes in very low rectal cancers, allowing the detection of subclinical metastatic disease. Although this technique can be potentially useful for a subgroup of patients with isolated inguinal metastases, it cannot be routinely recommended for patients with rectal tumors invading the anal canal at this moment.

Sentinel node biopsy by indocyanine green retention fluorescence detection for inguinal lymph node staging of anal cancer: preliminary experience

BACKGROUND

There is some evidence that sentinel lymph node (SLN) biopsy guided by dye injection and/or radioisotopes can improve staging of inguinal lymph nodes (LNs) in anal cancer. This study was performed to investigate the feasibility of fluorescence detection of SLN and lymphatic mapping in anal cancer.

METHODS

Twelve patients with anal cancer without evidence for inguinal LN involvement were included in the study. Intraoperatively, all patients received a peritumorous injection of 25 mg indocyanine green (ICG) for fluorescence imaging of the SLN with a near-infrared camera. For comparison, conventional SLN detection by technetium-(99)m-sulfur radiocolloid injection in combination with blue dye was also performed in all patients. The results of both techniques and the effect on the therapeutic regimen were analyzed.

RESULTS

Overall, ICG fluorescence imaging identified at least one SLN in 10 of 12 patients (detection rate, 83%). With the combination of radionuclide and blue dye, SLN were detected in 9 of 12 patients (detection rate, 75%). Metastatic involvement of the SLN was found in 2 of 10 patients versus 2 of 9 patients. Patients with metastatic involvement of the SLN received extended radiation field with inguinal boost.

CONCLUSIONS

ICG fluorescence imaging allows intraoperative lymphatic mapping and transcutaneous SLN detection for selective biopsy of inguinal SLN in anal cancer. This technique should be further evaluated in comparative studies with larger patient numbers.

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology.

Lymphatic mapping and sentinel lymph node biopsy in epidermoid carcinoma of the anal canal

AIM

Although 15-25% of patients with anal cancer present with superficial inguinal lymph node metastases but the routine application of groin irradiation is controversial because of serious side effects. Inguinal sentinel lymph node biopsy (SLNB) can be used to select patients appropriately for inguinal radiation. The study evaluates the efficiency and clinical impact of SLNB.

METHODS

Forty patients with anal cancer underwent 1 ml Tc(99m)-Nanocolloid injection in four sites around the tumour. Patients with inguinal radio colloid enrichment were selected for sentinel lymph node biopsy (SLNB). Lymph node status was examined by haematoxylin and eosin (H&E) as well as immunohistochemistry-staining. All SLN-positive patients were scheduled for inguinal radiation; SLN-negative patients with T1 and early T2 tumours were not scheduled for inguinal radiation.

RESULTS

SLN were detected in 36/40 patients. Three common patterns of lymphatic drainage were observed: mesenterial, iliacal and inguinal. Twenty patients with inguinal SLN underwent SLN-biopsy. 6/20 patients were SLN-positive. In 10/20 patients SLNB altered the therapy plan--four patients with T1-tumours and positive SLN had additional groin irradiation, whereas 6 patients with small T2-tumors and tumour-free inguinal SLN did not undergo inguinal irradiation.

CONCLUSIONS

Inguinal sentinel node biopsy in anal cancer is efficient and could assist in the decision for inguinal radiation. The validity and safety of the proposed therapeutic algorithm has to be proven by a larger, prospective study.

Detection of metastatic disease with sentinel lymph node dissection in colorectal carcinoma patients

BACKGROUND

In curative colorectal cancer surgery, radical lymph node dissection is essential for staging and decision-making for adjuvant treatment.

PURPOSE

The aims of the study were to analyse to what extent sentinel lymph node dissection (SLND) in colorectal cancer could upstage N0 patients and how lymphatic mapping could demonstrate micrometastatic disease.

PATIENTS AND METHODS

In a prospective study, patients were selected by CT scanning, avoiding bulky disease and distant metastasis. When standard staining (HE) was negative, micrometastases were searched for by immunohistochemistry (cytokeratin 11, CEA and Ca19-9 antibodies). Micrometastatic lymph nodes were classified N+(i).

RESULTS

Detection of sentinel lymph nodes was successful in 48 out of 52 colorectal cancer patients. Among the 44 M0 patients, 22 were N0 (i-) and 22 were N+ (13 with standard HE procedure, three were N+ (macrometastasis) with the SN as the only positive node and six patients had 1-4 micrometastatic SN (N+(i)). An overall potential upstaging of 9/44 could be considered after SLND. With a mean follow-up of 48 months survival, analysis showed that disease-specific survival of the group of six N+(i) patients was intermediate between the group of 22 N0 (i-) patients and the group of 16 N+ patients.

CONCLUSION

SLND may improve the detection of metastasis in conventionally bivalved nodes. Further studies could assess if micrometastatic disease detected in SN could be integrated into the risk factors for stage II patients in order to consider adjuvant chemotherapy.

Bilan préthérapeutique initial du carcinome épidermoïde invasif de l’anus

Anal epidermoid carcinoma is a rare malignant tumor, comprising less than 5% of all carcinomas of the colon, rectum, and anus. The primary therapy now includes radiotherapy, often in combination with chemotherapy. Radical surgery is now rarely indicated. Therapeutic indications are based on locoregional staging, the presence of visceral metastases and an evaluation of the medical history. Anorectal endosonography is helpful in evaluating locoregional extension. In addition, magnetic resonance imaging, positron emission tomography scanning and inguinal sentinel lymph node procedure should play a role in a more selective approach in patients with anal carcinoma.

Pathological Evaluation of Sentinel Lymph Nodes

The sentinel lymph nodes are the most likely site of nodal metastasis. Their focused analysis results in upstaging cancers, although the extra yield from a more intensive work-up is generally dominated by micrometastases and isolated tumor cells. Nodal staging is generally done to reflect systemic spread of solid tumors and guide treatment accordingly. However, in general, the two processes of haematogenous and lymphogenic spread are not causally interrelated, and the extrapolation from low-volume nodal involvement to systemic involvement and therapeutic consequences of this extrapolation are still under investigation.

Sentinel Lymph Node Biopsy in Cutaneous Squamous Cell Carcinoma: A Systematic Review of the English Literature

BACKGROUND

Although most cutaneous squamous cell carcinoma (SCC) is curable by a variety of treatment modalities, a small subset of tumors recur, metastasize, and result in death. Although risk factors for metastasis have been described, there are little data available on appropriate workup and staging of patients with high-risk SCC.

OBJECTIVE

We reviewed reported cases and case series of SCC in which sentinel lymph node biopsy (SLNB) was performed to determine whether further research is warranted in developing SLNB as a staging tool for patients with high-risk SCC.

METHODS

The English medical literature was reviewed for reports of SLNB in patients with cutaneous SCC. Data from anogenital and nonanogenital cases were collected and analyzed separately. The percentage of cases with a positive sentinel lymph node (SLN) was calculated. False negative and nondetection rates were tabulated. Rates of local recurrence, nodal and distant metastasis, and disease-specific death were reported.

RESULTS

A total of 607 patients with anogenital SCC and 85 patients with nonanogenital SCC were included in the analysis. A SLN could not be identified in 3% of anogenital and 4% of nonanogenital cases. SLNB was positive in 24% of anogenital and 21% of nonanogenital patients. False-negative rates as determined by completion lymphadenectomy were 4% (8/213) and 5% (1/20), respectively. Most false-negative results were reported in studies from 2000 or earlier in which the combination of radioisotope and blue dye was not used in the SLN localization process. Complications were reported rarely and were limited to hematoma, seroma, cutaneous lymphatic fistula, wound infection, and dehiscence.

CONCLUSIONS

Owing to the lack of controlled studies, it is premature to draw conclusions regarding the utility of SLNB in SCC. The available data, however, suggest that SLNB accurately diagnoses subclinical lymph node metastasis with few false-negative results and low morbidity. Controlled studies are needed to demonstrate whether early detection of subclinical nodal metastasis will lead to improved disease-free or overall survival for patients with high-risk SCC.

Sentinel lymph node in carcinoma of the anal canal: a review

AIMS

To review the studies investigating the efficacy of the sentinel lymph node (SLN) procedure in anal canal carcinoma and to evaluate its potential role in guiding a more selective approach for patients with the malignancy.

METHODS

A literature search in the PubMed database was preformed using the key words "sentinel lymph node" and "anal cancer". All indexed original articles (except case reports) on the SLN procedure in cancer of the anal canal were analysed.

RESULTS

There are five published series to date. Eighty-four patients were studied. Rates of SLN detection and removal ranged from 66 to 100% of patients investigated. Nodal metastases were found in 7.1 to 42% of cases. No serious complications were reported.

CONCLUSIONS

The technique has proven to be safe and effective in sampling inguinal SLNs. The detection of occult metastases in clinically unsuspicious nodes represents an important improvement in the process of staging these patients, which has not been possible with any other method of diagnosis. Although SLN procedure is still in an early phase of investigation in this type of cancer, it emerges as an objective method to guide individual therapeutic decisions.

Tratamento conservador do carcinoma do canal anal

OBJETIVO: Relatar os resultados do tratamento conservador do carcinoma de canal anal com radioterapia e quimioterapia do Centro de Tratamento e Pesquisa Hospital do Câncer A.C. Camargo. MÉTODO: De março de 1993 a dezembro de 2001, 47 pacientes com diagnóstico histológico de carcinoma do canal anal foram tratados de forma conservadora. A dose mediana de radioterapia na pelve e no tumor primário foi respectivamente de 45 e 55 Gy. A quimioterapia foi realizada com 5- Fluorouracil e Mitomicina-C, com doses medianas de 1000 mg/m² por quatro dias e 10 mg/m² por ciclo, respectivamente. Trinta e oito (80,8%) pacientes não receberam radioterapia em região inguinal. O tempo de seguimento mediano foi de 40 meses (oito dias a 116 meses). RESULTADOS: A resposta completa foi alcançada em 40 pacientes (85,1%). O controle local foi obtido em 31 (66%), e a função esfincteriana foi preservada em 38 (80,9%) casos. Metástases à distância foram detectadas em sete (14,9%) pacientes. A sobrevida global e sobrevida livre de doença em cinco anos foram de 61,5% e 50,1%, respectivamente. A sobrevida global e a sobrevida livre de doença em cinco anos para os pacientes que tiveram controle local foram 77,8% (p < 0,001) e 74,4% (p < 0,001). A sobrevida global e livre de doença em cinco anos para os pacientes com linfonodo inguinal clinicamente tumoral foi de 70,7% e 56,7%, respectivamente (p = 0,0085 e p = 0,0207). Doze (25,5%) pacientes necessitaram de interrupção temporária do tratamento. Cinco pacientes tiveram complicações crônicas leves. CONCLUSÃO: O tratamento realizado foi efetivo tanto para preservação do esfíncter anal quanto para controle local de doença. A presença de linfonodo inguinal clinicamente tumoral e a ausência de recidiva foram os principais fatores prognósticos para sobrevida global e sobrevida livre de doença. A taxa relativamente alta de recidiva em região inguinal sugere a necessidade de radioterapia eletiva nessa região.

Surgical considerations in anal cancer

SCC of the anus is rare; however, the surgeon is bound to encounter some of these patients during his or her career. It is important that the anatomic location and the histology be defined because the initial treatment may initially differ. Multimodality therapy is the treatment of choice in SCC of the anal canal, with surgery reserved for persistent or recurrent tumors. Multimodality therapy can be used selectively in SCC of the perianal skin, especially in large bulky tumors, followed by definitive surgery. Nevertheless, the initial treatment of perianal neoplasms is surgical therapy. In general, inguinal node metastases are treated with chemoradiation. In highly selected patients, groin dissections are performed, but this procedure is not routine.