In the pre-sentinel lymph node biopsy era, many studies showed that the extent or aggressiveness of regional surgical therapy did not have a significant impact on melanoma-specific survival, with the extent of nodal involvement at the time of diagnosis being the only predictor of outcome [8–10]. Sterne et al. have suggested that extensive lymph node dissection has a significant impact on both disease-free and melanoma-specific survival , and the findings of other studies have indicated that reducing the extent of surgery increases the risk of local failure and leads to lower survival rates [12–14].
Previous studies have also suggested that complete lymph node dissection not only improves local-regional control but also improves survival, particularly when the procedure is performed in a melanoma treatment center [15–19].
In our study, 33.3% of patients with involvement of deep nodes were alive 5 years after radical lymph node dissection and 19.0% were disease-free. Our data suggest that surgical dissection plays a major role in the staging of ilio-obturator nodal disease; prevents the morbidity of pelvic dissemination, which is associated with poor quality of life; and is related to 5-year survival for about one-third of patients [20–22].
One of the arguments against deep groin dissection is the associated morbidity. The rate of complications after superficial and deep groin dissection has been reported to be as high as 50% . Infection, hemorrhage, skin-flap necrosis, wound dehiscence, paresthesia and lymphocele with chronic lymphedema have been the most commonly reported short and long-term complications [24–28]. Although both the risks and benefits of such dissection must be considered, many studies have shown a change in morbidity with modification to the extent of surgery. In a review of the literature, Hughes et al. found no evidence that deep groin dissection caused greater morbidity than superficial dissection . Since 2001, the conservative surgical approach, without section of the inguinal ligament, has reduced postoperative morbidity, particularly postoperative pain.
Ten-year melanoma-specific survival rates range widely in the literature, reaching 40% in some reports, indicating the possibility of cure. Data from three major cancer institutions (Memorial Sloan-Kettering Cancer Center, York Avenue, NY, USA; Netherland Cancer Institute, Amsterdam, The Netherlands; and The University of Texas MD Anderson Cancer Center, Houston, TX, USA) have demonstrated that survival can be achieved in a substantial number of patients with deep nodal metastases, with 5-year survival rates ranging from 24% to 43% [9, 14, 23, 30]. In these studies, the number of metastatic nodes, the thickness of the primary melanoma and ulceration of the primary melanoma were independent prognostic factors.
Sentinel node-positive disease in the groin was related to involvement of deep nodes in 6.1% of the patients in our study, a finding similar to that of Santinami et al., who reported that 8.6% of patients had involvement of nodes in the iliac basin . Involvement of deep nodes cannot be predicted by histological or clinical features. Neither the degree of clinically detected nodal disease, as analyzed by Sterne et al., nor the status of Cloquet’s node, as proposed by Essner , are reliable methods for predicting the presence of disease in pelvic nodes. Conventional imaging and PET have been reported to have limited utility [31, 32]. In a retrospective review of the role of PET at the time of diagnosis of T2 to T4 melanoma, Clark et al. found that the imaging method was not useful in identifying early regional or distant metastases . In the present series, patients with evidence of metastatic deep involvement revealed at pelvic CT scan were excluded. In these cases, surgical treatment has no staging purpose and the extension of dissection has no effect on overall survival .
Our analyses showed that involvement of deep nodes was the most important prognostic factor for patients with stage III melanoma. Multivariate analysis indicated that other prognostic factors for both disease-free and melanoma-specific survival were the number of positive lymph nodes, age and method of diagnosis (sentinel node biopsy or clinical).
The findings of the present study suggest that combined inguinal and pelvic lymph node dissection should be considered for patients with clinical evidence of groin nodal disease, as this approach achieved survival of 5 years for about one-third of patients in the presence of deep disease. Patients with a positive sentinel node might be spared ilio-obturator dissection owing to the low risk of nodal involvement in this area.