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

Inguinal lymph node metastases from rectal adenocarcinoma: a systematic review

PURPOSE

Inguinal lymph nodes are a rare but recognised site of metastasis in rectal adenocarcinoma. No guideline or consensus exists for the management of such cases. This review aims to provide a contemporary and comprehensive analysis of the published literature to aid clinical decision-making.

METHODS

Systematic searches were performed using the PubMed, Embase, MEDLINE and Scopus and Cochrane CENTRAL Library databases from inception till December 2022. All studies reporting on the presentation, prognosis or management of patients with inguinal lymph node metastases (ILNM) were included. Pooled proportion meta-analyses were completed when possible and descriptive synthesis was utilised for the remaining outcomes. The Joanna Briggs Institute tool for case series was used to assess the risk of bias.

RESULTS

Nineteen studies were eligible for inclusion, encompassing 18 case series and one population-based study using national registry data. A total of 487 patients were included in the primary studies. The prevalence of ILNM in rectal cancer is 0.36%. ILNM are associated with very low rectal tumours with a mean distance from the anal verge of 1.1 cm (95% CI 0.92-1.27). Invasion of the dentate line was found in 76% of cases (95% CI 59-93). In patients with isolated inguinal lymph node metastases, modern chemoradiotherapy regimens in combination with surgical excision of inguinal nodes are associated with 5-year overall survival rates of 53-78%.

CONCLUSION

In specific subsets of patients with ILNM, curative-intent treatment regimens are feasible, with oncological outcomes akin to those demonstrated in locally advanced rectal cancers.

Role of Sentinel Lymph Node Biopsy for Skin Cancer Based on Clinical Studies

The sentinel lymph node is the first lymph node from the primary tumor. Sentinel lymph node biopsy (SLNB) is a surgical procedure that can detect occult nodal metastasis with relatively low morbidity. It may also have a therapeutic effect via regional disease control. The Multicenter Selective Lymphadenectomy-I (MSLT-I) trial revealed a prognostic benefit from SLNB in melanoma patients. However, it remains unclear whether there is a prognostic benefit from SLNB in patients with nonmelanoma skin cancer owing to a lack of randomized prospective studies. Nevertheless, SLNB provides important information about nodal status, which is one of the strongest factors to predict prognosis and may guide additional nodal treatment. Currently, SLNB is widely used in the management of not only patients with melanoma but also those with nonmelanoma skin cancer. However, the utilization and outcomes of SLNB differ among skin cancers. In addition, SLNB is not recommended for routine use in all patients with skin cancer. In this review, we provide a summary of the role of SLNB and of the indications for SLNB in each skin cancer based on previously published articles.

The Sentinel Lymph Node in Treatment Planning: A Narrative Review of Lymph-Flow-Guided Radiotherapy

The sentinel lymph node technique is minimally invasive and used routinely by surgeons, reducing the need for morbid extensive lymph node dissections, which is a significant advantage for cancer staging and treatment decisions. The sentinel lymph node could also help radiation oncologists to identify tumor drainage for each of their patients, leading to a more personalized radiotherapy, instead of a probabilistic irradiation based on delineation atlases. The aim is both to avoid recurrence in unexpected areas and to limit the volume of irradiated healthy tissues. The aim of our study is to evaluate the impact of sentinel lymph node mapping for radiation oncologists. This concept, relying on sentinel lymph node mapping for treatment planning, is known as lymph-flow-guided radiotherapy. We present an up-to-date narrative literature review showing the potential applications of the sentinel lymph node technique for radiotherapy, as well as the limits that need to be addressed before its routine usage.

Patterns of pathologic lymph nodes in anal cancer: a PET-CT-based analysis with implications for radiotherapy treatment volumes

Background

This study investigates the patterns of PET-positive lymph nodes (LNs) in anal cancer. The aim was to provide information that could inform future anal cancer radiotherapy contouring guidelines.

Methods

The baseline [18F]-FDG PET-CTs of 190 consecutive anal cancer patients were retrospectively assessed. LNs with a Deauville score (DS) of ≥3 were defined as PET-positive. Each PET-positive LN was allocated to a LN region and a LN sub-region; they were then mapped on a standard anatomy reference CT. The association between primary tumor localization and PET-positive LNs in different regions were analyzed.

Results

PET-positive LNs (n = 412) were identified in 103 of 190 patients (54%). Compared to anal canal tumors with extension into the rectum, anal canal tumors with perianal extension more often had inguinal (P < 0.001) and less often perirectal (P < 0.001) and internal iliac (P < 0.001) PET-positive LNs. Forty-two patients had PET-positive LNs confined to a solitary region, corresponding to first echelon nodes. The most common solitary LN region was inguinal (25 of 42; 60%) followed by perirectal (26%), internal iliac (10%), and external iliac (2%). No PET-positive LNs were identified in the ischiorectal fossa or in the inguinal area located posterolateral to deep vessels. Skip metastases above the bottom of the sacroiliac joint were quite rare. Most external iliac PET-positive LNs were located posterior to the external iliac vein; only one was located in the lateral external iliac sub-region.

Conclusions

The results support some specific modifications to the elective clinical target volume (CTV) in anal cancer. These changes would lead to reduced volumes of normal tissue being irradiated, which could contribute to a reduction in radiation side-effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08187-8.

Prognostic value of fluorodeoxyglucose positron emission tomography/computed tomography and inguinal sentinel lymph node biopsy in patients with anal cancer

AIM

The aim of this study was to assess the value of positron emission tomography (PET)/CT and sentinel lymph node (SLN) biopsy in staging inguinal lymph nodes in anal cancer patients and to determine if the results of the two methods could be of prognostic value.

METHOD

Sixty-three patients with anal cancer and clinically negative inguinal lymph nodes underwent lymphoscintigraphy and inguinal SLN biopsy and/or fluorodeoxyglucose (FDG) PET/CT scan. All patients were treated with radiotherapy combined with 5-fluorouracil and mitomycin-C.

RESULTS

Overall (OS) and disease-free survival (DFS) were 43 months (range 5-211) and 43 months (range 4-142) respectively. PET/CT examination showed high FDG uptake in the inguinal lymph nodes in 25% of patients. Thirty-five patients with inguinal uptake at lymphoscintigraphy underwent inguinal SLN biopsy and metastatic nodes were found in 31.4%. There was no statistical difference in OS (55 vs 41 months; P = 0.652) and DFS (48 vs 38 months; P = 0.992) between the group which showed inguinal uptake on PET/CT and the group which did not, while a positive inguinal SLN was associated with a worse OS (28 vs 59 months; P = 0.028) and DFS (56 vs 21 months; P = 0.046). When the two examinations were compared PET/CT showed a sensitivity, specificity, positive predictive value and negative predictive value of 22%, 82%, 33% and 73% respectively.

CONCLUSION

The technique of SLN biopsy had a better diagnostic accuracy than total body FDG-PET/CT for the staging of inguinal lymph nodes in anal cancer patients; moreover it was a stronger predictor of OS and DFS than PET/CT.

So Now My Patient Has Squamous Cell Cancer: Diagnosis, Staging, and Treatment of Squamous Cell Carcinoma of the Anal Canal and Anal Margin

Squamous cell carcinomas of the anal canal and the anal margin are rare malignancies that are increasing in incidence. Patients with these tumors often experience delayed treatment due to delay in diagnosis or misdiagnosis of the condition. Distinguishing between anal canal and anal margin tumors has implications for staging and treatment. Chemoradiation therapy is the mainstay of treatment for anal canal squamous cell, with abdominoperineal resection reserved for salvage treatment in cases of persistent or recurrent disease. Early anal margin squamous cell carcinoma can be treated with wide local excision, but more advanced tumors require a combination of chemoradiation therapy and surgical excision.

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.

Anal cancer - a review

Anal cancer accounts for only 1.5% of gastrointestinal malignancies but this disease has shown a steady increase in incidence particularly in HIV positive males. The understanding of pathophysiology and treatment of anal cancer has changed radically over last thirty years. Risk factors have been identified and organ preservation by chemoradiotherapy has become a standard. This article aims to review the clinical presentation, diagnostic evaluation, and treatment options for anal cancer in the light of current literature.

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.

Anal canal cancer: management of inguinal nodes and benefit of prophylactic inguinal irradiation (CORS-03 Study)

PURPOSE

To evaluate the benefit of prophylactic inguinal irradiation (PII) in anal canal squamous cell carcinoma (ASCC).

METHODS AND MATERIALS

This retrospective study analyzed the outcome of 208 patients presenting with ASCC treated between 2000 and 2004 in four cancer centers of the south of France.

RESULTS

The population study included 35 T1, 86 T2, 59 T3, 20 T4, and 8 T stage unknown patients. Twenty-seven patients presented with macroscopic inguinal node involvement. Of the 181 patients with uninvolved nodes at presentation, 75 received a PII to a total dose of 45-50 Gy (PII group) and 106 did not receive PII (no PII group). Compared with the no PII group, patients in the PII group were younger (60% vs. 41% of patients age <68 years, p = 0.01) and had larger tumor (T3-4 = 46% vs. 27% p = 0.01). The other characteristics were well balanced between the two groups. Median follow-up was 61 months. Fourteen patients in the no PII group vs. 1 patient in the PII group developed inguinal recurrence. The 5-year cumulative rate of inguinal recurrence (CRIR) was 2% and 16% in PII and no PII group respectively (p = 0.006). In the no PII group, the 5-year CRIR was 12% and 30% for T1-T2 and T3-T4 respectively (p = 0.02). Overall survival, disease-specific survival, and disease-free survival were similar between the two groups. In the PII group, no Grade >2 toxicity of the lower extremity was observed.

CONCLUSION

PII with a dose of 45 Gy is safe and highly efficient to prevent inguinal recurrence and should be recommended for all T3-4 tumors. For early-stage tumors, PII should also be discussed, because the 5-year inguinal recurrence risk remains substantial when omitting PII (about 10%).

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.

Inguinal lymph node metastases are recognized with high frequency in rectal adenocarcinoma invading the dentate line. The histological features at the invasive front may predict inguinal lymph node metastasis

AIM

Inguinal lymph node (ILN) metastasis occurs with high frequency in some of the patients with lower rectal cancer. The aim of this study was to identify risk factors for ILN metastasis in patients with low rectal adenocarcinoma.

METHOD

We retrospectively analysed 156 patients with lower rectal adenocarcinoma who underwent radical resection (R0) at a single institution.

RESULTS

Twenty-five (16%) patients had a tumour that invaded the dentate line, seven of whom had ILN metastasis. Invasion of the dentate line was significantly associated with a high rate of ILN metastasis, worse prognosis and local recurrence than with a tumour not invading the dentate line (P = 0.03). A Cox proportional hazard regression analysis revealed the histological characteristics at the invading front (Hif) also to be a risk factor for ILN metastasis.

CONCLUSION

Tumours which invade the dentate line have a high rate of ILN metastases and worse cancer specific end-points. The presence of poorly differentiated or mucinous adenocarcinoma components is an indication for bilateral groin irradiation.

Epidermoid cancers of the anal canal: current treatment

Epidermoid carcinoma of the anal canal is an uncommon disease, but has increased in incidence with the HIV epidemic. Prior to the 1970s, treatment consisted of radical surgery with abdominoperineal resection. With the pioneering work of Dr. Norman Nigro, this has shifted to a nonsurgical approach, with primary treatment consisting of multimodality therapy with radiation and chemotherapy. This review provides an overview of the historical, current, and future treatments of epidermoid anal canal malignancies.

Chemo-radiation with or without mandatory split in anal carcinoma: experiences of two institutions and review of the literature

Background

The split-course schedule of chemo-radiation for anal cancer is controversial.

Methods

Eighty-four patients with invasive anal cancer treated with definitive external beam radiotherapy (RT) with a mandatory split of 12 days (52 patients, Montreal, Canada) or without an intended split (32 patients, Zurich, Switzerland) were reviewed. Total RT doses were 52 Gy (Montreal) or 59.4 Gy (Zurich) given concurrently with 5-FU/MMC.

Results

After a mean follow-up of 40 ± 27 months, overall survival and local tumor control at 5 years were 57% and 78% (Zurich) compared to 67% and 82% (Montreal), respectively. Split duration of patients with or without local relapse was 15 ± 7 d vs. 14 ± 7 d (Montreal, NS) and 11 ± 11 d vs. 5 ± 7 d (Zurich; P < 0.001). Patients from Zurich with prolonged treatment interruption (≥ 7 d) had impaired cancer-specific survival compared with patients with only minor interruption (<7 d) (P = 0.06). Bowel toxicity was associated with prolonged RT (P = 0.03) duration as well as increased relapse probability (P = 0.05). Skin toxicity correlated with institution and was found in 79% (Montreal) and 28% (Zurich) (P < 0.0001).

Conclusions

The study design did not allow demonstrating a clear difference in efficacy between the treatment regimens with or without short mandatory split. Cause-specific outcome appears to be impaired by unplanned prolonged interruption.

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.

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M. Pocard, J.-C. Sabourin In theory, the concept of sentinel lymph node (SLN) biopsy can be applied to cancer surgery for all solid cancers. Yet sentinel lymph node biopsy has not become a standard part of gastrointestinal cancer surgery. It has been of value in the assessment of small early-stage gastric cancers, but has only achieved widespread practice in Japan. Studies of SLN biopsy in colon cancer have not shown it to be a reliable predictor of N+ status and therefore don't permit the omission of lymph node dissection in selected cases. On the other hand, as a form of intra-operative lymph node mapping, dye injection of the SLN may demonstrate aberrant lymphatic drainage and could occasionally permit the sparing of a middle colic artery whose sacrifice would otherwise be dictated by standard drainage patterns. SLN biopsy may have prognostic usefulness by demonstrating micrometastases; careful serial sectioning focussed on the SLN may detect nests of metastatic cells on HE staining, thereby converting a tumor from Stage I (TxN0M0) to Stage II (TxN1M0). This finding has been noted in 10-15% of cases. However, the prognostic value of micrometastases detected only by immunohistochemical staining or PCR has not been demonstrated. For cancers of the anal canal, SLN biopsy of inguinal nodes has been tested as a means of establishing the indications for inguinal lymph node dissection.