Background
Phase III RCT (GOG 88). 58 patients with stage I–II squamous cell carcinoma of the vulva with clinically negative ipsilateral inguinal lymph nodes, treated with radical vulvectomy. Compared ipsilateral superficial inguinal lymph node dissection vs ipsilateral inguinofemoral irradiation. The trial was stopped early due to excess groin recurrence in the radiation arm. This study is notable for demonstrating that inadequately administered radiation (with inadequate depth coverage) results in inferior groin control compared with surgical lymphadenectomy.
Interventions and follow up
Arm A: Ipsilateral superficial inguinal lymph node dissectio
Arm B: Ipsilateral inguinofemoral radiation 50 Gy (delivered with inadequate depth, failing to cover deep femoral nodes)
Primary endpoint: Inguinal lymph node recurrence
mFollow up: Trial stopped early
Arm B: Ipsilateral inguinofemoral radiation 50 Gy (delivered with inadequate depth, failing to cover deep femoral nodes)
Primary endpoint: Inguinal lymph node recurrence
mFollow up: Trial stopped early
Results
Groin recurrence: 5/26 (19.2%) radiation arm vs 0/28 (0%) surgery arm, P=.02
Trial stopped: Early termination due to significant excess groin recurrence in RT arm
Cancer-specific survival: Significantly worse in radiation arm due to groin recurrences
Trial stopped: Early termination due to significant excess groin recurrence in RT arm
Cancer-specific survival: Significantly worse in radiation arm due to groin recurrences
Adverse events
Main adverse events: Surgery arm: standard inguinal wound complications (seroma, wound breakdown), lymphedema. Radiation arm: early skin toxicity; importantly, groin recurrence was the dominant adverse outcome.
Conclusions
Superficial inguinofemoral radiation as administered in this trial was inferior to inguinal-femoral lymphadenectomy for groin control in early vulvar cancer. The key lesson was methodologic: the radiation fields did not adequately cover the deep femoral lymph nodes (which lie 6–8 cm deep to skin surface), leading to treatment failures. This trial highlighted the importance of radiation field depth and technique in groin coverage, rather than indicting radiation per se as inferior.
Key Limitations
Key Limitations: Radiation technique was flawed — fields used in GOG 88 did not adequately cover the deep femoral lymph node chain. This is considered a radiation technique failure rather than evidence against groin irradiation in principle. Subsequent radiation planning incorporating deeper fields (using CT-based planning and IMRT) is more likely to achieve equivalent or superior groin control. Small trial. The findings should not be interpreted as proof that RT cannot replace surgery for node-negative vulvar cancer.
Clinical Context
GOG 88 reinforced surgical lymphadenectomy (or sentinel node biopsy) as the standard for nodal assessment in early vulvar cancer, particularly after demonstrating that suboptimal radiation fails. However, when groin RT is indicated (e.g., postoperatively for positive nodes per GOG 37), it must include adequate depth coverage of the inguinofemoral nodal basin. Modern CT-planned IMRT for the groin achieves adequate deep femoral node coverage without the technique errors of GOG 88. The GROINSS-V II trial (inguinofemoral RT after positive sentinel node) has shown that properly administered groin RT can produce low recurrence rates comparable to full lymphadenectomy.
References